Abstract |
The presence of general transcription factors and other coactivators at the Drosophila hsp70 gene promoter in vivo has been examined by polytene chromosome immunofluorescence and chromatin immunoprecipitation at endogenous heat-shock loci or at a hsp70 promoter-containing transgene. These studies indicate that the hsp70 promoter is already occupied by TATA-binding protein (TBP) and several TBP-associated factors (TAFs), TFIIB, TFIIF (RAP30), TFIIH (XPB), TBP-free/TAF-containg complex (GCN5 and TRRAP), and the Mediator complex subunit 13 before heat shock. After heat shock, there is a significant recruitment of the heat-shock transcription factor, RNA polymerase II, XPD, GCN5, TRRAP, or Mediator complex 13 to the hsp70 promoter. Surprisingly, upon heat shock, there is a marked diminution in the occupancy of TBP, six different TAFs, TFIIB, and TFIIF, whereas there is no change in the occupancy of these factors at ecdysone-induced loci under the same conditions. Hence, these findings reveal a distinct mechanism of transcriptional induction at the hsp70 promoters, and further indicate that the apparent promoter occupancy of the general transcriptional factors does not necessarily reflect the transcriptional state of a gene.
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Authors | Lyubov A Lebedeva, Elena N Nabirochkina, Mariya M Kurshakova, Flavie Robert, Aleksey N Krasnov, Mihail B Evgen'ev, James T Kadonaga, Sofia G Georgieva, Làszlò Tora |
Journal | Proceedings of the National Academy of Sciences of the United States of America
(Proc Natl Acad Sci U S A)
Vol. 102
Issue 50
Pg. 18087-92
(Dec 13 2005)
ISSN: 0027-8424 [Print] United States |
PMID | 16330756
(Publication Type: Comparative Study, Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
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Chemical References |
- DNA Primers
- HSP70 Heat-Shock Proteins
- Transcription Factors
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Topics |
- Animals
- Chromatin Immunoprecipitation
- DNA Primers
- Drosophila
(genetics)
- Fluorescent Antibody Technique, Indirect
- HSP70 Heat-Shock Proteins
(genetics)
- Polymerase Chain Reaction
- Promoter Regions, Genetic
(genetics)
- Transcription Factors
(genetics, metabolism)
- Transcriptional Activation
(genetics, physiology)
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