Avian infectious bronchitis virus (IBV) is a gammacoronavirus that belongs to Group III of coronaviruses. They have a large genome containing the replicase gene consisting of two large ORFs, ORF1a and 1b that encode two replicase polyproteins ppa1a/1 ...
Avian infectious bronchitis virus (IBV) is a gammacoronavirus that belongs to Group III of coronaviruses. They have a large genome containing the replicase gene consisting of two large ORFs, ORF1a and 1b that encode two replicase polyproteins ppa1a/1ab, which are then auto-proteolytically processed into 15 or 16 matured nonstructural proteins to achieve viral genomic replication, assembly and maturation. This group contains avian viruses and differs from the other groups in that they do not encode the essential pathogenic factor non-structural protein 1 (NSP1) and instead start with NSP2. IBV NSP2 is one of the first replicase proteins to be translated and processed in the viral life cycle [1]. NSP2 is a weak protein kinase R (PKR) antagonist, which may suggest that it plays a role in interfering with intracellular immunity [2].