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  • American Association for the Advancement of Science (AAAS)  (6)
  • Nature Publishing Group (NPG)  (1)
  • 1
    Publication Date: 2011-07-12
    Description: In eukaryotes, accurate chromosome segregation during mitosis and meiosis is coordinated by kinetochores, which are unique chromosomal sites for microtubule attachment. Centromeres specify the kinetochore formation sites on individual chromosomes, and are epigenetically marked by the assembly of nucleosomes containing the centromere-specific histone H3 variant, CENP-A. Although the underlying mechanism is unclear, centromere inheritance is probably dictated by the architecture of the centromeric nucleosome. Here we report the crystal structure of the human centromeric nucleosome containing CENP-A and its cognate alpha-satellite DNA derivative (147 base pairs). In the human CENP-A nucleosome, the DNA is wrapped around the histone octamer, consisting of two each of histones H2A, H2B, H4 and CENP-A, in a left-handed orientation. However, unlike the canonical H3 nucleosome, only the central 121 base pairs of the DNA are visible. The thirteen base pairs from both ends of the DNA are invisible in the crystal structure, and the alphaN helix of CENP-A is shorter than that of H3, which is known to be important for the orientation of the DNA ends in the canonical H3 nucleosome. A structural comparison of the CENP-A and H3 nucleosomes revealed that CENP-A contains two extra amino acid residues (Arg 80 and Gly 81) in the loop 1 region, which is completely exposed to the solvent. Mutations of the CENP-A loop 1 residues reduced CENP-A retention at the centromeres in human cells. Therefore, the CENP-A loop 1 may function in stabilizing the centromeric chromatin containing CENP-A, possibly by providing a binding site for trans-acting factors. The structure provides the first atomic-resolution picture of the centromere-specific nucleosome.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Tachiwana, Hiroaki -- Kagawa, Wataru -- Shiga, Tatsuya -- Osakabe, Akihisa -- Miya, Yuta -- Saito, Kengo -- Hayashi-Takanaka, Yoko -- Oda, Takashi -- Sato, Mamoru -- Park, Sam-Yong -- Kimura, Hiroshi -- Kurumizaka, Hitoshi -- England -- Nature. 2011 Jul 10;476(7359):232-5. doi: 10.1038/nature10258.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21743476" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Autoantigens/*chemistry/metabolism ; Base Sequence ; Chromosomal Proteins, Non-Histone/*chemistry/metabolism ; Crystallography, X-Ray ; DNA/*chemistry/genetics/metabolism ; Histones/*chemistry/metabolism ; Humans ; Models, Molecular ; Molecular Conformation ; Molecular Sequence Data ; Nucleosomes/*chemistry/genetics/metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2018
    Description: 〈p〉Genomic DNA forms chromatin, in which the nucleosome is the repeating unit. The mechanism by which RNA polymerase II (RNAPII) transcribes the nucleosomal DNA remains unclear. Here we report the cryo–electron microscopy structures of RNAPII-nucleosome complexes in which RNAPII pauses at the superhelical locations SHL(–6), SHL(–5), SHL(–2), and SHL(–1) of the nucleosome. RNAPII pauses at the major histone-DNA contact sites, and the nucleosome interactions with the RNAPII subunits stabilize the pause. These structures reveal snapshots of nucleosomal transcription, in which RNAPII gradually tears DNA from the histone surface while preserving the histone octamer. The nucleosomes in the SHL(–1) complexes are bound to a "foreign" DNA segment, which might explain the histone transfer mechanism. These results provide the foundations for understanding chromatin transcription and epigenetic regulation.〈/p〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2019
    Description: 〈p〉RNA polymerase II (RNAPII) transcribes chromosomal DNA that contains multiple nucleosomes. The nucleosome forms transcriptional barriers, and nucleosomal transcription requires several additional factors in vivo. We demonstrate that the transcription elongation factors Elf1 and Spt4/5 cooperatively lower the barriers and increase the RNAPII processivity in the nucleosome. The cryo–electron microscopy structures of the nucleosome-transcribing RNAPII elongation complexes (ECs) reveal that Elf1 and Spt4/5 reshape the EC downstream edge and intervene between RNAPII and the nucleosome. They facilitate RNAPII progression through superhelical location SHL(–1) by adjusting the nucleosome in favor of the forward progression. They suppress pausing at SHL(–5) by preventing the stable RNAPII-nucleosome interaction. Thus, the EC overcomes the nucleosomal barriers while providing a platform for various chromatin functions.〈/p〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2019
