Cuzin (France) reported on the establishment of Sertoli cell lines from transgenic mice expressing the large T antigen of polyoma virus. He presented two cell lines 15P-1 and 45T-1. These two cell lines showed many specific characters of Sertoli cells; 15P-1 was able to support the haploidgenesis of testicular germ cells although FSH receptors were not expressed in either cell line.
Rossi (Italy) discussed the physiological role of the stimulation of c-kit receptor on germ cells by its ligand, SLF. He discovered the truncated form of c-kit receptor protein and its specific expression in haploid germ cells and the existence of the protein in sperm. He proposed an important hypothesis that the truncated form of c-kit protein in sperm may have some role for the activation of the egg at the time of sperm penetration in a MAP kinase and phospholipase C gamma mediated manner.
Nishimune (Japan) presented a molecular biological approach to the analysis of spermatogenesis. Using specific monoclonal antibody they have isolated a gene, calmegin, specifically expressed in pachytene spermatocytes to round spermatids. By a gene targeting experiment, calmegin KO mouse showed male infertility and KO sperm cannot bind to the egg. The physiological role of calmegin appears to be that of a molecular chaperone for one or more sperm surface proteins that mediate sperm-egg interactions.
Yoshitake Nishimune, Japan