UNC Homeobox Protein (UNCX)

The T-box transcription factor mab-9 has been shown to be required for the correct fate of the male-specific blast cells B and F, normal posterior hypodermal morphogenesis, and for the correct axon migration of motor neurons that project circumferential commissures to dorsal muscles. An RNAi screen designed to identify upstream transcriptional regulators of mab-9 showed that silencing of unc-4increases mab-9::gfp expression in the nervous system, specifically in posterior DA motor neurons. Over-expression of unc-4 from a heat-shock promoter has the opposite effect, causing repression of mab-9 in various cells. These results identify mab-9 as a novel target of the UNC-4/UNC-37 repressor complex in motor neurons, and suggest that mis-expression of mab-9 may contribute to the neuronal wiring defects in unc-4 and unc-37 mutants.