Advertisement
JBC

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Originally published In Press as doi:10.1074/jbc.M511097200 on November 2, 2005

J. Biol. Chem., Vol. 280, Issue 52, 42971-42977, December 30, 2005
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
280/52/42971    most recent
M511097200v1
Right arrow Submit a Letter to Editor
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowRequest Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Weinhold, B.
Right arrow Articles by Hildebrandt, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Weinhold, B.
Right arrow Articles by Hildebrandt, H.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

Genetic Ablation of Polysialic Acid Causes Severe Neurodevelopmental Defects Rescued by Deletion of the Neural Cell Adhesion Molecule*

Birgit Weinhold{ddagger}, Ralph Seidenfaden§1, Iris Röckle{ddagger}§, Martina Mühlenhoff{ddagger}, Frank Schertzinger§, Sidonie Conzelmann§, Jamey D. Marth¶, Rita Gerardy-Schahn{ddagger}2, and Herbert Hildebrandt§

From the {ddagger}Zelluläre Chemie, Zentrum Biochemie, Medizinische Hochschule Hannover, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany, §Institut für Zoologie (220), Universität Hohenheim, Garbenstrasse 30, 70593 Stuttgart, Germany, and Howard Hughes Medical Institute and Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California 92093

Received for publication, October 12, 2005


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
Poly-{alpha}2,8-sialic acid (polySia) is a unique modification of the neural cell adhesion molecule, NCAM, tightly associated with neural development and plasticity. However, the vital role attributed to this carbohydrate polymer has been challenged by the mild phenotype of mice lacking polySia due to NCAM-deficiency. To dissect polySia and NCAM functions, we generated polySia-negative but NCAM-positive mice by simultaneous deletion of the two polysialyltransferase genes, St8sia-II and St8sia-IV. Beyond features shared with NCAM-null animals, a severe phenotype with specific brain wiring defects, progressive hydrocephalus, postnatal growth retardation, and precocious death was observed. These drastic defects were selectively rescued by additional deletion of NCAM, demonstrating that they originate from a gain of NCAM functions because of polySia deficiency. The data presented in this study reveal that the essential role of polySia resides in the control and coordination of NCAM interactions during mouse brain development. Moreover, this first demonstration in vivo that a highly specific glycan structure is more important than the glycoconjugate as a whole provides a novel view on the relevance of protein glycosylation for the complex process of building the vertebrate brain.


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 
The cellular glycosylation machinery is a most impressive example of how cells enhance structural and functional complexity by use of only limited parts (<10%) of the genome. Glycans conjugated to lipids and proteins form the glycocalyx, the outer rim and prominent communication structure of animal cells (1, 2). Their paramount importance is emphasized by the growing group of congenital disorders of glycosylation, which manifest as severe multisystemic diseases including neuropathological symptoms (3).

Poly-{alpha}2,8-linked sialic acid (polySia)3 is a unique glycan added to the neural cell adhesion molecule, NCAM, and is known to exert an important influence on the development and function of the nervous system (4–6). The intriguing role assigned to polySia in promoting neurogenesis, migration, axon outgrowth, and synaptic plasticity has been explained predominantly by a negative regulation of cell-cell interactions due to the stereochemical properties of the large polyanion (shown schematically in Fig. 1A) (4, 7). Recent x-ray and neutron reflectivity data as well as direct force measurements confirm that an increased intermembrane repulsion in the presence of polySia overcomes homophilic NCAM binding and attenuates cadherin-dependent adhesion (8, 9). On the other hand, polySia is known to exert highly specific functions. For instance, NCAM trans-interactions with heparan sulfate proteoglycans involved in the formation and remodeling of hippocampal synapses depend on the presence of polySia (10, 11). Finally, competition experiments carried out with exogenously added polySia indicate that the carbohydrate polymer mediates autonomous, NCAM-independent functions. These concern the development of commissural axons in zebrafish (12), the strengthening of neuronal responses to brain-derived neurotrophic factor (BDNF) (13), and the functional modulation of the {alpha}-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) subtype of glutamate receptors (14).

In marked contrast to the predicted central roles of NCAM and polySia in neurodevelopment and plasticity of the mature nervous system, mice lacking the NCAM gene (N–/–) (15) and mice devoid of the NCAM-180 isoform (16) showed surprisingly mild phenotypes (for reviews, see Refs. 4 and 5). NCAM deficiency is accompanied by the loss of polySia (15, 16), and major defects observed in the Ncam knock-out models could be mimicked by enzymatic removal of polySia using endo-N-acetylneuraminidase (17). Combined, these findings led to the conclusion that polySia and not NCAM is the missing factor (18–22). Processes that can be disrupted by endo-N-acetylneuraminidase treatment are: (i) tangential migration of subventricular zone-derived neuroblasts along the rostral migratory stream to the olfactory bulb (18); (ii) lamination of the mossy fiber tract (22); (iii) long term potentiation and depression in the hippocampal CA1 region (19, 20); (iv) spatial learning (19); and (v) generation of the circadian locomotor rhythm in the suprachiasmatic nucleus (21).

The biosynthesis of polySia is the result of two polysialyltransferases, ST8Sia-II and ST8Sia-IV (23, 24). The two enzymes are highly conserved, but their time- and tissue-specific expression is independently regulated. ST8Sia-II is the dominating enzyme in the embryonic and early postnatal mouse, whereas ST8Sia-IV prevails in the adult (25, 26). The genetic ablation of St8sia-IV, therefore, generated mice in which the polySia synthesis was not significantly altered during development but almost completely absent in the adult (27). In contrast, depletion of St8sia-II generated animals with ongoing polySia synthesis in the adult brain (28). Both strains were born at Mendelian frequency, were fertile, and did not show gross anatomical abnormalities. Although distinct deficits have been identified in histological, electrophysiological, and behavioral analyses (27, 28), the data available today strongly suggest that each gene partially compensates for the absence of the other.

Information on the individual roles of NCAM and polySia during ontogeny is completely unavailable. Here we describe the phenotype of mice expressing normal NCAM levels in the absence of polySia, as obtained by simultaneous ablation of St8sia-II and St8sia-IV. The absence of polySia confers a lethal phenotype with specific defects of major brain fiber tracts. Phenotypic alterations that occurred in addition to those observed in NCAM-knock-out mice were completely reversed in triple knock-out animals lacking NCAM in addition to both polysialyltransferase genes. Collectively, our data demonstrate that polySia is essential in steering NCAM functions during development of the nervous system.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 REFERENCES
 
