Hyperdynamic plasticity of chromatin proteins in pluripotent embryonic stem cells.
Differentiation of embryonic stem (ES) cells from a pluripotent to a committed state involves global changes in genome expression patterns. Gene activity is critically determined by chromatin structure and interactions of chromatin binding proteins. Here, we show that major architectural chromatin proteins are hyperdynamic and bind loosely to chromatin in ES cells. Upon differentiation, the hyperdynamic proteins become immobilized on chromatin. Hyperdynamic binding is a property of pluripotent cells, but not of undifferentiated cells that are already lineage committed. ES cells lacking the nucleosome assembly factor HirA exhibit elevated levels of unbound histones, and formation of embryoid bodies is accelerated. In contrast, ES cells, in which the dynamic exchange of H1 is restricted, display differentiation arrest. We suggest that hyperdynamic binding of structural chromatin proteins is a functionally important hallmark of pluripotent ES cells that contributes to the maintenance of plasticity in undifferentiated ES cells and to establishing higher-order chromatin structure.
Meshorer
Eran
E
National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
Yellajoshula
Dhananjay
D
George
Eric
E
Scambler
Peter J
PJ
Brown
David T
DT
Misteli
Tom
T
D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002452:Cell Count / Q000379:methods; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism*; D042002:Chromatin Assembly and Disassembly / Q000502:physiology*; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D004622:Embryo, Mammalian; D047108:Embryonic Development / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000378:metabolism; D056488:Histone Chaperones; D000076983:Histone Methyltransferases; D011495:Histone-Lysine N-Methyltransferase / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D007211:Indoles; D015850:Interleukin-6 / Q000172:deficiency; D007381:Intermediate Filament Proteins / Q000378:metabolism; D007700:Kinetics; D053605:Leukemia Inhibitory Factor; D051379:Mice; D018345:Mice, Knockout; D008967:Molecular Biology / Q000379:methods; D009419:Nerve Tissue Proteins / Q000378:metabolism; D064231:Nestin; D017711:Nonlinear Dynamics; D050814:Octamer Transcription Factor-3 / Q000378:metabolism; D039904:Pluripotent Stem Cells / Q000378:metabolism*; D040081:Protein Array Analysis / Q000379:methods; D011496:Protein Methyltransferases; D013997:Time Factors; D014157:Transcription Factors / Q000172:deficiency
D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; C484187:Hira protein, mouse; D056488:Histone Chaperones; D006657:Histones; D007211:Indoles; D015850:Interleukin-6; D007381:Intermediate Filament Proteins; D053605:Leukemia Inhibitory Factor; C507838:Lif protein, mouse; D009419:Nerve Tissue Proteins; C577485:Nes protein, mouse; D064231:Nestin; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D014157:Transcription Factors; D000090266:Chromobox Protein Homolog 5; D049452:Green Fluorescent Proteins; C007293:DAPI; D000076983:Histone Methyltransferases; D011496:Protein Methyltransferases; D011495:Histone-Lysine N-Methyltransferase