Fas Binding Factor 1 (FBF1)

FBF1 encodes an RNA-binding protein that is one of 12 C. elegans members of the PUF family (Pumilio and FBF) of translational regulators; FBF-1 also plays a role in regulating adaptation in the AWC chemosensory neuron by binding and enhancing translation of the egl-4 mRNA; in maintaining germline stem cells, the FBF proteins, acting through NOS-3, negatively regulate the activity of gld-1 mRNA, which encodes a translational repressor required for meiotic entry; in regulating the sperm-to-oocyte switch, the FBFs act downstream of GLD-3 to negatively regulate the activity of fem-3 mRNA, which encodes a novel protein required for germline sex determination; consistent with their role in germline development, FBF-1 and FBF-2 are expressed in the germline cytoplasm, becoming enriched in the mitotic region during the L4 larval and adult stages.