RNA-binding protein that is required for primordial germ cell (PGC) differentiation and indirectly necessary for the migration of PGCs through the endoderm. May promote meiotic cell division during spermatogenesis. Shows a preference for G- and U-rich RNAs and probably binds the 3'-UTR of target mRNAs. Stimulates the initiation of translation of mRNAs through the recruitment of poly(A)-binding proteins (PABPs) (By similarity). Interacts with the C-terminus of pabp1 and with epabp. Prior to oocyte maturation, found in a complex with epabp and pum2 proteins and spdy1 mRNA; pum2 dissociates from the complex during maturation (By similarity). Germ-line specific; expressed in adult testis and ovary. Localized specifically to the oocyte and embryonic germ plasm and to migrating primordial germ cells (PGCs). Expressed constantly during oogenesis from the previtellogenic (stage I) oocyte to the mature (stage VI) oocyte, and after fertilization until the early tadpole stage. Belongs to the RRM DAZ family.