Properties of SOLD1 amino acid (aa) sequences. (A) Comparison of amino acid (aa) sequencesbetween ovine (ov) SOLD1, caprine(ca) SOLD1 and bovine (bo) SOLD1. Residues identical among the three SOLD1s are shown by hyphens. The aa sequences were aligned using ClustalW 1.83 on the DNA Data Bank of Japan (DDBJ) web site http://clustalw.ddbj.nig.ac.jp/top-e.html. The arrow indicates the putative primary cleavage site of the signal peptide of each SOLD1. The potential N-glycosylation sites are underlined in blue. (B) Comparison of aa sequences between ruminant SOLD1s and the phylogenetically close Ly-6 domain in each proteins selected by ProDom software (see Materials and Methods). Pink characters show residues identical in the Ly-6 domains. The sequence gaps are shown by dots. (C) Phylogenetic tree of mature sheep and goat SOLD1 proteins and the Ly-6 domain regions of some secreted Ly-6 superfamily members. The tree was constructed using TreeView following the alignment of protein sequences given by the ClustalW 1.83 algorithm. The numbers at the base of each branch division represent bootstrap values after 10,000 repeats. The scale bar shows the evolutionary distance between aa sequences estimated using the Kimura method . The scale bar represents 0.1 aa replacements per amino acid site. Key: Bab, baboon; Bov, Bovine; Cap, Caprine; Hum, Human; Mou, Mouse; Ovi, Ovine; Rab, Rabbit.