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DNA binding mechanism revealed by high resolution crystal structure of Arabidopsis thaliana WRKY1 protein.

Duan MR, Nan J, Liang YH, Mao P, Lu L, Li L, Wei C, Lai L, Li Y, Su XD - Nucleic Acids Res. (2007)

Bottom Line: Previous investigations showed that DNA binding of the WRKY proteins was localized at the WRKY domains and these domains may define novel zinc-binding motifs.A novel zinc-binding site is situated at one end of the beta-sheet, between strands beta4 and beta5.These results provided us with structural information to understand the mechanism of transcriptional control and signal transduction events of the WRKY proteins.

View Article: PubMed Central - PubMed

Affiliation: The National Laboratory of Protein Engineering and Plant Genetic Engineering, Peking University, Beijing 100871, PR China.

ABSTRACT
WRKY proteins, defined by the conserved WRKYGQK sequence, are comprised of a large superfamily of transcription factors identified specifically from the plant kingdom. This superfamily plays important roles in plant disease resistance, abiotic stress, senescence as well as in some developmental processes. In this study, the Arabidopsis WRKY1 was shown to be involved in the salicylic acid signaling pathway and partially dependent on NPR1; a C-terminal domain of WRKY1, AtWRKY1-C, was constructed for structural studies. Previous investigations showed that DNA binding of the WRKY proteins was localized at the WRKY domains and these domains may define novel zinc-binding motifs. The crystal structure of the AtWRKY1-C determined at 1.6 A resolution has revealed that this domain is composed of a globular structure with five beta strands, forming an antiparallel beta-sheet. A novel zinc-binding site is situated at one end of the beta-sheet, between strands beta4 and beta5. Based on this high-resolution crystal structure and site-directed mutagenesis, we have defined and confirmed that the DNA-binding residues of AtWRKY1-C are located at beta2 and beta3 strands. These results provided us with structural information to understand the mechanism of transcriptional control and signal transduction events of the WRKY proteins.

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Related in: MedlinePlus

AtWRKY1 is partially NPR1-dependent in SA pathway. Four weeks old wild type (Col-0), npr1-3 and 35S::NPR1 Arabidopsis were sprayed with 2 mM SA and harvested at indicated time points. PR1 transcripts were detected the same as AtWRKY1 except for the difference of probe. The ethidium bromide stain of rRNA is shown for each lane to allow assessment of equal loading.
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Figure 1: AtWRKY1 is partially NPR1-dependent in SA pathway. Four weeks old wild type (Col-0), npr1-3 and 35S::NPR1 Arabidopsis were sprayed with 2 mM SA and harvested at indicated time points. PR1 transcripts were detected the same as AtWRKY1 except for the difference of probe. The ethidium bromide stain of rRNA is shown for each lane to allow assessment of equal loading.

Mentions: SA is an important signal molecule in plant disease resistance. It has been previously shown that SA treatment can induce the expression of PR genes and activate systemic acquired resistance (SAR), which makes plants resistant against a spectrum of pathogens (47). To study the potential involvement of AtWRKY1 in SA signaling pathway and its possible relation to NPR1, a key protein in SAR, we characterized the expression profile of AtWRKY1 by RNA gel blot in wild-type Arabidopsis seedlings, npr1-3 mutant (12) and NPR1-H line (33) in response to exogenous SA treatment. As an important marker of SAR, PR1 was also examined to monitor the SA treatment procedure. In consistence with previous reports, PR1 began to accumulate at 4 h post-treatment and the induction of PR1 was abolished in npr1-3 while increased in NPR1-H than that in wild type (Figure 1). The induced expression of AtWRKY1 was observed after 8 h post-treatment and became obvious later than that of PR1. In npr1-3, AtWRKY1 can still be expressed but at a lower level than that in wild-type plants. The opposite trend appeared in NPR1-H with higher expression level of AtWRKY1 than in wild type (Figure 1). These data suggested that AtWRKY1 was involved in SA signaling pathway and its induced expression was partially dependent on NPR1.Figure 1.


