RNA-binding protein that binds to the consensus sequence 5'-CUCUGUAUCUUGU-3' in mRNA 3'-UTRs and modulates mRNA expression and stability. Functions redundantly with puf-6 and puf-7 in oocyte formation and organization, early embryonic cell divisions, and repression of expression of glp-1 and other maternal mRNAs in late oogenesis. Localizes to perinuclear and cytoplasmic P granules. Detected in differentiating oocytes with highest levels observed in developing ooctyes in the distal portion of the proximal gonad. Expressed during a specific period of late oogenesis, from late meiotic pachytene to late diakinesis. Repressed prior to terminal oocyte differentiation. Production of viable embryos and predominantly normal oocytes with a low percentage showing misorganization. Does not affect germline development in adult hermaphrodites. Impaired repression of glp-1 and fog-1. Simultaneous knockdown of puf-5, puf-6 and puf-7 results in abnormally small oocytes, disorganization of oocyte nuclei and cells, inefficient yolk uptake by oocytes, embryonic arrest with impaired eggshell formation and cytokinesis defects, impaired repression of glp-1 in late oogenesis, and mislocalization of rme-2 to the cytoplasm instead of the plasma membrane.