Identification of a testis-specific gene (C15orf2) in the Prader-Willi syndrome region on chromosome 15.

Prader-Willi syndrome (PWS) results from the loss of paternal contributions for a 2-Mb imprinted region on the proximal long arm of human chromosome 15. Hitherto, five paternally active genes have been identified in this region (ZNF127, NDN, MAGEL2, SNURF-SNRPN, and IPW). Here we report the identification of a novel gene in the PWS critical region, which has been designated "chromosome 15 open reading frame 2" (C15orf2). C15orf2 is an intronless gene located between MAGEL2 and SNURF-SNRPN. It is associated with a CpG island, which is methylated in all tissues tested except for germ cells. C15orf2 is transcribed as a 7.5-kb mRNA and contains an open reading frame encoding a predicted 1156-amino-acid protein of unknown function. Transcription of C15orf2 occurs exclusively in the testis, and in adult testis samples, we observed biallelic expression. By zoo-blot analysis, we found related sequences in DNA from other primates, but not in nonprimate DNA. We conclude that C15orf2 may play a role in primate spermatogenesis.