Signaling pathways mediating the suppression of Arabidopsis thaliana Ku gene expression by abscisic acid.

Pei Feng Liu, Wen Chi Chang, Yung Kai Wang, Hwan You Chang, Rong Long Pan

Department of Life Sciences, National Tsing Hua University, Hsin Chu, Taiwan 30043, Republic of China.

Biochimica et biophysica acta 2008 Mar

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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).

Citation

Pei Feng Liu, Wen Chi Chang, Yung Kai Wang, Hwan You Chang, Rong Long Pan. Signaling pathways mediating the suppression of Arabidopsis thaliana Ku gene expression by abscisic acid. Biochimica et biophysica acta. 2008 Mar;1779(3):164-74