Deduced amino acid sequences at the fusion protein cleavage site of Newcastle disease viruses showing variation in antigenicity and pathogenicity

Abstract

The amino acid sequence at the F2/F1 cleavage site of the F0 fusion protein of 17 strains of Newcastle disease virus (NDV) was deduced from sequencing a 32 nucleotide area of the genome by reverse transcription and polymerase chain reaction (PCR) techniques. With the addition of sequences at the same area previously published for 9 other viruses comparisons were made of a total of 26 NDV strains and isolates (11 of low virulence, 15 of high virulence or mesogenic) covering ten antigenic groups determined by reactions with monoclonal antibodies. All the virulent viruses and the mesogenic strain Komarov showed the amino acid sequence¹¹²R/K-R-Q-K/R-R¹¹⁶ for the C-terminus of the F2 protein and phenylalanine (F) at the N-terminus of the F1 protein, residue 117. The mesogenic isolate of the antigenic variant NDV responsible for the recent panzootic in racing pigeons, often termed “pigeon paramyxovirus type 1”, examined in this study had the sequence¹¹²G-R-Q-K-R-F¹¹⁷. The deduced amino acid sequence in the corresponding region of all viruses of low virulence was¹¹²G/E-K/R-Q-G/E-R-L¹¹⁷.