title: saRNA-guided Ago2 targets the RITA complex to promoters to stimulate transcription.
abstract: Small activating RNAs (saRNAs) targeting specific promoter regions are able to stimulate gene expression at the transcriptional level, a phenomenon known as RNA activation (RNAa). It is known that RNAa depends on Ago2 and is associated with epigenetic changes at the target promoters. However, the precise molecular mechanism of RNAa remains elusive. Using human CDKN1A (p21) as a model gene, we characterized the molecular nature of RNAa. We show that saRNAs guide Ago2 to and associate with target promoters. saRNA-loaded Ago2 facilitates the assembly of an RNA-induced transcriptional activation (RITA) complex, which, in addition to saRNA-Ago2 complex, includes RHA and CTR9, the latter being a component of the PAF1 complex. RITA interacts with RNA polymerase II to stimulate transcription initiation and productive elongation, accompanied by monoubiquitination of histone 2B. Our results establish the existence of a cellular RNA-guided genome-targeting and transcriptional activation mechanism and provide important new mechanistic insights into the RNAa process.
authors.affiliation: Department of Urology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA 94158, USA.
authors.forename: Victoria
authors.initials: V
authors.lastname: Portnoy
authors.affiliation: Department of Urology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA 94158, USA.
authors.forename: Szu Hua Sharon
authors.initials: SH
authors.lastname: Lin
authors.affiliation: Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA.
authors.forename: Kathy H
authors.initials: KH
authors.lastname: Li
authors.affiliation: Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA.
authors.forename: Alma
authors.initials: A
authors.lastname: Burlingame
authors.affiliation: Department of Urology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA 94158, USA.
authors.forename: Zheng-Hui
authors.initials: ZH
authors.lastname: Hu
authors.affiliation: Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94158, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Urology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA 94158, USA.|Laboratory of Molecular Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China.
authors.forename: Long-Cheng
authors.initials: LC
authors.lastname: Li
mesh_terms: D060565:Argonaute Proteins / Q000378:metabolism*; D019921:Biotinylation; D045744:Cell Line, Tumor; D002843:Chromatin / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics; D053487:DEAD-box RNA Helicases / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D006801:Humans; D009363:Neoplasm Proteins / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012313:RNA / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism; D058727:RNA, Small Untranslated / Q000378:metabolism*; D061805:Transcription Elongation, Genetic; D014157:Transcription Factors; D061785:Transcription Initiation, Genetic; D015533:Transcriptional Activation; D054875:Ubiquitination
chemical_list: C466422:AGO2 protein, human; D060565:Argonaute Proteins; C493956:CDKN1A protein, human; C484387:CTR9 protein, human; D002843:Chromatin; D050759:Cyclin-Dependent Kinase Inhibitor p21; D006657:Histones; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D058727:RNA, Small Untranslated; D014157:Transcription Factors; D012313:RNA; D012319:RNA Polymerase II; C098487:DHX9 protein, human; D053487:DEAD-box RNA Helicases