Mice—All protocols for animal use were in compliance with German law and approved by the animal welfare commission of the Universität Hohenheim. St8sia-II and St8sia-IV single knock-out strains, which have been backcrossed with C57BL/6J mice for at least six generations, were intercrossed to obtain double heterozygous St8sia-II+/– St8sia-IV+/– animals. To generate all different allelic combinations St8sia-II+/– St8sia-IV+/– were backcrossed to St8sia-II+/+ St8sia-IV–/– or St8sia-II–/– St8sia-IV+/+, respectively, and resulting St8sia-II+/– St8sia-IV–/– mice were bred with St8sia-II–/– St8sia-IV+/–. Wild-type mice were obtained from crosses between St8siaII+/+ St8siaIV+/– or between St8siaII+/– St8siaIV+/+. Triple knock-out mice deficient in NCAM and polysialyltransferase between intercrosses genes were obtained by St8sia-II+/– St8sia-IV–/– and Ncam–/– mice and subsequent backcrosses. All offspring were born in the expected Mendelian ratios. Genotyping was performed by PCR using the following primers: NCAM1 (5'-CTGCCTCAGATAGTGACCCAGTGC-3'), NCAM2 (5'-CGGAGAACCTGCGTGCAATCCATC-3'), and NCAM3 (5'-TTGGAGGCAGGGAGCTGACCACAT-3') to amplify Ncam; SWB8 (5'-ATGTCTGGAAAGGAATGGATGTCT-3'), SWF13 (5'-AACGCTTTACCAACTGTGCTATCT-3'), and SWB14 (5'-TTGGGGTCTTGTGGTAAATCAGTC-3') to amplify St8sia-II; LW13 (5`-CTCAGTTCTGGCTATTTCTTTTGT-3'), LW4 (5'-GAGCTCACAACGACTCTCCGAGC-3'), and LW18 (5'-ACCGCGAGGCGGTTTTCTCCGGC-3') to amplify St8sia-IV.

Western Blot Analysis—Total brain isolated from mice on postnatal day 1 was homogenized in 500 µl of lysis buffer (20 mM Tris-HCl, pH 8.0, 150 mM NaCl, 5 mM EDTA, 1 mM phenylmethylsulfonyl fluoride, 70 µg/ml aprotinin, 10 µg/ml leupeptin, 2% Triton X-100). Detergent extracts were clarified by centrifugation, and one aliquot was treated with 20 ng µl–1 endoneuraminidase (17) for 45 min on ice. Proteins were separated by SDS-PAGE (40 µg total protein per lane) and electroblotted on nitrocellulose transfer membranes. Equal loading and protein transfer were controlled by Ponceau S staining. After the dye was removed (washing in water), immunostaining was carried out using anti-polySia antibody 735 or anti-NCAM antibody KD11 in a concentration of 2.5 µg ml–1. Bound antibodies were detected with peroxidase-coupled anti-mouse IgG and developed by enhanced chemiluminescence.

Tissue Preparation, Histology, and Immunohistochemistry—P0–P4 postnatal mice were anesthetized by hypothermia and killed by rapid decapitation. Brains were removed and fixed by immersion in 4% paraformaldehyde for several days before dissection. Older mice were deeply anesthetized with 20 ml/kg 1.5% ketamine, 0.2% xylazine in normal saline (0.9% NaCl) and transcardially perfused with 4% paraformaldehyde before brains were removed and postfixed overnight. Brains were embedded in 4% agar-agar (Roth) and cut into 50-µm serial sections using a vibrating microtome. Unstained free-floating vibratome sections were examined with a stereomicroscope (Zeiss SV 11) under modified dark field illumination. For standard histological examination, sections were air dried onto Superfrost Plus slides (Menzel Gläser), dehydrated and stained with cresyl violet/thionine (Nissl stain). Immunofluorescence staining of free-floating vibratome sections was performed with polyclonal rabbit anti-calbindin (Swant) and AlexaFluor 488-conjugated secondary antibodies (Molecular Probes) according to the manufacturers' instructions. Micrographs were archived digitally using AxioVision version 3.1 software (Zeiss).

Morphometric Measurements—Area and length measurements were performed on digital images using NIH ImageJ. To address the dimensions of the anterior commissure, the anterior and posterior limbs were followed on coronal serial sections, and diameters were measured perpendicular to their trajectory at the level of midline crossing (if applicable) to jointly assess both limbs, and directly rostral or caudal of the branching point for separate measurements of the anterior and posterior limbs, respectively. The rostrocaudal extent of the internal capsule was calculated as the product of the number of coronal sections on which the internal capsule was present multiplied by the thickness of the sections (50 µm). The cross-sectional areas of the corticospinal and mammillothalamic tracts were measured as illustrated in the respective figures (see "Results"), and for each animal the mean values of the left and right tracts were calculated.

DiI Tracing—DiI (Molecular Probes) was applied on fixed brains cut in coronal orientation from rostral up to the desired level. Crystals of DiI were placed unilaterally on the pars externa of the anterior olfactory nucleus to mark the anterior commissure or on the medullary pyramids to label the corticospinal tract of the hindbrain. After incubation in 4% paraformaldehyde for 2 weeks at 37 °C, 100-µm vibratome sections were cut in horizontal or coronal planes and examined with a fluorescence stereomicroscope (Leica MZ FLIII).

Statistics—Statistical analyses were performed using Graphpad Prism software. For comparisons of more than two groups, one-way ANOVA with Newman-Keuls multiple comparison test as a post-test (two-tailed) was applied. Chi-square tests were used to assess frequency distributions or to compare actual with expected frequencies.


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 REFERENCES
 
Polysialyltransferase-deficient Mice Exhibit a Lethal Phenotype—Mice with single inactivation of the polysialyltransferase genes, St8sia-II (II–/–) (28) and St8sia-IV (IV–/–) (27), were cross-bred. Offspring from double-heterozygous animals (II+/–IV+/–; F6 backcross on C57BL/6J mice) were further intercrossed and yielded all expected genotypes including mice doubly deficient for the polysialyltransferases (II–/–IV–/–). Western blot analysis was used to display the expression of polySia (Fig. 1B, upper panel) and NCAM (Fig. 1B, lower panel) in brain homogenates of postnatal day 1 (P1) pups. Mice of all genotypes except II–/–IV–/– retained polySia-immunoreactivity. The complete absence of polySia in II–/–IV–/– animals excluded the existence of a third polysialyltransferase that could modify NCAM. Consistent with the high expression level of ST8Sia-II in perinatal animals (24–26), the absence of ST8Sia-II (Fig. 1B, II–/–IV+/+ and II–/–IV+/–) lowers the polySia content more drastically than the absence of ST8Sia-IV (Fig. 1B, II+/+IV–/– and II+/–IV–/–). NCAM protein expression, in contrast, is not affected by the lack of polySia synthesis. The two major NCAM isoforms expressed at P1, NCAM-180 and –140 (29), are present at similar level in all genotypes (Fig. 1B, lower panel).

Polysialyltransferase double-null offspring (II–/–IV–/–) were born overtly normal and at a Mendelian frequency (Fig. 1, C and E). However, during the first weeks of postnatal development, animals failed to thrive (Fig. 1, D and F), whereas littermates of all other genotypes including animals with only one functional polysialyltransferase allele (II–/–IV+/– or II+/–IV–/–) showed growth in the range of the wild type. After 3 weeks of age, about 50% of the II–/–IV–/– animals died, and less than 20% survived >4 weeks (Fig. 1E). Along with the growth retardation, polysialyltransferase double mutants appeared increasingly cachectic and revealed severe deficits in simple tests of motor coordination, strength, and balance. For example, II–/–IV–/– animals were unable to hang upside down on a standard wire cage lid or to balance on a horizontal pole. Apart from cachexia, with reduced mass of fatty tissue and limb muscles, histological screens of other hematoxylin-eosin-stained tissue sections (heart, lung, stomach, pancreas, gut, liver, spleen, and kidney) did not show obvious abnormalities. In contrast to the dramatically affected development of polysialyltransferase-deficient mice, N–/– offspring derived from N+/– x N+/– crossings had physically normal development, with only a slight reduction of body weight (Fig. 1G), and matched the expected Mendelian distribution at the age of 4 weeks (n = 27, 54, 24 for N+/+, N+/–, and N–/–; p > 0.8, chi-square test).


