Strain-specific Presence of Two TGN38 Isoforms and Absence of TGN41 in Mouse (*)
- From the (1)Institute of Applied Biochemistry and the Institute of Biological Sciences and Gene Experiment Center, University of Tsukuba, Tsukuba, Ibaraki 305, Japan
- ¶ To whom correspondence should be addressed: Institute of Biological Sciences, University of Tsukuba, Tsukuba, Ibaraki 305, Japan. Tel.: 81-298-53-6356; Fax: 81-298-53-6006.
Abstract
TGN38 and TGN41 are isoforms of an integral membrane protein that is predominantly localized to the trans-Golgi network (TGN) in rat cells. They have been proposed to form a heterodimer and to be involved in the budding of exocytic transport vesicles from the TGN. By cDNA cloning and analysis using polymerase chain reaction, we found that there were two TGN38 isoforms in a strain of mouse (ICR), whereas other strains examined (BALB/c, DBA/2, and C57BL/6) had only one TGN38. The major difference between the two isoforms was in the number of characteristic octapeptide repeats. Apart from this, there were several nucleotide substitutions between them. The two isoforms appeared to be derived from two distinct genes but not from one gene via alternative splicing. Furthermore, we failed to show the presence of TGN41 in all the strains examined. This result suggests that TGN38 may function as a monomer or a homodimer in mouse cells.
Footnotes
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↵§ The first two authors contributed equally to this work.
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↵* This work was supported in part by grants from the Ministry of Education, Science and Culture of Japan, the Special Research Project on Circulation Biosystem in University of Tsukuba, the Saneyoshi Scholarship foundation, the Nissan Science Foundation, and Sankyo Co., Ltd. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The nucleotide sequence(s) reported in this paper has been submitted to the GenBank
/EMBL Data Bank with accession number(s) D50031 and D50032.
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↵1 The abbreviations used are:
- TGN
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trans-Golgi network
- bp
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base pair(s)
- PCR
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polymerase chain reaction
- RACE
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rapid amplification of cDNA ends.
