FV amino acid sequence comparison. The human FV amino acid sequence (“Human”) and the bovine FV amino acid sequences (“Bovine”) were compared pairwise against the murine FV sequence. A multiple comparison of all three sequences simultaneously was also done (“Mult”). All comparisons were performed by the MegAlign computer program (DNASTAR, Madison, WI), using the Clustal method. The numbers on the top of the bar indicate the domain boundaries in murine FV, deduced from sequence comparison with the human and bovine proteins. Values for each domain are the percentage amino acid identity, with the percentage amino acid similarity in parentheses.