Transcriptional Regulation of 
1,3-Galactosyltransferase in Embryonal Carcinoma Cells by Retinoic Acid
MASKING OF LEWIS X ANTIGENS BY α-GALACTOSYLATION (*)
- From the Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
- §To whom all correspondence should be addressed: Dept. of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, P. O. Box 26901 BSEB 325, Oklahoma City, OK 73190 . Tel.: 405-271-2481; Fax: 405-271-3910.
Abstract
Treatment of mouse teratocarcinoma F9 cells with all-trans-retinoic acid (RA) causes a 9-fold increase in steady-state levels of mRNA for UDP-Gal:β-D-Gal α1,3-galactosyltransferase
(α1,3GT) beginning at 36 h. Enzyme activity rises in a similar fashion, which also parallels the induction of laminin and
type IV collagen. Nuclear run-on assays indicate that this increase in α1,3GT in RA-treated F9 cells, like that of type IV
collagen, is transcriptionally regulated. Differentiation also results in increased secretion of soluble α1,3GT activity into
the growth media. The major α-galactosylated glycoprotein present in the media of RA-treated F9 cells, but not of untreated
cells, was identified as laminin. Differentiation of F9 cells is accompanied by an increase in α-galactosylation of membrane
glycoproteins and a decrease in expression of the stage-specific embryonic antigen, SSEA-1 (also known as the Lewis X antigen
or Le
), which has the structure Galβ1-4(Fucα1-3)GlcNAcβ1-R. However, flow cytometric analyses with specific antibodies and lectins,
following treatment of cells with α-galactosidase, demonstrate that differentiated cells contain Le
antigens that are masked by α-galactosylation. Thus, RA induces α1,3GT at the transcriptional level, resulting in major alterations
in the surface phenotype of the cells and masking of Le
antigens.
Footnotes
-
↵* This work was supported by National Institutes of Health Grant CA37626 (to R. D. C.). 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.
-
↵1 The abbreviations used are:
- RA
-
all-trans-retinoic acid
- BSA
-
bovine serum albumin
- PBS
-
phosphate-buffered saline
- TBS
-
Tris-buffered saline
- α1,3GT
-
UDP-Gal:β-D-Gal α1,3-galactosyltransferase
- β1,4GT
-
UDP-Gal:β-D-GlcNAc β1,4-galactosyltransferase
- α1,3FT
-
GDP-Fuc:β-D-GlcNAc α1,3-fucosyltransferase
- GS I-B
-
G. simplicifolia I-B
isolectin
- dbcAMP
-
dibutyryl cyclic adenosine monophosphate
- PAGE
-
polyacrylamide gel electrophoresis.
-
- Received September 26, 1995.
- Revision received November 30, 1995.
- © 1996 by The American Society for Biochemistry and Molecular Biology, Inc.
