Multiple alignment of the deduced amino acid sequences of zebrafish Abcg2 (zAbcg2) and human ABCG2 (hABCG2). The multiple alignment was produced using ClustalW. * indicates positions that have a single, fully conserved residue; colons and periods, positions that have strong and weak similarity, respectively; dashes, gaps; the solid line under the alignments, the ATP-binding cassette region; and shaded boxes, the 3 motifs, Walker A, Walker B, and ABC signature.