The remaining 11 genes for which we identified an RNAi phenotype have no previously reported function. RNAi of two of these genes caused an Unc phenotype, suggesting roles in the neuromuscular system: ceh-6 is a POU homeodomain protein, and D1081.2 encodes a MADS-box transcription factor [24,25]. Another gene, K02B12.8, produced a Him RNAi phenotype, suggesting a possible function in meiotic chromosome segregation. RNAi of D1081.8, which encodes a novel protein with a Myb-like DNA-binding domain, resulted in 100% embryonic lethality, as did, unsurprisingly, F52B5.6, which is thought to encode a ribosomal protein [26,27]. K02B12.3 resulted in sterility by RNAi; this gene encodes a WD-domain protein which is weakly similar to TUP1, a general transcriptional repressor in Saccharomyces cerevisiae [28]. Finally, T19A6.2A, which is similar to a human breast cancer autoantigen, resulted in slow growth [29]. The ability of RNAi by feeding to detect a wide range of phenotypes for these genes demonstrates its value for studying gene function in C. elegans.
