title: Nucleosome linker proteins HMGB1 and histone H1 differentially enhance DNA ligation reactions.
abstract: We previously reported that HMGB1, which originally binds to chromatin in a manner competitive with linker histone H1 to modulate chromatin structure, enhances both intra-molecular and inter-molecular ligations. In this paper, we found that histone H1 differentially enhances ligation reaction of DNA double-strand breaks (DSB). Histone H1 stimulated exclusively inter-molecular ligation reaction of DSB with DNA ligase IIIbeta and IV, whereas HMGB1 enhanced mainly intra-molecular ligation reaction. Electron microscopy of direct DNA-protein interaction without chemical cross-linking visualized that HMGB1 bends and loops linear DNA to form compact DNA structure and that histone H1 is capable of assembling DNA in tandem arrangement with occasional branches. These results suggest that differences in the enhancement of DNA ligation reaction are due to those in alteration of DNA configuration induced by these two linker proteins. HMGB1 and histone H1 may function in non-homologous end-joining of DSB repair and V(D)J recombination in different manners.
authors.affiliation: Department of Pathological Biochemistry, Medical Research Institute, Tokyo Medical and Dental University, Chiyoda-ku, Tokyo, 101-0062, Japan
authors.forename: Shiho
authors.initials: S
authors.lastname: Yamanaka
authors.forename: Eisaku
authors.initials: E
authors.lastname: Katayama
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Yoshioka
authors.forename: Sumiko
authors.initials: S
authors.lastname: Nagaki
authors.forename: Michiteru
authors.initials: M
authors.lastname: Yoshida
authors.forename: Hirobumi
authors.initials: H
authors.lastname: Teraoka
mesh_terms: D004247:DNA / Q000378:metabolism* / Q000648:ultrastructure; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000378:metabolism*; D024243:HMGB1 Protein / Q000494:pharmacology*; D006657:Histones / Q000494:pharmacology*; D009707:Nucleosomes / Q000201:enzymology; D000075223:Poly-ADP-Ribose Binding Proteins; D029867:Xenopus Proteins
chemical_list: D024243:HMGB1 Protein; D006657:Histones; D009707:Nucleosomes; D000075223:Poly-ADP-Ribose Binding Proteins; D029867:Xenopus Proteins; D004247:DNA; D011088:DNA Ligases; D000072481:DNA Ligase ATP; C000618816:DNA ligase III alpha protein, Xenopus