title: Ringlike structure of the Deinococcus radiodurans genome: a key to radioresistance?
abstract: The bacterium Deinococcus radiodurans survives ionizing irradiation and other DNA-damaging assaults at doses that are lethal to all other organisms. How D. radiodurans accurately reconstructs its genome from hundreds of radiation-generated fragments in the absence of an intact template is unknown. Here we show that the D. radiodurans genome assumes an unusual toroidal morphology that may contribute to its radioresistance. We propose that, because of restricted diffusion within the tightly packed and laterally ordered DNA toroids, radiation-generated free DNA ends are held together, which may facilitate template-independent yet error-free joining of DNA breaks.
authors.affiliation: Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Smadar
authors.initials: S
authors.lastname: Levin-Zaidman
authors.forename: Joseph
authors.initials: J
authors.lastname: Englander
authors.forename: Eyal
authors.initials: E
authors.lastname: Shimoni
authors.forename: Ajay K
authors.initials: AK
authors.lastname: Sharma
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Minton
authors.forename: Abraham
authors.initials: A
authors.lastname: Minsky
mesh_terms: D002843:Chromatin / Q000648:ultrastructure; D003037:Cobalt Radioisotopes; D004249:DNA Damage; D004260:DNA Repair; D004269:DNA, Bacterial / Q000032:analysis / Q000378:metabolism / Q000528:radiation effects / Q000648:ultrastructure*; D034301:Deinococcus / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure; D016680:Genome, Bacterial; D008345:Manganese / Q000378:metabolism; D017895:Manganese Compounds / Q000494:pharmacology; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D009690:Nucleic Acid Conformation; D011836:Radiation Tolerance; D011839:Radiation, Ionizing; D011938:Rec A Recombinases / Q000378:metabolism; D011995:Recombination, Genetic; D013431:Sulfates / Q000494:pharmacology; D013698:Templates, Genetic; D014466:Ultraviolet Rays
chemical_list: D002843:Chromatin; D003037:Cobalt Radioisotopes; D004269:DNA, Bacterial; D017895:Manganese Compounds; D013431:Sulfates; D008345:Manganese; D011938:Rec A Recombinases; C039798:manganese sulfate