MDCK cells stably expressing shRNA for IRF7 enhances influenza A virus production.

<p>(A) The total RNA from parental or transduced MDCK cells was isolated and subjected to quantitative real-time RT-PCR. The knockdown efficiency of IRF7 mRNA expression level by transduced shRNA showed an 80% reduction. (B). The MDCK cells were infected with PR8 virus at a MOI of 0.0003. On day 3 after PR8 infection, the amount of viral RNA in culture supernatant was determined by quantitative real-time RT-PCR. (C) The MDCK cells were infected with A/Narita/1/2009 (A (H1N1) pdm09) virus at a MOI of 0.0003. On day 3 after virus infection, the amount of viral RNA in culture supernatant was determined by quantitative real-time RT-PCR. The relative viral RNA levels were normalized to values for 18S rRNA which was included in carrier RNA, and expressed as the relative (n-fold) value to the level of RNA from control. The data are representative results of three independent experiments. Asterisks indicate statistically significant differences compared with the control (*P<0.05).