GAGA factor and the TFIID complex collaborate in generating an open chromatin structure at the Drosophila melanogaster hsp26 promoter.
The upstream regulatory region of the Drosophila melanogaster hsp26 gene includes two DNase I-hypersensitive sites (DH sites) that encompass the critical heat shock elements. This chromatin structure is required for heat shock-inducible expression and depends on two (CT)n*(GA)n elements bound by GAGA factor. To determine whether GAGA factor alone is sufficient to drive formation of the DH sites, we have created flies with an hsp26/lacZ transgene wherein the entire DNA segment known to interact with the TFIID complex has been replaced by a random sequence. The replacement results in a loss of heat shock-inducible hsp26 expression and drastically diminishes nuclease accessibility in the chromatin of the regulatory region. Chromatin immunoprecipitation experiments show that the decrease in TFIID binding does not reduce GAGA factor binding. In contrast, the loss of GAGA factor binding resulting from (CT)n mutations decreases TFIID binding. These data suggest that both GAGA factor and TFIID are necessary for formation of the appropriate chromatin structure at the hsp26 promoter and predict a regulatory mechanism in which GAGA factor binding precedes and contributes to the recruitment of TFIID.
Leibovitch
Boris A
BA
Department of Biology, Washington University, St. Louis, Missouri 63130, USA.
Lu
Quinn
Q
Benjamin
Lawrence R
LR
Liu
Yingyun
Y
Gilmour
David S
DS
Elgin
Sarah C R
SC
D000818:Animals; D001665:Binding Sites; D002843:Chromatin / Q000235:genetics / Q000648:ultrastructure*; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004274:DNA, Recombinant / Q000235:genetics; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics*; D018398:Homeodomain Proteins / Q000502:physiology*; D006358:Hot Temperature; D007814:Larva; D046911:Macromolecular Substances; D008957:Models, Genetic; D016296:Mutagenesis; D017354:Point Mutation; D011485:Protein Binding; D016385:TATA Box / Q000235:genetics*; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000502:physiology*; D019473:Transcription Factors, TFII / Q000502:physiology*
D002843:Chromatin; D004274:DNA, Recombinant; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D006360:Heat-Shock Proteins; D018398:Homeodomain Proteins; C087442:Hsp26 protein, Drosophila; D046911:Macromolecular Substances; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D019473:Transcription Factors, TFII; C063460:Trl protein, Drosophila; D004247:DNA