Translational repression of the McKusick-Kaufman syndrome transcript by unique upstream open reading frames encoding mitochondrial proteins with alternative polyadenylation sites

► MKKS mRNA has multiple uORFs and alternative polyadenylation sites at the 5′-UTR. ► The presence of uORFs at the MKKS 5′-UTR represses the translation of the main ORF. ► Two uORFs of the MKKS mRNA are translated as mitochondrial proteins in human cells.