CEH-28 activates egl-17 expression specifically in M4. egl- 17::gfp expression was completely lost in M4 in ceh-28 mutants, while expression in the vulva was unaffected.
CEH-28 activates egl-17 expression specifically in M4. egl- 17::gfp expression was completely lost in M4 in ceh-28 mutants, while expression in the vulva was unaffected.
In wild-type animals, strong Pdbl-1::gfp expression was observed in the M4 cell in 96% of transgenic adults. In comparison, strong Pdbl-1::gfp expression in M4 was observed in only 17% of ceh-28(cu11) adults (n=53)and 19% of ceh-28(tm1258) adults.
The distal enhancer is modular and contains multiple functionally important sequences. Enhancer DE1 predominantly activated transcription in the m3, m4, m5, and m7 pharyngeal muscles.
The M4 enhancer contains two candidate CEH-28 binding sites: one located at bp -825, which is conserved in other Caenorhabditis species, and a second at bp -738. Authors tested the effect of mutations in each of these sites on M4 enhancer activity either alone or in a double mutant. Mutation of the site at -825 led to a decrease in the intensity of GFP expression level and a moderate decrease in the frequency of animals expressing GFP, whereas mutation of the site at -738 had little effect on enhancer activity. In comparison, a double mutant affecting both of these sites had a stronger reduction in both the intensity and frequency of GFP expression in M4,