title: HP1 proteins are essential for a dynamic nuclear response that rescues the function of perturbed heterochromatin in primary human cells.
abstract: Cellular information is encoded genetically in the DNA nucleotide sequence and epigenetically by the "histone code," DNA methylation, and higher-order packaging of DNA into chromatin. Cells possess intricate mechanisms to sense and repair damage to DNA and the genetic code. However, nothing is known of the mechanisms, if any, that repair and/or compensate for damage to epigenetically encoded information, predicted to result from perturbation of DNA and histone modifications or other changes in chromatin structure. Here we show that primary human cells respond to a variety of small molecules that perturb DNA and histone modifications by recruiting HP1 proteins to sites of altered pericentromeric heterochromatin. This response is essential to maintain the HP1-binding kinetochore protein hMis12 at kinetochores and to suppress catastrophic mitotic defects. Recruitment of HP1 proteins to pericentromeres depends on histone H3.3 variant deposition, mediated by the HIRA histone chaperone. These data indicate that defects in pericentromeric epigenetic heterochromatin modifications initiate a dynamic HP1-dependent response that rescues pericentromeric heterochromatin function and is essential for viable progression through mitosis.
authors.affiliation: Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
authors.forename: Rugang
authors.initials: R
authors.lastname: Zhang
authors.forename: Song-tao
authors.initials: ST
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Michael
authors.initials: M
authors.lastname: Bonner
authors.forename: John
authors.initials: J
authors.lastname: Pehrson
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Yen
authors.forename: Peter D
authors.initials: PD
authors.lastname: Adams
mesh_terms: D018797:Cell Cycle Proteins / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D002478:Cells, Cultured; D002503:Centromere / Q000187:drug effects / Q000378:metabolism; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D006570:Heterochromatin / Q000187:drug effects / Q000378:metabolism*; D056488:Histone Chaperones; D006657:Histones / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D018832:Molecular Chaperones / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; C086057:HIRA protein, human; D006570:Heterochromatin; D056488:Histone Chaperones; D006657:Histones; D006877:Hydroxamic Acids; D018832:Molecular Chaperones; D014157:Transcription Factors; C120756:macroH2A histone; D000090266:Chromobox Protein Homolog 5; C012589:trichostatin A