Modification of poly(A) tail length constitutes the main posttranscriptional mechanism by which gene expression is regulated during spermatogenesis. Embryonic poly(A)-binding protein (EPAB) and somatic cytoplasmic poly(A)-binding protein (PABPC1) are the 2 key proteins implicated in this pathway. In this study we characterized the temporal and spatial expression of Epab and Pabpc1 in immature (D6-D32) and mature (D88) mouse testis and in isolated spermatogenic cells. Both Epab and Pabpc1 expression increased during early postnatal life and reached their peak at D32 testis. This was due to an increase in both spermatogonia (SG) and spermatocytes. In the mature testis, the highest levels of Epab were detected in SG, followed by round spermatids (RSs), while the most prominent Pabpc1 expression was detected in spermatocytes and RSs. Our findings suggest that PABPC1 may play a role in translational regulation of gene expression by cytoplasmic polyadenylation, which occurs in spermatocytes, while both EPAB and PABPC1 may help stabilize stored polyadenylated messenger RNAs in RSs.
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