SMYD3-NY, a novel SMYD3 mRNA transcript variant, may have a role in human spermatogenesis.

Identification of genes specifically expressed in adult and fetal testis is important to further our understanding of testis development and function. In this study, a novel SMYD3 transcript variant, termed SMYD3-NY (GenBank Accession No. AY186742), was identified by hybridization of adult and fetal human testis cDNA probes with a human cDNA microarray. SMYD3-NY transcript was expressed at 2.3-fold higher levels in adult human testis than in fetal testis, with a low expression level in human spermatozoa. Bioinformatical analysis showed that SMYD3-NY protein has the SET domain that is involved in histone methyltransferase (HTMase) activity. Southern blotting showed that SMYD3-NY is distributed in several tissues, including testis. In summary, SMYD3-NY is a novel transcript variant of the SMYD3 gene, and SMYD3-NY protein may influence transcriptional regulation during spermatogenesis via HTMase activity.