Figure 3.

An apparent frameshift in the annotated gene B0281.4. This image was generated from a BLIXEM window of ACeDB. The top of the figure shows the predicted gene structure for B0281.4, and each horizontal line represents a homology. The ruler is marked in base pairs. The region within the box is expanded to give the lower part of the figure. The theoretical translation across this window is given in the three reading frames, (+1), (+2), and (+3). The amino acid sequence encoded at the end of the predicted first exon, ALVETDIPVSYFLLTHHG, lies in the second reading frame, whereas the amino acid sequence encoded at the start of the predicted second exon, ESEN, lies in the third reading frame. The homologous sequence for the other two genes in this tandem cluster, B0281.5 and B0281.6, is retained from the BLIXEM window, whereas additional homologous sequences have been removed for clarity. The homology extends from the second exon into the predicted first intron in the third reading frame (underlined). The homology continues with the sequences AEKDDS for B0281.5 and AEDGDS for B0281.6 (these sequences have been added to the BLIXEM window), but this homology has shifted to the first reading frame (underlined). A splice to a position inside the predicted first exon would then remove nonhomologous residues of the predicted B0281.4 protein, yielding a full coding-region match between B0281.4, B0281.5, and B0281.6, and other homologs.