DNA-binding and chromatin localization properties of CHD1.
CHD1 is a novel DNA-binding protein that contains both a chromatin organization modifier (chromo) domain and a helicase/ATPase domain. We show here that CHD1 preferentially binds to relatively long A.T tracts in double-stranded DNA via minor-groove interactions. Several CHD1-binding sites were found in a well-characterized nuclear-matrix attachment region, which is located adjacent to the intronic enhancer of the kappa immunoglobulin gene. The DNA-binding activity of CHD1 was localized to a 229-amino-acid segment in the C-terminal portion of the protein, which contains sequence motifs that have previously been implicated in the minor-groove binding of other proteins. We also demonstrate that CHD1 is a constituent of bulk chromatin and that it can be extracted from nuclei with 0.6 M NaCl or with 2 mM EDTA after mild digestion with micrococcal nuclease. In contrast to another chromo-domain protein, HP1, CHD1 is not preferentially located in condensed centromeric heterochromatin, even though centromeric DNA is highly enriched in (A+T)-rich tracts. Most interestingly, CHD1 is released into the cytoplasm when cells enter mitosis and is reincorporated into chromatin during telophase-cytokinesis. These observations lend credence to the idea that CHD1, like other proteins with chromo or helicase/ATPase domains, plays an important role in the determination of chromatin architecture.
Stokes
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DG
Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA.
Perry
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RP
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism*; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D007399:Interphase; D051379:Mice; D008938:Mitosis; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
C489844:Chd1 protein, mouse; D002843:Chromatin; D017931:DNA Primers; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D004247:DNA