DISTINCTIVE FEATURES OF THE 5'-TERMINAL SEQUENCES OF THE HUMAN MITOCHONDRIAL MESSENGER-RNAS

The 5''-end proximal sequences of all the putative mRNA coded for by the heavy strand of HeLa cell mitochondrial DNA were determined and aligned with the DNA sequence. All these mRNA start directly at, or very near to, an AUG or AUA triplet, with the exception of one which starts at an AUU. The available evidence indicates that the terminal or subterminal AUG and AUA, and possibly also the terminal AUU, are initiator codons for the corresponding polypeptides. In most cases, the individual mRNA coding sequences are flanked on their 5'' side by a tRNA gene, without any intervening nucleotide.