Figure 4.

siRNA mediated pathway. (1) The exogenous siRNA pathway is activated when the virus-derived dsRNA is recognized and cleaved by the Dcr2 and r2d2 complex into about 19-21 bp long siRNA. siRNAs duplexes are loaded onto the RISC (RNA induced silencing complex), which degrades the passenger strand (2). The RNAi signal or the siRNA from the virus-infected cell enters the neighboring uninfected cell through a gap junction or cytoplasmic bridge (3). Viral dsRNA released from the infected ruptured cell is taken up by the cells, which provides adaptive immunity by the siRNA pathway.