Linked Life Data

9278450

Source:http://linkedlifedata.com/resource/pubmed/id/9278450

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
36
pubmed:dateCreated
1997-10-2
pubmed:databankReference
pubmed:abstractText
Methionine adenosyltransferase is a ubiquitous enzyme that catalyzes the only known route of biosynthesis of S-adenosylmethionine, the major methyl group donor in cell metabolism. In mammals, two different methionine adenosyltransferases exist: one is confined to the liver, and the other one is distributed in extrahepatic tissues. In the present study, we report the cloning of the 5'-flanking region of liver-specific methionine adenosyltransferase gene from rat. Two closely spaced sites for transcriptional initiation were identified by primer extension analysis. The major transcription start site was determined to be 29 nucleotides downstream from the putative TATA box. Transient transfection assays of constructs containing sequentially deleted 5'-flanking sequences fused to the luciferase gene showed that rat hepatic methionine adenosyltransferase promoter was able to efficiently drive reporter expression not only in liver-type cells (rat hepatoma H35 cells and human hepatoblastoma HepG2 cells) but also in Chinese hamster ovary cells. Two regions spanning nucleotides -1251 to -958 and -197 to +65 were found to be crucial for the promoter efficiency. The distal upstream region contains elements that positively regulate promoter activity in H35 and HepG2 cells but are ineffective in Chinese hamster ovary cells. Eight protein binding sites were characterized in both regions by DNase I footprinting analysis. Two of these elements, sites A and B, located in the distal region, were found to be essential for the regulation of promoter activity. Electrophoretic mobility shift assays and competition experiments showed that site A is recognized by an NF1 protein. Site B was able to interact with a member of HNF-3 family when nuclear extracts from rat liver and H35 cells were used in the in vitro assay, but an additional binding activity to an NHF1-like protein was obtained with the hepatoma cell extracts. It is suggested that this differential binding can contribute to the cell specificity of promoter function.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
272
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
22875-83
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Characterization of rat liver-specific methionine adenosyltransferase gene promoter. Role of distal upstream cis-acting elements in the regulation of the transcriptional activity.
pubmed:affiliation
Instituto de Investigaciones Biomédicas, C.S.I.C. Arturo Duperier 4, 28029 Madrid, Spain.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't