RdRP mice display highly augmented antiviral defenses.

(A) Heat map of differentially expressed genes in CNS tissue. Microarray data are presented as fold change (blue = 1-fold induction; purple = 8-fold upregulation; red = ≥15-fold upregulation). WT+EMCV: expression profile of genes significantly upregulated >4-fold in spinal cords of WT FVB mice infected with EMCV (n = 2) compared with uninfected WT FVB mice (n = 2). RdRP: uninfected transgenic RdRP FVB mice (n = 3) compared with uninfected WT FVB mice (n = 3), data are representative of two independent experiments. RdRP+EMCV: RdRP FVB mice infected with EMCV (n = 2) compared with uninfected WT FVB mice (n = 2). For a complete list of upregulated genes see S1–S3 Tables. (B) mRNA levels of the prominent antiviral genes, Oasl2, Isg15, Ifit1, and Rig-I, determined by RT-PCR in cerebrum, spinal cord, and cerebellum tissues of uninfected (WT FVB or RdRP FVB) or virally-infected FVB mice (WT+EMCV or RdRP+EMCV) (n = 5 mice per group, relative to Gapdh mRNA, mean ± SEM). (C and D) Cerebrum, spinal cord, and cerebellum tissue homogenates (C, n = 2 mice per group, 1 per lane; D, n = 1 uninfected mouse of specified age in months per lane) were analyzed by immunoblotting using antibodies for RIG-I and ISG15. Antibody for β-ACTIN served as control. (E) RT-PCR analysis of viral titers in murine tissues two days post infection with EMCV (n = 8 mice per genotype, relative to endogenous Gapdh mRNA, mean ± SEM). (F) Survival curve following EMCV infection (n = 8 mice per genotype). Results are presented as a Kaplan-Meier plot and are representative of two independent experiments. * P<0.05; ** P<0.01; *** P<0.001; **** P<0.0001.