Plays a role in the maintenance of the undifferentiated state of germ cells regulating the spermatogonia cell cycle and inducing a prolonged transit in G1 phase. Affects cell proliferation probably by repressing translation of specific mRNAs. Maintains the germ cell lineage by suppressing both Bax-dependent and -independent apoptotic pathways. Essential in the early stage embryo to protect the migrating primordial germ cells (PGCs) from apoptosis. Binds mRNA from germ cells. Interacts with PUM2. Co-localizes with PUM2, EIF2S1 and TIAL1 in the stress granules. Co-localizes with DCP1A in the P-body. Expressed in undifferentiated spermatogonial cells. Found in the male and female gonads of early embryo and, after birth, it is found only in the testis. Expressed in primordial germ cells (PGCs) until 14.5 dpc in male gonad and until 13.5 dpc in female gonad; after this age its expression disappears and then it is found after birth only in male germ cells. The Nanos-type zinc finger is composed of two C2HC motifs, each motif binding one molecule of zinc. It is essential for the translation repression activity of the protein. Belongs to the nanos family.