Figure 1
View larger version (58K):
[in this window]
[in a new window]
  		FIGURE 1.
PolySia-NCAM expression and postnatal development of St8sia-II and St8sia-IV double-mutant mice. A, scheme of polysialylated NCAM. PolySia is added to two N-glycosylation sites in the fifth immunoglobulin-like (Ig) domain. NCAM-140 and NCAM-180 differ by alternative splicing of exon 18. TMD, transmembrane domain. B, Western blot of extracts of postnatal day 1 brains (genotypes as indicated). Antibody 735 displays polysialylated NCAM as a diffuse high molecular weight smear (upper panel). After removal of polySia with endo-N-acetylneuraminidase (endoN (17)), discrete bands of 180 and 140 kDa are visible with the anti-NCAM antibody KD11 (lower panel). C and D, II–/–IV–/– mice at P1 are indistinguishable from double-heterozygous littermates (C), but growth is drastically retarded in 4-week-old animals (D). E, genotype distribution of offspring from II+/–IV–/– females and II–/–IV+/– males at the day of birth (P0, n = 83) and after 3 weeks (3w, n = 109), and 4 weeks of age (4w, n = 88). Significant deviations from Mendelian distributions are indicated (*, p < 0.05; ***, p < 0.001, chi-square test). F, body weight of control (ctrl., n ≥ 12) and II–/–IV–/– mice (n ≥ 3) at different postnatal ages. Beginning with P21, means ± S.D. are plotted separately for males (m, n ≥ 12 for controls and n ≥ 6 for II–/–IV–/–) and females (f, n ≥ 12 for controls and n ≥ 5 for II–/–IV–/–). **, p < 0.01; ***, p < 0.001. G, body weight of P40 females with different genotypes as indicated (Ncam knock-out; N–/–, polysialyltransferase double knock-outs; II–/–IV–/–, triple knock-out animals with deleted NCAM and polysialyltransferase genes (N–/–II–/–IV–/–); triple). Heterozygous (II+/–IV+/–; II+/–IV+/+; II+/+IV+/–) and wild-type animals were indistinguishable and used as controls. Bars represent means ± S.D. of n = 17 (control), n = 4 (N–/–), n = 6 (II–/–IV–/–), and n = 3 (N–/–II–/–IV–/–) 4–6-week-old animals. One-way ANOVA, p < 0.0001; ***, significant difference against all other groups, p < 0.001.

 


Figure 2
View larger version (50K):
[in this window]
[in a new window]
  		FIGURE 2.
Small olfactory bulbs and expansion of the rostral migratory stream observed in II–/–IV–/– mice correspond to the phenotype of Ncam-deficient mice. A–D, top view of the forebrains and cresyl violet-stained sagittal sections of 4-week-old II+/–IV+/– (A, C) and II–/–IV–/– littermates (B, D). Note the smaller size of the olfactory bulbs (ob; asterisks in B and D), the moderately enlarged lateral ventricle (lv), and the accumulation of cells in the anterior subventricular zone and rostral migratory stream (D, arrow) in the polysialyltransferase double-null mice. E and F, relative forebrain size (without olfactory bulbs) and size of olfactory bulbs (ob) were judged by measuring the area in top view in controls (ctrl.; pooled data for wild-type and heterozygous animals, n = 9), Ncam knock-outs (N–/–, n = 3), polysialyltransferase double-null (II–/–IV–/–, n = 6), and St8sia-II, St8sia-IV, Ncam triple-null mice (triple, n = 3). Animals with extensive hydrocephalus were excluded from forebrain size measurements. One-way ANOVA, p > 0.05 (E) and p < 0.0001 (F). **, significant difference against controls, p < 0.01 each. Scale bars, 1 mm.

 
Gain of NCAM Functions in polySia-negative Mice—Major defects in brain morphology as described for Ncam knock-out mice (N–/–) (15, 16, 18, 22, 30, 31) were recapitulated in the polysialyltransferase-negative animals (II–/–IV–/–), documenting the fact that they are caused by the absence of polySia and not by the lack of NCAM. Shared defects concern: (i) small olfactory bulbs (Fig. 2, see also Fig. 4B); (ii) a massive accumulation of cells in the proximal part of the rostral migratory stream (Fig. 2D); and (iii) the defasciculation and aberrant lamination of the mossy fiber tract (Fig. 3). Beyond that, II–/–IV–/– mice have unique defects including postnatal growth retardation and precocious death, and as will be demonstrated below (Figs. 4, 5, 6), they exhibit massive hydrocephalus and abnormalities of major brain fiber tracts.

This splitting of defects into two categories, (i) mild defects shared with N–/– and (ii) severe defects that manifest exclusively in II–/–IV–/– mice, prompted us to hypothesize that the defects of the second category are due to a gain of NCAM function. To investigate this possibility, triple knock-out mice were generated by introducing N–/– alleles into II–/–IV–/– mice. The resulting N–/–II–/–IV–/– animals were viable, and postnatal development was indistinguishable from wild-type and N–/– animals (Fig. 1G). Like N–/– mice, the triple knock-outs displayed small olfactory bulbs (Fig. 2F) and defasciculated mossy fiber tracts (Fig. 3, D and H).

A conspicuous malformation of mature II–/–IV–/– mice (3 weeks or older) was a domed cranium due to hydrocephalus formation. Compared with the normal brain morphology of double heterozygotes (II+/–IV+/–; Fig. 4, A and C), sagittal and coronal brain sections of hydrocephalic II–/–IV–/– animals (Fig. 4, B and D) demonstrated a massive dilatation of the lateral and third ventricles in conjunction with thinning of the cerebral cortex, hypoplasia of the corpus callosum, and displacement and deformation of the hippocampal formation and the fimbria. In contrast, the fourth ventricle (exemplarily shown in Fig. 4B) is not significantly enlarged and the gross anatomy of the cerebellum appears normal. Of 16 II–/–IV–/– mice (derived from 11 different litters) that survived for more than 3 weeks, seven animals (derived from six different litters) displayed the dramatic phenotype as shown in Fig. 4, B and D, and six animals exhibited a moderate ventriculomegaly (see Fig. 2D for an example). Only three double-null mutants but all double heterozygotes (II+/–IV+/–; eight in total) had normal-sized ventricles (p < 0.001, chi-square test). Newborn II–/–IV–/– mice mostly displayed a mild dilatation of the lateral ventricles (see Fig. 5G for an example), whereas severe ventricular dilatation was rare (3 of 14 neonates examined). Among mature II–/–IV–/– animals the drastic reduction in body weight was observed irrespective of the different ventricular conditions (mean weights ± S.D. of animals with marked (n = 7), moderate (n = 6), and no ventricular dilatation (n = 3) were 7.2 ± 2.8, 7.8 ± 3.3 and 6.6 ± 2.2 g, respectively). Together, these observations suggest that hydrocephalus in polySia-negative mice develops progressively and is not linked to growth retardation and lethality. In accordance with reported data (15, 32), none of the six N–/– or N–/–II–/–IV–/– animals additionally analyzed in the present study developed signs of hydrocephalus, but all displayed a slight enlargement of the lateral ventricles (Figs. 4E and 5J). Thus, compared with NCAM-deficient mice, the II–/–IV–/– animals have a significantly increased incidence of hydrocephalus (p < 0.05, chi-square test).


