Functional dissection of circadian clock- and phytochrome-regulated transcription of the Arabidopsis CAB2 gene.

AUTOR(ES)

Anderson, S L

RESUMO

Both the circadian clock and phytochrome regulate expression of the Arabidopsis genes encoding the light-harvesting chlorophyll a/b-binding proteins (CAB genes). Phytochrome activates CAB transcription, and it has been proposed that the circadian clock negatively regulates CAB transcription. The tobacco nuclear proteins CUF-1 (CAB upstream factor 1) and CGF-1 (CAB GATA factor 1) bind the Arabidopsis CAB2 promoter, and the CGF-1 binding site is contained within a minimal clock- and phytochrome-regulated region of the promoter. We have used in vivo cab2::luciferase gene bioluminescence markers containing site-directed mutations in the CUF-1 and CGF-1 binding sites to define the role of these proteins in CAB2 regulation and to further delineate the terminal genomic targets of the phytochrome and circadian clock signal transduction pathways. Results from these studies confirm that CUF-1 is not required to generate the circadian clock- or phytochrome-responsive CAB2 expression pattern but rather functions as a positive factor to increase CAB2 expression levels. CGF-1 interaction with the CAB2 promoter mediates the acute increase in CAB2 expression in response to phytochrome activation and contributes to the light-induced high-amplitude circadian oscillation in CAB2 expression.

Documentos Relacionados

• Arabidopsis PSEUDO-RESPONSE REGULATOR7 Is a Signaling Intermediate in Phytochrome-Regulated Seedling Deetiolation and Phasing of the Circadian Clock
• The Involvement of Gibberellin 20-Oxidase Genes in Phytochrome-Regulated Petiole Elongation of Arabidopsis
• Guanine nucleotide binding protein involvement in early steps of phytochrome-regulated gene expression.
• A Clock- and Light-Regulated Gene That Links the Circadian Oscillator to LHCB Gene Expression
• Nuclear-Cytoplasmic Partitioning of Phytochrome-Regulated Transcripts in Pisum sativum1