Mutations of the T/t-complex of the mouse interfere with multiple cellular interactions during fertilization and development, including sperm-egg recognition, blastocyst formation and mesenchymal cell migration. In 1979, it was shown that these mutations selectively interfere with the expression of the cell surface enzyme, galactosyltransferase (GalTase). Consequently, during the past seven years we have been examining the function of this cell surface enzyme, GalTase, in those cell interactions that are controlled by T/t-complex alleles. Results show that surface GalTase participates in cell interactions during fertilization and development by recognizing and binding to its specific lactosaminoglycan (LAG) substrate on adjacent cell surfaces and in the extracellular matrix. In this way, GalTase functions as a cell surface """"""""receptor"""""""" mediating, at least in part, sperm-egg binding and mesenchymal cell migration on basal lamina matrices. We have determined that surface GalTase also participates during embryonal carcinoma cell adhesions, as well as during cell adhesions in the preimplantation embryo. Thus, it appears that surface GalTase:LAG complexes may mediate, in part, those cellular interactions during fertilization and early development that are regulated by the T/t-complex alleles. It is now appropriate to examine the molecular control of GalTase expression. In this application, we propose to clone the embryonal carcinoma GalTase cDNA, study the transcriptional and translational heterogeneity of GalTase before and after embryonal carcinoma cell differentiation into endoderm, determine the effects of inhibiting GalTase expression on embryonal carcinoma cell differentiation, and determine GalTase gene number and heterogeneity in normal and T/t-mutant cells. These studies will offer new insights into the regulation of glycoconjugate heterogeneity in general, and the expression and function of surface GalTase, in particular. They will also lay the foundation for future studies in which we will perturb the expression of GalTase during development in transgenic mice, both positively and negatively, and examine the consequences on fertilization, blastocyst formation, and cell migration.

Project Start
1986-12-01
Project End
1989-11-30
Budget Start
1988-12-01
Budget End
1989-11-30
Support Year
3
Fiscal Year
1989
Total Cost
Indirect Cost
Name
University of Texas MD Anderson Cancer Center
Department
Type
Hospitals
DUNS #
001910777
City
Houston
State
TX
Country
United States
Zip Code
77030
Hathaway, Helen J; Evans, Susan C; Dubois, Daniel H et al. (2003) Mutational analysis of the cytoplasmic domain of beta1,4-galactosyltransferase I: influence of phosphorylation on cell surface expression. J Cell Sci 116:4319-30
Shi, X; Amindari, S; Paruchuru, K et al. (2001) Cell surface beta-1,4-galactosyltransferase-I activates G protein-dependent exocytotic signaling. Development 128:645-54
Wassler, M J; Shur, B D (2000) Clustering of cell surface (beta)1,4-galactosyltransferase I induces transient tyrosine phosphorylation of focal adhesion kinase and loss of stress fibers. J Cell Sci 113 Pt 2:237-45
Johnson, F M; Shur, B D (1999) The level of cell surface beta1,4-galactosyltransferase I influences the invasive potential of murine melanoma cells. J Cell Sci 112 ( Pt 16):2785-95
Lu, Q; Shur, B D (1997) Sperm from beta 1,4-galactosyltransferase-null mice are refractory to ZP3-induced acrosome reactions and penetrate the zona pellucida poorly. Development 124:4121-31
Lu, Q; Hasty, P; Shur, B D (1997) Targeted mutation in beta1,4-galactosyltransferase leads to pituitary insufficiency and neonatal lethality. Dev Biol 181:257-67
Hinton, D A; Evans, S C; Shur, B D (1995) Altering the expression of cell surface beta 1,4-galactosyltransferase modulates cell growth. Exp Cell Res 219:640-9
Gong, X; Dubois, D H; Miller, D J et al. (1995) Activation of a G protein complex by aggregation of beta-1,4-galactosyltransferase on the surface of sperm. Science 269:1718-21
Youakim, A; Shur, B D (1994) Alteration of oligosaccharide biosynthesis by genetic manipulation of glycosyltransferases. Ann N Y Acad Sci 745:331-5
Youakim, A; Hathaway, H J; Miller, D J et al. (1994) Overexpressing sperm surface beta 1,4-galactosyltransferase in transgenic mice affects multiple aspects of sperm-egg interactions. J Cell Biol 126:1573-83

Showing the most recent 10 out of 26 publications