Linked Life Data

7726576

Source:http://linkedlifedata.com/resource/pubmed/id/7726576

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1995-5-19
pubmed:abstractText
The P450/6 beta A (CYP3A2) gene encoding a testosterone 6 beta-hydroxylase is expressed predominantly in liver and induced by the treatment of rats with various compounds. To understand the mechanism of the basal transcriptional activation of the CYP3A2 gene, the cis-acting elements in the proximal promoter region (-165 to -73) of the CYP3A2 gene were identified in this study. Nuclear extract from rat livers interacted with three sites, 6 beta A-A (-106 to -87), 6 beta A-B (-140 to -119) and 6 beta A-C (-163 to -145). These sites were detectable by DNase I footprinting and gel mobility shift assays and found to share nucleotide sequence similarity with each other (T(A/C)(A/C)N(A/G)AAG(G/T)(C/T)CA). Direct repeats of AGTTCA (-134 to -120) and AG(G/C)TCA (-162 to -148) are also detected in 6 beta A-B and 6 beta A-C sites, respectively. To elucidate the relationship of these sites with basal transcriptional activation of the CYP3A2 gene, varying lengths of the proximal promoter region (-164 to +41) fused to a CAT reporter gene were transfected in human hepatoma (HepG2) and mouse adrenal tumor (Y-1) cells. The relative level of CAT activity in HepG2 cells was slightly increased by the deletion of the 5'-portion from -164 to -111 bp, but was reduced to 14% of the control (the construct including from -110 to +41) by the deletion from -110 to -81 including the 6 beta A-A site. On the other hand, these deletions have no clear effect on the level of the activity in Y-1 cells. Substitution mutations at two nucleotides in the 6 beta A-A site resulted in the reduction of CAT activity in HepG2 cells to 12% of the activity in the wild-type construct. The interaction of an oligonucleotide corresponding to the 6 beta A-A site (-106 to -87) with liver nuclear factors was completely inhibited by the addition of a typical oligonucleotide for hepatocyte nuclear factor-4 (HNF-4) binding site (F. M. Sladek, W. Zhong, E. Lai, and J. E. Darnell, Jr., 1990, Genes Dev. 4, 2353-2365) but not of oligonucleotides corresponding to 6 beta A-B or 6 beta A-C sites. These results suggest an essential role of the binding of HNF-4 and/or HNF-4-related nuclear factors to the 6 beta A-A site on the basal transcriptional activation of the CYP3A2 gene in liver cells.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0003-9861
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
318
pubmed:geneSymbol
CYP3A2
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
71-9
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Transcriptional elements directing a liver-specific expression of P450/6 beta A (CYP3A2) gene-encoding testosterone 6 beta-hydroxylase.
pubmed:affiliation
Department of Pharmacology, School of Medicine, Keio University, Tokyo, Japan.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't