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Histone acetylation facilitates RNA polymerase II transcription of the Drosophila hsp26 gene in chromatin
Author(s) -
Nightingale Karl P.,
Wellinger Ralf E.,
Sogo Jose M.,
Becker Peter B.
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.10.2865
Subject(s) - biology , rna polymerase ii , chromatin , histone , transcription (linguistics) , genetics , rna polymerase , rna polymerase ii holoenzyme , gene , polymerase , rna polymerase iii , drosophila melanogaster , histone modifying enzymes , rna , histone h2a , microbiology and biotechnology , gene expression , promoter , linguistics , philosophy
A number of activators are known to increase transcription by RNA polymerase (pol) II through protein acetylation. While the physiological substrates for those acetylases are poorly defined, possible targets include general transcription factors, activator proteins and histones. Using a cell‐free system to reconstitute chromatin with increased histone acetylation levels, we directly tested for a causal role of histone acetylation in transcription by RNA pol II. Chromatin, containing either control or acetylated histones, was reconstituted to comparable nucleosome densities and characterized by electron microscopy after psoralen cross‐linking as well as by in vitro transcription. While H1‐containing control chromatin severely repressed transcription of our model hsp 26 gene, highly acetylated chromatin was significantly less repressive. Acetylation of histones, and particularly of histone H4, affected transcription at the level of initiation. Monitoring the ability of the transcription machinery to associate with the promoter in chromatin, we found that heat shock factor, a crucial regulator of heat shock gene transcription, profited most from histone acetylation. These experiments demonstrate that histone acetylation can modulate activator access to their target sites in chromatin, and provide a causal link between histone acetylation and enhanced transcription initiation of RNA pol II in chromatin.