Characterization of EPABP [embryonic poly(a) binding protein] and pabpc1 [poly(A) binding protein, cytoplasmic 1] expression in testis

ePABP (embryonic poly(A) binding protein), functions in translational regulation of the maternal mRNAs stored during oocyte development. In the early embryos after embryonic genome activation and in the somatic cells, translational control of the mRNAs is carried out by PABPC1 (poly(A) binding protein, cytoplasmic 1). In mammalians, transcription ceases at midspermiogenesis stage of spermatogenesis. In this study, we aimed to characterize expressional levels and cellular localizations of the ePABP and PABPC1 mRNAs in the postnatal mouse testes and isolated spermatogenic cells. For this purpose, testes were obtained from C57BL/6male mice at different ages of postnatal development (D6, D8, D16, D20, D29, D32 and D88). ePABP and PABPC1 gene expression in the dissected testes and isolated spermatogenic cells were detected by qRT-PCR. Also, cellular localization of the ePABP mRNA by using RNA in situ hybridization was revealed in the postnatal mouse testes. As a result of this study, ePABP gene expression was found to be very low levels at D6, D8, D16 and D20 testes; it began to increase at D29 and reached the highest level at D32. While PABPC1 expression at D6 and D8 testes was observed at low levels, it started to increase at D16 and reached the highest level at D32. ePABP gene expression in the spermatogonia, spermatocytes and round spermatids derived from D32 testis was determined higher than other days. Similar to ePABP findings, PABPC1 expression in the spermatogonia, spermatocytes and round spermatids was higher than other days. It was found that ePABP mRNA was localized to only in the seminiferous tubules and exhibited cytoplasmic localizations in the spermatogenic cells of the seminiferous tubules. Also, ePABP mRNA was demonstrated to be higher particularly in the spermatogonia at D29, D32 and D88 testes. These results show that ePABP and PABPC1 genes may function in translational control of the mRNAs transcribed during mouse spermatogenesis.