Effects Of PSF And P54nrb Proteins On PRRSV Proliferation In MARC-145 Cells

Porcine reproductive and respiratory syndrome virus(PRRSV)is a swine disease virus that is widely affected and seriously endangered,causing serious economic losses to the normal production of pig industry in China.Therefore,it is particularly important to understand the PRRSV infection situation,the development trend and the situation of prevention and control.In this study,3 526 suspected samples collected from various regions of Shandong Province in 2015-2017 were tested for PRRSV antigen by PCR,and 12 478 serum samples were collected for PRRSV antibody detection by ELISA,and the occurrence and prevalence of the disease were summarized.The results showed that the positive antigen rate of PRRSV fluctuated greatly in Shandong Province from 2015 to 2017.The positive antigen rate of PRRSV was 40.56 %,46.15 % and 37.24 % respectively,and the positive antigen rate fluctuated between 33-50 % every quarter in three years.The positive antibody rate of PRRSV remained high,with 84.39 %,86.38 % and 78.51 % respectively.It is indicated that PRRSV vaccine immunization or PRRSV wild-type infection is quite common in pigs in Shandong Province.Through the investigation of PRRSV infection in Shandong Province,we have grasped the situation and trend of PRRSV infection in the past three years.It shows that the situation of PRRSV infection in Shandong Province is stable,but there is still the risk of outbreak,which has positive significance for the prevention and control of PRRS.In previous studies,Proteomic analysis of MARC-145 cells infected with PRRSV highly pathogenic strain showed that antisense pathway was significantly up-regulated and key antisense pathway proteins such as PSF?p54nrb and Matrin 3 were up-regulated.To explore the effects of PSF and p54 nrb protein on the proliferation of PRRSV in MARC-145 cells,the primers of PSF?p54nrb and PRRSV N genes were designed,and a quantitative fluorescence PCR method was established to verify the reliability of the quantitative analysis method for the expression of the above genes.The accuracy and sensitivity of detecting PSF?p54nrb and PRRSV N genes can be greatly increased by fluorescence quantitative method,and the detection level of PSF?p54nrb and PRRSV N genes can be improved.In order to further understand the role and influence of PSF and p54 nrb in the proliferation of PRRSV,the expression of PSF and p54 nrb protein in MARC-145 cells was down-regulated by RNA interference and up-regulated by recombinant lentivirus,respectively.The results showed that the down-regulation of PSF and p54 nrb proteins inhibited the proliferation of PRRSV in MARC-145 cells,and the proliferation of PRRSV was more obvious when the above two proteins were down-regulated at the same time.The proliferation of PRRSV in the up-regulated PSF and p54 nrb proteins groups was significantly higher than that in the control group,and the co-up-up-regulation of PSF and p54 nrb proteins significantly increased PRRSV.Comprehensive analysis of the expression of PSF and p54 nrb proteins on the proliferation of PRRSV showed that the expression of PSF and p54 nrb proteins contributed to the proliferation of PRRSV,and the synergistic effect of PSF and p54 nrb on the proliferation of PRRSV was more obvious.Therefore,PSF and p54 nrb proteins play an important role in the proliferation of PRRSV,and have a positive significance for the functional study of PSF and p54 nrb proteins,and provide a reference for the further study and prevention and control of PRRSV.