The p55 subunit of Drosophila chromatin assembly factor 1 is homologous to a histone deacetylase-associated protein.
To gain a better understanding of DNA replication-coupled chromatin assembly, we have isolated the cDNA encoding the smallest (apparent molecular mass, 55 kDa; termed p55) subunit of Drosophila melanogaster chromatin assembly factor 1 (dCAF-1), a multisubunit protein that is required for the assembly of nucleosomes onto newly replicated DNA in vitro. The p55 polypeptide comprises seven WD repeat motifs and is homologous to the mammalian RbAp48 protein, which is associated with the HD1 histone deacetylase. dCAF-1 was immunopurified by using affinity-purified antibodies against p55; the resulting dCAF-1 preparation possessed the four putative subunits of dCAF-1 (p180, p105, p75, and p55) and was active for DNA replication-coupled chromatin assembly. Moreover, dCAF-1 activity was specifically depleted with antibodies against p55. Thus, p55 is an integral component of dCAF-1. p55 is localized to the nucleus and is present throughout Drosophila development. Consistent with the homology between p55 and the HD1-associated RbAp48 protein, histone deacetylase activity was observed to coimmunoprecipitate specifically with p55 from a Drosophila nuclear extract. Furthermore, a fraction of the p55 protein becomes associated with the newly assembled chromatin following DNA replication. These findings collectively suggest that p55 may function as a link between DNA replication-coupled chromatin assembly and histone modification.
Department of Biology and Center for Molecular Genetics, University of California at San Diego, La Jolla 92093-0347, USA.
J K
JK
Tyler
M
M
Bulger
R T
RT
Kamakaka
R
R
Kobayashi
J T
JT
Kadonaga
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000096:biosynthesis / Q000737:chemistry*; D002467:Cell Nucleus / Q000378:metabolism; D056504:Chromatin Assembly Factor-1; D002868:Chromosomal Proteins, Non-Histone; D004261:DNA Replication; D018076:DNA, Complementary; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D004331:Drosophila melanogaster; D004625:Embryo, Nonmammalian; D018507:Gene Expression Regulation, Developmental; D006655:Histone Deacetylases / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D007814:Larva; D046911:Macromolecular Substances; D008322:Mammals; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000737:chemistry*; D011679:Pupa; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D012091:Repetitive Sequences, Nucleic Acid; D056505:Retinoblastoma-Binding Protein 4; D056524:Retinoblastoma-Binding Protein 7; D017386:Sequence Homology, Amino Acid
D002352:Carrier Proteins; D056504:Chromatin Assembly Factor-1; D002868:Chromosomal Proteins, Non-Histone; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D009687:Nuclear Proteins; C082637:RBBP4 protein, human; C490746:RBBP7 protein, human; C489969:Rbbp4 protein, mouse; C096378:Rbbp7 protein, mouse; D011994:Recombinant Proteins; D056505:Retinoblastoma-Binding Protein 4; D056524:Retinoblastoma-Binding Protein 7; D006655:Histone Deacetylases