Alignment of a region containing uORF1 (closest to the start codon of the main ORF) from S. cerevisiae YJL139c (YUR1) with the orthologous sequences from four other Saccharomyces species. A, sequence alignment. The start and stop codons of the uORF are marked in yellow. B, DNA sequence similarity profile of uORF1. C, DNA sequence similarity profile of the entire 5'-UTR of YUR1 and its homologues.