Myc transcriptional activity is upregulated during MuHV-4 latency in GC cells.

<p>(A) MuHV-4 infected cells exhibit augmented expression of Myc-dependent genes. FACS purified infected (CD19⁺CD95^hiGL7^hiYFP⁺) or control uninfected (CD19⁺CD95^hiGL7^hiYFP⁻) GC B-cells from C57BL/6 mice infected with MuHV-4-YFP were analysed at 13 days pi for transcription of genes encoding for cyclins (Cyc) B1, D1, D2, D3, E1, cyclin-dependent kinase (Cdk) 4, IL10, B-ATF, MIF and CD70 by qPCR. Transcription of each gene, normalized to GAPDH, is represented as fold induction relative to control uninfected cells purified form the same pool of 5 spleens. Error bars represent SEM from three independent experiments. (B and C) <i>Cγ1-cre^KI/WT</i>; <i>c-myc^fl/fl</i> (GC Myc KO) mice are unable to mount a GC reaction. GC Myc KO and control mice immunized with NP-CGG were analysed at day 10 post-immunization for frequencies of GC (CD19⁺CD95^hiGL7^hi) and IgG1 (CD19⁺IgD⁻IgM⁻IgG1⁺) B-cells, by flow cytometry. (D, E and F) GC Myc KO mice exhibit normal numbers of IgG2a/2b B-cells. GC Myc KO and control mice immunized with CFA-OVA were analysed 14 days later for frequencies of GC, IgG1 and IgG2a/2b (CD19⁺IgD⁻IgM⁻IgG2a/2b⁺) B-cells by flow cytometry. Each point represents an individual mouse; four mice (n = 4) were analyzed for each experimental condition; grey bars indicate the mean. Representative FACS plots from individual animals are shown (top panels).