Jurkat Cells Hsp90 Gene Expression And Regulation Of The Level Of Chromatin Research

Heat shock protein 90 (HSP90) is one of the most popular proteins in eukaryotic cell. It can refold the misfolded proteins produced during heat shock and facilitate the degradation of denatured proteins. HSP90 also helps the maturation, transportation and activity regulation of some hormone receptors, transcription factors, kinases and nitrogen monoxide synthase. Thus HSP90 plays a wide and important role in the cells, and its expression regulation study is of physical importance.Eukaryotic genome is packaged into chromatin in the nucleus. There must be some change at chromatin level during gene expression regulation. Chromatin Immunoprecipitation (ChIP) assay was developed in recent years to detect protein factors that bind to chromatin. By using this mothod, the binding of p53, CREB, c-Jun, p300 and mSin3A to hsp90β gene promoter under normal, heat shock and UV conditions was analysed. Later, the impact of chromatin remoleling complex, SWI/SNF, to the regulation of hsp90 gene was investigated by transient transfection and RT-PCR method. 1. The binding of transcription factors to hsp90β promoter under differentenvironmental conditions (1). The binding of p53 to hsp90β promoterDNA sequence analysis revealed that there is a p53 binding site on the promoter of hsp90β gene. ChIP assay proved that p53 bound to the site in untreated cells, heat shocked cells and UV irradiated cells. Previous results of our lab indicated that heat shock induced the expression of HSP90β, while UV repressed that. So, p53 may recruit different complexes to activate and repress the expression of hsp90β gene. (2). The binding of CREB and c-Jun to hsp90β promoterChIP assay proved that CREB bound to CRE and AP-1 sites both in untreated cells and PHA-activated cells. While phospho-c-Jun bound to the two sites only in PHA-activated cells. These results indicated that CREB played roles for the constitutive and PHA-activated expression of hsp90β gene, but c-Jun functioned mainly in PHA-activated expression. (3). The binding of p300 and mSin3A to hsp90β promoter...