Involvement of heme in the transcriptional activation of CYPIIB1/B2 gene by phenobarbitone in rat liver—Studies with succinylacetone

Venkateswar, Venkataraman and Padmanaban, Govindarajan (1991) Involvement of heme in the transcriptional activation of CYPIIB1/B2 gene by phenobarbitone in rat liver—Studies with succinylacetone. In: Archives of Biochemistry and Biophysics, 290 (1). pp. 167-172.

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Abstract

Earlier studies in this laboratory had implicated heme to function as a positive modulator of phenobarbitonemediated activation of CYPIIB1/B2 gene transcription in rat liver. However, recent reports have indicated that succinylacetone, a specific inhibitor of δ-aminolevulinate dehydrase, does not affect this process. The present studies indicate that succinylacetone does inhibit the phenobarbitone-mediated increase in CYPIIB1/B2 mRNAs and their transcription in rat liver at early time points (45 min to 3 h), but the inhibition is not pronounced at later time points (16 h). Succinylacetone is a weaker inhibitor of heme biosynthesis than CoCl2, 3-amino-1,2,4-triazole, or thioacetamide used earlier in this laboratory. Succinylacetone induces δ-aminolevulinate synthase, whereas the other compounds depress the levels of the enzyme. There is a good correlation between the amount of freshly synthesized nuclear heme pool and the activation of CYPIIB1/B2 transcription by phenobarbitone. A model implicating a nuclear heme pool regulating the transcription of δ-aminolevulinate synthase, CYPIIB1/ B2, and heme oxygenase genes is proposed.

Item Type:	Journal Article
Publication:	Archives of Biochemistry and Biophysics
Publisher:	Elsevier science
Additional Information:	Copyright of this article belongs to Elsevier science.
Department/Centre:	Division of Biological Sciences > Biochemistry Division of Biological Sciences > Molecular Reproduction, Development & Genetics
Date Deposited:	24 Nov 2010 07:37
Last Modified:	24 Nov 2010 07:37
URI:	http://eprints.iisc.ac.in/id/eprint/33901

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