RNA interference targeting UL25 gene as a gene therapy approach against BHV-1

Infectious bovine rhinotracheitis (IBR) is an important economic viral disease, which is caused by bovine herpesvirus-1. BHV1-UL25 plays an important role in the encapsidation process and the stabilization of the packaged DNA into the capsid. The application of lentiviral mediated shRNAs for knocking down the target genes is a powerful antiviral approach. Thus, in the present study, an RNAi- based antiviral approach was designed and assayed by the targeting of BHV1-UL25.

The suitable shRNA molecules were purposed using online software. Three recombinant lentiviral vectors expressing shRNAs down regulating the UL25 gene of BHV-1 were constructed.The effectiveness of designed shRNAs was assayed by the observation of BHV-1 cytopathic effects, calculating TCID50 titers, and evaluating the changes in viral gene expression using real-time RT PCR.

All the shRNAs sufficiently decreased BHV1 titers (more than 90%) in comparison with the control groups. We observed the reduction value of more than 99% in the expression of viral RNA in the cells treated with all the shRNAs in comparison with the control groups. The reduction rate of BHV1-UL25 expression with shRNAs was more than 93%, in comparison with that in the cells expressing the selected domain. The reduction values were more than 99% for all three shRNAs compared to the cells expressing the selected BHV1-UL25 domain infected with a scrambled vector.

The results indicated that lentiviral mediated shRNAs targeting BHV1- UL25 had considerable antiviral attributes. In conclusion, RNAi may be considered as a strong treatment proposal against viruses such as BHV-1.