Synchronization of cytoplasmic and transferred mitochondrial ribosomal protein gene expression in land plants is linked to Telo-box motif enrichment
1 Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, China
2 Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Room 342, Physiology Building, 320 Yueyang Road, Shanghai, China
3 School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, China
4 Institute of Plant Physiology and Ecology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, China
5 Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, China
6 Department of Molecular and Cell Biology, Center for Systems Biology, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
BMC Evolutionary Biology 2011, 11:161 doi:10.1186/1471-2148-11-161Published: 13 June 2011
Chloroplasts and mitochondria evolved from the endosymbionts of once free-living eubacteria, and they transferred most of their genes to the host nuclear genome during evolution. The mechanisms used by plants to coordinate the expression of such transferred genes, as well as other genes in the host nuclear genome, are still poorly understood.
In this paper, we use nuclear-encoded chloroplast (cpRPGs), as well as mitochondrial (mtRPGs) and cytoplasmic (euRPGs) ribosomal protein genes to study the coordination of gene expression between organelles and the host. Results show that the mtRPGs, but not the cpRPGs, exhibit strongly synchronized expression with euRPGs in all investigated land plants and that this phenomenon is linked to the presence of a telo-box DNA motif in the promoter regions of mtRPGs and euRPGs. This motif is also enriched in the promoter regions of genes involved in DNA replication. Sequence analysis further indicates that mtRPGs, in contrast to cpRPGs, acquired telo-box from the host nuclear genome.
Based on our results, we propose a model of plant nuclear genome evolution where coordination of activities in mitochondria and chloroplast and other cellular functions, including cell cycle, might have served as a strong selection pressure for the differential acquisition of telo-box between mtRPGs and cpRPGs. This research also highlights the significance of physiological needs in shaping transcriptional regulatory evolution.