Mammalian spermatozoal mRNAs: tools for the functional analysis of male gametes

Mammalian spermatogenesis reflects a dynamic partnership between somatic genes which display altered expression patterns within the testes and germ cell specific genes expressed solely during male gametogenesis. Among the latter include the haploid-specific transition proteins and protamines which facilitate the molecular restructuring of the chromatin during the terminal differentiation of the spermatid nucleus. Previously, we have shown that the human protamines PRM1, PRM2 and transition protein TNP2 transcripts persist in mature spermatozoa subsequent to their functional role during spermiogenesis. We now demonstrate the conserved presence of these same spermatozoal mRNAs in mouse. While the basis for the persistence of these haploid-specific transcripts remains poorly defined, the results presented firmly establish that the presence of mRNA in mammalian spermatozoa is a general phenomenon. The potential use of these transcripts as a tool for investigating molecular pathologies is discussed.