Regulation of human heme oxygenase-1 gene expression under thermal stress

Shoji Okinaga, Kazuhiro Takahashi, Kazuhisa Takeda, Miki Yoshizawa, Hiroyoshi Fujita, Hidetada Sasaki, Shigeki Shibahara

Research output: Contribution to journalArticlepeer-review

113 Citations (Scopus)


Heme oxygenase-1 is an essential enzyme in heme catabolism, and its human gene promoter contains a putative heat shock element (HHO-HSE). This study was designed to analyze the regulation of human heme oxygenase-1 gene expression under thermal stress. The amounts of heme oxygenase-1 protein were not increased by heat shock (incubation at 42°C) in human alveolar macrophages and in a human erythroblastic cell line, YN-1-0-A, whereas heat shock protein 70 (HSP70) was noticeably induced. However, heat shock factor does bind in vitro to HHO-HSE and the synthetic HHO-HSE by itself is sufficient to confer the increase in the transient expression of a reporter gene upon heat shock. The deletion of the sequence, located downstream from HHO-HSE, resulted in the activation of a reporter gene by heat shock. These results suggest that HHO-HSE is potentially functional but is repressed in vivo. Interestingly, heat shock abolished the remarkable increase in the levels of heme oxygenase-1 mRNA in YN-1-0-A cells treated with hemin or cadmium, in which HSP70 mRNA was noticeably induced. Furthermore, transient expression assays showed that heat shock inhibits the cadmium-mediated activation of the heme oxygenase-1 promoter, whereas the HSP70 gene promoter was activated upon heat shock. Such regulation of heme oxygenase-1 under thermal stress may be of physiologic significance in erythroid cells.

Original languageEnglish
Pages (from-to)5074-5084
Number of pages11
Issue number12
Publication statusPublished - 1996 Jun 15


Dive into the research topics of 'Regulation of human heme oxygenase-1 gene expression under thermal stress'. Together they form a unique fingerprint.

Cite this