Published in: Biochimica et Biophysica Acta, Gene Structure And Expression, vol. 1490, no.3, pp. 348-354 (February 29, 2000):

"Transcriptional Regulation Involving the Intronic Heat Shock Element of the Rat hsp27 Gene."

Lyndon F. Cooper ^{a, b} , Katsumi Uoshima ^c, and Zhanying Guo ^b.

^a Department of Biochemistry and Biophysics, School of Medicine, 308 Brauer Hall, CB #7450, University of North Carolina, , Chapel Hill, NC 27599, USA
^b Department of Prosthodontics, School of Dentistry, 308 Brauer Hall, CB #7450, University of North Carolina, , Chapel Hill, NC 27599, USA,
^c Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, , Tokyo 113, Japan

While sequencing the first intron of the rat heat shock protein 27 gene (hsp27), we identified a consensus heat shock regulatory element (HSE). This intronic HSE (i-HSE) is conserved among mammalian hsp27 genes. The aim of this study was to investigate possible effects of this intronic HSE (i-HSE) on transcription from the rat hsp27 promoter. Gel mobility shift assays indicated that the i-HSE bound heat shock transcription factor 1 (HSF1) in a manner equivalent to that of HSE present in hsp27 promoter (p-HSE). The effect of i-HSE on transcription from the hsp27 promoter was evaluated using reporter constructs transiently transfected in the osteosarcoma cell line ROS17/2.8. When inserted 5' to a 145 bp fragment of the hsp27 promoter not containing p-HSE, a 215 bp fragment of hsp27 intron 1 containing i-HSE enhanced CAT activity and conferred heat shock-inducible activity to the construct. This intronic fragment containing i-HSE also enhanced CAT activity in either normal or heat-shocked culture conditions when inserted 3' to the CAT open reading frame. However, in chimeric reporter constructs with a 273 bp hsp27 promoter containing p-HSE directly 5' to CAT reporter, and with a 215 bp fragment containing i-HSE inserted 3' to the CAT open reading frame, transcription from hsp27 promoter was reduced under normal and heat-stressed culture conditions. Mutation of the i-HSE reversed this effect. Further study is required to define the mechanism by which the i-HSE-containing region of the hsp27 promoter may mediate negative regulation of hsp27 transcription.

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