Figure 4.

Binding of NP to YY1 in the nuclei leads to an antiviral reaction in planthoppers. (A) Recombinantly expressed His-YY1 binds recombinantly expressed Flag-NP in the co-immunoprecipitation (Co-IP) and Western blot assay. The expression products from the pET28a vector were used as a negative control. (B) NP was pulled down from viruliferous planthoppers in the Co-IP and Western blot assay using an anti-human YY1 polyclonal antibody. An IgG antibody was used as a negative control. (C) YY1 was pulled down from viruliferous planthoppers in the Co-IP and Western blot assay using an anti-NP monoclonal antibody. An IgG antibody was used as a negative control. (D) Subcellular colocalization of NP and YY1 in the salivary gland and midgut cells of viruliferous planthoppers as determined by immunohistochemistry analysis. The green signal is from an Alexa Fluor 488-labeled anti-NP monoclonal antibody. The red signal is from an Alexa Fluor 594-labeled anti-human YY1 polyclonal antibody. The blue signal is the nuclei stained with Hoechst. The boxed region is enlarged and shown in three different panels on the right side. The samples without the treatment of primary antibodies are shown as negative controls. Scale bars: 20 μm. (E) Relative RNA levels of RSV NP and genomic RNA3 and YY1 in the planthoppers at 3 d after injection of dsRNA of YY1 (dsYY1) and RSV crude preparations measured by quantitative real-time PCR (qPCR). The control group was injected with dsRNA of GFP (dsGFP) and RSV crude preparations. The RNA levels of NP, RNA3, and YY1 are normalized to that of EF2. (F) The relative RNA levels of RSV NP and genomic RNA3 and YY1 in the planthoppers at 7 d after injection of dsRNA of YY1 (dsYY1) and RSV crude preparations measured by qPCR. ns, no significant difference. *P < 0.05. **P < 0.01. ***P < 0.001