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Mediator Affects Pol II Recruitment and Nucleosome Displacement at Heat Shock Protein (HSP) Genes in Saccharomyces cerevisiae
Author(s) -
Moustafa Yara,
Gross David S.
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.769.9
Subject(s) - mediator , biology , microbiology and biotechnology , nucleosome , chromatin remodeling , chromatin , hsf1 , coactivator , gene , heat shock protein , genetics , transcription factor , hsp70
Mediator, an evolutionarily conserved transcriptional coactivator, plays a critical role in governing both constitutive and induced levels of heat shock protein (HSP) gene expression in budding yeast. Yet how Mediator, and in particular each of its four structural modules – Head, Middle, Tail and Kinase – participates in HSP gene regulation and crosstalk with other transcriptional coactivators remains unclear. Using the conditional depletion technique termed Anchor Away, we have studied the role of two essential Middle Module subunits, Med14 and Med7, in the transcription and chromatin remodeling of HSP genes. Depletion of either subunit disrupts integrity of Mediator, as assessed by a failure of Med20 (Head) to be recruited to induced HSP genes. Pol II recruitment is also affected, and its loss parallels that of Med7. Strikingly, quantitative depletion of Med14 has a relatively modest effect on Pol II recruitment at HSP genes. Nucleosome disassembly triggered by heat shock is likewise differentially affected by loss of Med14 and Med7. These findings suggest that Mediator integrity is important, but not essential, for Pol II recruitment and chromatin remodeling upon heat shock. The interplay between Mediator and other transcriptional coactivators (SAGA, TFIID, RSC, Swi/Snf) in regulating stress‐induced transcription is under investigation. This work is supported by NSF grant MCB‐1025025 awarded to D.S.G.