
 Fig . 12. BPXV switches to use p38-Υ under long-term selective pressure of p38-α inhibitor. p38-α MAPK is a critical cellular factor that positively regulates BPXV replication. Long-term sequential passage ( P  ≥ 40) of BPXV in Vero cells in the presence of p38-α inhibitor (SB239063) induces generation of viral mutants that preferentially utilize p38-Υ instead of p38-α, thereby becoming resistant against the targeting agent (SB239063).