The Functional Study Of Congenital Cataract-causing Gene Heat Shock Factor 4(HSF4)

HSF4 belongs to the family of heat shock transcription factors (HSFs) that can bind to the heat shock element (HSE) and activate the transcription of downstream target genes in response to different stresses. HSF4b is the major HSF4 protein in ocular lens. mutations in HSF4b have been reported related with autosomal dominant and autosomal recessive cataract. To date, there are only a few of published papers about the function of HSF4b in lens. Meantime, the responsible mechanisms of its mutants causing cataract is not clear.Our lab got whole length cDNA of HSF4b from human lens epithelial cell RNA by RT-PCR. I constructed the vetor pEGFP-N1-HSF4b, and then transfected it into the HLE cell. subcellular localization of HSF4b was carried out by using this fluorescent protein vector to transfect or co-transfect HLE cell. Interesting, the subcellular localization of wild type HSF4b showed it was accumulated into some small points and distributed uniformly in the nucleus, which was similar to a splicing factor SC35. We hypothesized whether HSF4b take part in the splicing complex, and whether it had a splicing factor function, though people thought it was a transcription factor generally. But I found they did not co-location after co-transfecting them into the HLE. After SC35, I chose coilin and gama-H2AX as my new targets. They are common biomakers of cajal body and DNA Double-strand Breaks .But ICC (immunocytochemistry) experimental show that, they do not co-location with HSF4b, too. HSF4b may be the component of a new nuclear domain. I will try other biomakers of nuclear domains to do the co-location experimental. If they do not co-location with HSF4b, I will try other way to find out the HSF4b function in the cells and lens.