title: Mutations affecting light regulation of nuclear genes encoding chloroplast glyceraldehyde-3-phosphate dehydrogenase in Arabidopsis.
abstract: Expression of nuclear genes that encode the A and B subunits of chloroplast glyceraldehyde-3-phosphate dehydrogenase (GAPA and GAPB) of Arabidopsis is known to be regulated by light. We used a negative selection approach to isolate mutants that were defective in light-regulated expression of the GAPA gene. Two dominant mutants belonging to the same complementation group, uga1-1 and uga1-2, were then characterized. These two mutants showed a dramatic reduction in GAPA mRNA level in both mature plants and seedlings. Surprisingly, mutations in uga1-1 and uga1-2 had no effect on the expression of GAPB and several other light-regulated genes. In addition, we found that the chloroplast glyceraldehyde-3-phosphate dehydrogenase enzyme activity of the mutants was only slightly lower than that of the wild type. Western-blot analysis showed that the GAPA protein level was nearly indistinguishable between the wild-type and the uga mutants. These results suggested that posttranscriptional control was involved in the up-regulation of the GAPA protein in the mutants. The uga1-1 mutation was mapped to the bottom arm of chromosome V of the Arabidopsis genome.
authors.affiliation: Department of Biological Sciences, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Chui Sien
authors.initials: CS
authors.lastname: Chan
authors.forename: Hsiao-Ping
authors.initials: HP
authors.lastname: Peng
authors.forename: Ming-Che
authors.initials: MC
authors.lastname: Shih
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000528:radiation effects; D002467:Cell Nucleus / Q000235:genetics; D002736:Chloroplasts / Q000201:enzymology*; D002874:Chromosome Mapping; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000528:radiation effects; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics*; D008027:Light; D009154:Mutation / Q000235:genetics*
chemical_list: D005987:Glyceraldehyde-3-Phosphate Dehydrogenases