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ABSTRACT: Background
Basic region/leucine zippers (bZIPs) are transcription factors (TFs) encoded by a large gene family in plants. ABF3 and ABI5 are Group A bZIP TFs that are known to be important in abscisic acid (ABA) signaling. However, questions of whether ABF3 regulates ABI5 are still present.Results
In vitro kinase assay results showed that Thr-128, Ser-134, and Thr-451 of ABF3 are calcium-dependent protein kinase phosphorylation sites. Bimolecular fluorescence complementation (BiFC) analysis results showed a physical interaction between ABF3 and 14-3-3?. A Thr-451 to Ala point mutation abolished the interaction but did not change the subcellular localization. In addition, the Arabidopsis protoplast transactivation assay using a luciferase reporter exhibited ABI5 activation by either ABF3 alone or by co-expression of ABF3 and 14-3-3?. Moreover, chromatin immunoprecipitation-qPCR results showed that in Arabidopsis, ABI5 ABA-responsive element binding proteins (ABREs) of the promoter region (between -?1376 and -?455) were enriched by ABF3 binding under normal and 150 mM NaCl salt stress conditions.Conclusion
Taken together, our results demonstrated that ABI5 expression is regulated by ABF3, which could contribute to salt stress tolerance in Arabidopsis thaliana.
SUBMITTER: Chang HC
PROVIDER: S-EPMC6689043 | biostudies-literature | 2019 Aug
REPOSITORIES: biostudies-literature
Chang Hui-Chun HC Tsai Min-Chieh MC Wu Sih-Sian SS Chang Ing-Feng IF
Botanical studies 20190809 1
<h4>Background</h4>Basic region/leucine zippers (bZIPs) are transcription factors (TFs) encoded by a large gene family in plants. ABF3 and ABI5 are Group A bZIP TFs that are known to be important in abscisic acid (ABA) signaling. However, questions of whether ABF3 regulates ABI5 are still present.<h4>Results</h4>In vitro kinase assay results showed that Thr-128, Ser-134, and Thr-451 of ABF3 are calcium-dependent protein kinase phosphorylation sites. Bimolecular fluorescence complementation (BiFC ...[more]