PROTOONCOGENE ACTIVITY IN THE TESTIS OF THE LIZARD, PODARCIS-SICULA-SICULA, DURING THE ANNUAL REPRODUCTIVE-CYCLE

Since proto-oncogenes play a central role in the regulation of cellula r growth and differentiation, localization of MYC, FOS, and JUN protei ns has been studied in the testis of the lizard, Podarcis s. sicula, d uring the annual reproductive cycle by immunocytochemistry using antis era against c-myc, c-fos, and c-jun products. MYC was localized in the nuclei of spermatogonia (SPG), I and II spermatocytes (SPC), and sper matids (SPT). Strong immunoreactivity was detected in Sertoli cells ju st prior to the onset of the early spring spermatogenic wave coincidin g with the androgen peak. FOS protein was present in the nuclei of SPG and SPC. In SPG an exclusive nuclear localization was seen during the active spermatogenic period (February-March and September). A perinuc lear localization was observed during other months. Immunoreactivity i n Sertoli cells was also observed during the periods of active spermat ogenesis. JUN protein was localized in the cytoplasm of SPG as well as in I and II SPC and was detected in the nuclei of I and II SPC during April and October when spermatogenic waves occur. These data suggest that protooncogene activities have regulatory roles in the spermatogen esis of the lizard. (C) 1997 Academic Press.