FIG. 4.

Nucleotide sequence alignment of regions 5′ of the structural genes vspA, vspC, and vspO. Identical nucleotides are highlighted by shaded boxes. An arrow at nt -71 indicates the end of the region displaying 100% homology between vspO and vspC genes and the beginning of the region of 100% homology between vspC and vspA. This arrow also marks the junction between the two-vsp upstream cassettes 1 and 2 (14). Solid rectangles below nucleotides represent two nucleotide differences which are unique to the vspA upstream region and served as vspA fingerprints. The position of the cas-2 oligonucleotide, used as a probe, is shown by a labeled broken line. Nucleotides representing a putative ribosome binding site (SD) and the initiation codon ATG are shown by brackets. A 34-bp sequence in which the 5′ end of the recombination event between vspA and vspO has occurred is underlined.