Present address: Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA.
The pentatricopeptide repeat-SMR protein ATP4 promotes translation of the chloroplast atpB/E mRNA
Article first published online: 8 OCT 2012
© 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd
The Plant Journal
Volume 72, Issue 4, pages 547–558, November 2012
How to Cite
Zoschke, R., Kroeger, T., Belcher, S., Schöttler, M. A., Barkan, A. and Schmitz-Linneweber, C. (2012), The pentatricopeptide repeat-SMR protein ATP4 promotes translation of the chloroplast atpB/E mRNA. The Plant Journal, 72: 547–558. doi: 10.1111/j.1365-313X.2012.05081.x
- Issue published online: 2 NOV 2012
- Article first published online: 8 OCT 2012
- Accepted manuscript online: 18 JUN 2012 12:54PM EST
- Received 4 May 2012; revised 8 June 2012; accepted 12 June 2012.
- pentatricopeptide repeat;
- RNA binding;
- Zea mays
The regulation of chloroplast translation by nuclear gene products makes a major contribution to the control of chloroplast gene expression, but the underlying mechanisms are poorly understood. We describe a pentatricopeptide repeat (PPR) protein in maize, ATP4, that is necessary for translation of the chloroplast atpB open reading frame. We demonstrate that ATP4 associates in vivo with sequences near the 5′ end of the unusually long 5′ UTR of the atpB/E mRNA, that it facilitates ribosome association with this mRNA, and that it is required for accumulation and activity of the chloroplast ATP synthase. ATP4 is multifunctional, in that it also enhances atpA translation and is required for accumulation of specific processed atpF and psaJ transcripts. ATP4 belongs to a sub-class of PPR proteins that include a small MutS-related (SMR) domain. SMR domains had previously been associated primarily with DNA-related functions, but our findings imply that at least some PPR-SMR proteins can act on RNA. ATP4 is orthologous to the Arabidopsis protein SVR7, but the phenotypes of atp4 and svr7 mutants suggest that the functions of these orthologs have not been strictly conserved.