| Cells produce a group of conserved proteins called heat shock proteins (HSPs) when exposed to elevated temperature . HSPs have been found for 20 years and can be grouped into several classes depending upon their approximate molecular weights and degrees of homology: HSP110, HSP90, HSP70, HSP60, HSP40 small HSPs and ubiquitins. HSP90 family is one of the most important families. HSP90 have been recognized as cytoplasmic proteins that are abundant in the absence of stress and induced to higher levels of synthesis by elevated temperatures or other stressful conditions. As a molecular chaperone, in many organisms tissues and ce(?), these proteins have been found in association with several different regulatory and structural proteins, such as several viral oncogene products that posses tyrosine kinase activity, eIF-2α, steroid receptors and casein kinase II. HSP90 plays an important role in cell growth, development and differentiation as well as protection of cells from various kinds of injury when they were exposed to stressful conditions. The study of its expression regulation mechanism will not only lead to a better understanding of its biological functions, but also can establish a good model for studying regulation mechanism of induced eukaryotic gene expression.Heat shock protein 90 genes (hsp90) were found to be one of the few classes of h(?)ps which contain introns. Two copies of human hsp90 that differ slightly in molecular mass have been identified: hsp90α and hsp90β, the mRNAs of which are referred to 2.95 kb and 2.7kb. We have been studying their induced expression mechanism since 1985. Our previous works shown the expression of human hsp90α and hsp90β can be induced by the dual induction of heat shock or PHA activation. Their regulation depend mainly on transcription and shows different expression kinetics upon the two inducers. We found that three typical HSEs located in the first intron of hsp90β are the mainly cis-element participants in heat...
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