Rhox Homeobox Family, Member 2 (RHOXF2)

The mouse Pem gene resides on the X chromosome and is expressed exclusively in testis, epididymis, ovary, and placenta. Due to the rapid evolution of Pem, it has been difficult to identify a human ortholog. By searching databases using the sequence encoded by exon 4 of mouse Pem as bait, followed by RT-PCR of testis RNA, Wayne et al. (2002) cloned PEPP2. The deduced 288-amino acid protein contains a glutamine-rich N terminus, a homeodomain, and a proline-rich C terminus. Northern blot analysis detected a 1.2- to 1.3-kb transcript in testis and in an erythroleukemia cell line; expression was not detected in several other tissues and cell lines.MacLean et al. (2005) identified human PEPP1 and PEPP2 as the likely orthologs of 1 or more Rhox genes, but extensive searching failed to identify any other human homeobox genes in the region syntenic to the mouse Rhox gene cluster.