Gonadotropin-regulated testicular helicase (GRTH/DDX25): a master post-transcriptional regulator of spermatogenesis.

Gonadotropin-regulated testicular RNA helicase (GRTH/DDX25) is a multifunctional protein that is essential for the completion of spermatogenesis. Male mice lacking GRTH are sterile due to the lack of sperm caused by failure of spermatids to elongate. GRTH is a transport protein and as a component of mRNP particles is involved in gene-specific mRNA export (several spermatogenic genes and also its own message) from nuclear to cytoplasmic sites (i.e., chromatoid bodies–mRNA storage/processing and polyribosomes/translation) during spermatogenesis. GRTH is necessary to maintain the structure and function of the chromatoid body in round spermatids. In polyribosomes, GRTH regulates the translation of mRNAs encoding spermatogenic factors. In addition, GRTH prevents germ cell apoptosis. A missense mutation of the GRTH/DDX25 gene associated with the absence of phosphorylated GRTH cytoplasmic species in 5.8% of infertile patients with azoospermia indicates the relevance of GRTH as a post-transcriptional regulator of spermatogenesis