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چکیده
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Infectious bronchitis (IB), as an economically important disease of chickens, could be resulted in reducing egg and meat in poultry farms. Causative agent of the disease, avian bronchitis virus (IBV), is a member of genus Coronavirus of the family Coronaviridae. The nucleocapsid (N) is a structural protein of the virus that has an important role in transcription, packaging and replication of the genomic RNA and host immunization. In this study, secondary structure, post-translational modifications (Glycosylation, phosphorylation) and antigenic sites variations of N protein were investigated among IBV reference strains from different regions of the world (Arkansas Vaccine: GQ504721, Beaudette: M28565, CK/CH/XDC-2/2013: KM213963, H120 Vaccine: FJ888351, ITA/90254/2005: FN430414, NGA/A116E7/2006: FN430415), using bioinformatic analysis. Secondary structure in the strains showed different patterns. According to phylogenetic tree analysis, six viral strains were classified in four distinct groups I (Beaudette), II (Arkansas Vaccine and H120 Vaccine), III (ITA/90254/2005 and NGA/A116E7/2006), IV (CK/CH/XDC-2/2013) and potential phosphorylation sites of each group strains were related exactly. No clear difference were observed in N-glycosylation sites of all six strains. The highest divergence of amino acid sequences was shown between Beaudette, H120 Vaccine and NGA/A116E7/2006 with CK/CH/XDC-2/2013 while the lowest divergence was related to ITA/90254/2005 with NGA/A116E7/2006. Potential antigenic sites were varied among the strains except between H120 Vaccine and NGA/A116E7/2006. In conclusion, survey on bioinformatics and evolutionary properties of IBV strains N protein would be very helpful in finding future effective approaches to control of IB especially in designing an appropriate vaccine based on the viral strains.
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