title: A Transcription Factor γMYB1 Binds to the P1BS cis-Element and Activates PLA2-γ Expression with its Co-Activator γMYB2.
abstract: Phospholipase A2(PLA2) hydrolyzes phospholipid molecules to produce two products that are both precursors of second messengers of signaling pathways and signaling molecules per se.Arabidopsis thaliana PLA2 paralogs (-β,-γ and -δ) play critical roles during pollen development, pollen germination and tube growth. In this study, analysis of the PLA2-γ promoter using a deletion series revealed that the promoter region -153 to -1 is crucial for its pollen specificity. Using a yeast one-hybrid screening assay with the PLA2-γ promoter and an Arabidopsis transcription factor (TF)-only library, we isolated two novel MYB-like TFs belonging to the MYB-CC family, denoted here as γMYB1 and γMYB2. By electrophoretic mobility shift assay, we found that these two TFs bind directly to the P1BS (phosphate starvation response 1-binding sequence)cis-element of the PLA2-γ promoter. γMYB1 alone functioned as a transcriptional activator for PLA2-γ expression, whereas γMYB2 directly interacted with γMYB1 and enhanced its activation. Overexpression of γMYB1 in the mature pollen grain led to increased expression of not only the PLA2-γ gene but also of several genes whose promoters contain the P1BS cis-element and which are involved in the Pi starvation response, phospholipid biosynthesis and sugar synthesis. Based on these results, we suggest that the TF γMYB1 binds to the P1BS cis-element, activates the expression of PLA2-γ with the assistance of its co-activator, γMYB2, and regulates the expression of several target genes involved in many plant metabolic reactions.
authors.affiliation: Division of Life Sciences, Korea University, Seoul 136-701, Korea.
authors.forename: Ha Thi Kim
authors.initials: HT
authors.lastname: Nguyen
authors.affiliation: Division of Life Sciences, Korea University, Seoul 136-701, Korea.
authors.forename: Soo Youn
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Division of Life Sciences, Korea University, Seoul 136-701, Korea.
authors.forename: Kwang-Moon
authors.initials: KM
authors.lastname: Cho
authors.affiliation: Division of Life Science, Applied Life Science (BK21 Plus Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea; Division of Plant Sciences, University of Missouri, Columbia, MO, USA.
authors.forename: Jong Chan
authors.initials: JC
authors.lastname: Hong
authors.affiliation: Division of Life Sciences, Korea University, Seoul 136-701, Korea jsshin@korea.ac.kr haejin.kim@unl.edu.
authors.forename: Jeong Sheop
authors.initials: JS
authors.lastname: Shin
authors.affiliation: Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, NE 68588, USA jsshin@korea.ac.kr haejin.kim@unl.edu.
authors.forename: Hae Jin
authors.initials: HJ
authors.lastname: Kim
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002467:Cell Nucleus / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D054500:Group IB Phospholipases A2 / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011058:Pollen / Q000235:genetics; D011401:Promoter Regions, Genetic; D020218:Response Elements; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C000613251:gammaMYB1 protein, Arabidopsis; C000613252:gammaMYB2 protein, Arabidopsis; D054500:Group IB Phospholipases A2; C000613253:phospholipase A2 gamma, Arabidopsis
keywords: Arabidopsis; MYB; P1BS cis-element; PLA2-γ; Transcription factor