Extended Data Fig. 10: IFITM1 does not affect Epstein-Barr virus infection in B cells.
(a) Knockdown of IFITM1 in B cells by infection with lentiviruses encoding shIFITM1 (1-shIFITM1 and 2-shIFITM1), then cells were incubated with cell-free EBV-GFP for 3 hours and remaining extracellular viruses were removed by washing with 1×PBS. EBV copy numbers were then measured by TaqMan-qPCR. (b) B cells were infection with lentiviruses encoding wild-type IFITM1 (IFITM1w), or dual mutations (IFITM1m1+2), then cells were incubated with cell-free EBV-GFP for 3 hours and remaining extracellular viruses were removed by washing with 1×PBS. EBV copy numbers were then measured by TaqMan-qPCR. (c) Analysis of the anti-EBV effects of sIFITM1 on B cells, exposure of B cells to EBV-GFP for 3 hours, with sIFITM1 being added 2 hours in advance at different concentrations (0, 1, and 5 ng/µL), EBV copy numbers were then measured by TaqMan-qPCR. Data are presented as mean values ± s.e.m., n = 4 independent experiments, *p < 0.05, **p < 0.01 (a-c). (d) According to the method in Fig. 1k and l, anti-EBV effects of sIFITM1 was tested on B cells in vivo. (e) A schematic diagram showing two models of EBV infection: an insusceptibility model (left), in which IFITM1 inhibits EBV entry by competing with EBV gH/gL and gB for binding to EphA2; and a susceptibility model (right), in which YTHDF3 recognizes m6A modification sites on IFITM1 and interacts with RNA degradation-related proteins DDX5, then leads to the degradation of IFITM1. The loss of IFITM1 would result in exposure of EphA2, which may aid EBV entry.
