Targeted cleavage of nad6 mRNA induced by a modified pentatricopeptide repeat protein in plant mitochondria

We altered the expression of the mitochondrial nad6 gene encoding a subunit of respiratory complex I, via the modification of the specificity of the RNA-binding protein RNA PROCESSING FACTOR 2 (RPF2). Modified RPF2 binds and specifically induces cleavage of nad6 RNA, almost eliminating expression of the Nad6 protein and consequently complex I accumulation and activity. To our knowledge, this is the first example of a targeted block in expression of a specific mitochondrial transcript by a custom-designed RNA-binding protein. This opens the path to reverse genetics studies on mitochondrial gene functions.