Spermatogenesis is a complex process regulated by extracellular and intracellular factors as well as cellular interactions among interstitial cells of the testis, Sertoli cells, and germ cells. In the testis, this gene is expressed in Sertoli cells but not germ cells. However, this gene is not expressed in a patient who exhibited spermatogenic arrest at the spermatocyte stage. Spermatogenic arrest is an interruption of germ cell differentiation that may result in oligospermia or azoospermia. The proteins encoded by this gene contain plant homeodomain (PHD) finger domains, also known as leukemia associated protein (LAP) domains, believed to be involved in transcriptional regulation. Thus this protein, which localizes to the nucleus of transfected cells, has been implicated in the transcriptional regulation of spermatogenesis. Two protein isoforms are encoded by transcript variants of this gene. [provided by RefSeq, Jul 2008]