The spatial and temporal regulation of gene expression during development occurs at the level of both gene transcription and gene translation. Now,Walser and colleagues reveal that three members of the PUF family of translational repressors that regulate certain aspects of germline development in C. elegans also negatively regulate vulval development in this organism (see ). PUF proteins - socalled because the first to be identified were the Drosophila Pumilio and the C. elegans FBF proteins- bind to their target mRNAs through PUF repeat motifs. Using detailed genetic analyses, the researchers show that fbf-1 and fbf-2 act redundantly to inhibit the specification of the primary vulval cell fate,which is induced by MAPK signalling. puf-8, they report, plays a distinct role in vulval development by temporally restricting the response of vulval precursor cells to this and other patterning signals. Because PUF proteins are highly conserved, the researchers suggest that these translational repressors may fine-tune other signalling pathways during animal development.
