title: Arabidopsis DREB2C functions as a transcriptional activator of HsfA3 during the heat stress response.
abstract: The dehydration-responsive element binding protein (DREB) family is important in regulating plant responses to abiotic stresses. DREB2C is one of the Arabidopsis class 2 DREBs and is induced by heat stress (HS). Here, we present data concerning the interaction of DREB2C with heat shock factor A3 (HsfA3) in the HS signal transduction cascade. RT-PCR showed that HsfA3 is the most up-regulated gene among the 21 Arabidopsis Hsfs in transgenic plants over-expressing DREB2C. DREB2C and HsfA3 displayed similar transcription patterns in response to HS and DREB2C specifically transactivated the DRE-dependent transcription of HsfA3 in Arabidopsis mesophyll protoplasts. Yeast one-hybrid assays and invitro electrophoretic mobility shift assays further showed that DREB2C interacts with two DREs located in the HsfA3 promoter with a binding preference for the distal DRE2. Deletion mutants of DREB2C indicated that transactivation activity was located in the C-terminal region. In addition, dual activator-reporter assays showed that the induction of heat shock protein (Hsp) genes in transgenic plants could be attributed to the transcriptional activity of HsfA3. Taken together, these results indicate that DREB2C and HsfA3 are key players in regulating the heat tolerance of Arabidopsis.
authors.affiliation: Division of Applied Life Science, Graduate School of Gyeongsang National University, Plant Molecular Biology and Biotechnology Research Center, Jinju 660-701, Republic of Korea.
authors.forename: Huan
authors.initials: H
authors.lastname: Chen
authors.forename: Jung Eun
authors.initials: JE
authors.lastname: Hwang
authors.forename: Chan Ju
authors.initials: CJ
authors.lastname: Lim
authors.forename: Dool Yi
authors.initials: DY
authors.lastname: Kim
authors.forename: Sang Yeol
authors.initials: SY
authors.lastname: Lee
authors.forename: Chae Oh
authors.initials: CO
authors.lastname: Lim
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000235:genetics*; D018869:Heat-Shock Response / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics*; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C000620136:HSFA3 protein, Arabidopsis; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D010940:Plant Proteins; D015534:Trans-Activators; D014157:Transcription Factors