Model of NDV V protein regulating apoptosis in DF-1 cells. When NDV invaded the DF-1 cells, the virus replicated and translated a number of V proteins. V protein inhibits the activation of Bax and activates Bcl-2, thereby inhibiting apoptosis. TXNL1 inhibits the activation of Bcl-2 and activates the Bax-Caspase-3 pathway, thereby promoting cell apoptosis. At the same time, the V protein inhibits the expression of TXNL1. In this process, apoptosis inhibits the replication of NDV.