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Biochemistry Seminar: Karim-Jean Armache, NYU Langone Med Center

  • Date
    Wed, Apr 30

    Time
    12:00 PM — 1:00 PM

    Address
    Marshak
    City College of New York
    160 Convent Ave

    Location
    Marshak, MR 1027

    p: 212.650.8803

    Admission
    Free

  • Event Details

    Karim-Jean Armache, NYU LMC, will give a talk on "Structural characterization of silent chromatin"

    Karim-Jean Armache, Asst. Prof. of Dept of Biochemistry & Molecular Pharmacology, NYU Langone Medical Center, will give a talk on "Structural characterization of silent chromatin"


    ABSTRACT

    Gene silencing is essential for regulating cell fate in eukaryotes. It has been shown that gene silencing factors can specifically bind and organize nucleosomes to form higher-order, compacted chromatin structures and that binding of these factors is regulated by posttranslational modifications of histone tails. I will discuss our structural and biochemical studies of silencing complexes, one example being a structure formed by the silencing domain of Sir3 on a nucleosome. The ‘silent information regulator’ (SIR) complex mediates heterochromatin formation at the mating type loci and telomeres in budding yeast. The crystal structure of the Sir3 BAH domain bound to a nucleosome core particle shows an extensive correlation between molecular contacts and mutations that were shown by genetic screens to impact silencing. Moreover the structure explains how covalent modifications on histone H4 lysine 16 (H4K16) and histone H3 lysine 79 (H3K79) regulate formation of a silencing complex that contains the nucleosome as a central component. Our data provide the visualization of a structure that silences genes important to determine cell fate, a hallmark issue in epigenetics.
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