Fig. 1.

Nucleotide sequence alignment of the 5′NCR (A) and 3′NCR (B) regions of the 12 available fully sequenced PRRSV strains including PL97-1. Except for PL97-1, which was sequenced in this study, all other sequence information was obtained from the GenBank database indicated in Table 2. The consensus sequence of all 12 PRRSV strains is shown on top, and only differences from that sequence in the PRRSV strains are indicated. Deletions are indicated by hyphens. Dash-line boxes indicate a highly conserved region in the 5′NCRs (A) and 3′NCRs (B) present in all 12 PRRSV genomes. (A) The open box indicates a stretch of 23–24 nucleotides at the utmost 5′-end of the NVSL 97-7985 and MLV RespPRRS/Repro PRRSV strains, respectively, which were not reported. (B) The open box represents a string of deletions of 3, 18, and 17 nucleotides in the beginning of the 3′NCR of the Lelystad PRRSV strain.