Human ELAC2 gene encodes the tRNAseZ responsible for mitochondrial tRNA 3’ processing which acts on precursors already cleaved by RNAseP

Abstract

Accurate tRNA processing is crucial for human mitochondrial genome expression, but the mechanisms and key enzymes involved are poorly characterized. Here we demonstrate for the first time that human protein ELAC2 localizes both in mitochondria and the nucleus. Using the RNAi gene silencing in HeLa cells we show that the ELAC2 gene encodes tRNAseZ endonuclease which is responsible for the mitochondrial tRNA 3' processing in vivo. In addition we demonstrate that the order of precursor cleavage in mitochondria follows the rule that tRNase Z can only cleave molecules already processed by RNase P.