Expression pattern of prmt5 in adult fish and embryos of medaka, Oryzias latipes.

DNA methylation is an important biochemical epigenetic determinant of gene expression in cells and therefore actively involved in gene regulation, chromosomal conformation, and protein activity. Protein arginine methyltransferases (PRMTs) play a major role in the methylation of proteins that have an arginine residue, catalyzing both the asymmetric dimethylation of arginine (aDMA) and symmetric dimethylation of arginine (sDMA). PRMT5, a type II PRMT which catalyzes sDMA, has been shown to have a pivotal role in pole plasm assembly and germ cell development in Drosophila and also to be an associate factor of Blimp1 for germ cell development in mouse. Here, we report a homolog of prmt5 identified in medaka, Oryzias latipes, which was detected in the brain, gill, muscle, heart, liver, spleen, intestine, testis and ovary of adult fish by reverse transcriptase-PCR. The expression of prmt5 in the gonads is restricted to oocytes of the ovary, spermatogonia, and spermatocytes of testis. The prmt5 transcripts were detected as early as the one-cell stage and in all the tissues of embryos during embryogenesis. In summary, prmt5 is a maternal determinant factor of embryogenesis of medaka, possibly playing an important role in oogenesis and spermatogenesis in adult medaka.