Figure 3
View larger version (35K):
[in this window]
[in a new window]
  		FIGURE 3.
Aberrant lamination of hippocampal mossy fibers in II–/–IV–/– and Ncam-deficient mice. A–D, calbindin immunofluorescence (green) and nuclear counter-staining with 4',6-diamidino-2-phenylindole (blue) of the hippocampal formation in 4–6-week-old wild-type (wt, A), N–/– (B), II–/–IV–/– (C), and II–/–IV–/–N–/– mice (triple, D). CA3, CA3 subfield of the hippocampus; dg, dentate gyrus. E–H, higher magnification of the calbindin-stained mossy fiber bundles corresponding to the boxed areas in A–D, showing the normal fasciculation and separation of the suprapyramidal (sp) and infrapyramidal (ip) mossy fiber bundles in the wild type and their altered appearance in the other genotypes. Scale bars, 100 µm.

 


Figure 4
View larger version (30K):
[in this window]
[in a new window]
  		FIGURE 4.
Formation of hydrocephalus in II–/–IV–/– mice. A–E, montage of cresyl violet-stained sagittal sections (A and B) and unstained coronal sections (C—E) under modified dark field illumination through brains from mature II+/–IV+/– (A, C), II–/–IV–/– (B, D), and N–/–II–/–IV–/– animals (E). B and D represent cases with severe dilatation of the lateral (lv) and third ventricles (3v), thinning of the cortex (cx) and corpus callosum (cc), and distortion of the hippocampus (hp) and fimbria (fi). In B, note the deformation and reduced size of the olfactory bulb (ob), the normal size of the fourth ventricle (4v), and the normal gross anatomy of the cerebellum (cb). Scale bars, 1 mm.

 
A feature observed exclusively in the polySia-negative II–/–IV–/– mice was the absence of the anterior commissure (Fig. 5, A–J), which connects the olfactory structures and lateral parts of the temporal lobe. This defect occurred in 100% of the II–/–IV–/– animals, even in the rare cases in which ventricles were not dilated, as in the example shown in Fig. 5I (p < 0.001, chi-square test of II–/–IV–/– (n = 18) versus control (n = 12), N–/– (n = 6), or N–/–II–/–IV–/– (n = 5), respectively). Anterograde tracing of the anterior limb of the anterior commissure with DiI highlights the defect (Fig. 5, A–D). In II–/–IV–/– neonates this fiber tract is stunted and deviates early from its path (Fig. 5, B, D), whereas the tract is regularly shaped in double heterozygotes (Fig. 5, A, C, and E). Ablation of NCAM in the triple knock-out mice fully restored both limbs of the anterior commissure (Fig. 5, H and J, and TABLE ONE), demonstrating that loss of polySia resulted in a gain of NCAM function, which is responsible for the defects.


View this table:
[in this window]
[in a new window]
  		TABLE ONE
Size comparison of the anterior commissure of polysialyltransferase and Ncam-deficient mice

Agenesis of both limbs of the anterior commissure in 4-6-week-old polysialyltransferase-deficient mice (II-/-IV-/-) is completely restored after additional ablation of NCAM (N-/-II-/-IV-/-).

 


Figure 5
View larger version (73K):
[in this window]
[in a new window]
  		FIGURE 5.
Malformations of anterior commissure and corticospinal tract in II–/–IV–/– mice. A and B, DiI tracing of the anterior branch of the anterior commissure (ac) in P2 control and II–/–IV–/– mice. Assembly of horizontal sections with selective contrast enhancement reveals normal midline (dotted line) crossing in controls (A) and aberrant guidance and fasciculation in II–/–IV–/– littermates (B, arrows). C and D, cresyl violet-stained sections corresponding to A and B. E—H, cresyl violet-stained coronal sections of P1 brains at the level of the anterior commissure (ac)of II+/–IV+/– (E), N–/– (F), II–/–IV–/– (G), and N–/–II–/–IV–/– mice (H). The arrow in G indicates a rudiment of the posterior branch of the anterior commissure. Note normal size of the corpus callosum (cc, arrowhead) and slight expansion of the lateral ventricles (lv, asterisk) of the II–/–IV–/– specimen. I, unstained coronal section of a mature II–/–IV–/– brain with a rudiment of the anterior commissure, posterior branch (arrow), and normally developed lateral olfactory tracts (lo) and corpus callosum (cc). J, normal anterior commissure and slightly enlarged lateral ventricles (lv)in N–/–II–/–IV–/– brain. K and L, anterograde DiI tracing of the corticospinal tract (cst) in mature control (K) and II–/–IV–/– mice (L). Assembling coronal sections at the level of the medullary pyramids (1), the pyramidal decussation (2, pyx), and the dorsal funiculus (3; contrast is selectively increased in inserts) illustrates hypoplasia but complete crossing of the midline (dotted line) in II–/–IV–/– mice. M and N, unstained coronal sections through the medulla showing the corticospinal tract (red-framed) of mature control (M) and II–/–IV–/– mice (N) at the level of the seventh cranial nerve (VII, black arrows). O, statistical evaluation of the cross-sectional corticospinal tract area. Bars present means ± S.D. of n = 6 (control and II–/–IV–/–) or n = 3(N–/–; N–/–II–/–IV–/–) 4–6-week-old animals; p < 0.0001, one-way ANOVA; a, b, and c, significant differences between groups, p < 0.001). Scale bars, 500 µm.

 
Moreover, the cross-sectional area of the corticospinal tract measured at the level of the medullary pyramids in the caudal hindbrain was markedly reduced in 4–6-week-old II–/–IV–/– mutants (Fig. 5, K–O). DiI tracing of this tract showed, however, that all of the remaining fibers correctly cross the midline and project into the contralateral dorsal funiculus of the spinal cord (Fig. 5, K and L). This phenotype, even though resembling the hypoplasia of the corticospinal tract in 3-month-old N–/– animals (33), was significantly more severe in II–/–IV–/– when compared directly with either N–/– or N–/–II–/–IV–/– mice (Fig. 5O).

Among the non-decussating fiber tracts a marked diminution of the internal capsule with the adjacent corona radiata (Fig. 6, A–C) and of the mammillothalamic tract (Fig. 6, D–H) was detected in II–/–IV–/– animals. Both defects were evident in all neonate (Fig. 6, A and E) and mature (Fig. 6, B and F) II–/–IV–/– mice examined and were completely reversed by additional deletion of NCAM (N–/–II–/–IV–/–; Fig. 6, B (triple) and G).

