Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human heme oxygenase is induced by its substrate heme, but not induced by heat shock [Yoshida et al. (1988) Eur. J. Biochem. 171, 457-461]. In order to study the molecular mechanisms of heme-mediated induction of human heme oxygenase, we have isolated and characterized the genomic clones for heme oxygenase. The human heme oxygenase gene (HO gene) is about 14 kb long and organized into five exons. The transcription initiation site was identified by S1 nuclease mapping and primer-extension analyses. Using HeLa whole cell extracts, we confirmed that the transcription of the cloned HO gene is initiated accurately at the assigned initiation site. In its 5'-flanking region, a potential heat-shock element (HSE) is present 367 bp upstream from the initiation site, although, in contrast to rat heme oxygenase, human enzyme is not induced by heat shock. We therefore analyzed the effects of heat shock on the transient expression of chimeric fusion genes harboring the promoter of the human HO gene ligated to the Escherichia coli gene gpt in mouse amelanotic melanoma cells. The 5'-flanking region of the human HO gene bearing a potential HSE failed to confer the heat-inducibility of gpt RNA production, suggesting that the HSE of the human HO gene is not functional.
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PMID:Structural organization of the human heme oxygenase gene and the function of its promoter. 253 23

Heme oxygenase, an essential enzyme of heme catabolism, is inducible by its substrate heme, by heavy metals, and by various other substances. To study the molecular mechanisms of the induction of heme oxygenase, we isolated the heme oxygenase gene from a rat genomic DNA library using cloned cDNA as hybridization probes and determined its complete nucleotide sequence. The gene is composed of 6830 nucleotides, and is organized in four introns and five exons. The transcription initiation site was identified by S1 nuclease mapping analysis. Using HeLa cell lysate, we confirmed that the transcription of cloned heme oxygenase gene is initiated accurately at the assigned initiation site. In the 5'-flanking region of the heme oxygenase gene, we found several potential binding sites for different transcription factors: a transcription factor Sp1, a positive regulator for the control of amino acid synthesis (GCN4), a heat shock transcription factor, and a metal-dependent transcription factor. Furthermore, the intron 1 contains the sequence that shows about 65% homology to that of the neuronal identifier sequence, a possible enhancer element.
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PMID:Nucleotide sequence and organization of the rat heme oxygenase gene. 303 76