Abstract
Mechanisms contributing to the maintenance of heterochromatin in proliferating cells are poorly understood. We demonstrate that chromatin assembly factor 1 (CAF-1) binds to mouse HP1 proteins via an N-terminal domain of its p150 subunit, a domain dispensable for nucleosome assembly during DNA replication. Mutations in p150 prevent association with HP1 in heterochromatin in cells that are not in S phase and the formation of CAF-1-HP1 complexes in nascent chromatin during DNA replication in vitro. We suggest that CAF-1 p150 has a heterochromatin-specific function distinct from its nucleosome assembly function during S phase. Just before mitosis, CAF-1 p150 and some HP1 progressively dissociate from heterochromatin concomitant with histone H3 phosphorylation. The HP1 proteins reassociate with chromatin at the end of mitosis, as histone H3 is dephosphorylated.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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3T3 Cells
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Amino Acid Sequence
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Animals
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Chromatin Assembly Factor-1
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Chromobox Protein Homolog 5
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Chromosomal Proteins, Non-Histone / metabolism*
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DNA Replication / genetics
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DNA-Binding Proteins / metabolism*
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Fluorescent Antibody Technique
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Green Fluorescent Proteins
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Heterochromatin / metabolism*
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Histones / metabolism
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Luminescent Proteins
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Mice
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Mitosis
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Molecular Sequence Data
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Mutation
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Nuclear Proteins*
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Phosphorylation
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Protein Binding
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Repressor Proteins / metabolism
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S Phase
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Transcription Factors*
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Tripartite Motif-Containing Protein 28
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Yeasts / genetics
Substances
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Chaf1a protein, mouse
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Chromatin Assembly Factor-1
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Chromosomal Proteins, Non-Histone
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DNA-Binding Proteins
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Heterochromatin
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Histones
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Luminescent Proteins
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Nuclear Proteins
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Repressor Proteins
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Transcription Factors
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Chromobox Protein Homolog 5
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Green Fluorescent Proteins
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Trim28 protein, mouse
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Tripartite Motif-Containing Protein 28