Expression of germ cell nuclear factor in mouse germ cells and sperm during postnatal period

Aim: To assess the spatial and temporal expression of germ cell nuclear factor (GCNF) in male mouse germ cells during postnatal development and in sperm before and after capacitation. Methods: The indirect immunofluorescence method with anti-GCNF antiserum was used to investigate the GCNF expression in mice at day 8, 10, 14, 17, 20, 28, 35, 70, and 420 after birth and in sperm before and after capacitation. Results: With the proceeding of spermatogenesis, GCNF was first detected in the nuclei of spermatogonia and a few early stage primary spermatocytes at day 8, which was increased gradually at day 10 to 14 inclusive. From day 17 to day 20, the GCNF was concentrated in round spermatids, while both spermatogonia and early stage primary spermatocytes became GCNF negative. From day 28 until day 420, strong GCNF expression was shown in round spermatids and pachytene spermatocytes, while spermatogonia, early primary spermatocytes and elongating spermatids were all GCNF negative. In addition, it was also found that GCNF was localized on the acrosomal cap region of spermatozoa and there was a big change in GCNF expression during capacitation, from 98 % GCNF positive before capacitation to about 20 % positive following capacitation. The localization of GCNF in caput and cauda spermatozoa was similar. Conclusion: GCNF may play important roles in spermatogenesis, capacitation and fertilization.