GLYCOSYLATION IN GOLGI-APPARATUS OF EARLY SPERMATIDS OF RAT - A HIGH-RESOLUTION LECTIN CYTOCHEMICAL STUDY

In the present study, lectin cytochemistry in combination with enzyme and chemical treatments and ultrastructural immunocytochemistry were a pplied to investigate the formation of acrosomal glycoproteins in endo plasmic reticulum (ER) and Golgi apparatus (GA) of early rat spermatid s. In addition, the vesicles involved in glycoprotein traffic were inv estigated using a monoclonal antibody against clathrin. The results ob tained suggest the occurrence of high mannose and complex type N-linke d oligosaccharides and mucin type O-linked oligosaccharides. In N-link ed glycoproteins, Man residues are incorporated into the nascent oligo saccharide in the ER, Fuc residues of the inner core of the oligosacch aride in the cis region of GA, GlcNAc in medial cisternae of GA and Ga l residues in the transmost cisternae of GA. In O-linked glycoproteins , the addition of GalNAc occurs in cis and trans cisternae of GA. Gal beta 1,3GalNAc sequence was detected in medial and trans cisternae of GA. Sialic acid was detected in both N- and O-linked oligosaccharides in medial and trans cisternae of GA but not in acrosomes. Immunoreacti vity to clathrin was observed in the intermediate zone between ER and GA and in vesicles of the trans side of GA.