Isolation of uvh1, an Arabidopsis mutant hypersensitive to ultraviolet light and ionizing radiation.
A genetic screen for mutants of Arabidopsis that are hypersensitive to UV light was developed and used to isolate a new mutant designated uvh1. UV hypersensitivity in uvh1 was due to a single recessive trait that is probably located on chromosome 3. Although isolated as hypersensitive to an acute exposure to UV-C light, uvh1 was also hypersensitive to UV-B wavelengths, which are present in sunlight that reaches the earth's surface. UV-B damage to both wild-type and uvh1 plants could be significantly reduced by subsequent exposure of UV-irradiated plants to photoreactivating light, showing that photoreactivation of UV-B damage is important for plant viability and that uvh1 plants are not defective in photoreactivation. A new assay for DNA damage, the Dral assay, was developed and used to show that exposure of wild-type and uvh1 plants to a given dose of UV light induces the same amount of damage in chloroplast and nuclear DNA. Thus, uvh1 is not defective in a UV protective mechanism. uvh1 plants were also found to be hypersensitive to ionizing radiation. These results suggest that uvh1 is defective in a repair or tolerance mechanism that normally provides plants with resistance to several types of DNA damage.
Harlow
G R
GR
Department of Molecular and Cellular Biology, University of Arizona, Tucson 85721.
Jenkins
M E
ME
Pittalwala
T S
TS
Mount
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DW
D017360:Arabidopsis / Q000235:genetics* / Q000528:radiation effects; D002467:Cell Nucleus / Q000528:radiation effects; D002736:Chloroplasts / Q000528:radiation effects; D004247:DNA / Q000528:radiation effects*; D004249:DNA Damage; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D017343:Genes, Plant; D005808:Genes, Recessive; D008027:Light; D016296:Mutagenesis; D013472:Sunlight; D014466:Ultraviolet Rays
D004247:DNA