Mutations in the DET1 gene affect cell-type-specific expression of light-regulated genes and chloroplast development in Arabidopsis.
When grown in the absence of light, the det1 mutant of Arabidopsis thaliana develops characteristics of a light-grown plant by morphological, cellular, and molecular criteria. Here, we show that recessive mutations at the DET1 locus also result in cell-type inappropriate accumulation of RNAs for light-regulated nuclear and chloroplast genes. det1 root plastids are differentiated into chloroplasts and are present in very high numbers in root cortex cells in contrast to the few starch-containing amyloplasts normally found in Arabidopsis roots. To assay the effect of the det1 mutation on the expression of photoregulated promoters, we used fusion constructs to stably transform wild-type and det1 mutants. We show that the three red-light-regulated chlorophyll a/b binding protein promoters are inappropriately expressed in the roots of det1 seedlings and the blue-light-controlled anthocyanin biosynthetic gene, chalcone synthase, is expressed ectopically in leaf mesophyll cells. These results, together with out previous findings, suggest that the DET1 gene product is a negatively acting regulatory molecule that is used in common by the light stimulus transduction pathway and by temporal or spatial regulatory signals in plants.
Chory
J
J
Plant Biology Laboratory, Salk Institute for Biological Studies, San Diego, CA 92138.
Peto
C A
CA
D015152:Blotting, Northern; D002736:Chloroplasts / Q000502:physiology* / Q000648:ultrastructure; D003001:Cloning, Molecular; D005786:Gene Expression Regulation; D008027:Light; D008854:Microscopy, Electron; D010944:Plants / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
D012333:RNA, Messenger