HIV-1 Tat stimulates transcription complex assembly through recruitment of TBP in the absence of TAFs
UMass Chan Affiliations
Program in Gene Function and ExpressionProgram in Molecular Medicine
Howard Hughes Medical Institute
Document Type
Journal ArticlePublication Date
2005-02-19Keywords
AnimalsGene Products, tat
Globins
HIV-1
Hela Cells
Humans
Promoter Regions (Genetics)
Recombinant Proteins
TATA-Binding Protein Associated Factors
TATA-Box Binding Protein
*Transcription, Genetic
Transfection
tat Gene Products, Human Immunodeficiency Virus
Life Sciences
Medicine and Health Sciences
Metadata
Show full item recordAbstract
The human immunodeficiency virus type I (HIV-1) transactivator protein Tat is an unusual transcriptional activator that is thought to act solely by promoting RNA polymerase II processivity. Here we study the mechanism of Tat action by analyzing transcription complex (TC) assembly in vivo using chromatin immunoprecipitation assays. We find, unexpectedly, that like typical activators Tat dramatically stimulates TC assembly. Surprisingly, however, the TC formed on the HIV-1 long terminal repeat is atypical and contains TATA-box-binding protein (TBP) but not TBP-associated factors (TAFs). Tat function involves direct interaction with the cellular cofactor positive transcription elongation factor b (P-TEFb). Artificial tethering of P-TEFb subunits to HIV-1 promoter DNA or nascent RNA indicates that P-TEFb is responsible for directing assembly of a TC containing TBP but not TAFs. On the basis of this finding, we identify P-TEFb-dependent cellular promoters that also recruit TBP in the absence of TAFs. Thus, in mammalian cells transcription of protein-coding genes involves alternative TCs that differ by the presence or absence of TAFs.Source
PLoS Biol. 2005 Feb;3(2):e44. Epub 2005 Feb 8. Link to article on publisher's siteDOI
10.1371/journal.pbio.0030044Permanent Link to this Item
http://hdl.handle.net/20.500.14038/38904PubMed ID
15719058Related Resources
Link to Article in PubMedae974a485f413a2113503eed53cd6c53
10.1371/journal.pbio.0030044