title: Regulatory functions and chromatin loading dynamics of linker histone H1 during endoreplication inDrosophila.
abstract: Eukaryotic DNA replicates asynchronously, with discrete genomic loci replicating during different stages of S phase.Drosophilalarval tissues undergo endoreplication without cell division, and the latest replicating regions occasionally fail to complete endoreplication, resulting in underreplicated domains of polytene chromosomes. Here we show that linker histone H1 is required for the underreplication (UR) phenomenon inDrosophilasalivary glands. H1 directly interacts with the Suppressor of UR (SUUR) protein and is required for SUUR binding to chromatin in vivo. These observations implicate H1 as a critical factor in the formation of underreplicated regions and an upstream effector of SUUR. We also demonstrate that the localization of H1 in chromatin changes profoundly during the endocycle. At the onset of endocycle S (endo-S) phase, H1 is heavily and specifically loaded into late replicating genomic regions and is then redistributed during the course of endoreplication. Our data suggest that cell cycle-dependent chromosome occupancy of H1 is governed by several independent processes. In addition to the ubiquitous replication-related disassembly and reassembly of chromatin, H1 is deposited into chromatin through a novel pathway that is replication-independent, rapid, and locus-specific. This cell cycle-directed dynamic localization of H1 in chromatin may play an important role in the regulation of DNA replication timing.
authors.affiliation: Institute of Molecular and Cellular Biology, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russian Federation.
authors.forename: Evgeniya N
authors.initials: EN
authors.lastname: Andreyeva
authors.affiliation: Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Travis J
authors.initials: TJ
authors.lastname: Bernardo
authors.affiliation: Institute of Molecular and Cellular Biology, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russian Federation.|Novosibirsk State University, Novosibirsk 630090, Russian Federation.
authors.forename: Tatyana D
authors.initials: TD
authors.lastname: Kolesnikova
authors.affiliation: Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Xingwu
authors.initials: X
authors.lastname: Lu
authors.affiliation: Institute of Molecular and Cellular Biology, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russian Federation.|Novosibirsk State University, Novosibirsk 630090, Russian Federation.
authors.forename: Lyubov A
authors.initials: LA
authors.lastname: Yarinich
authors.affiliation: Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Boris A
authors.initials: BA
authors.lastname: Bartholdy
authors.affiliation: Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Xiaohan
authors.initials: X
authors.lastname: Guo
authors.affiliation: Institute of Molecular and Cellular Biology, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russian Federation.
authors.forename: Olga V
authors.initials: OV
authors.lastname: Posukh
authors.affiliation: Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Sean
authors.initials: S
authors.lastname: Healton
authors.affiliation: Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Willcockson
authors.affiliation: Institute of Molecular and Cellular Biology, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russian Federation.
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Pindyurin
authors.affiliation: Institute of Molecular and Cellular Biology, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russian Federation.|Novosibirsk State University, Novosibirsk 630090, Russian Federation.
authors.forename: Igor F
authors.initials: IF
authors.lastname: Zhimulev
authors.affiliation: Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Arthur I
authors.initials: AI
authors.lastname: Skoultchi
authors.affiliation: Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: Dmitry V
authors.initials: DV
authors.lastname: Fyodorov
mesh_terms: D000818:Animals; D002843:Chromatin / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004330:Drosophila / Q000235:genetics* / Q000254:growth & development; D029721:Drosophila Proteins / Q000378:metabolism; D062951:Endoreduplication; D006570:Heterochromatin / Q000378:metabolism; D006657:Histones / Q000378:metabolism*; D007814:Larva / Q000235:genetics / Q000378:metabolism; D016196:S Phase / Q000235:genetics; D012469:Salivary Glands / Q000378:metabolism
chemical_list: D002843:Chromatin; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D006570:Heterochromatin; D006657:Histones; C464850:SuUR protein, Drosophila
keywords: endoreplication; intercalary heterochromatin; linker histone H1; polytene chromosomes; replication timing; suppressor of underreplication