RNA-binding protein, which may be required during spermatogenesis. Interacts with DAZ and DAZL. Predominantly cytoplasmic. Nuclear at some stages of spermatozoides development. In midpachytene spermatocytes, it is localized in both the cytoplasm and the nuclei and is clearly excluded from the sex vesicles. In round spermatids, it localizes mainly in the nuclei, whereas in elongated spermatids, it localizes to the cytoplasm. Mainly expressed in testis. Expressed at much lower level in liver, heart and brain. Also expressed in ovary. Expressed throughout testes development, in both the prenatal and postnatal periods. First expressed in midpachytene spermatocytes in stage VII tubules. Acetylation at Lys-150 is predominantly observed in the nuclear fraction, and may regulate nucleocytoplasmic transport.