title: Reversion-reporter transgenes to analyze all six base-substitution pathways in Arabidopsis.
abstract: To expand the repertoire of Arabidopsis (Arabidopsis thaliana) mutation-reporter transgenes, we constructed six mutant alleles in the same codon of the β-glucuronidase-encoding GUS transgene. Each allele reverts to GUS+ only via a particular one of the six transition/transversion pathways. AcV5 epitope tags, fused carboxyl terminal to the inactive GUS- proteins, enabled semiquantitative immunoassays in plant protein extracts. Spontaneous G:C→T:A transversions, previously not measured using reporter transgenes, were quite frequent. This may reflect mispairing of adenine with 8-oxoguanine in DNA attacked by endogenous oxyradicals. Spontaneous G:C→A:T was modest and other reversions were relatively low, as reported previously. Frequencies of ultraviolet C-induced TT→TC and TC→TT reversions were both high. With increased transgene copy number, spontaneous G:C→T:A reversions increased but ultraviolet C-induced reversions decreased. Frequencies of some reversion events were reduced among T4 versus T3 generation plants. Based on these and other analyses of sources of experimental variation, we propose guidelines for the employment of these lines to study genotoxic stress in planta.
authors.affiliation: Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331-7302, USA.
authors.forename: Stephanie R
authors.initials: SR
authors.lastname: Bollmann
authors.forename: Colin M
authors.initials: CM
authors.lastname: Tominey
authors.forename: Peter D
authors.initials: PD
authors.lastname: Hoffman
authors.forename: Taylor M C
authors.initials: TM
authors.lastname: Hoffman
authors.forename: John B
authors.initials: JB
authors.lastname: Hays
mesh_terms: D000483:Alleles; D019943:Amino Acid Substitution / Q000235:genetics*; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000528:radiation effects; D001483:Base Sequence; D018628:Gene Dosage / Q000235:genetics; D017930:Genes, Reporter / Q000235:genetics*; D005818:Genetic Engineering / Q000379:methods*; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D007477:Ions; D008670:Metals; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000235:genetics / Q000528:radiation effects; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D030821:Plants, Genetically Modified; D017422:Sequence Analysis, DNA; D019076:Transgenes / Q000235:genetics*; D014466:Ultraviolet Rays
chemical_list: D007477:Ions; D008670:Metals; D050505:Mutant Proteins; D005966:Glucuronidase