Figure 5
siRNA-mediated knockdown of chBRD2 promotes NDV replication in DF-1 cells. A The effect of chBRD2 siRNA or control siRNA on the transcription of the endogenous chBRD2 gene in DF-1 cells. DF-1 cells grown in 6-well plates were transfected with the indicated siRNAs (10 μM) at a dose of 30 pmol, and the knockdown efficiency of the chBRD2 gene was detected by qRT-PCR at 48 hpt. The relative transcription levels of the chBRD2 gene were compared with those of the control GAPDH gene. Error bars represent standard deviations (mean ± SD) (***P < 0.001 compared to the value of the control siRNA group). B The growth kinetics of rSS1GFP were compared using multicycle growth curves in chBRD2 siRNA#2- or control siRNA-treated cells or non-transfected cells. The cell culture supernatants were collected at the indicated time points (6, 12, 24, 36, 48, and 72 hpi), and the viral titres were titrated using TCID50 (50% tissue culture infective dose) in DF-1 cells. Error bars represent standard deviations (mean ± SD) (*P < 0.05; **P < 0.01 compared to the value of non-transfected cells). C The CPE of rSS1GFP was observed in chBRD2 siRNA#2- or control siRNA-treated DF-1 cells at 12, 24, 36 and 48 hpi. The original magnification was 1 × 200. Viral RNA synthesis corresponding to the NP and P genes (D) and viral gene transcription corresponding to the M and GFP genes (E) of rSS1GFP in chBRD2 siRNA#2- or control siRNA-treated cells or non-transfected cells was detected by qRT-PCR at 6, 12 and 24 hpi. Error bars represent standard deviations (mean ± SD) (*P < 0.05; **P < 0.01 compared to the value of non-transfected cells). F The expression levels of the M and GFP proteins in chBRD2 siRNA#2- or control siRNA-treated cells were examined by western blot at 6, 12 and 24 hpi, respectively. The relative expression levels of the M and GFP proteins compared to control GAPDH expression levels were determined by densitometry using ImageJ software version 1.8.0. Error bars represent standard deviations (mean ± SD) (*P < 0.05; **P < 0.01 compared to the value of the control siRNA group).