FIG 5.

IFN response in A549 knockout cells transfected with m⁶A-deficient viral RNA. (a to l) IFN production after transfection of virion RNA. Confluent wild-type (a, e, i), MDA5 knockout (b, f, j), RIG-I knockout (c, g, k), or MAVS knockout (d, h, l) A549-Dual cells were transfected with the same amounts of SeV (a to d, 10⁵ RNA copies), MeV (e to h, 2 × 10⁵ RNA copies), and hMPV (i to l, 10⁷ RNA copies) virion RNAs from either METTL3 KO or WT cells. (m to p) IFN production after transfection of total RNA from VSV-infected cells. Confluent wild-type (m), MDA5 knockout (n), RIG-I knockout (o), or MAVS knockout (p) A549-Dual cells were transfected with the same amounts of total RNA from VSV-infected METTL3 KO cells or METTL3 WT cells containing 5 × 10⁶ copies of viral RNA. Cell culture supernatants were harvested at 16 and 24 h after inoculation, IFN-β in the supernatant at indicated time points was measured by a commercial ELISA kit. Data shown are the mean ± SD from n = 3 biologically independent experiments. Statistical significance was determined by two-sided Student's t test: *, P < 0.5; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001.