HSF1 functions as a transcription regulator for Dp71 expression.

Heat shock factor 1 (HSF1) is one of the most important transcriptional molecules in the heat shock process; however, HSF1 can also regulate the expression of other proteins. Dystrophin Dp71 is one of the most widely expressed isoforms of the dystrophin gene family. In our experiments, we showed for the first time that HSF1 can function as a transcriptional factor for endogenous Dp71 expression in vivo and in vitro. We demonstrated that the messenger RNA (mRNA) and protein expression of Dp71 were significantly reduced in HSF1-knockout mice compared with wild-type mice in brain, lung, liver, spleen, and kidney. Overexpression of HSF1 significantly enhanced the mRNA and protein expression of Dp71 in HeLa cells. Inhibiting the expression of HSF1 in HeLa cells significantly reduced the expression of Dp71. By use of the EMSA technique, the chromatin immunoprecipitation assay, and the luciferase reporter system, we demonstrated that HSF1 can directly bind the HSE in the Dp71 promoter region. We concluded from our data that HSF1 functions as a transcriptional regulator of Dp71 expression.