Cloning and Sequence Analysis of N Gene of Transmissible Gastroenteritis Virus HYM-09 Isolated from Dog in China

Transmissible gastroenteritis virus (TGEV) is the etiological agent of TGE, and dogs are potential carriers of TGEV. In this study, genomic RNA were extracted from TGEV designated HYM-09 isolated from dog naturally infected with TGEV. The nucleocapsid (N) gene of HYM-09 was amplified by RT-PCR and cloned into pMD18-T vector. The N gene cDNA was sequenced and encompassed an open reading frame of 1,149 nucleotides, encoding a 382-amino acids protein. Sequence analyses of the N genes were performed, including homologous comparison, phylogenetic tree analysis and residue substitution analysis. The results showed that there existed some unique mutations in the HYM-09 isolate N gene, but HYM-09 N gene shared over 96 % homologous identities compared with 12 TGEV reference strains derived from other regions or countries respectively. The phylogenetic tree analysis revealed that the HYM-09 branched into the most strains group. This study shows that the nucleotide sequence analysis can form a base or further study on the mutation trend of non-porcine TGEV.