Maternal RNA-binding protein that is required for germ cells proliferation and self-renewal. Acts by forming a complex with pum and brat that regulates translation and mRNA stability. The complex binds to the Nanos Response Element (NRE), a 16 bp sequence in the hb mRNA 3'-UTR and prevents its translation. Controls posterior development. Rescuing factor for the abdominal defect of posterior group mutants. The other posterior group genes are not required for nanos function but rather play a role in localization or distribution of nanos protein. Interacts with pum and brat. Acts via the formation of a quaternary complex composed of pum, nos, brat and the 3'-UTR mRNA of hb. Interacts with cup. Binds RNA with no specificity. Posterior part of the embryo. While the transcript is present throughout the embryo, nos translation is controlled by smg, and the protein is found in pole plasm and pole cells. Expressed maternally. Present during oogenesis and early stages of embryogenesis. The Nanos-type zinc finger is composed of two C2HC motifs, each motif binding one molecule of zinc. The presence of the zinc molecules is essential for the translation repression activity of the protein. Belongs to the nanos family.