Modulation of heat shock gene expression by the TAC1 chromatin-modifying complex.
Rapid induction of the Drosophila melanogaster heat shock gene hsp70 is achieved through the binding of heat shock factor (HSF) to heat shock elements (HSEs) located upstream of the transcription start site (reviewed in ref. 3). The subsequent recruitment of several other factors, including Spt5, Spt6 and FACT, is believed to facilitate Pol II elongation through nucleosomes downstream of the start site. Here, we report a novel mechanism of heat shock gene regulation that involves modifications of nucleosomes by the TAC1 histone modification complex. After heat stress, TAC1 is recruited to several heat shock gene loci, where its components are required for high levels of gene expression. Recruitment of TAC1 to the 5'-coding region of hsp70 seems to involve the elongating Pol II complex. TAC1 has both histone H3 Lys 4-specific (H3-K4) methyltransferase (HMTase) activity and histone acetyltransferase activity through Trithorax (Trx) and CREB-binding protein (CBP), respectively. Consistently, TAC1 is required for methylation and acetylation of nucleosomal histones in the 5'-coding region of hsp70 after induction, suggesting an unexpected role for TAC1 during transcriptional elongation.
Smith
Sheryl T
ST
Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Petruk
Svetlana
S
Sedkov
Yurii
Y
Cho
Elizabeth
E
Tillib
Sergei
S
Canaani
Eli
E
Mazo
Alexander
A
D000818:Animals; D002843:Chromatin / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000502:physiology; D004625:Embryo, Nonmammalian / Q000502:physiology; D005786:Gene Expression Regulation; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D006358:Hot Temperature; D046911:Macromolecular Substances; D009707:Nucleosomes / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D014157:Transcription Factors; D014158:Transcription, Genetic
D002843:Chromatin; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018840:HSP70 Heat-Shock Proteins; D006657:Histones; D046911:Macromolecular Substances; D009707:Nucleosomes; D014157:Transcription Factors; C063460:Trl protein, Drosophila