Nanos Homolog 1 (NANOS1)

The deduced 292-amino acid protein has a calculated molecular mass of 32 kD. The C terminus contains a conserved RNA-binding domain that consist of 2 zinc fingers of about 52 amino acids. The NOS1 transcript has a long 3-prime untranslated region. Database analysis detected homologous proteins in several vertebrate and invertebrate species, and the zinc finger region of NANOS1 shares 62% identity with the zinc finger region of Drosophila Nanos. Northern blot analysis detected a 2.0-kb transcript expressed exclusively in testis. RT-PCR also detected expression in embryonic stem cells and in fetal testis and fetal ovary. Immunohistochemical localization of NOS1 in adult testis detected abundant expression in spermatogonia, with strongest staining in the perinuclear cytoplasm. Like PUM2, NOS1 was expressed during meiosis in spermatocytes.