New Arabidopsis cue mutants suggest a close connection between plastid- and phytochrome regulation of nuclear gene expression

• Published in: Plant physiology (Bethesda) 1998-11, Vol.118 (3), p.803-815
• Main Authors: Lopez-Juez, E. (The Salk Institute, La Jolla, CA.), Jarvis, R.P, Takeuchi, A, Page, A.M, Chory, J
• Format: Article
• Language: English
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; AHILAMIENTO; ANATOMIA DE LA PLANTA; ANATOMIE VEGETALE; Arabidopsis - genetics; Arabidopsis - ultrastructure; ARABIDOPSIS THALIANA; Biological and medical sciences; BIOSINTESIS; BIOSYNTHESE; BIOSYNTHESIS; CAB3 GENES; CELL STRUCTURE; CHLOROPHYLL A/B-BINDING PROTEIN-UNDEREXPRESSED MUTANTS; CHLOROPHYLLE; CHLOROPHYLLS; Chloroplasts; CLOROFILAS; CONTENIDO PROTEICO; DARKNESS; ENZYMIC ACTIVITY; ESTRUCTURA CELULAR; ETIOLATION; ETIOLEMENT; EXPRESION GENICA; EXPRESSION DES GENES; FENOTIPOS; FITOCROMA; Fundamental and applied biological sciences. Psychology; GENE; GENE EXPRESSION; Gene expression regulation; Gene Expression Regulation, Plant; GENES; Genetic mutation; GENETIC REGULATION; GENETIC VARIATION; GENETICA; GENETICS; GENETIQUE; GENOTIPOS; GENOTYPE; GENOTYPES; Growth and Development; LIGHT; LIGHT HARVESTING COMPLEXES; Light-Harvesting Protein Complexes; LUMIERE; LUZ; Microscopy, Electron; Molecular and cellular biology; Molecular genetics; MUTANT; MUTANTES; MUTANTS; Mutation; NOYAU CELLULAIRE; NUCLEI; NUCLEO; NUCLEUS; OBSCURIDAD; OBSCURITE; OXIDOREDUCTASES; OXIDORREDUCTASAS; OXYDOREDUCTASE; PHENOTYPE; PHENOTYPES; Photosynthetic Reaction Center Complex Proteins - genetics; PHYTOCHROME; Phytochrome - metabolism; PLANT ANATOMY; Plant cells; Plants; PLANTULAS; PLANTULE; PLASTE; PLASTIDIOS; PLASTIDS; Plastids - metabolism; PROTEIN CONTENT; PROTEINAS; PROTEINE; PROTEINS; PROTOCHLOROPHYLLIDES; SEEDLINGS; STRUCTURE CELLULAIRE; TENEUR EN PROTEINES; ULTRAESTRUCTURA; ULTRASTRUCTURE; VARIACION GENETICA; VARIATION GENETIQUE
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.118.3.803

We searched for new components that are involved in the positive regulation of nuclear gene expression by light by extending a screen for Arabidopsis cue (chlorophyll a/b-binding [CAB] protein-underexpressed) mutants (H.-M. Li, K. Culligan, R.A. Dixon, J. Chory [1995] Plant Cell 7: 1599-1610). cue mutants display reduced expression of the CAB3 gene, which encodes light-harvesting chlorophyll protein, the main chloroplast antenna. The new mutants can be divided into (a) phytochrome-deficient mutants (hy1 and phyB), (b) virescent or delayed-greening mutants (cue3, cue6, and cue8), and (c) uniformly pale mutants (cue4 and cue9). For each of the mutants, the reduction in CAB expression correlates with the visible phenotype, defective chloroplast development, and reduced abundance of the light-harvesting chlorophyll protein. Levels of protochlorophyllide oxidoreductase (POR) were reduced to varying degrees in etiolated mutant seedlings. In the dark, whereas the virescent mutants displayed reduced CAB expression and the lowest levels of POR protein, the other mutants expressed CAB and accumulated POR at near wild-type levels. All of the mutants, with the exception of cue6, were compromised in their ability to derepress CAB expression in response to phytochrome activation. Based on these results, we propose that the previously postulated plastid-derived signal is closely involved in the pathway through which phytochrome regulates the expression of nuclear genes encoding plastid proteins