عنوان مقاله [English]
Newcastle disease virus is an important virus in poultry industry. Use of killed or attenuated vaccine against the disease elevates immunological protection. The F gene is a major determinant in virulence of the virus. Therefore, in this study we aimed to sequence the F gene of Razi LaSota-derived and plaque-purified NDV strain IR12 and analyze it. The virus was inoculated into 10-day-old SPF embryonated chicken eggs and then the allantoic fluid was subjected to sucrose gradient purification using ultra centrifuge. The purified virus band was then subjected to RNA extraction and cDNA synthesis using gene specific primers. PCR was run using specific primers to amplify the F gene and then the band was gel extracted and cloned to pJet1.2 plasmids in a 3 to 1 ratio and transformed to a suitable competent cell. The extracted plasmid was then digested with BglII restriction enzyme to confirm the presence of the insert and then the plasmid was Sanger se As a result, the gene sequence F was completely sequenced and compared with the lentogenic strains found in the gene bank.quenced. The sequence was then assembled using MEGA6, the cleavage-site sequence of
112G-R-Q-G-R-L117 was obtained and then the phylogenetic tree was drawn. As a result, the gene sequence F was completely sequenced and compared with the lentogenic strains found in the gene bank.