Title: Cloning and phylogenetic analysis of the ORF7 full length gene of four strains of Porcine reproductive and respiration syndrome
Abstract: Objective The objective of this study was to analyze the genetic variation of the nucleocapsid protein(N protein) in Porcine Reproductive and Respiratory Syndrome Virus(PRRSV) in China by cloning and sequencing the ORF7 gene of 5 PPRSV strains and comparing it to other PRRSV epidemic strains in GenBank.Methods One pair of primers was designed according to the published full genome sequence of the ATCC VR-2332 strain in GenBank;the ORF7 full length gene of three Gansu epidemic strains(named GSZY,GSBY,and GSLZ strains),one Shanxi epidemic strain(named the Shanxi strain),and one Jiangxi epidemic strain(named the Jiangxi strain) were amplified by RT-PCR.The PCR products were cloned into a pGEM-T Easy vector,and recombinant vectors were constructed and then sequenced.Multiple sequences of ORF7 gene nucleotides and amino acids were compared with those of 13 PRRSV strains and analyzed using DNA Star software.Results Results indicated that the ORF7 gene shared 91.9%-94.3% homology of nucleotides with an American virus(ATCC VR-2332 strain),which caused the variation of PRRS in the early stages,while shared 98.7%-99.7% homology with other epidemic strains in China,and 57.7%-58.2% homology with a European strain(LV strain).Conclusion Results showed that there is variation in the N protein(amino) acid(sequence) of the American strain but that it is relatively conserved among strains in China.
Publication Year: 2009
Publication Date: 2009-01-01
Language: en
Type: article
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