    Description: 〈p〉RNA polymerase II (RNAPII) transcribes chromosomal DNA that contains multiple nucleosomes. The nucleosome forms transcriptional barriers, and nucleosomal transcription requires several additional factors in vivo. We demonstrate that the transcription elongation factors Elf1 and Spt4/5 cooperatively lower the barriers and increase the RNAPII processivity in the nucleosome. The cryo–electron microscopy structures of the nucleosome-transcribing RNAPII elongation complexes (ECs) reveal that Elf1 and Spt4/5 reshape the EC downstream edge and intervene between RNAPII and the nucleosome. They facilitate RNAPII progression through superhelical location SHL(–1) by adjusting the nucleosome in favor of the forward progression. They suppress pausing at SHL(–5) by preventing the stable RNAPII-nucleosome interaction. Thus, the EC overcomes the nucleosomal barriers while providing a platform for various chromatin functions.〈/p〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Natural Sciences in General
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  • 5
    Publication Date: 2018
    Description: 〈p〉Genomic DNA forms chromatin, in which the nucleosome is the repeating unit. The mechanism by which RNA polymerase II (RNAPII) transcribes the nucleosomal DNA remains unclear. Here we report the cryo–electron microscopy structures of RNAPII-nucleosome complexes, in which RNAPII pauses at the superhelical locations, SHL(-6), SHL(-5), SHL(-2), and SHL(-1), of the nucleosome. RNAPII pauses at the major histone-DNA contact sites, and the nucleosome interactions with the RNAPII subunits stabilize the pause. These structures reveal snapshots of nucleosomal transcription, where RNAPII gradually tears DNA from the histone surface, while preserving the histone octamer. Interestingly, the nucleosomes in the SHL(-1) complexes are bound to a "foreign" DNA segment, which might explain the histone transfer mechanism. These results provide the foundations for understanding chromatin transcription and epigenetic regulation.〈/p〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Natural Sciences in General
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  • 6
    Publication Date: 2018-11-02
    Description: Genomic DNA forms chromatin, in which the nucleosome is the repeating unit. The mechanism by which RNA polymerase II (RNAPII) transcribes the nucleosomal DNA remains unclear. Here we report the cryo–electron microscopy structures of RNAPII-nucleosome complexes in which RNAPII pauses at the superhelical locations SHL(–6), SHL(–5), SHL(–2), and SHL(–1) of the nucleosome. RNAPII pauses at the major histone-DNA contact sites, and the nucleosome interactions with the RNAPII subunits stabilize the pause. These structures reveal snapshots of nucleosomal transcription, in which RNAPII gradually tears DNA from the histone surface while preserving the histone octamer. The nucleosomes in the SHL(–1) complexes are bound to a "foreign" DNA segment, which might explain the histone transfer mechanism. These results provide the foundations for understanding chromatin transcription and epigenetic regulation.
    Keywords: Biochemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 7
    Publication Date: 2017-04-15
    Description: Nucleosomes are dynamic entities that are repositioned along DNA by chromatin remodeling processes. A nucleosome repositioned by the switch-sucrose nonfermentable (SWI/SNF) remodeler collides with a neighbor and forms the intermediate "overlapping dinucleosome." Here, we report the crystal structure of the overlapping dinucleosome, in which two nucleosomes are associated, at 3.14-angstrom resolution. In the overlapping dinucleosome structure, the unusual "hexasome" nucleosome, composed of the histone hexamer lacking one H2A-H2B dimer from the conventional histone octamer, contacts the canonical "octasome" nucleosome, and they intimately associate. Consequently, about 250 base pairs of DNA are left-handedly wrapped in three turns, without a linker DNA segment between the hexasome and octasome moieties. The overlapping dinucleosome structure may provide important information to understand how nucleosome repositioning occurs during the chromatin remodeling process.
    Keywords: Biochemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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