PTBP1 and infection: The expression level of EV71 VP1 was decreased in PTB knockdown cells at 4 h, 8 h, and 12 h post-EV71 infection, respectively (Fig. 5C), while the expression level of EV71 VP1 was increased in PTB-overexpression cells during infection (Fig. 5D), indicating that PTB promotes the expression of viral protein.