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Upstream nucleosomes and Rgr1p are required for nucleosomal repression of transcription
Author(s) -
Moss David R.,
Laybourn Paul J.
Publication year - 2000
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2000.01940.x
Subject(s) - biology , nucleosome , derepression , psychological repression , transcription (linguistics) , upstream activating sequence , rna polymerase ii , microbiology and biotechnology , repressor , general transcription factor , genetics , promoter , histone , transcription factor , enhancer , dna , gene , gene expression , linguistics , philosophy
The mechanisms of transcription repression and derepression in vivo are not fully understood. We have obtained evidence that begins to clarify the minimum requirements for counteracting nucleosomal repression in vivo . Location of the TATA element near the nucleosome dyad does not block RNA polymerase II transcription in vivo if there is a nucleosome‐free region located immediately upstream. However, location of the TATA element similarly within the nucleosome does block transcription if the region upstream of it is nucleosome bound. Histone H4 depletion derepresses transcription in the latter case, supporting the idea that the nucleosomes are responsible for the repression. These results raise the intriguing possibility that the minimum requirement for derepression of transcription in vivo is a nucleosome‐free region upstream of the core promoter. Importantly, we find that a C‐terminal deletion in RGR1 , a component of the mediator/holoenzyme complex and a global repressor, can also derepress transcription.