BPV virions are enriched in acetylation of histone H4. (A) Representative immunoblots of BPV virions and bovine keratinocyte control cells probed with antibodies against the indicated histone H4 modification. On the right are the same immunoblots, stripped and reprobed with antibody against pan histone H3 to ensure even loading. (B) Quantification of immunoblots in panel A. Histone modification signals were normalized to panH3 signals, and the levels are represented relative to the signal for BPV1. Significance was determined by an unpaired t test. n.s., P > 0.05; *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001; n = 2; error = SD.