DNA binding mechanism revealed by high resolution crystal structure of Arabidopsis thaliana WRKY1 protein.

Duan MR, Nan J, Liang YH, Mao P, Lu L, Li L, Wei C, Lai L, Li Y, Su XD - Nucleic Acids Res. (2007)

AtWRKY1 is partially NPR1-dependent in SA pathway. Four weeks old wild type (Col-0), npr1-3 and 35S::NPR1 Arabidopsis were sprayed with 2 mM SA and harvested at indicated time points. PR1 transcripts were detected the same as AtWRKY1 except for the difference of probe. The ethidium bromide stain of rRNA is shown for each lane to allow assessment of equal loading.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1851648&req=5

Figure 1: AtWRKY1 is partially NPR1-dependent in SA pathway. Four weeks old wild type (Col-0), npr1-3 and 35S::NPR1 Arabidopsis were sprayed with 2 mM SA and harvested at indicated time points. PR1 transcripts were detected the same as AtWRKY1 except for the difference of probe. The ethidium bromide stain of rRNA is shown for each lane to allow assessment of equal loading.
Mentions: SA is an important signal molecule in plant disease resistance. It has been previously shown that SA treatment can induce the expression of PR genes and activate systemic acquired resistance (SAR), which makes plants resistant against a spectrum of pathogens (47). To study the potential involvement of AtWRKY1 in SA signaling pathway and its possible relation to NPR1, a key protein in SAR, we characterized the expression profile of AtWRKY1 by RNA gel blot in wild-type Arabidopsis seedlings, npr1-3 mutant (12) and NPR1-H line (33) in response to exogenous SA treatment. As an important marker of SAR, PR1 was also examined to monitor the SA treatment procedure. In consistence with previous reports, PR1 began to accumulate at 4 h post-treatment and the induction of PR1 was abolished in npr1-3 while increased in NPR1-H than that in wild type (Figure 1). The induced expression of AtWRKY1 was observed after 8 h post-treatment and became obvious later than that of PR1. In npr1-3, AtWRKY1 can still be expressed but at a lower level than that in wild-type plants. The opposite trend appeared in NPR1-H with higher expression level of AtWRKY1 than in wild type (Figure 1). These data suggested that AtWRKY1 was involved in SA signaling pathway and its induced expression was partially dependent on NPR1.Figure 1.

Bottom Line: Previous investigations showed that DNA binding of the WRKY proteins was localized at the WRKY domains and these domains may define novel zinc-binding motifs.A novel zinc-binding site is situated at one end of the beta-sheet, between strands beta4 and beta5.These results provided us with structural information to understand the mechanism of transcriptional control and signal transduction events of the WRKY proteins.

View Article: PubMed Central - PubMed

Affiliation: The National Laboratory of Protein Engineering and Plant Genetic Engineering, Peking University, Beijing 100871, PR China.

ABSTRACT
WRKY proteins, defined by the conserved WRKYGQK sequence, are comprised of a large superfamily of transcription factors identified specifically from the plant kingdom. This superfamily plays important roles in plant disease resistance, abiotic stress, senescence as well as in some developmental processes. In this study, the Arabidopsis WRKY1 was shown to be involved in the salicylic acid signaling pathway and partially dependent on NPR1; a C-terminal domain of WRKY1, AtWRKY1-C, was constructed for structural studies. Previous investigations showed that DNA binding of the WRKY proteins was localized at the WRKY domains and these domains may define novel zinc-binding motifs. The crystal structure of the AtWRKY1-C determined at 1.6 A resolution has revealed that this domain is composed of a globular structure with five beta strands, forming an antiparallel beta-sheet. A novel zinc-binding site is situated at one end of the beta-sheet, between strands beta4 and beta5. Based on this high-resolution crystal structure and site-directed mutagenesis, we have defined and confirmed that the DNA-binding residues of AtWRKY1-C are located at beta2 and beta3 strands. These results provided us with structural information to understand the mechanism of transcriptional control and signal transduction events of the WRKY proteins.

Show MeSH
Related in: MedlinePlus