Regulation of human hsp90α gene expression

Abstract

Mammalian HSP90α and HSP90β are encoded by two individual genes. On the basis of the upstream sequences of the human hsp90α gene, GenBank accession number U25822, we have constructed CAT reporter plasmids driven by individual fragments of the hsp90α gene. We found that (1) the proximal heat shock element complex located at −96/−60 enhances hsp90α promoter expression; (2) heat shock induction depends upon the coexistence of distal heat shock element at −1031/−1022 and the proximal heat shock element complex of the hsp90α gene; (3) unlike hsp90β, downstream sequences of the transcription start site inhibit hsp90α expression. We conclude that the regulatory mechanisms for the expression of hsp90α and hsp90β genes are different.