Cloning and Sequence Analysis of F Gene of a Genetype VI Newcastle Disease Virus Isolated from Duck

Using the genome RNA of NDV-SS strain of Newcastle disease virus (NDV) isolated from duck as a template,the F gene of NDV-SS strain was amplified by reverse transcription polymerase chain reaction (RT-PCR). Then its gene cloning was completed,and its nucleotide sequence was determined. Nucleotide sequence homology and evolutionary processes analyses on amino acids sequence of F gene between SS strain and other NDV reference strains published in GenBank was executed using the sequence analysis soft. The F gene sequence of SS strain showed that NDV-SS strain was determined with its full-length of 1662 bp coding 553 amino acids. Amino acids sequence of F protein proteolytic cleavage position was 112R-R-Q-K-R-F117,indicated it is the virulent NDV strain.And the results of nucleotide sequence homology and evolutionary processes analyses showed that this strain belonged to the gene type Ⅵ,and had a close relationship with IT-227 and Italy-2736 strain. The presumable result was that this strain evolved from the NDV of pigeon origin.