S1 gene sequence analysis of a nephropathogenic strain of avian infectious bronchitis virus in Egypt

Abdel-Moneim, Ahmed S; El-Kady, Magdy F; Ladman, Brian S; Gelb, Jack

Polymerase chain reaction and S1 gene cycle sequencing RT-PCR of Egypt/F/03 resulted in a product of 1600 base pairs using S1 primers OLIGO 5' and OLIGO 3'. Egypt/F/ 03 is closely related to the Beaudette US reference strain; 98% nucleotide identity and 96% amino acid identity (Table 1 and Fig. 2 ). It showed 97% similarities both in nucleotides and amino acids to H120 and 98% nucleotide and 96% amino acid homology to M41 (Table 1) . Egypt/ F/03 showed 34 point mutations from H120; 20 silent and 14 non silent mutations. On the other hand, it showed 30 point mutations; 10 silent and 20 non silent mutations from M41 (Fig. 3, 4) . Sixteen potential glycosylation sites were found in Egypt/F/03 while 17 were found in H120 and M41 (Fig. 4) . All potential glycosylation sites found in Egypt/F/03 were shared with those found in H120 and M41 (Fig. 4) .