Drosophila NAP-1 is a core histone chaperone that functions in ATP-facilitated assembly of regularly spaced nucleosomal arrays.
We describe the cloning and analysis of Drosophila nucleosome assembly protein 1 (dNAP-1), a core histone-binding protein that functions with other chromatin assembly activities in a Drosophila chromatin assembly factor 1-containing fraction (dCAF-1 fraction) in the ATP-facilitated assembly of regularly spaced nucleosomal arrays from purified core histones and DNA. Purified, recombinant dNAP-1 acts cooperatively with a factor(s) in the dCAF-1 fraction in the efficient and DNA replication-independent assembly of chromatin. In the presence of histone H1, the repeat length of the chromatin is similar to that of native chromatin from Drosophila embryos. By coimmunoprecipitation analysis, dNAP-1 was found to be associated with histones H2A and H2B in a crude whole-embryo extract, which suggests that dNAP-1 is bound to the histones in vivo. Studies of the localization of dNAP-1 in the Drosophila embryo revealed that the factor is present in the nucleus during S phase and is predominantly cytoplasmic during G2 phase. These data suggest that NAP-1 acts as a core histone shuttle which delivers the histones from the cytoplasm to the chromatin assembly machinery in the nucleus. Thus, NAP-1 appears to be one component of a multifactor chromatin assembly machinery that mediates the ATP-facilitated assembly of regularly spaced nucleosomal arrays.
Ito
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Department of Biology, University of California at San Diego, La Jolla 92093-0347, USA.
Bulger
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M
Kobayashi
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Kadonaga
J T
JT
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018797:Cell Cycle Proteins; D002843:Chromatin / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004330:Drosophila / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D007150:Immunohistochemistry; D008954:Models, Biological; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D056490:Nucleosome Assembly Protein 1; D009707:Nucleosomes / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D018797:Cell Cycle Proteins; D002843:Chromatin; D018076:DNA, Complementary; D029721:Drosophila Proteins; D006657:Histones; D018832:Molecular Chaperones; C533554:Nap1 protein, Drosophila; D009687:Nuclear Proteins; D056490:Nucleosome Assembly Protein 1; D009707:Nucleosomes; D011506:Proteins; D011994:Recombinant Proteins; D000255:Adenosine Triphosphate