Identification of a new transcript specifically expressed in mouse spermatocytes: mmrp2

In an effort to examine the molecular basis of gametogenesis, we screened Riken cDNA database and the clone 4930481F22 that is expressed preponderantly in mouse testis was identified. In the course of the research, a new isoform of 4930481F22 clone was found, isolated from mouse testis and sequenced. It only lacks the 7th exon of 4930481F22 transcript. The new isoform only has 837 bp and encodes a putative 28.4 kDa protein. We investigated the expression pattern at the mRNA level by RT-PCR and in situ hybridization in testis. The new isoform was only expressed in the gonad, where it began to be detected at day 8 after birth. In situ hybridization proved that the new isoform mostly expressed in spermatocytes. The structure of the predicted protein and the expression pattern of the mRNA suggest that the new isoform could have an important role in meiosis. We temporarily named it mmrp 2 (Mouse Meiosis Related Protein 2).