In:
Endocrinology, The Endocrine Society, Vol. 141, No. 10 ( 2000-10-01), p. 3587-3594
Kurzfassung:
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.
Materialart:
Online-Ressource
ISSN:
0013-7227
,
1945-7170
DOI:
10.1210/endo.141.10.7689
Sprache:
Englisch
Verlag:
The Endocrine Society
Publikationsdatum:
2000
ZDB Id:
2011695-0
