Figure 3

Comparison of the nucleotide coding and amino acid sequences of the feline A3C genes. (a) Pairwise comparison of the domestic cat A3 cDNA to the predicted A3Ca, A3Cb and A3Cc genomic coding sequences and the predicted amino acid sequences. (b) Amino acid sequence alignment of A3C cDNA and the predicted proteins for A3C genes. Highlighted in yellow are amino acid residues different between the A3Cs based on the genomic sequence, whereas amino acid sites displaying non-synonymous amino acid substitutions are boxed in blue and red for A3Cb and A3Cc, respectively, as identified by SNP genotyping of eight domestic cat breeds for exons 2-4 of A3Ca, A3Cb and A3Cc (for more details see Table 4 in Additional data file 2). Arrows indicate exonic junctions. Below the alignments, variant amino acids are boxed in red for A3Cc (for example, W65R) and blue for A3Cb with respect to the breed from which they were identified: Turkish van (VAN), Egyptian mau (MAU), Sphynx (SPH), Birman (BIR) and Japanese bobtail (BOB). A dash indicates the amino acid is identical to genomic sequence. Numbers adjacent to breed identifiers refer to alleles 1 and 2 identified by clonal sequence analysis of the PCR products that are in phase for exons 3 and 4, but not for exon 2 (1/2). The residue corresponding to functionally significant amino acid replacement identified in human A3G (D128K) is highlighted by an asterisk (see text).