title: ATR and ATM play both distinct and additive roles in response to ionizing radiation.
abstract: The ATR and ATM protein kinases are known to be involved in a wide variety of responses to DNA damage. The Arabidopsis thaliana genome includes both ATR and ATM orthologs, and plants with null alleles of these genes are viable. Arabidopsis atr and atm mutants display hypersensitivity to gamma-irradiation. To further characterize the roles of ATM and ATR in response to ionizing radiation, we performed a short-term global transcription analysis in wild-type and mutant lines. We found that hundreds of genes are upregulated in response to gamma-irradiation, and that the induction of virtually all of these genes is dependent on ATM, but not ATR. The transcript of CYCB1;1 is unique among the cyclin transcripts in being rapidly and powerfully upregulated in response to ionizing radiation, while other G(2)-associated transcripts are suppressed. We found that both ATM and ATR contribute to the induction of a CYCB1;1:GUS fusion by IR, but only ATR is required for the persistence of this response. We propose that this upregulation of CYCB1;1 does not reflect the accumulation of cells in G(2), but instead reflects a still unknown role for this cyclin in DNA damage response.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of New Hampshire, Durham, NH 03824, USA. k.culligan@unh.edu
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Culligan
authors.forename: Clare E
authors.initials: CE
authors.lastname: Robertson
authors.forename: Julia
authors.initials: J
authors.lastname: Foreman
authors.forename: Peter
authors.initials: P
authors.lastname: Doerner
authors.forename: Anne B
authors.initials: AB
authors.lastname: Britt
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D064007:Ataxia Telangiectasia Mutated Proteins; D002453:Cell Cycle / Q000528:radiation effects; D018797:Cell Cycle Proteins / Q000502:physiology*; D019926:Cyclin B / Q000235:genetics; D004249:DNA Damage / Q000528:radiation effects; D018744:DNA, Plant / Q000528:radiation effects; D005720:Gamma Rays; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D014158:Transcription, Genetic / Q000528:radiation effects; D015854:Up-Regulation
chemical_list: C576589:ATM protein, Arabidopsis; D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C462528:CycB1 protein, Arabidopsis; D019926:Cyclin B; D018744:DNA, Plant; C576892:ATR protein, Arabidopsis; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases