Fig 2

SnRV wt molecular clone is infectious.

(A, B) Kinetics of SnRV spread. BF-2 cells were infected with equal amounts - normalized by qRT-PCR with SnRV pol-derived primers (A) or RT activity (B) - of SnRV wt, SnRV Env^mut, or SnRV from E-11 cultures (SnRV E-11). On the indicated days postinfection, the culture supernatants were sampled (140 µl) to quantify viral RNA levels by qRT-PCR (A), or harvested (10 ml) for pelleting the virions by ultracentrifugation to determine the pellets’ RT activity by SG-PERT (B). The fold change (log₂) between each time point and (A) the initial time point (day 3 postinfection) or (B) the background sample (a pellet of a supernatant of naïve BF-2 culture) was calculated. Values represent the mean ± SD of three technical repeats. (C) Phenotypic changes in SnRV-infected BF-2 cells. Sub-confluent BF-2 cultures were infected (SnRV wt or SnRV Env^mut), or not. The cultures were passaged for 18 days postinfection, stained with crystal violet, and imaged by light microscopy. Bar; 100 µm.