Distinct patterns of expression of the beta-1,4-galactosyltransferases during testicular development in the mouse.

Glycosylation is one of the most important post-translational modifications and it is clear that the single step of beta-1,4-galactosylation is performed by a family of beta-1,4-galactosyltransferases (beta4-GalTs) and that each member of this family may play a distinct role in different tissues and cells. In this study, we characterized the gene expression of six beta4-GalTs in mouse testis and analyzed the changes of galactosylation of testis glycoproteins during postnatal development. Northern blot analysis revealed that beta4-GalT-I and beta4-GalT-IV were expressed mainly in newborn mouse testis and that the expression of beta4-GalT-II increased markedly and persisted at the highest levels in adult mouse testis. The expression of beta4-GalT-III and beta4-GalT-V, however, remained relatively at low levels during mouse testicular development. In contrast, the expression of beta4-GalT-VI was undetectable in mouse testis. The gene expression of beta4-GalT-II in mouse testis was further analyzed by in situ hybridization due to its unique expression pattern. Strong hybridization signals were detected in the seminiferous tubules and the expression varied among the different stages of spermatogenic differentiation. The distinct gene expression patterns of beta4-GalTs in mouse testis could affect the differential galactosylation of testis glycoproteins, as revealed by lectin histochemistry analysis.