Specificity versus redundancy in the RAP2.4 transcription factor family of Arabidopsis thaliana: transcriptional regulation of genes for chloroplast peroxidases

Autor: Ulrike Ellersiek, Elena Reifschneider, Jote Tafese Bulcha, Margarete Baier, Radoslaw Rudnik
Rok vydání: 2017
Předmět:
0301 basic medicine
DNA
Bacterial
Chloroplasts
Arabidopsis thaliana
Arabidopsis
Plant Science
Chloroplast
Gene Expression Regulation
Enzymologic
03 medical and health sciences
Ascorbate Peroxidases
Gene Expression Regulation
Plant
Two-Hybrid System Techniques
Gene expression
Transcriptional regulation
Ascorbate peroxidase Chloroplast
Gene Regulatory Networks
Promoter Regions
Genetic
Transcription factor
Gene
RAP2.4
Binding Sites
biology
Arabidopsis Proteins
food and beverages
Peroxiredoxin
Promoter
ROS
DNA-binding domain
DNA
Peroxiredoxins
biology.organism_classification
Molecular biology
Cell biology
030104 developmental biology
Peroxidases
ERF
Chloroplast-to-nucleus signaling
Antioxidant enzymes
Ascorbate peroxidase
Transcription Factor Gene
Reactive Oxygen Species
Protein Binding
Transcription Factors
Research Article
Zdroj: BMC Plant Biology
ISSN: 1471-2229
Popis: Background The Arabidopsis ERFIb / RAP2.4 transcription factor family consists of eight members with highly conserved DNA binding domains. Selected members have been characterized individually, but a systematic comparison is pending. The redox-sensitive transcription factor RAP2.4a mediates chloroplast-to-nucleus redox signaling and controls induction of the three most prominent chloroplast peroxidases, namely 2-Cys peroxiredoxin A (2CPA) and thylakoid- and stromal ascorbate peroxidase (tAPx and sAPx). To test the specificity and redundancy of RAP2.4 transcription factors in the regulation of genes for chloroplast peroxidases, we compared the DNA-binding sites of the transcription factors in tertiary structure models, analyzed transcription factor and target gene regulation by qRT-PCR in RAP2.4, 2-Cys peroxiredoxin and ascorbate peroxidase T-DNA insertion lines and RAP2.4 overexpressing lines of Arabidopsis thaliana and performed promoter binding studies. Results All RAP2.4 proteins bound the tAPx promoter, but only the four RAP2.4 proteins with identical DNA contact sites, namely RAP2.4a, RAP2.4b, RAP2.4d and RAP2.4h, interacted stably with the redox-sensitive part of the 2CPA promoter. Gene expression analysis in RAP2.4 knockout lines revealed that RAP2.4a is the only one supporting 2CPA and chloroplast APx expression. Rap2.4h binds to the same promoter region as Rap2.4a and antagonizes 2CPA expression. Like the other six RAP2.4 proteins, Rap2.4 h promotes APx mRNA accumulation. Chloroplast ROS signals induced RAP2.4b and RAP2.4d expression, but these two transcription factor genes are (in contrast to RAP2.4a) insensitive to low 2CP availability, and their expression decreased in APx knockout lines. RAP2.4e and RAP2.4f gradually responded to chloroplast APx availability and activated specifically APx expression. These transcription factors bound, like RAP2.4c and RAP2.4g, the tAPx promoter, but hardly the 2CPA promoter. Conclusions The RAP2.4 transcription factors form an environmentally and developmentally regulated transcription factor network, in which the various members affect the expression intensity of the others. Within the transcription factor family, RAP2.4a has a unique function as a general transcriptional activator of chloroplast peroxidase activity. The other RAP2.4 proteins mediate the fine-control and adjust the relative availability of 2CPA, sAPx and tAPx. Electronic supplementary material The online version of this article (doi:10.1186/s12870-017-1092-5) contains supplementary material, which is available to authorized users.
Databáze: OpenAIRE
Externí odkaz: