Localization of Topoisomerase 2α and β During the RatSpematogenesis Cycle

摘要

Spermatogenesis involves the processes of germ cell proliferation, meiosis, and maturation. Germ cells atdifferent spermatogenetic developmental stages exist through out the seminiferous tubules. In cross-sections ofseminiferous tubules, staging of spermatogenesis is usually performed using PAS-hematoxylin staining, however, moststudies also involve immunofluorescence analysis, which can be negatively affected by cell staining. Therefore, findingstaging markers compatible with commonly used immunofluorescence techniques could be technically advantageous. Inthis study rat testis sections were evaluated for immunofluorescence expression profiles of topoisomerase 2α andtopoisomerase 2β (Top2α and Top2β). Stage-specific patterns were seen for both proteins. Topoisomerase 2α was presentin the nuclei of the spermatocytes from spermatogenesis stages 7 to 14. Alternatively, topoisomerase 2β was present in thenuclei of elongating and condensing spermatids. It was observed initially as 2-4 small foci in spermiogenesis step 2, thenas a single focus near the nuclear membrane of round spermatids from spermiogenesis steps 3 to 8. The Top2β foci weredistinct from the chromatoid body and proximal to the Golgi apparatus, which is known to be adjacent to the acrosome.Based on these specific findings we propose that the Top2β locates to the acrosome and that Top2α and Top2βimmunofluorescence may be useful staging markers.