To establish that NSs exerts an efficient viral translation in the presence of a transcription inhibitor, we tested whether coinfection of MP-12 and rMP12-rLuc increases the translation of rLuc mRNA of rMP12-rLuc in the presence of ActD. VeroE6 cells were mock-infected or co-infected with rMP12-rLuc and MP-12; rMP12-rLuc was infected at an moi. of 2, while MP-12 was infected at moi. of 0.1 or 1, as indicated in Figure 3 . The cell extracts were harvested at 16 h.p.i., and the rLuc activities ( Figure 3A ) and accumulation of viral RNAs ( Figure 3B ) were examined. As expected, ActD-treatment reduced the rLuc activities in cells infected with rMP12-rLuc alone ( Figure 3A ). Coinfection of MP-12 resulted in the reduction of both rLuc activities ( Figure 3A ) and the amounts of rLuc mRNA ( Figure 3B , lane 4) in the absence of ActD. In the presence of ActD, MP-12 co-infection also reduced the rLuc mRNA abundance ( Figure 3B , lane 9), whereas it increased rLuc activities ( Figure 3A ). The results suggested that NSs protein expressed from MP-12 S-segment promoted an efficient translation of the rLuc mRNA of rMP12-rLuc in the presence of ActD. We also noted that MP-12 coinfection did not reduce the abundance of the viral-sense rMP-12-rLuc S segment in the presence of ActD, and yet it caused the reduction of rLuc mRNA abundance ( Figure 3B , lane 9), which we believe implies that NSs expression and ActD treatment generated a cellular environment that was more favorable for rMP-12-rLuc RNA replication than for transcription.