FIG 1.

ATM-p53 response is activated during MHV68 lytic replication. 3T3 fibroblasts (A) or MB114 endothelial cells (B) were mock infected (M) or infected (I) with MHV68 at an MOI of 5 PFU/cell. Cells were treated with 1 μM doxorubicin (Doxo) for 4 h as a positive control for DDR induction. Cells were harvested at the indicated times postinfection (A) or 18 h postinfection (B), SDS-PAGE was performed, and immunoblot analyses were conducted using antibodies specific to the indicated antigens. Detection of β-actin serves as a loading control. (C and D) C57BL/6 mice were intraperitoneally mock inoculated or inoculated with 10⁶ PFU of H2B-YFP-expressing MHV68. Animals were sacrificed 4 days postinfection, and bulk splenocytes were isolated and processed for flow cytometry to detect H2B-YFP (C) and p53 (D). Data shown in panel D are representative histograms for p53. The range of p53 mean fluorescence intensity (MFI) from two independent experiments is shown. Splenocytes from mock-inoculated animals were exposed to 10 Gy of gamma radiation (γ-IR) as a positive control for p53 induction.