Table 3.
List of PRRSV-ORFs, corresponding viral proteins and potential for virus neutralization.
| ORFs | Proteins | Function | Mediating virus neutralization |
|---|---|---|---|
| ORF1a | nsp1α, nsp1β | Papain like cysteine protease (PLP), zinc-finger protein, antagonists for IFN induction and signaling (JAK/STAT pathway) | NA |
| nsp2 | PLP, deubiquitinase, IFN induction antagonist, transmembrane (TM) protein for replication complex | ||
| nsp3 | TM protein for replication complex | ||
| nsp4 | IFN induction antagonist | ||
| nsp5 | TM protein for replication complex, antagonist for JAK/STAT signaling | ||
| nsp6 | Predicted nsp, function unknown | ||
| nsp7α, nsp7β | Function unknown | ||
| nsp8 | Function unknown, contains N-terminal domain of nsp9 | ||
| ORF1a’-TF | nsp2TF, nsp2N | PLPs | NA |
| ORF1b | nsp9 | RNA-dependent RNA polymerase | NA |
| nsp10 | RNA NTPase/helicase; contains putative zinc-binding domain | ||
| nsp11 | Uridylate-specific endoribonuclease, IFN induction antagonist | ||
| nsp12 | Unknown | ||
| ORF2a | GP2a | Minor glycosylated protein; essential for virus infection; forming complex with GP3-4; responsible for receptor binding | Yes, but only reported for PRRSV-1 Lelystad strain |
| ORF2b | E | Minor unglycosylated but myristoylated structural protein, essential for virus infection; forming complex; possesses ion-channel-like properties and may function as a viroporin in the envelope | NA |
| ORF3 | GP3 | Minor glycosylated structural protein; forming complex with GP2a and GP4 which is responsible for receptor recognition; | Yes |
| ORF4 | GP4 | Minor glycosylated structural protein; forming complex with GP2a-3-4 and responsible for receptor recognition | Yes, might be a driving force in PRRSV evolution |
| ORF5 | GP5 | Major glycosylated structural protein with a variable number of potential N-glycosylation sites | Yes, initially considered as major neutralizing target among all PRRSV structure proteins |
| ORF5a | GP5a | Minor unglycosylated protein; essential for virus viability; | No |
| ORF6 | M | Forming heterodimer with GP5 which is crucial for virus infectivity; plays a key role in virus assembly and budding | Not sure, but mutation of Tyr10 of M results neutralization resistance mutant |
| ORF7 | N | Component of the viral capsid; IFN antagonist | No |