Abstract: Abstrct:【Objective】To evaluate the inhibition ability of shRNAs targeting to M protein gene of Porcine Reproductive and Respiratory Syndrome virus;【Method】shRNA-expressing plasmids were constructed and delivered to HEK293A or Marc145 cells,efficiency of RNA interfering was assayed by semiquantitative RT-PCR, indirect immunofluorescence assay(IFA), virus titre of TCID50 and real time PCR;【Results】After cotransfection with fusion-protein expressing plasmids, the fluorescence in HEK293A cells treated by shRNA expressing plasmids became obviously weaker comparing to those cotransfected with target gene expressing plasmid and pSUPER plasmid. Different shRNA expressing vectors were also cotransfected into HEK293A cells with vectors expressing M proteins of PRRSV, and the mRNA level of M protein was inhibited to 54%-64% assayed by semi-quantitative PCR. These plasmids expressing shRNA were also delivered into Marc145 cells. After infection, these cells showed a significant decrease in virus yield when compared to control cells, by detection using virus titers (TCID50), IFA and real-time RT-PCR; 【Conclusion】shRNA targeting to M protein gene of PRRSV could inhibit M protein expression and PRRSV replication in Marc145 cells.

Key words: PRRSV, RNA interference (RNAi), M protein gene