These authors contributed equally to this work.
The mitochondrial PPR protein LOVASTATIN INSENSITIVE 1 plays regulatory roles in cytosolic and plastidial isoprenoid biosynthesis through RNA editing
Article first published online: 19 NOV 2009
© 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd
The Plant Journal
Volume 61, Issue 3, pages 456–466, February 2010
How to Cite
Tang, J., Kobayashi, K., Suzuki, M., Matsumoto, S. and Muranaka, T. (2010), The mitochondrial PPR protein LOVASTATIN INSENSITIVE 1 plays regulatory roles in cytosolic and plastidial isoprenoid biosynthesis through RNA editing. The Plant Journal, 61: 456–466. doi: 10.1111/j.1365-313X.2009.04082.x
Re-use of this article is permitted in accordance with the Terms and Conditions set out at http://www3.interscience.wiley.com/authorresources/onlineopen.html
- Issue published online: 21 JAN 2010
- Article first published online: 19 NOV 2009
- Received 6 August 2009; revised 21 October 2009; accepted 30 October 2009; published online 21 December 2009.
- HMG-CoA reductase;
- respiratory chain complex;
- RNA editing
Unlike animals, plants synthesize isoprenoids via two pathways, the cytosolic mevalonate (MVA) pathway and the plastidial 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway. Little information is known about the mechanisms that regulate these complex biosynthetic networks over multiple organelles. To understand such regulatory mechanisms of the biosynthesis of isoprenoids in plants, we previously characterized the Arabidopsis mutant, lovastatin insensitive 1 (loi1), which is resistant to lovastatin and clomazone, specific inhibitors of the MVA and MEP pathways, respectively. LOI1 encodes a pentatricopeptide repeat (PPR) protein localized in mitochondria that is thought to have RNA binding ability and function in post-transcriptional regulation of mitochondrial gene expression. LOI1 belongs to the DYW subclass of PPR proteins, which is hypothesized to be correlated with RNA editing. As a result of analysis of RNA editing of mitochondrial genes in loi1, a defect in RNA editing of three genes, nad4, ccb203 and cox3, was identified in loi1. These genes are related to the respiratory chain. Wild type (WT) treated with some respiration inhibitors mimicked the loi1 phenotype. Interestingly, HMG-CoA reductase activity of WT treated with lovastatin combined with antimycin A, an inhibitor of complex III in the respiratory chain, was higher than that of WT treated with only lovastatin, despite the lack of alteration of transcript or protein levels of HMGR. These results suggest that HMGR enzyme activity is regulated through the respiratory cytochrome pathway. Although various mechanisms exist for isoprenoid biosynthesis, our studies demonstrate the novel possibility that mitochondrial respiration plays potentially regulatory roles in isoprenoid biosynthesis.