| First Author | Johnston DS | Year | 1995 |
| Journal | Dev Biol | Volume | 171 |
| Issue | 1 | Pages | 224-32 |
| PubMed ID | 7556898 | Mgi Jnum | J:28800 |
| Mgi Id | MGI:76339 | Doi | 10.1006/dbio.1995.1273 |
| Citation | Johnston DS, et al. (1995) The gene encoding murine alpha 1,3-galactosyltransferase is expressed in female germ cells but not in male germ cells. Dev Biol 171(1):224-32 |
| abstractText | An essential step in murine fertilization is the binding of acrosome-intact sperm to specific O-linked glycans on zona pellucida glycoprotein 3 (ZP3). While there is agreement on the primary role of O-linked glycans in sperm-ZP3 binding, there is a striking lack of consensus on both the terminal monosaccharide(s) required for a functional binding site and the cognate protein on the sperm cell surface that recognizes this glycan. Much current debate centers on the essential role of nonreducing terminal N-acetyl-glucosaminyl or alternatively, alpha-galactosyl residues, to form a functional sperm binding ligand. Relevant to this debate, we demonstrated that alpha 1,3-galactosyltransferase (alpha 3-GT), which adds nonreducing terminal alpha-galactosyl residues to glycans, is not expressed in murine spermatocytes or spermatids. The objectives of this study were to determine whether alpha 3-GT is expressed in female germ cells and to compare the pattern of expression of two other terminal glycosyltransferases, beta 1,4-galactosyltransferase (beta 4-GT) and alpha 2,6-sialyltransferase (alpha 6-ST), between male and female germ cells. Total RNA was isolated from growing oocytes obtained from 15-day-old animals, fully grown oocytes, and eggs as well as spermatogonia, spermatocytes, and spermatids. The presence of alpha 3-GT, beta 4-GT, and alpha 6-ST mRNAs was analyzed by an RT-PCR-based assay. Our data demonstrate that the alpha 3-GT gene is expressed in female germ cells, but not in male germ cells. In contrast, both beta 4-GT and alpha 6-ST are expressed during oogenesis and spermatogenesis. This differential expression of alpha 3-GT in female germ cells is consistent with the model of sperm-egg binding in which a nonreducing terminal alpha-galactosyl residue is required for a functional determinant on ZP3 and with our hypothesis that the biological significance for the suppression of alpha 3-GT expression in male germ cells is to prevent sperm-sperm aggregation. |