In contrast, fiber tracts such as the corpus callosum, fimbria, and hippocampal commissure, found to be seriously damaged in hydrocephalic II–/–IV–/– adults (Fig. 4), were perfectly developed in II–/–IV–/– neonates and in mature II–/–IV–/– mice not showing severe hydrocephalus (examples are shown for corpus callosum in Fig. 5, G (for neonatal) and I (for mature brain)). In the few mice with almost regularly shaped ventricles, the width of the cerebral cortex from the pial surface to the white matter was indistinguishable from wild-type, double-heterozygous, or N–/–II–/–IV–/– animals (see Figs. 5, I and J, and 6B). Therefore, defects of these brain structures, as well as the distortion of the hippocampus (Fig. 4, B and D) seem to be secondary to ventricular dilatation.

Important in this context is the marked expansion of the hippocampus that was observed in all II–/–IV–/– mice without hydrocephalus (see Fig. 6B). Although further studies will be required to evaluate the basis of this effect, we hypothesize that spatial alterations due to the reduction of the internal capsule enable a passive extension of adjacent tissue to fill the available space. Conversely, an increase of hydrostatic pressure of the cerebrospinal fluid, the most likely reason for the development of hydrocephalus, would counteract this expansion. Fiber tracts, which were regularly shaped and properly positioned in all II–/–IV–/– mice, are the ipsilaterally projecting lateral olfactory tract (Fig. 5I) and fasciculus retroflexus (Fig. 6, E and F), the optic nerve and chiasm (data not shown), and the optic tract (Fig. 6B) and posterior commissure (Fig. 6F).


   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
REFERENCES
 
The animal models described in this article allow the dissection between NCAM and polySia functions during mouse neurodevelopment. By simultaneous deletion of St8sia-II and St8sia-IV, a complete elimination of polySia was achieved, but in contrast to findings in Ncam knock-out mice, expression of NCAM was retained. As summarized in TABLE TWO, the severe phenotype of II–/–IV–/– mice combines two types of defects: (i) defects that establish independent of the presence of NCAM and are shared by polysialyltransferase-(II–/– IV–/–) and NCAM-depleted mice (N–/– or N–/–II–/–IV–/–); and (ii) defects caused by a gain of NCAM functions. These alterations manifest exclusively in II–/–IV–/– mice and are fully reversed by the additional deletion of the NCAM gene in N–/–II–/–IV–/– mice.


View this table:
[in this window]
[in a new window]
  		TABLE TWO
Phenotype comparison of polysialyltransferase- and Ncam-deficient mice

 
The gain of NCAM functions in II–/–IV–/– mice causes anomalies of specific brain fiber tracts, progressive hydrocephalus, and impaired postnatal growth and viability. The complete rescue of these fatal developmental defects by deletion of NCAM demonstrates unequivocally that the major function of polySia is to mask NCAM and thus guarantee that NCAM contacts take place in a highly organized, time- and site-specific manner. Invertebrates, which do not synthesize polySia-like structures, control the cell surface presentation of NCAM orthologues (FasII and apCAM) by internalization and proteolytic degradation (34, 35). It is likely that concealing NCAM by polysialylation provides an additional regulatory level required in the complex vertebrate organism.


Figure 6
View larger version (107K):
[in this window]
[in a new window]
  		FIGURE 6.
Size reduction of the internal capsule and mammillothalamic tract in II–/–IV–/– mice. A, montage of cresyl violet-stained horizontal sections showing the rostrocaudal extent of the internal capsule (ic, arrows) and the corona radiata (asterisks) in P1 II+/–IV+/– (left) and II–/–IV–/– (right) littermates. B, unstained coronal sections of the posterior (dorsal) thalamus showing aberrant fiber projections (arrow) and absence of corona radiata (asterisk) of a mature II–/–IV–/– brain (left) and normal morphology of a corresponding N–/–II–/–IV–/– brain (triple, right). Note expansion of the hippocampus (hp)inthe II–/–IV–/– specimen lacking ventricular dilatation and identical positioning of the optic tract (ot) indicating the same rostrocaudal level of the two sections. C, statistical evaluation of the rostrocaudal extent of the internal capsule. Means ± S.D. of n = 8 (control (ctrl.)), n = 6(II–/–IV–/– mice without severe hydrocephalus), or n = 3(N–/– and N–/–II–/–IV–/–) 4–6-week-old animals; p < 0.0001, one-way ANOVA, ***, significant difference against all other groups, p < 0.001. D and E, cresyl violet-stained sagittal sections through the diencephalon of P1 II+/–IV+/– (D) and II–/–IV–/– (E) littermates at the level of the fasciculus retroflexus (fr) and the mammillothalamic tract (mt, arrow). F and G, unstained coronal sections through the diencephalon of mature II–/–IV–/– (F) and triple knock-out (N–/–II–/–IV–/–) mice (G) at the level of the posterior commissure (pc). H, statistical evaluation of the cross-sectional area of the mammillothalamic tract at the level of the posterior commissure. Means ± S.D. of n = 8 (control), n = 7(II–/–IV–/–), or n = 3 (N–/– and N–/–II–/–IV–/–) 4–6-week-old animals; p < 0.0001, one-way ANOVA, ***, significant difference against all other groups, p < 0.001. Scale bars, 500 µm.

 
As in the present study, deleterious NCAM effects have been described in two other systems with ectopic NCAM presentation. Dominant embryonic lethality was observed in mice mis-expressing NCAM as a soluble protein (36), and most recently, alterations reminiscent to schizophrenia were described in a conditional mouse model over-expressing soluble NCAM in late stages of neural development and in the adult (37). Including the current study, the animal models engineered to allow ectopic NCAM interactions prove impressively the importance of a strictly controlled NCAM homeostasis in the living system.

Although polySia-NCAM is abundantly expressed throughout brain development (38), gain of NCAM function because of polySia-deficiency affects a well defined and highly diverse set of commissural and non-commissural fiber tracts. This diversity argues against a common cellular mechanism underlying the defects. To deduce which step of axonal development or maintenance is actually impaired by the untimely NCAM interactions, future studies must concentrate on investigating the dysgenesis of each individual fiber tract. These studies must also address the questions of whether fatal NCAM contacts in II–/–IV–/– mice are due to premature interactions in cis (i.e. in the plane of the membrane) or in trans (i.e. between apposing cells or cells and extracellular matrix) and whether homophilic or heterophilic NCAM interactions are affected (for review, see Ref. 39).

Remarkably, depletion of L1, like depletion of polysialyltransferases, induces a complex phenotype including hydrocephalus and defective brain fiber tracts (40–43). Recent studies separated the phenotype of L1-deficient mice into defects caused by the loss of homo- and heterophilic L1-interactions (44). Although the hydrocephalus develops because of the lack of homophilic L1 interactions, malformations such as hypoplasia of the corpus callosum and corticospinal tract can be clearly attributed to failures of heterophilic L1 binding (44). Because L1 is a lateral binding partner of NCAM (45), we are currently investigating the possibility that NCAM/L1 interactions are enhanced in the absence of polySia leading to sequestration and functional inactivation of L1. In contrast, signaling via the NCAM-GFR{alpha}1 complex should not be influenced by polySia depletion, because both GFR{alpha}1 and GDNF (glial cell line-derived neurotrophic factor) bind to polysialylated and non-polysialylated forms of NCAM (46).

