Functional analysis of a light-responsive plant bZIP transcriptional regulator

• Published in: The Plant cell Vol. 6; no. 11; pp. 1607 - 1621
• Main Authors: Feldbrügge, Michael, Sprenger, Markus, Dinkelbach, Maria, Yazaki, Kazufumi, Harter, Klaus, Weisshaar, Bernd
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Physiologists 01.11.1994
• Subjects: Acyltransferases - biosynthesis; Acyltransferases - genetics; adn; adn recombinado; adn recombine; Amino Acid Sequence; arn mensajero; arn messager; Base Sequence; chemical composition; Complementary DNA; composicion quimica; composition chimique; DNA; DNA-Binding Proteins - biosynthesis; DNA-Binding Proteins - genetics; expresion genica; expression des genes; gene; gene expression; Gene Expression Regulation, Plant - radiation effects; Genes; genetica; genetics; genetique; glicosidasas; glycosidase; glycosidases; Leucine Zippers; Light; lumiere; luz; Messenger RNA; Molecular Sequence Data; nucleotide sequence; Open reading frames; Parsley; petroselinum crispum; Plant cells; Plant Proteins - biosynthesis; Plant Proteins - genetics; Plasmids; Promoter Regions, Genetic - genetics; proteinas; proteine; proteins; Protoplasts; Reading Frames; recombinant dna; secuencia nucleica; Seedlings; Seeds - growth & development; sequence nucleique; Space life sciences; transferasas; transferase; transferases; Vegetables - genetics; Vegetables - growth & development; Vegetables - metabolism; Vegetables - radiation effects
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.6.11.1607

Common plant regulatory factor 1 (CPRF1) is a parsley basic region/leucine zipper (bZIP) transcription factor that recognizes specific nucleotide sequences containing ACGT cores. Such a sequence is contained within LRU1, the composite light regulatory unit that is necessary and sufficient for light-dependent activity of the parsley chalcone synthase (CHS) promoter. After light treatment of both and green seedlings, mRNA levels increased prior to CHS mRNA accumulation. The change in CPRF1 mRNA leads to a light-responsive increase in CPRF1 protein. Transient expression analysis in parsley protoplasts using the CPRF1 promoter fused to the beta-glucuronidase (GUS) open reading frame indicated that light-dependent CPRF1 mRNA accumulation was under transcriptional control. The 5' untranslated region of the CPRF1 gene includes a cis-acting nucleotide sequence that contains two ACGT elements at a distance of 12 bp between their palindromic centers. This feature is reminiscent of as-1 and octopine synthase (ocs) elements identified in promoters from plant pathogens. This double ACGT Element element, designated dACE CPRFs, stimulated transcription when placed 5' to a heterologous core promoter. CPRF1 bound to dACE CPRF1 DNA as well as to the ACGT element from the CHS promoter in vitro. Cotransfection experiments demonstrated that CPRF1 interacts with these elements in vivo and that overexpression of CPRF1 actually reduced light-dependent transcription from the CHS promoter. CPRF1 thus appears to contribute to the regulation of the CPRF1 gene and to interfere with the activities of light-regulated promoters.