title: AGO2 and SETDB1 cooperate in promoter-targeted transcriptional silencing of the androgen receptor gene.
abstract: In mammals, RNA interference is primarily a post-transcriptional mechanism. Evidence has accumulated for additional role in transcriptional gene silencing (TGS) but the question for a good paradigm for small interfering antigene RNA (agRNA)-induced chromatin modification remains unanswered. Here, we show that SETDB1, a histone H3-lysine 9 (H3K9)-specific methyltransferase, cooperates with Argonaute-2 (AGO2) and plays an essential role in agRNA-induced TGS. The androgen receptor (AR) gene was transcriptionally silenced by agRNA targeted to its promoter, and we show that this repression was mitigated by knockdown of SETDB1 or AGO2. Chromatin immunoprecipitation demonstrated that agRNA-driven AGO2 was first targeted to the AR promoter, followed by SETDB1. SIN3A and HDAC1/2, the components of the SIN3-HDAC complex, immunoprecipitated with SETDB1, and localized at the agRNA-targeted promoter. Agreeing with the presence of SETDB1, trimethyl-H3K9 was enriched in the AR promoter. Both EZH2 and trimethyl-H3K27 were also present in the targeted locus; accordingly, EZH2 immunoprecipitated with SETDB1. DNA methylation level was not significantly changed, suggesting the absence of de novo methylating activity in agRNA-induced AR promoter. Our results demonstrate that SETDB1, together with AGO2, plays an essential role in TGS through recruiting chromatin remodeler and/or other modifiers, consequently creating a repressive chromatin milieu at the targeted promoter.
authors.affiliation: Development and Differentiation Research Center, KRIBB, 111 Gwahangno, Yuseong-gu, Daejeon 305-806, South Korea Department of Functional Genomics, University of Science and Technology (UST), 113 Gwahangno, Yuseong-gu, 305-333 Daejeon, South Korea.
authors.forename: Sunwha
authors.initials: S
authors.lastname: Cho
authors.affiliation: Development and Differentiation Research Center, KRIBB, 111 Gwahangno, Yuseong-gu, Daejeon 305-806, South Korea.
authors.forename: Jung Sun
authors.initials: JS
authors.lastname: Park
authors.affiliation: Development and Differentiation Research Center, KRIBB, 111 Gwahangno, Yuseong-gu, Daejeon 305-806, South Korea Department of Functional Genomics, University of Science and Technology (UST), 113 Gwahangno, Yuseong-gu, 305-333 Daejeon, South Korea ykkang@kribb.re.kr.
authors.forename: Yong-Kook
authors.initials: YK
authors.lastname: Kang
mesh_terms: D000818:Animals; D060565:Argonaute Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D000071221:Enhancer of Zeste Homolog 2 Protein; D020868:Gene Silencing; D011495:Histone-Lysine N-Methyltransferase; D006657:Histones / Q000378:metabolism; D051379:Mice; D041681:NIH 3T3 Cells; D063151:Polycomb Repressive Complex 2 / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011496:Protein Methyltransferases / Q000378:metabolism* / Q000502:physiology; D022661:RNA, Untranslated / Q000032:analysis; D011944:Receptors, Androgen / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: C466422:AGO2 protein, human; D060565:Argonaute Proteins; D006657:Histones; D022661:RNA, Untranslated; D011944:Receptors, Androgen; D011496:Protein Methyltransferases; C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein; D011495:Histone-Lysine N-Methyltransferase; D063151:Polycomb Repressive Complex 2; C454062:SETDB1 protein, human