The CRYPTOCHROME1-Dependent Response to Excess Light Is Mediated through the Transcriptional Activators ZINC FINGER PROTEIN EXPRESSED IN INFLORESCENCE MERISTEM LIKE1 and ZML2 in Arabidopsis

• Published in: The Plant cell Vol. 24; no. 7; pp. 3009 - 3025
• Main Authors: Shaikhali, Jehad, de Dios Barajas-Lopéz, Juan, Ötvös, Krisztina, Kremnev, Dmitry, Garcia, Ana Sánchez, Srivastava, Vaibhav, Wingsle, Gunnar, Bako, Laszlo, Strand, Åsa
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Biologists 01-07-2012
• Subjects: Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - physiology; Arabidopsis - radiation effects; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Biochemistry and Molecular Biology; Biokemi och molekylärbiologi; Cell Biology; Cellbiologi; Cryptochromes - genetics; Cryptochromes - metabolism; DNA; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; GATA transcription factors; GATA Transcription Factors - genetics; GATA Transcription Factors - metabolism; Gene Expression Regulation, Plant - genetics; Genes; Inflorescence - genetics; Inflorescence - metabolism; Inflorescence - physiology; Inflorescence - radiation effects; Light; Meristem - genetics; Meristem - metabolism; Meristem - physiology; Meristem - radiation effects; Models, Molecular; Mutagenesis, Insertional; Phenotype; Photosystem II Protein Complex - physiology; Plant Biotechnology; Plant cells; Plants; Polymerase chain reaction; Protein Interaction Mapping; Protein Multimerization; Proteins; Protoplasts; Reactive Oxygen Species - metabolism; Recombinant Fusion Proteins; Regulon - genetics; Response Elements - genetics; Seedlings; Seedlings - genetics; Seedlings - metabolism; Seedlings - physiology; Seedlings - radiation effects; Transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism; Transcriptional Activation; Växtbioteknologi
• ISSN: 1040-4651; 1532-298X; 1532-298X
• DOI: 10.1105/tpc.112.100099

Exposure of plants to light intensities that exceed the electron utilization capacity of the chloroplast has a dramatic impact on nuclear gene expression. The photoreceptor Cryptochrome 1 (cry1) is essential to the induction of genes encoding photoprotective components in Arabidopsis thaliana. Bioinformatic analysis of the cry1 regulon revealed the putative cis-element CryR1 (GnTCKAG), and here we demonstrate an interaction between CryR1 and the zinc finger GATA-type transcription factors ZINC FINGER PROTEIN EXPRESSED IN INFLORESCENCE MERISTEM LIKE1 (ZML1) and ZML2. The ZML proteins specifically bind to the CryR1 cis-element as demonstrated in vitro and in vivo, and TCTAG was shown to constitute the core sequence required for ZML2 binding. In addition, ZML2 activated transcription of the yellow fluorescent protein reporter gene driven by the CryR1 cis-element in Arabidopsis leaf protoplasts. T-DNA insertion lines for ZML2 and its homolog ZML1 demonstrated misregulation of several cry1-dependent genes in response to excess light. Furthermore, the zml1 and zml2 T-DNA insertion lines displayed a high irradiance-sensitive phenotype with significant photoinactivation of photosystem II (PSII), indicated by reduced maximum quantum efficiency of PSII, and severe photobleaching. Thus, we identified the ZML2 and ZML1 GATA transcription factors as two essential components of the cry1-mediated photoprotective response.