RNA processing in human mitochondria

Abstract

Mammalian mitochondrial DNA is transcribed as precursor polycistronic transcripts containing 13 mRNAs, 2 rRNAs, punctuated by 22 tRNAs. The mechanisms involved in the excision of mitochondrial tRNAs from these polycistronic transcripts have remained largely unknown. We have investigated the roles of ELAC2, mitochondrial RNase P proteins 1 and 3, and pentatricopeptide repeat domain protein 1 in the processing of mitochondrial polycistronic transcripts. We used a deep sequencing approach to characterize the 5′ and 3′ ends of processed mitochondrial transcripts and provide a detailed map of mitochondrial tRNA processing sites affected by these proteins. We show that MRPP 1 and MRPP 3 process th..