DZIP1 (DAZ interacting protein 1) is also known as DZIP or DZIP2 and is a 867 amino acid protein which is expressed as three isoforms, designated DZIPb, DZIPt1 and DZIPt2. DZIP1 is localized to testis, oocytes, ovary and fetal brain, as well as in embryonic stem cells and germ cells. In testis, DZIP1 is localized to the nucleus and also shows some cytoplasmic distribution in spermatogonia. DZIP1 belongs to the C2H2-type zinc-finger protein family, and, characteristc of the C2H2-type zinc-finger protein family, DZIP1 contains one C2H2-type zinc-finger region through which it is thought to interact with DAZ, an interaction that promotes spermiogenesis. DZIP1 expression is not found in those afflicted with Sertoli cell-only syndrome (characterized by the absence of germ cells in the testis), suggesting that the lack of DZIP1 may be involved in the pathogenesis of Sertoli cell-only syndrome-induced male sterility.