Studies On The RNA Polymorphism Of Porcine Reproductive And Respiratory Syndrome Virus

A highly pathogenic disease which was characterized by high-fever,high morbidity and mortality rate was outbreaked in the south of China in 2006. And then spreaded quickly to mostly provinces. The disease has caused enormous economic losses to the hog industry in China. The disease appeared in july 2006.And then it rapid spreaded in Fujian.The purpose of this study was to excogitate a method of studying polymorphisms of the virus by the mRNA differential dispiay technique and to acquire differentially expresser genes that related to gene mutation,In this study, mRNA differential dispiay technique was used to analyse differentially expressed cDNA fragments from four strains in our lab.Which were PRRSV-FJ02A, PRRSV-FJ06A, PRRSV-FJ07A and PRRSV-FJ08A. Three anchor primers and twenty random primers for mRNA differential were displayed.After primers screening test,denaturing polyacrylamide gel electrophoresis, and silver staining.Ten differentially expressed fragments were obtained. Then two fragments gene were cloned and the sequences were analysed. The result showed that in the end of the two fragments there were the same secquence with the primers which were used in the mRNA differential dispiay technique. And the length of the two fragments is 209bp and 272bp.Using the program NCBI and DNASTAR software to analysis the two sequence,the result showed that the two fragments compared with the VR2332 strain the nucleotide homology was 78.6% and 68.6%.And both of them had some base mutations and deletions.So I think that the two fragments may be the fragment that lead to the virus mutation and can obtained the variability PRRSV genes by the mRNA differential display technology.