TFEB and infection: Infection of the knockdown cells with IBV showed that knockdown of TFE3 facilitated IBV replication, and a similar trend effect was observed when both TFEB and TFE3 were simultaneously knocked down, as revealed by Western blot analysis of IBV N protein (Figure 4D), and RT-qPCR analysis of viral genomic RNA in knockdown and control cells (Figure 4E).