title: Occupancy of the Drosophila hsp70 promoter by a subset of basal transcription factors diminishes upon transcriptional activation.
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.
authors.affiliation: Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de Recherche Scientifique, Unité Mixte de Recherche 7104, Université Louis Pasteur de Strasbourg, BP 10142, Illkirch, France.
authors.forename: Lyubov A
authors.initials: LA
authors.lastname: Lebedeva
authors.forename: Elena N
authors.initials: EN
authors.lastname: Nabirochkina
authors.forename: Mariya M
authors.initials: MM
authors.lastname: Kurshakova
authors.forename: Flavie
authors.initials: F
authors.lastname: Robert
authors.forename: Aleksey N
authors.initials: AN
authors.lastname: Krasnov
authors.forename: Mihail B
authors.initials: MB
authors.lastname: Evgen'ev
authors.forename: James T
authors.initials: JT
authors.lastname: Kadonaga
authors.forename: Sofia G
authors.initials: SG
authors.lastname: Georgieva
authors.forename: Làszlò
authors.initials: L
authors.lastname: Tora
mesh_terms: D000818:Animals; D047369:Chromatin Immunoprecipitation; D017931:DNA Primers; D004330:Drosophila / Q000235:genetics*; D019084:Fluorescent Antibody Technique, Indirect; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000235:genetics* / Q000502:physiology
chemical_list: D017931:DNA Primers; D018840:HSP70 Heat-Shock Proteins; D014157:Transcription Factors