Alternative splicing of APE2 and AAP1 orthologs in the Saccharomycetacea. (A) Splicing pattern is shown for each of the species analyzed, along with the species phylogeny as in Figure 1A. A clear ortholog of APE2 could not be identified outside the Saccharomycetacea. (B) The K. lactis APE2/AAP1 ortholog contains an intron, but no alternative 5′ or 3′ splice sites. Translation from an AUG codon in the intron is predicted to produce an alternate isoform. (C,D) Duplicated APE2 and AAP1 genes in S. cerevisiae. APE2 uses alternative 3′ splice sites, as previously reported, while AAP1 lacks the intron. In addition, there may be a transcription start site within the intron and translation from an AUG codon in the intron is predicted to produce an alternate isoform. Mito indicates the presence of a predicted mitochondrial targeting sequence in the optional first exon.