Defects of the olfactory bulbs, expansion of the rostral migratory stream, and delamination of hippocampal mossy fibers observed in II–/–IV–/– mice are shared with all other polySia-negative models independently of the presence of NCAM (15, 16, 18, 22, 30, 31). Consequently, the function of polySia in these areas is not the masking of NCAM but may be the modulation of other cell surface interactions by stereochemical means. As discussed extensively in earlier studies, polySia prevents inappropriate contacts of cells with their environment, permitting tangential migration of precursors in the rostral migratory stream to the olfactory bulbs (18, 31) and supporting correct fasciculation of mossy fibers (22, 30).

In conclusion, the lethal phenotype of polysialyltransferase-deficient mice and its rescue by additional ablation of NCAM reveals that the unique and highly specific posttranslational modification with polysialic acid plays a vital role in steering NCAM interactions in vivo.


   FOOTNOTES
 
* This work was supported by grants from the Deutsche Forschungsgemeinschaft (to R. G.-S., H. H., and M. M.), National Institutes of Health (to J. D. M.), the Fonds der Chemischen Industrie (to R. G.-S.), and the Deutsche Krebshilfe (to M. M. and H. H.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Back

1 Present address: Institut de Biologie du Développement de Marseille, Campus de Luminy, 13288 Marseille 9, France. Back

2 To whom correspondence should be addressed. Tel.: 49-511-532-9802; Fax: 49-511-532-8801; E-mail: Gerardy-schahn.rita{at}mh-hannover.de.

3 The abbreviations used are: polySia, polysialic acid; NCAM, neural cell adhesion molecule; ANOVA, analysis of variance; P, postnatal day (e.g. P1). Back


   ACKNOWLEDGMENTS
 
We thank H. Cremer for Ncam knock-out mice, U. Rutishauser, K. Stummeyer, M. Eckhardt, and J. Falk for critically reading the manuscript, and U. Peters and D. Wittenberg for expert technical assistance.



   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 REFERENCES
 

  1. Lowe, J. B., and Marth, J. D. (2003) Annu. Rev. Biochem. 72, 643–691[CrossRef][Medline] [Order article via Infotrieve]
  2. Haltiwanger, R. S., and Lowe, J. B. (2004) Annu. Rev. Biochem. 73, 491–537[CrossRef][Medline] [Order article via Infotrieve]
  3. Jaeken, J., and Matthijs, G. (2001) Annu. Rev. Genomics Hum. Genet. 2, 129–151[Medline] [Order article via Infotrieve]
  4. Rutishauser, U., and Landmesser, L. (1996) Trends Neurosci. 19, 422–427[Medline] [Order article via Infotrieve]
  5. Durbec, P., and Cremer, H. (2001) Mol. Neurobiol. 24, 53–64[CrossRef][Medline] [Order article via Infotrieve]
  6. Kleene, R., and Schachner, M. (2004) Nat. Rev. Neurosci. 5, 195–208[CrossRef][Medline] [Order article via Infotrieve]
  7. Fujimoto, I., Bruses, J. L., and Rutishauser, U. (2001) J. Biol. Chem. 276, 31745–31751[Abstract/Free Full Text]
  8. Johnson, C. P., Fragneto, G., Konovalov, O., Dubosclard, V., Legrand, J. F., and Leckband, D. E. (2005) Biochemistry 44, 546–554[CrossRef][Medline] [Order article via Infotrieve]
  9. Johnson, C. P., Fujimoto, I., Rutishauser, U., and Leckband, D. E. (2005) J. Biol. Chem. 280, 137–145[Abstract/Free Full Text]
  10. Storms, S. D., and Rutishauser, U. (1998) J. Biol. Chem. 273, 27124–27129[Abstract/Free Full Text]
  11. Dityatev, A., Dityateva, G., Sytnyk, V., Delling, M., Toni, N., Nikonenko, I., Muller, D., and Schachner, M. (2004) J. Neurosci. 24, 9372–9382[Abstract/Free Full Text]
  12. Marx, M., Rutishauser, U., and Bastmeyer, M. (2001) Development (Camb.) 128, 4949–4958[Medline] [Order article via Infotrieve]
  13. Vutskits, L., Djebbara-Hannas, Z., Zhang, H., Paccaud, J. P., Durbec, P., Rougon, G., Muller, D., and Kiss, J. Z. (2001) Eur. J. Neurosci. 13, 1391–1402[CrossRef][Medline] [Order article via Infotrieve]
  14. Vaithianathan, T., Matthias, K., Bahr, B., Schachner, M., Suppiramaniam, V., Dityatev, A., and Steinhauser, C. (2004) J. Biol. Chem. 279, 47975–47984[Abstract/Free Full Text]
  15. Cremer, H., Lange, R., Christoph, A., Plomann, M., Vopper, G., Roes, J., Brown, R., Baldwin, S., Kraemer, P., Scheff, S., Barthels, D., Rajewsky, K., and Willie, W. (1994) Nature 367, 455–459[CrossRef][Medline] [Order article via Infotrieve]
  16. Tomasiewicz, H., Ono, K., Yee, D., Thompson, C., Goridis, C., Rutishauser, U., and Magnuson, T. (1993) Neuron 11, 1163–1174[CrossRef][Medline] [Order article via Infotrieve]
  17. Stummeyer, K., Dickmanns, A., Mühlenhoff, M., Gerardy-Schahn, R., and Ficner, R. (2005) Nat. Struct. Mol. Biol. 12, 90–96[CrossRef][Medline] [Order article via Infotrieve]
  18. Ono, K., Tomasiewicz, H., Magnuson, T., and Rutishauser, U. (1994) Neuron 13, 595–609[CrossRef][Medline] [Order article via Infotrieve]
  19. Becker, C. G., Artola, A., Gerardy-Schahn, R., Decker, T., Welzl, H., and Schachner, M. (1996) J. Neurosci. Res. 45, 143–152[CrossRef][Medline] [Order article via Infotrieve]
  20. Muller, D., Wang, C., Skibo, G., Toni, N., Cremer, H., Calaora, V., Rougon, G., and Kiss, J. Z. (1996) Neuron 17, 413–422[CrossRef][Medline] [Order article via Infotrieve]
  21. Shen, H., Watanabe, M., Tomasiewicz, H., Rutishauser, U., Magnuson, T., and Glass, J. D. (1997) J. Neurosci. 17, 5221–5229[Abstract/Free Full Text]
  22. Seki, T., and Rutishauser, U. (1998) J. Neurosci. 18, 3757–3766[Abstract/Free Full Text]
  23. Mühlenhoff, M., Eckhardt, M., and Gerardy-Schahn, R. (1998) Curr. Opin. Struct. Biol. 8, 558–564[CrossRef][Medline] [Order article via Infotrieve]
  24. Angata, K., and Fukuda, M. (2003) Biochimie (Paris) 85, 195–206
  25. Hildebrandt, H., Becker, C., Mürau, M., Gerardy-Schahn, R., and Rahmann, H. (1998) J. Neurochem. 71, 2339–2348[Medline] [Order article via Infotrieve]
  26. Ong, E., Nakayama, J., Angata, K., Reyes, L., Katsuyama, T., Arai, Y., and Fukuda, M. (1998) Glycobiology 8, 415–424[Abstract/Free Full Text]
  27. Eckhardt, M., Bukalo, O., Chazal, G., Wang, L., Goridis, C., Schachner, M., Gerardy-Schahn, R., Cremer, H., and Dityatev, A. (2000) J. Neurosci. 20, 5234–5244[Abstract/Free Full Text]
  28. Angata, K., Long, J. M., Bukalo, O., Lee, W., Dityatev, A., Wynshaw-Boris, A., Schachner, M., Fukuda, M., and Marth, J. D. (2004) J. Biol. Chem. 279, 32603–32613[Abstract/Free Full Text]
  29. He, H. T., Finne, J., and Goridis, C. (1987) J. Cell Biol. 105, 2489–2500[Abstract/Free Full Text]
  30. Cremer, H., Chazal, G., Goridis, C., and Represa, A. (1997) Mol. Cell. Neurosci. 8, 323–335[CrossRef][Medline] [Order article via Infotrieve]
  31. Chazal, G., Durbec, P., Jankovski, A., Rougon, G., and Cremer, H. (2000) J. Neurosci. 20, 1446–1457[Abstract/Free Full Text]
  32. Wood, G. K., Tomasiewicz, H., Rutishauser, U., Magnuson, T., Quirion, R., Rochford, J., and Srivastava, L. K. (1998) Neuroreport 9, 461–466[Medline] [Order article via Infotrieve]
  33. Rolf, B., Bastmeyer, M., Schachner, M., and Bartsch, U. (2002) J. Neurosci. 22, 8357–8362[Abstract/Free Full Text]
  34. Schuster, C. M., Davis, G. W., Fetter, R. D., and Goodman, C. S. (1996) Neuron 17, 655–667[CrossRef][Medline] [Order article via Infotrieve]
  35. Bailey, C. H., Kaang, B. K., Chen, M., Martin, K. C., Lim, C. S., Casadio, A., and Kandel, E. R. (1997) Neuron 18, 913–924[CrossRef][Medline] [Order article via Infotrieve]
  36. Rabinowitz, J. E., Rutishauser, U., and Magnuson, T. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 6421–6424[Abstract/Free Full Text]
  37. Pillai-Nair, N., Panicker, A. K., Rodriguiz, R. M., Gilmore, K. L., Demyanenko, G. P., Huang, J. Z., Wetsel, W. C., and Maness, P. F. (2005) J. Neurosci. 25, 4659–4671[Abstract/Free Full Text]
  38. Seki, T., and Arai, Y. (1993) Neurosci. Res. 17, 265–290[CrossRef][Medline] [Order article via Infotrieve]
  39. Walmod, P. S., Kolkova, K., Berezin, V., and Bock, E. (2004) Neurochem. Res. 29, 2015–2035[CrossRef][Medline] [Order article via Infotrieve]
  40. Dahme, M., Bartsch, U., Martini, R., Anliker, B., Schachner, M., and Mantei, N. (1997) Nat. Genet. 17, 346–349[CrossRef][Medline] [Order article via Infotrieve]
  41. Fransen, E., D'Hooge, R., Van Camp, G., Verhoye, M., Sijbers, J., Reyniers, E., Soriano, P., Kamiguchi, H., Willemsen, R., Koekkoek, S. K., De Zeeuw, C. I., De Deyn, P. P., Van der Linden, A., Lemmon, V., Kooy, R. F., and Willems, P. J. (1998) Hum. Mol. Genet. 7, 999–1009[Abstract/Free Full Text]
  42. Demyanenko, G. P., Tsai, A. Y., and Maness, P. F. (1999) J. Neurosci. 19, 4907–4920[Abstract/Free Full Text]
  43. Rolf, B., Kutsche, M., and Bartsch, U. (2001) Brain Res. 891, 247–252[CrossRef][Medline] [Order article via Infotrieve]
  44. Itoh, K., Cheng, L., Kamei, Y., Fushiki, S., Kamiguchi, H., Gutwein, P., Stoeck, A., Arnold, B., Altevogt, P., and Lemmon, V. (2004) J. Cell Biol. 165, 145–154[Abstract/Free Full Text]
  45. Horstkorte, R., Schachner, M., Magyar, J. P., Vorherr, T., and Schmitz, B. (1993) J. Cell Biol. 121, 1409–1421[Abstract/Free Full Text]
  46. Paratcha, G., Ledda, F., and Ibanez, C. F. (2003) Cell 113, 867–879[CrossRef][Medline] [Order article via Infotrieve]

Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:


Home page
 J. Biol. Chem.Home page
D. A. Foley, K. G. Swartzentruber, and K. J. Colley
Identification of Sequences in the Polysialyltransferases ST8Sia II and ST8Sia IV That Are Required for the Protein-specific Polysialylation of the Neural Cell Adhesion Molecule, NCAM
J. Biol. Chem., June 5, 2009; 284(23): 15505 - 15516.
[Abstract] [Full Text] [PDF]

Home page
 BrainHome page
H. Hildebrandt, M. Muhlenhoff, I. Oltmann-Norden, I. Rockle, H. Burkhardt, B. Weinhold, and R. Gerardy-Schahn
Imbalance of neural cell adhesion molecule and polysialyltransferase alleles causes defective brain connectivity
Brain, May 14, 2009; (2009) awp117v1.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
T. Yoshihara, K. Sugihara, Y. Kizuka, S. Oka, and M. Asano
Learning/Memory Impairment and Reduced Expression of the HNK-1 Carbohydrate in {beta}4-Galactosyltransferase-II-deficient Mice
J. Biol. Chem., May 1, 2009; 284(18): 12550 - 12561.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
Y. Kizuka, Y. Tonoyama, and S. Oka
Distinct Transport and Intracellular Activities of Two GlcAT-P Isoforms
J. Biol. Chem., April 3, 2009; 284(14): 9247 - 9256.
[Abstract] [Full Text] [PDF]

Home page
 GlycobiologyHome page
Y. Kanato, K. Kitajima, and C. Sato
Direct binding of polysialic acid to a brain-derived neurotrophic factor depends on the degree of polymerization
Glycobiology, December 1, 2008; 18(12): 1044 - 1053.
[Abstract] [Full Text] [PDF]

Home page
 MicrobiologyHome page
A. Zelmer, M. Bowen, A. Jokilammi, J. Finne, J. P. Luzio, and P. W. Taylor
Differential expression of the polysialyl capsule during blood-to-brain transit of neuropathogenic Escherichia coli K1
Microbiology, August 1, 2008; 154(8): 2522 - 2532.
[Abstract] [Full Text] [PDF]

