Table 1.
Description of the primers used for reverse transcription and PCR
| RT-PCR type | Primer sequencea | Primer specificity | Size of RT-PCR productb |
|---|---|---|---|
| ORF 7 | RT primer | All known PRRSV-types | American-type PRRSV: 660 bp |
| 5′ TCG CCC TAA T 3′ | |||
| Forward PCR primer | European-type PRRSV: 637 bp | ||
| 5′ GCC CCT GCC CAI CAC G 3′ | |||
| Reverse PCR primer | |||
| 5′ TCG CCC TAA TTG AAT AGG TGA 3′ | |||
| EU ORF 5 PCR | RT primer | European-type PRRSV | 719 bp |
| 5′ TAT GTI ATG C 3′ | |||
| Forward PCR primer | |||
| 5′ CAA TGA GGT GGG CIA CAA CC 3′ | |||
| Reverse PCR primer | |||
| 5′ TAT GTI ATG CTA AAG GCT AGC AC 3′ | |||
| US ORF 5 PCR | RT primer | American-type PRRSV | 818 bp |
| 5′ AAA GGT GCA G 3′ | |||
| Forward PCR primer | |||
| 5′ GCT CCA TTT CAT GAC ACC TG 3′ | |||
| Reverse PCR primer | |||
| 5′ AAA GGT GCA GAA GCC CTA GC 3′ |
a
PCR primer pairs were used in singleplex PCR reactions on cDNA primed with a cocktail of the three RT primers. Note that RT primers are 3′-end truncated versions of the corresponding reverse PCR primer, lending a semi-nested effect to the RT-PCR test. `I' denotes inosines.
b All RT-PCR products extend from 50–150bp upstream from the start codon to 60–70 downstream from the stop codon, thus containing the whole coding sequence for the indicated gene. The combined size of the ORF 5 and 7 amplicons corresponds to 9% of the whole viral sequence.