Angel2 phosphatase activity is required for non-canonical mitochondrial RNA processing in metazoa

Canonical RNA processing in mammalian mitochondria necessitates that tRNAs are recognised by nucleases to release flanking transcripts. However, not all mitochondrial transcripts are punctuated by tRNAs, and the mechanism and factors involved in their processing has remained unsolved. Here, we demonstrate that phosphatase activity of the carbon catabolite repressor 4 domain containing family member ANGEL2 is required for the hydrolysis of 3′ phosphates, resulting from non-canonical processing. Interaction studies in Drosophila further identify that members of the FAST kinase domain containing protein family are involved in the formation of these 3′ phosphates. Our results therefore resolve the mechanism of RNA processing in metazoan mitochondria, by defining the outstanding non-canonical processing mechanism. Ribosome profiling of two AngelKO and two wild-type samples from Drosophila melanogaster, in technical quadruplicate