title: Signaling pathways mediating the suppression of Arabidopsis thaliana Ku gene expression by abscisic acid.
abstract: The Ku heterodimer facilitates the regulation of DNA repair, DNA replication, cell cycle, and telomere maintenance. The plant hormone abscisic acid (ABA) is a plant growth inhibitor. This study investigates how Arabidopsis thaliana Ku (AtKu) genes are regulated by ABA in 3-week-old seedlings. First, beta-Glucuronidase assay and real time quantitative PCR analysis results indicate that ABA represses the AtKu gene in a time- and concentration-dependent manner. However, adding of ABA biosynthesis inhibitors, fluride and tungate, did not eliminate AtKu suppression. Moreover, analysis of inhibitor treatments and ABA-responsive mutants suggested that AtKu repression by ABA was mediated through the pathway of extracellular Ca(2+), phospholipase D alpha, p38-type mitogen-activated protein kinase (MAPK), MAPK6 and ABA transcription factors, ABI3 and ABI5. Finally, no cross-talk in modulating AtKu gene expression existed between ABA and antagonist hormones (auxins and gibberellic acid).
authors.affiliation: Department of Life Sciences, National Tsing Hua University, Hsin Chu, Taiwan 30043, Republic of China.
authors.forename: Pei Feng
authors.initials: PF
authors.lastname: Liu
authors.forename: Wen Chi
authors.initials: WC
authors.lastname: Chang
authors.forename: Yung Kai
authors.initials: YK
authors.lastname: Wang
authors.forename: Hwan You
authors.initials: HY
authors.lastname: Chang
authors.forename: Rong Long
authors.initials: RL
authors.lastname: Pan
mesh_terms: D000040:Abscisic Acid / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004265:DNA Helicases / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D008954:Models, Biological; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C463462:KU70 protein, Arabidopsis; D000040:Abscisic Acid; D004265:DNA Helicases; C469228:Ku80 protein, Arabidopsis