Mechanisms of Gene Regulation
Foster, Carol M. , Zarkovic, Jelena , Umbach, Ann L. , Bollinger, Jeaninne M. , Ulker, Bekir , Somssich, Imre , Dale, Sachie , Rhoads, David M. .
Identification of genes encoding signaling components of MRR.
Disruption of mitochondrial function causing altered nuclear gene expression is called mitochondrial retrograde regulation (MRR). Little is known about the specific cellular consequences of mitochondrial dysfunction in plants, but it appears that altered mitochondrial activity contributes to overall stress responses through MRR. Molecular mechanisms used by MRR pathways are starting to be defined. One approach to understanding MRR is to investigate Arabidopsis mutants that have perturbed MRR. MRR-deficient mutant-3 (mrrd3) isolated from our genetic screen exhibits induction of alternative oxidase (AOX1a) by inhibition of the TCA cycle, but not by cytochrome respiratory pathway (CP) inhibition, while other mutants (mrrd1, 2, 4) lack induction from both inhibitions. Array data has uncovered interesting targets of MRR from TCA cycle inhibition at 10h and/or CP inhibition at 6h, time points when AtAOX1a induction is highest. WRKY transcription factors 6, 30, 33, and 40 were induced by TCA cycle and CP inhibition and AtAOX1a induction from CP inhibition was absent or reduced in corresponding knockout (KO) lines. We are now combining these approaches to determine the effects of CP or TCA cycle inhibition on specific target genes in the mrrd mutant lines and the WRKY KO lines to gain a better understanding of MRR in Arabidopsis. Because genes encoding regulatory proteins are likely induced before these target genes, we are also identifying genes encoding potential regulatory proteins induced at earlier time points in CP or TCA cycle inhibition.
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1 - Arizona State University, Polytechnic Campus, Department of Applied Biological Sciences, 340 Wanner Hall, 7001 E. Williams Field Road, Mesa, AZ, 85212, USA
2 - Arizona State University, School of Life Sciences
3 - Duke University, Department of Biology
4 - Durham University, School of Biological and Biomedical Sciences, Science Site, South Road, Durham, DH1 3L3, United Kingdom
5 - Max-Planck-Institute for Plant Breeding, Dept. Plant-Microbe Interactions, Carl-von-Linné Weg 10, Koeln, D-50829, Germany
6 - Arizona State University, Department of Applied Biological Sciences
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM