title: pRB family proteins are required for H3K27 trimethylation and Polycomb repression complexes binding to and silencing p16INK4alpha tumor suppressor gene.
abstract: Genetic studies have demonstrated that Bmi1 promotes cell proliferation and stem cell self-renewal with a correlative decrease of p16(INK4a) expression. Here, we demonstrate that Polycomb genes EZH2 and BMI1 repress p16 expression in human and mouse primary cells, but not in cells deficient for pRB protein function. The p16 locus is H3K27-methylated and bound by BMI1, RING2, and SUZ12. Inactivation of pRB family proteins abolishes H3K27 methylation and disrupts BMI1, RING2, and SUZ12 binding to the p16 locus. These results suggest a model in which pRB proteins recruit PRC2 to trimethylate p16, priming the BMI1-containing PRC1L ubiquitin ligase complex to silence p16.
authors.affiliation: Department of Biochemistry and Biophysics, Lineberger Comprehensive Cancer Center, Program in Molecular Biology and Biotechnology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors.forename: Yojiro
authors.initials: Y
authors.lastname: Kotake
authors.forename: Ru
authors.initials: R
authors.lastname: Cao
authors.forename: Patrick
authors.initials: P
authors.lastname: Viatour
authors.forename: Julien
authors.initials: J
authors.lastname: Sage
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yue
authors.initials: Y
authors.lastname: Xiong
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D000071221:Enhancer of Zeste Homolog 2 Protein; D020868:Gene Silencing; D011495:Histone-Lysine N-Methyltransferase / Q000378:metabolism; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009363:Neoplasm Proteins; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D063150:Polycomb Repressive Complex 1; D063151:Polycomb Repressive Complex 2; D063146:Polycomb-Group Proteins; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D050720:Retinoblastoma-Like Protein p107 / Q000502:physiology*; D050717:Retinoblastoma-Like Protein p130 / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism; D043222:Ubiquitin Thiolesterase / Q000235:genetics / Q000378:metabolism
chemical_list: C400134:BAP1 protein, human; C069077:BMI1 protein, human; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004268:DNA-Binding Proteins; D006657:Histones; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C116662:PRC1 protein, human; D063146:Polycomb-Group Proteins; D011518:Proto-Oncogene Proteins; C489485:Rbl1 protein, mouse; C493838:Rbl2 protein, mouse; D012097:Repressor Proteins; D050720:Retinoblastoma-Like Protein p107; D050717:Retinoblastoma-Like Protein p130; C430461:SUZ12 protein, human; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D025801:Ubiquitin; C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein; D011495:Histone-Lysine N-Methyltransferase; D063151:Polycomb Repressive Complex 2; D063150:Polycomb Repressive Complex 1; D043222:Ubiquitin Thiolesterase