title: New nuclear partners for nucleosome assembly protein 1: unexpected associations.
abstract: Histone chaperones are important players in chromatin dynamics. They are instrumental in nucleosome assembly and disassembly and in histone variant exchange reactions that occur during DNA transactions. The molecular mechanisms of their action are not well understood and may involve interactions with various protein partners in the context of the nucleus. In an attempt to further elucidate nuclear roles of histone chaperones, we performed a proteomic search for nuclear partners of a particular histone chaperone, nucleosome assembly protein 1 (Nap1). Proteins recognized as Nap1 partners by immuno-affinity capture and Far Western blots were identified by mass spectrometry. The identified partners are known to participate in a number of nuclear processes, including DNA replication, recombination, and repair as well as RNA transcription and splicing. Finding nuclear actin among the Nap1 partners may be of particular significance, in view of actin's role in transcription, transcription regulation, and RNA splicing. We are proposing a model of how actin-Nap1 interaction may be involved in transcription elongation through chromatin. In addition, awareness of the interactions between Nap1 and Hsp70, another identified partner, may help to understand nucleosome dynamics around sites of single-strand DNA break repair. These studies represent a starting point for further investigation of Nap1 associations in human cells.
authors.affiliation: Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA.
authors.forename: Corrine
authors.initials: C
authors.lastname: Seebart
authors.forename: Jessica
authors.initials: J
authors.lastname: Prenni
authors.forename: Miroslav
authors.initials: M
authors.lastname: Tomschik
authors.forename: Jordanka
authors.initials: J
authors.lastname: Zlatanova
mesh_terms: D000199:Actins / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism*; D002467:Cell Nucleus / Q000235:genetics* / Q000378:metabolism*; D042002:Chromatin Assembly and Disassembly; D053904:DNA Breaks, Single-Stranded; D004260:DNA Repair; D004261:DNA Replication; D005786:Gene Expression Regulation; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis* / Q000737:chemistry* / Q000378:metabolism*; D006367:HeLa Cells; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007120:Immunochemistry; D013058:Mass Spectrometry; D008954:Models, Biological; D046912:Multiprotein Complexes / Q000032:analysis* / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism*; D056490:Nucleosome Assembly Protein 1 / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009707:Nucleosomes / Q000235:genetics* / Q000378:metabolism*; D040901:Proteomics; D012326:RNA Splicing
chemical_list: D000199:Actins; D018840:HSP70 Heat-Shock Proteins; D006657:Histones; D046912:Multiprotein Complexes; D056490:Nucleosome Assembly Protein 1; D009707:Nucleosomes