Figure 4

Alignment of the N amino acid sequences of IVI-1173 and of representative PRRSV strains. The 7 amino acid differences between the genotype 1 prototype strain LV and IVI-1173 are shown in blue bold letters. The red star highlights the substitution of the conserved threonine at position 90 of N with an alanine in IVI-1173. Be1 and LA2 (genotype 1) are the closest to IVI-1173 at the nucleotide and amino acid level of N. VR-2332 is the prototype genotype 2 PRRSV. Lena and RVB-581 are highly virulent genotype 1 subtype 3 and genotype 2 strains, respectively. PrimePac (genotype 2) is the only strain for which the lack of N detection by SDOW17 was reported, which is due to substitution of a conserved aspartic acid at position 62 with a tyrosine (red triangle).