Recombination Analysis of M Protein of a Canine Coronavirus Wild Strain Isolated from Nanjing City

Two M gene sequences of Canine coronavirus (CCV), from a wild strain NJ17 from a diarrhea dog faecal sample in Nanjing City and CCV 1-71 reference strain, were cloned and sequenced. The results showed, CCV 1-71 shared high similarity (98.9~99.5%) to CCV V1, V2 and a CCV strain from giant panda isolated in China 2003. It suggested that the above CCV strains existed quasispecies from a same ancestor strain. On M gene, CCV NJ17 shared 87.0~91.9% identities with other CCV strains and typical strains of Transmissible gastroenteritis virus (TGEV) of swine, and Feline coronaviruses (FCoVs) in the GenBank. The CCV NJ17 might be a separated evolutionary strain in China. Recombination mark sequences of all the landed strains on the M gene putative recombination region had a “CTTTAG” nucleotides , meeting to “CTT(A/T)(A/T)G” that always appeared near to the recombination “hot spot” in Infectious bronchitis virus RNA genome. The first 50 amino acid residues on N terminal of CCV NJ17 M protein was higher similar to FCoV 7