Identification of SUMO-dependent chromatin-associated transcriptional repression components by a genome-wide RNAi screen.
SUMO modification of many transcription factors is linked to transcriptional repression. The molecular mechanisms by which SUMO attachment represses transcription are largely unknown. Here we report a genome-wide RNA interference screen in Drosophila melanogaster cells for components regulating and mediating SUMO-dependent transcriptional repression. Analysis of >21,000 double-stranded RNAs (dsRNAs) identified 120 genes whose dsRNA-mediated knockdowns impaired SUMO-dependent transcriptional repression. Several of these genes encode chromatin-associated proteins, including the ATP-dependent chromatin remodeler Mi-2, the D. melanogaster ortholog of the C. elegans protein MEP-1, and the polycomb protein Sfmbt. Knockdown of these proteins did not impair SUMO conjugation, demonstrating that they act downstream of SUMO attachment. Biochemical analyses revealed that MEP-1, Mi-2, and Sfmbt interact with each other, bind to SUMO, and are recruited to promoters in a SUMOylation-dependent manner. Our results suggest that MEP-1, Mi-2, and Sfmbt are part of a common repression complex established by DNA-bound SUMO-modified transcription factors.
Stielow
Bastian
B
Institute of Molecular Biology and Tumor Research, Philipps-University of Marburg, Emil-Mannkopff-Strasse 2, D-35032 Marburg, Germany.
Sapetschnig
Alexandra
A
Krüger
Imme
I
Kunert
Natascha
N
Brehm
Alexander
A
Boutros
Michael
M
Suske
Guntram
G
D000818:Animals; D002843:Chromatin / Q000235:genetics*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics*; D005786:Gene Expression Regulation; D016678:Genome; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism; D008322:Mammals; D056245:Mi-2 Nucleosome Remodeling and Deacetylase Complex; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000235:genetics; D025842:SUMO-1 Protein / Q000378:metabolism*; D013045:Species Specificity; D014158:Transcription, Genetic
D002843:Chromatin; D029721:Drosophila Proteins; D012330:RNA, Double-Stranded; D025842:SUMO-1 Protein; D006655:Histone Deacetylases; D056245:Mi-2 Nucleosome Remodeling and Deacetylase Complex