title: Live-cell single-molecule tracking reveals co-recognition of H3K27me3 and DNA targets polycomb Cbx7-PRC1 to chromatin.
abstract: The Polycomb PRC1 plays essential roles in development and disease pathogenesis. Targeting of PRC1 to chromatin is thought to be mediated by the Cbx family proteins (Cbx2/4/6/7/8) binding to histone H3 with a K27me3 modification (H3K27me3). Despite this prevailing view, the molecular mechanisms of targeting remain poorly understood. Here, by combining live-cell single-molecule tracking (SMT) and genetic engineering, we reveal that H3K27me3 contributes significantly to the targeting of Cbx7 and Cbx8 to chromatin, but less to Cbx2, Cbx4, and Cbx6. Genetic disruption of the complex formation of PRC1 facilitates the targeting of Cbx7 to chromatin. Biochemical analyses uncover that the CD and AT-hook-like (ATL) motif of Cbx7 constitute a functional DNA-binding unit. Live-cell SMT of Cbx7 mutants demonstrates that Cbx7 is targeted to chromatin by co-recognizing of H3K27me3 and DNA. Our data suggest a novel hierarchical cooperation mechanism by which histone modifications and DNA coordinate to target chromatin regulatory complexes.
authors.affiliation: Department of Chemistry, University of Colorado Denver, Denver, United States.
authors.forename: Chao Yu
authors.initials: CY
authors.lastname: Zhen
authors.affiliation: Department of Chemistry, University of Colorado Denver, Denver, United States.
authors.forename: Roubina
authors.initials: R
authors.lastname: Tatavosian
authors.affiliation: Department of Chemistry, University of Colorado Denver, Denver, United States.
authors.forename: Thao Ngoc
authors.initials: TN
authors.lastname: Huynh
authors.affiliation: Department of Chemistry, University of Colorado Denver, Denver, United States.
authors.forename: Huy Nguyen
authors.initials: HN
authors.lastname: Duc
authors.affiliation: Department of Integrative Biology, University of Colorado Denver, Denver, United States.
authors.forename: Raibatak
authors.initials: R
authors.lastname: Das
authors.affiliation: Department of Chemistry, University of Colorado Denver, Denver, United States.
authors.forename: Marko
authors.initials: M
authors.lastname: Kokotovic
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Grimm
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States.
authors.forename: Luke D
authors.initials: LD
authors.lastname: Lavis
authors.affiliation: Department of Chemistry, University of Colorado Denver, Denver, United States.
authors.forename: Jun
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Chemistry, University of Colorado Denver, Denver, United States.
authors.forename: Frances J
authors.initials: FJ
authors.lastname: Mejia
authors.affiliation: Department of Chemistry, University of Colorado Denver, Denver, United States.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States.
authors.forename: Tingting
authors.initials: T
authors.lastname: Yao
authors.affiliation: Department of Chemistry, University of Colorado Denver, Denver, United States.
authors.forename: Xiaojun
authors.identifier: 0000-0002-3931-7625
authors.initials: X
authors.lastname: Ren
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D006657:Histones / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D000066450:Mouse Embryonic Stem Cells; D063150:Polycomb Repressive Complex 1 / Q000378:metabolism*; D011485:Protein Binding; D000072760:Single Molecule Imaging
chemical_list: C519505:Cbx7 protein, mouse; D002843:Chromatin; D006657:Histones; D004247:DNA; D063150:Polycomb Repressive Complex 1
keywords: Epigenetics; Polycomb; biophysics; chromatin; chromosomes; combinatorial recognition; genes; live-cell imaging; none; single-molecule tracking; structural biology