MOLECULAR-CLONING AND SEQUENCE DETERMINATION OF THE PEPLOMER PROTEIN GENE OF FELINE INFECTIOUS PERITONITIS VIRUS TYPE-I

cDNA clones spanning the entire region of the peplomer (S) gene of fel ine infectious peritonitis virus (FIPV) type I strain KU-2, were obtai ned and their complete nucleotide sequences were determined. A long op en reading frame (ORF) encoding 1464 amino acid residues was found in the gene, which was 12 residues longer than the ORF of the FIPV type I I strain 79-1146. The sequences of FIPV type I and mainly FIPV type II were compared. The homologies at the N- (amino acid residues 1-693) a nd C- (residues 694-1464) terminal halves were 29.8 and 60.7%, respect ively. This was much lower than that between FIPV type II and other an tigenically related coronaviruses, such as transmissible gastroenterit is virus of swine and canine coronavirus. This supported the serologic al relatedness of the viruses and confirmed that the peplomer protein of FIPV type I has distinct structural features that differ from those of antigenically related viruses.