title: Relaxed Chromatin Formation and Weak Suppression of Homologous Pairing by the Testis-Specific Linker Histone H1T.
abstract: Linker histones bind to nucleosomes and compact polynucleosomes into a higher-order chromatin configuration. Somatic and germ cell-specific linker histone subtypes have been identified and may have distinct functions. In this study, we reconstituted polynucleosomes containing human histones H1.2 and H1T, as representative somatic and germ cell-specific linker histones, respectively, and found that H1T forms less compacted chromatin, as compared to H1.2. An in vitro homologous pairing assay revealed that H1T weakly inhibited RAD51/RAD54-mediated homologous pairing in chromatin, although the somatic H1 subtypes, H1.0, H1.1, H1.2, H1.3, H1.4, and H1.5, substantially suppressed it. An in vivo recombination assay revealed that H1T overproduction minimally affected the recombination frequency, but significant suppression was observed when H1.2 was overproduced in human cells. These results suggested that the testis-specific linker histone, H1T, possesses a specific function to produce the chromatin architecture required for proper chromosome regulation, such as homologous recombination.
authors.affiliation: Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University , 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Machida
authors.affiliation: Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University , 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Hayashida
authors.affiliation: Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University , 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Motoki
authors.initials: M
authors.lastname: Takaku
authors.affiliation: Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University , 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Fukuto
authors.affiliation: Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University , 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
authors.forename: Jiying
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University , 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
authors.forename: Aiko
authors.initials: A
authors.lastname: Kinomura
authors.affiliation: Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University , 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tashiro
authors.affiliation: Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University , 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.|Institute for Medical-oriented Structural Biology, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kurumizaka
mesh_terms: D002460:Cell Line; D004265:DNA Helicases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D006657:Histones / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D006801:Humans; D009687:Nuclear Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009707:Nucleosomes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D051135:Rad51 Recombinase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011995:Recombination, Genetic
chemical_list: D004268:DNA-Binding Proteins; D006657:Histones; D009687:Nuclear Proteins; D009707:Nucleosomes; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; D004265:DNA Helicases; C103532:RAD54L protein, human