Transcriptional regulation of human 11β-hydroxylase (hCYP11B1)

Xiao Li Wang, Mary Bassett, Yin Zhang, Yin Su, Colin Clyne, Perrin C. White, William E. Rainey

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65 Scopus citations

Abstract

Steroid 11β-hydroxylase is a mitochondrial enzyme that catalyzes the conversion of deoxycortisol to cortisol. The gene encoding human 11β-hydroxylase (hCYP11B1) is expressed in the adrenal cortex under the control of circulating levels of ACTH. The current study was undertaken to define the cis-regulatory elements and transacting factors that regulate hCYP11B1 transcription. The hCYP11B1 5'-flanking DNA was studied using transient transfection of luciferase reporter constructs in NCI-H295R human adrenocortical cells. A cAMP analogue ((Bu)2cAMP) increased expression of a construct containing -1102 bp of hCYP11B1 5'-flanking DNA (pB1-1102). An element at position -71/-64 (TGACGTGA, previously termed Ad1) resembling a consensus cAMP response element (CRE) was required for maximal induction by cAMP. The Ad1 element bound several transcriptional factors in electrophoretic mobility shift assays, including CRE-binding protein, activating transcription factor-1 (ATF-1), and ATF-2, but only the ATF-2 complex migrated similarly to a complex seen using H295R nuclear extract. In addition, Western analysis of H295R and adrenal lysates demonstrated expression of high levels of ATF-2 and ATF-1. CRE-binding protein levels varied among the strains of H295R cells tested. Transcription of CYP11B1 also appeared to be regulated by steroidogenic factor-1 (SF-1). Luciferase reporter gene activity was increased after cotransfection with expression vectors containing SF-1. An element in hCYP11B1 at positions -242/-234 (CCAAGGCTC), previously termed Ad4, was required for maximal induction by SF-1 and was found to bind SF-1 in electrophoretic mobility shift assays. The key role for SF-1 in hCYP11B1 transcription is in contrast to its lack of an effect on expression of the hCYP11B2 (aldosterone synthase) isozyme. The differential effects of SF-1 on transcription of hCYP11B1 and hCYP11B2 may be one of the mechanisms controlling differential expression of these isozymes within the zonae fasciculata and glomerulosa of the human adrenal cortex.

Original languageEnglish (US)
Pages (from-to)3587-3594
Number of pages8
JournalEndocrinology
Volume141
Issue number10
DOIs
StatePublished - 2000

ASJC Scopus subject areas

  • Endocrinology

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    Wang, X. L., Bassett, M., Zhang, Y., Su, Y., Clyne, C., White, P. C., & Rainey, W. E. (2000). Transcriptional regulation of human 11β-hydroxylase (hCYP11B1). Endocrinology, 141(10), 3587-3594. https://doi.org/10.1210/endo.141.10.7689