Virus-Infection or 5′ppp-RNA Activates Antiviral Signal through Redistribution of IPS-1 Mediated by MFN1
Figure 7
A dominant negative mutant of RIG-I fails to induce IPS-1 redistribution.
A, IPS-1-HeLa cells stably expressing wild-type human RIG-I (RIG-I WT) or mutant RIG-I (RIG-I K270A) were mock-treated or infected with NDV for 12 h and expression of IFNB1 mRNA was analyzed by qRT-PCR. Open and filled bars indicate RNA samples from mock-treated and NDV-infected cells, respectively. Data represent means ± s.d. (n = 3). B, IPS-1-HeLa cells expressing RIG-I WT or RIG-I K270A were infected with NDV for 12 h and stained with anti-RIG-I antibody and anti-NP antibody. RIG-I staining is diffuse in uninfected cells however infection by NDV produced RIG-I foci. Some RIG-I foci are co-localized with NDV NP foci. C, IPS-1-HeLa cells expressing RIG-I WT or RIG-I K270A were infected with NDV for 12 h and IPS-1 redistribution was examined. IPS-1 and NP were stained with anti-IPS-1 antibody and anti-NP antibody, respectively. The area enclosed by the red rectangle is enlarged at the right. Although the redistributed IPS-1 surrounds NP foci in RIG-I WT cells, K270A mutation of RIG-I failed to induce the redistribution of IPS-1, but not the formation of NP foci.