Linked Life Data

12573485

Source:http://linkedlifedata.com/resource/pubmed/id/12573485

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2003-2-7
pubmed:abstractText
Phenobarbital (PB) responsiveness of CYP2B genes has been shown to be mediated by a PB responsive unit (PBRU). The core of the PBRU contains two nuclear receptor sites, NR-1 and NR-2, and a nuclear factor-1 (NF 1) binding site, which are required for PB responsiveness, but the importance of sequences flanking the core is not clear. We have used intravenous administration of plasmid DNA in the tail veins of mice to transfect hepatocytes in vivo and analyze sequence requirements for PB induction. In this assay PB treatment increased transactivation by the Cyp2b10 PBRU about 100-fold, which is similar to the increase in the expression of the endogenous gene while the Cyp2b9 PBRU was unresponsive. Analysis of chimeras of the two PBRUs and deletion mutants of the Cyp2b10 PBRU indicated that the core region containing the NR-1, NR-2 and NF-1 core sites is not sufficient for PB responsiveness. Additional sequence at the 3' side of the core sequence, which included a previously defined accessory factor-1 (AF-1) site, partially restored responsiveness. This region contained a binding site for NF-1 only in Cyp2b10 and not in Cyp2b9, but the intact site was not required for PB responsiveness. Purified constitutive androstane receptor (CAR)/retinoid X receptor (RXR) bound to the core NR-1 and NR-2 sites and to a third NR-3 site to the 5' side of the core in Cyp2b10. No binding of CAR/RXR to the Cyp2b9 PBRU was observed. These results indicate that changes in the NR sites which eliminate CAR/RXR binding are sufficient for the non-responsiveness to PB of Cyp2b9, but changes in sequences flanking the core independently eliminate PB responsiveness. The results demonstrate the advantages of transfection of mouse hepatocytes in vivo by tail vein injection of DNA as a method for transcriptional analysis of genes in vivo and show that sequences flanking the core region of the PBRU are required for PB induction in vivo.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
1619
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
254-62
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Transcriptional analysis in vivo of the hepatic genes, Cyp2b9 and Cyp2b10, by intravenous administration of plasmid DNA in mice.
pubmed:affiliation
Department of Molecular and Integrative Physiology and College of Medicine at Urbana-Champaign, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.