Dominant role of the second heat shock element in expression of the HSP70-1 gene in rat liver after whole body hyperthermia.
We investigated the regulatory expression of the HSP70-1 gene in rat liver after whole body hyperthermia (rectal temperature of 42 degrees C for 30 min). After heat treatment, HSP70-1 mRNA showed a peak at 1 h, and its protein product began to increase at 3 h. Under these conditions, we identified cis-acting elements involved in the regulatory expression of the HSP70-1 gene by in vivo genomic footprinting. We observed that the second heat shock element (HSE-2; -201 to -178) was clearly protected from methylation by dimethyl sulfate in parallel with the increase in HSP70-1 mRNA. On the contrary, the most proximal HSE-1 (-120 to -101) was protected only slightly. Furthermore, the flanking regions of HSE-2, that is, an NF-kappa B-like element on the upstream side and a GC box on the down-stream side were also protected simultaneously in accordance with the induced expression of the HSP70-1 gene. Gel mobility shift assays with nuclear extracts from rat liver at 30 min after heat treatment showed maximal DNA binding activity equally with oligonucleotides containing HSE-1 and HSE-2, respectively, and also demonstrated the participation of heat shock factor-1 (HSF1) in both cases. These results suggest that, in addition to HSF1, other regulatory factors might be involved in the dominant protection of HSE-2 in the promoter of the HSP70-1 gene in rat liver after whole body hyperthermia.
Konishi
T
T
Department of Biochemistry, University of Occupational and Environmental Health, Yahatanishi-ku, Kitakyushu.
Nomoto
M
M
Shimizu
K
K
Abe
T
T
Itoh
H
H
D000818:Animals; D001483:Base Sequence; D001833:Body Temperature Regulation / Q000502:physiology*; D018983:DNA Footprinting; D005786:Gene Expression Regulation / Q000502:physiology*; D005809:Genes, Regulator; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics*; D008099:Liver / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D051381:Rats; D017207:Rats, Sprague-Dawley
D018840:HSP70 Heat-Shock Proteins