Home page
 GlycobiologyHome page
T. Miyazaki, K. Angata, P. H. Seeberger, O. Hindsgaul, and M. Fukuda
CMP substitutions preferentially inhibit polysialic acid synthesis
Glycobiology, February 1, 2008; 18(2): 187 - 194.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
I. Oltmann-Norden, S. P. Galuska, H. Hildebrandt, R. Geyer, R. Gerardy-Schahn, H. Geyer, and M. Muhlenhoff
Impact of the Polysialyltransferases ST8SiaII and ST8SiaIV on Polysialic Acid Synthesis during Postnatal Mouse Brain Development
J. Biol. Chem., January 18, 2008; 283(3): 1463 - 1471.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
S. P. Galuska, R. Geyer, R. Gerardy-Schahn, M. Muhlenhoff, and H. Geyer
Enzyme-dependent Variations in the Polysialylation of the Neural Cell Adhesion Molecule (NCAM) in Vivo
J. Biol. Chem., January 4, 2008; 283(1): 17 - 28.
[Abstract] [Full Text] [PDF]

Home page
 GlycobiologyHome page
K. Koles, J.-M. Lim, K. Aoki, M. Porterfield, M. Tiemeyer, L. Wells, and V. Panin
Identification of N-Glycosylated Proteins from the Central Nervous System of Drosophila Melanogaster
Glycobiology, December 1, 2007; 17(12): 1388 - 1403.
[Abstract] [Full Text] [PDF]

Home page
 Stem CellsHome page
T. Glaser, C. Brose, I. Franceschini, K. Hamann, A. Smorodchenko, F. Zipp, M. Dubois-Dalcq, and O. Brustle
Neural Cell Adhesion Molecule Polysialylation Enhances the Sensitivity of Embryonic Stem Cell-Derived Neural Precursors to Migration Guidance Cues
Stem Cells, December 1, 2007; 25(12): 3016 - 3025.
[Abstract] [Full Text] [PDF]

Home page
 Mol. Cell. Biol.Home page
K. Angata, V. Huckaby, B. Ranscht, A. Terskikh, J. D. Marth, and M. Fukuda
Polysialic Acid-Directed Migration and Differentiation of Neural Precursors Are Essential for Mouse Brain Development
Mol. Cell. Biol., October 1, 2007; 27(19): 6659 - 6668.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
F. Conchonaud, S. Nicolas, M.-C. Amoureux, C. Menager, D. Marguet, P.-F. Lenne, G. Rougon, and V. Matarazzo
Polysialylation Increases Lateral Diffusion of Neural Cell Adhesion Molecule in the Cell Membrane
J. Biol. Chem., September 7, 2007; 282(36): 26266 - 26274.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
S. N. Fewou, H. Ramakrishnan, H. Bussow, V. Gieselmann, and M. Eckhardt
Down-regulation of Polysialic Acid Is Required for Efficient Myelin Formation
J. Biol. Chem., June 1, 2007; 282(22): 16700 - 16711.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
M. A. Lopez-Fernandez, M.-F. Montaron, E. Varea, G. Rougon, C. Venero, D. N. Abrous, and C. Sandi
Upregulation of Polysialylated Neural Cell Adhesion Molecule in the Dorsal Hippocampus after Contextual Fear Conditioning Is Involved in Long-Term Memory Formation
J. Neurosci., April 25, 2007; 27(17): 4552 - 4561.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
K. Aoki, M. Perlman, J.-M. Lim, R. Cantu, L. Wells, and M. Tiemeyer
Dynamic Developmental Elaboration of N-Linked Glycan Complexity in the Drosophila melanogaster Embryo
J. Biol. Chem., March 23, 2007; 282(12): 9127 - 9142.
[Abstract] [Full Text] [PDF]

Home page
 GlycobiologyHome page
R. A. Pon, N. J. Biggs, and H. J. Jennings
Polysialic acid bioengineering of neuronal cells by N-acyl sialic acid precursor treatment
Glycobiology, March 1, 2007; 17(3): 249 - 260.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
S. S. Mendiratta, N. Sekulic, F. G. Hernandez-Guzman, B. E. Close, A. Lavie, and K. J. Colley
A Novel {alpha}-Helix in the First Fibronectin Type III Repeat of the Neural Cell Adhesion Molecule Is Critical for N-Glycan Polysialylation
J. Biol. Chem., November 24, 2006; 281(47): 36052 - 36059.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
S. P. Galuska, I. Oltmann-Norden, H. Geyer, B. Weinhold, K. Kuchelmeister, H. Hildebrandt, R. Gerardy-Schahn, R. Geyer, and M. Muhlenhoff
Polysialic Acid Profiles of Mice Expressing Variant Allelic Combinations of the Polysialyltransferases ST8SiaII and ST8SiaIV
J. Biol. Chem., October 20, 2006; 281(42): 31605 - 31615.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
O. Senkov, M. Sun, B. Weinhold, R. Gerardy-Schahn, M. Schachner, and A. Dityatev
Polysialylated Neural Cell Adhesion Molecule Is Involved in Induction of Long-Term Potentiation and Memory Acquisition and Consolidation in a Fear-Conditioning Paradigm.
J. Neurosci., October 18, 2006; 26(42): 10888 - 109898.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
W. Zhao, T.-L. L. Chen, B. M. Vertel, and K. J. Colley
The CMP-sialic Acid Transporter Is Localized in the Medial-Trans Golgi and Possesses Two Specific Endoplasmic Reticulum Export Motifs in Its Carboxyl-terminal Cytoplasmic Tail
J. Biol. Chem., October 13, 2006; 281(41): 31106 - 31118.
[Abstract] [Full Text] [PDF]

Home page
 J. Leukoc. Biol.Home page
T. Avril, S. J. North, S. M. Haslam, H. J. Willison, and P. R. Crocker
Probing the cis interactions of the inhibitory receptor Siglec-7 with {alpha}2,8-disialylated ligands on natural killer cells and other leukocytes using glycan-specific antibodies and by analysis of {alpha}2,8-sialyltransferase gene expression
J. Leukoc. Biol., October 1, 2006; 80(4): 787 - 796.
[Abstract] [Full Text] [PDF]

Home page
 Mol. Cell. Biol.Home page
P. K. Grewal, M. Boton, K. Ramirez, B. E. Collins, A. Saito, R. S. Green, K. Ohtsubo, D. Chui, and J. D. Marth
ST6Gal-I Restrains CD22-Dependent Antigen Receptor Endocytosis and Shp-1 Recruitment in Normal and Pathogenic Immune Signaling.
Mol. Cell. Biol., July 1, 2006; 26(13): 4970 - 4981.
[Abstract] [Full Text] [PDF]

Home page
 Learn. Mem.Home page
C. Florian, J. Foltz, J.-C. Norreel, G. Rougon, and P. Roullet
Post-training intrahippocampal injection of synthetic poly-{alpha}-2,8-sialic acid-neural cell adhesion molecule mimetic peptide improves spatial long-term performance in mice
Learn. Mem., May 1, 2006; 13(3): 335 - 341.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
280/52/42971    most recent
M511097200v1
Right arrow Submit a Letter to Editor
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowRequest Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Weinhold, B.
Right arrow Articles by Hildebrandt, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Weinhold, B.
Right arrow Articles by Hildebrandt, H.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 All ASBMB Journals   Molecular and Cellular Proteomics 
 Journal of Lipid Research   ASBMB Today 
Copyright © 2005 by the American Society for Biochemistry and Molecular Biology.
Advertisement
spacer
Advertisement
Advertisement