Identification and Characterization of Reproductive KRAB-ZF Genes in Mice

The mammalian genome contains numerous genes encoding transcription factors that contain Krüppel-associated box (KRAB) and C2H2-type zinc finger (ZF) motifs (KRAB-ZF). In the present study, we identified KRAB-ZF genes expressed in the mouse testis or ovary, and selected three genes that exhibit gonad-specific or gonad-predominant expression. In vitro analyses showed that these gonadal KRAB-ZF proteins are localized in cell nuclei and are able to repress transcriptional activity. We further analyzed one of the gonad-specific reproductive genes, Zfp819, and found that it is expressed exclusively in spermatogenic cells. Overexpression of Zfp819 suppressed cell proliferation and induced apoptosis. Microarray analysis of Zfp819-overexpressing cells allowed us to identify numerous, potential target genes. A number of the down-regulated genes were found to show gene expression levels inversely correlated with Zfp819 during spermatogenesis. Some of the down-regulated genes were previously reported to play significant roles in spermatogenesis and apoptosis. Collectively, our study provides the first comprehensive information regarding the expression of reproductive KRAB-ZF genes in mice and reveals potential functions of Zfp819.