title: The human SPT20-containing SAGA complex plays a direct role in the regulation of endoplasmic reticulum stress-induced genes.
abstract: One of the central questions in eukaryotic transcription is how activators can transmit their signal to stimulate gene expression in the context of chromatin. The multisubunit SAGA coactivator complex has both histone acetyltransferase and deubiquitination activities and remodels chromatin to allow transcription. Whether and how SAGA is able to regulate transcription at specific loci is poorly understood. Using mass spectrometry, immunoprecipitation, and Western blot analysis, we have identified human SPT20 (hSPT20) as the human homologue of the yeast Spt20 and show that hSPT20 is a bona fide subunit of the human SAGA (hSAGA; previously called TFTC/STAGA/PCAF) complex and that hSPT20 is required for the integrity of the hSAGA complex. We demonstrate that hSPT20 and other hSAGA subunits, together with RNA polymerase II, are specifically recruited to genes induced by endoplasmic reticulum (ER) stress. In good agreement with the recruitment of hSAGA to the ER stress-regulated genes, knockdown of hSTP20 hampers ER stress response. Surprisingly, hSPT20 recruitment was not observed for genes induced by another type of stress. These results provide evidence for a direct and specific role of the hSPT20-containing SAGA complex in transcriptional induction of ER stress-responsive genes. Thus, hSAGA regulates the transcription of stress-responsive genes in a stress type-dependent manner.
authors.affiliation: Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR 7104 CNRS, ULP, INSERM U.964, Parc d'Innovation, Illkirch Cedex, CU de Strasbourg, France.
authors.forename: Zita
authors.initials: Z
authors.lastname: Nagy
authors.forename: Anne
authors.initials: A
authors.lastname: Riss
authors.forename: Christophe
authors.initials: C
authors.lastname: Romier
authors.forename: Xavier
authors.initials: X
authors.lastname: le Guezennec
authors.forename: Ashok R
authors.initials: AR
authors.lastname: Dongre
authors.forename: Meritxell
authors.initials: M
authors.lastname: Orpinell
authors.forename: Jiahuai
authors.initials: J
authors.lastname: Han
authors.forename: Henk
authors.initials: H
authors.lastname: Stunnenberg
authors.forename: Làszlò
authors.initials: L
authors.lastname: Tora
mesh_terms: D000107:Acetylation; D000595:Amino Acid Sequence; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D050880:p300-CBP Transcription Factors / Q000235:genetics / Q000378:metabolism*; D000099224:p300-CBP-Associated Factor
chemical_list: D021122:Protein Subunits; D012319:RNA Polymerase II; D014157:Transcription Factors; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; C502592:SUPT20H protein, human