FIG 1.

Latent MHV68 alters host gene expression. Male C57BL/6 mice were infected intranasally with MHV68, ORF73.stop mutant virus (ORF73), or mockulum (mock), and spleens, livers, and brains (3 experiments) were harvested at 28 dpi. RNA was extracted using the ToTALLY RNA kit (Ambion) from tissues incubated in RNAlater-ICE (Ambion). Equal amounts of RNA were pooled from three to four mice per condition for each microarray chip. RNA was labeled and hybridized to Affymetrix M430 2.0 microarrays at the Multiplexed Gene Analysis Core Facility at Washington University in St. Louis, MO. Data were normalized using the Robust Multi-array Average normalization routine in Affymetrix's Expression Console software. Microarray data were analyzed by both factorial analysis and two-way ANOVA. Differentially expressed genes identified by both analyses are shown in the heat map after hierarchical clustering of the genes. The heat map represents the fold change relative to results for mock-infected mice, with red representing the row maximum and blue the row minimum value. Statistical significance was performed by using a standard Student t test in the case of factorial analysis. P values were corrected for multiple hypothesis testing. Gene expression differences were considered significant if the adjusted P value was <0.05 and a >1.5-fold change was observed in expression levels.