title: Towards understanding the extreme radiation resistance of Ustilago maydis.
abstract: Ustilago maydis is a phytopathogenic fungus exhibiting extreme resistance to UV and ionizing radiation. The molecular mechanisms underlying this resistance are as yet unknown. The recently determined genome sequence was examined for clues to the radiation resistance, focusing on proteins in homologous recombination, but there was little that was unusual about them. Furthermore, by comparison, its recombinational repair system seems to be only minimally related to the extended synthesis-dependent DNA strand-annealing system of Deinococcus radiodurans. Thus, consideration should be given to the possibility that incremental structural changes in repair proteins or their elevated expression are the basis for the extreme radiation resistance in U. maydis. Evolution of a system enabling the survival of U. maydis under such conditions could be a secondary consequence of adaptation to an environment of continual genotoxic stress encountered in its habitat.
authors.affiliation: Cornell University Weill Medical College, Department of Microbiology and Immunology, New York, NY 10021, USA. wkhollo@med.cornell.edu
authors.forename: William K
authors.initials: WK
authors.lastname: Holloman
authors.forename: Jan
authors.initials: J
authors.lastname: Schirawski
authors.forename: Robin
authors.initials: R
authors.lastname: Holliday
mesh_terms: D000818:Animals; D005075:Biological Evolution; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000235:genetics; D034301:Deinococcus / Q000235:genetics / Q000528:radiation effects; D011836:Radiation Tolerance / Q000235:genetics*; D011839:Radiation, Ionizing; D011995:Recombination, Genetic; D014466:Ultraviolet Rays; D014588:Ustilago / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects*
chemical_list: D045643:DNA Repair Enzymes