Linked Life Data

8076631

Source:http://linkedlifedata.com/resource/pubmed/id/8076631

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1994-10-6
pubmed:abstractText
The binding of transcription factor AP-1 and vitamin D receptor (VDR) to the composite AP-1 plus vitamin-D-responsive promoter region (AP-1 + VDRE) of the human osteocalcin gene was characterized in osteocalcin-producing (MG-63) and non-producing (U2-Os, SaOs-2) human osteosarcoma cell lines. In mobility-shift assays with AP-1 + VDRE, AP-1, and VDRE probes and nuclear extracts from these cells, one AP-1-specific and two VDR-specific (fast and slow mobility) interactions were observed. Characterization of the complexes indicated that AP-1 and VDR do not bind simultaneously to the AP-1 + VDRE oligonucleotide. Intensity of the complexes was greatly influenced by cell density: in MG-63 and SaOs-2 cells, AP-1 binding was strong during the proliferative period disappearing at confluency whereas, in U2-Os cells, AP-1 binding was prominent also at the confluent stage. Furthermore, MG-63 cells possessed the faster migrating VDR complex at all stages of confluency whereas, in U2-Os and SaOs-2 cells, it was very weak or absent. There were no detectable differences in the levels of VDR protein between these cell lines. In U2-Os cells, the level of c-jun mRNA was higher than in the other two cell lines, whereas none of these cell lines exhibited detectable levels of c-fos mRNA at the confluent stage. Exogenous c-Jun protein effectively blocked the VDR-DNA interaction. Further, all these cell lines expressed mRNA for retinoid X receptor alpha (RXR alpha), the factor suggested to be required for the VDR-DNA interaction. The presence of an accessory factor in the VDR-DNA complexes was indirectly shown by treatment of the cells with 9-cis retinoic acid and by cycloheximide. Both treatments reduced VDR binding without affecting the VDR protein level. These results suggest that AP-1 interferes with VDR binding to the AP-1 + VDRE element and that the vitamin D responsiveness of the osteocalcin gene correlates with weak AP-1 binding and strong binding of the faster migrating VDR complex.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
224
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11-20
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:8076631-Base Sequence, pubmed-meshheading:8076631-Blotting, Northern, pubmed-meshheading:8076631-Blotting, Western, pubmed-meshheading:8076631-Cycloheximide, pubmed-meshheading:8076631-DNA, pubmed-meshheading:8076631-Gene Expression, pubmed-meshheading:8076631-Humans, pubmed-meshheading:8076631-Molecular Sequence Data, pubmed-meshheading:8076631-Osteocalcin, pubmed-meshheading:8076631-Osteosarcoma, pubmed-meshheading:8076631-Polymerase Chain Reaction, pubmed-meshheading:8076631-Promoter Regions, Genetic, pubmed-meshheading:8076631-Proto-Oncogene Proteins c-fos, pubmed-meshheading:8076631-Proto-Oncogene Proteins c-jun, pubmed-meshheading:8076631-RNA, Messenger, pubmed-meshheading:8076631-Receptors, Calcitriol, pubmed-meshheading:8076631-Transcription, Genetic, pubmed-meshheading:8076631-Tretinoin, pubmed-meshheading:8076631-Tumor Cells, Cultured
pubmed:year
1994
pubmed:articleTitle
Functional interference between AP-1 and the vitamin D receptor on osteocalcin gene expression in human osteosarcoma cells.
pubmed:affiliation
Department of Biochemistry and Biotechnology and A. I. Virtanen Institute, University of Kuopio, Finland.
pubmed:publicationType
Journal Article, Comparative Study