Description
Intracellular sorting of mRNAs is an essential process to regulate gene expression and protein localization. Most of mitochondrial proteins are nuclear-encoded and imported into mitochondria, through post-translational or co-translational processes. To determine cytosolic mRNAs targeted to the mitochondrial surface, a genome-scale analysis of mRNAs associated with mitochondria has been performed in plants. As expected, many messengers encoding mitochondrial proteins were found associated with mitochondria, but numerous mRNAs encoding cytosolic proteins were also detected. This suggests multiple roles for mRNA targeting, in addition to the co-translational import of mitochondrial proteins. Moreover, correlations between mRNA targeting and function of mitochondrial proteins indicate a coordinated control of mRNAs localization within metabolic pathways. At last, upstream AUGs in 5''UTR, known to regulate translation efficiency of downstream sequences, affect mRNA targeting. A mutational approach coupled with in vivo mRNA visualization confirms this observation, and highlights the role of upstream AUGs as regulators of mRNA targeting to the mitochondrial surface. Overall design: Analysis of two types of RNAseq data, each in triplicates. Total RNA from S. tuberosome cell, and mitochondrial associated RNA from S. tuberosum cells.