Linked Life Data

12202226

Source:http://linkedlifedata.com/resource/pubmed/id/12202226

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2002-8-30
pubmed:abstractText
Signal transduction pathways induced by cytokines can modulate the level of HIV-1 gene transcription and replication in a variety of cells including those from the central nervous system. Here, we investigated the effect of TGFbeta-1 signaling the factors, including Smads, on transcription of the viral LTR in human astrocytic cells. Ectopic expression of Smad-3 increased activity of the viral promoter, while its partner protein, Smad-4, caused a slight decrease in viral gene transcription. Further, Smad-4 was able to suppress transcriptional activation of the LTR by Smad-3 as well as by C/EBPbeta, another activator of LTR transcription in these cells. Results from promoter deletion experiments identified the C/EBP-binding site, which is positioned between nucleotides -114 and -102 as one of the targets for Smad-mediated regulation of the LTR. Band-shift studies showed inhibition of C/EBP binding to its target DNA in protein extract from cells overexpressing Smad-3 and Smad-4. Results from GST pull-down assay and combined immunoprecipitation/Western blot of protein extracts from human astrocytes verified the association of Smad-3 and Smad-4 with C/EBPbeta, suggesting that interaction of C/EBPbeta with Smad-3 and Smad-4 may have a negative impact upon C/EBPbeta-mediated activation of the LTR. Interestingly, Smad-4 showed no inhibitory effect on viral gene transcription in cells expressing Tat protein. However, in the presence of Smad-3, expression of Smad-4 exerted a negative effect on Tat-mediated activation of the LTR promoter. These observations pointed to the functional interplay between viral and cellular proteins in modulating LTR transcription.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0042-6822
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
299
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
240-7
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Interaction between TGFbeta signaling proteins and C/EBP controls basal and Tat-mediated transcription of HIV-1 LTR in astrocytes.
pubmed:affiliation
Center for Neurovirology and Cancer Biology, College of Science and Technology, Temple University, 1900 North 12th Street, 015-96, Room 203, Philadelphia, PA 19122, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.