Host Factor Rab4b Promotes Japanese Encephalitis Virus Replication

Although the <i>Japanese encephalitis virus</i> (JEV) infects various cell types, its receptor molecules are still not clearly understood. In our laboratory's prior research, Rab4b was identified as a potential host factor that facilitates JEV infection in PK15 cells, utilizing a genome-wide CRISPR/Cas9 knockout library (PK-15-GeCKO). To further explore the effect of Rab4b on JEV replication, we used the <i>Rab4b</i> knockout PK15 cell line using the CRISPR/Cas9 technology and overexpressing the <i>Rab4b</i> PK15 cell line, with IFA, RT-qPCR, and Western blot to study the effect of Rab4b on viral replication in the whole life cycle of the JEV. The results show that the knockout of <i>Rab4b</i> inhibited the replication of the JEV in PK15 cells, and the overexpression of <i>Rab4b</i> promoted the replication of the JEV in PK15 cell lines. Furthermore, we demonstrated for the first time that host factor Rab4b facilitates the adsorption, internalization, assembly, and release of the JEV, thereby promoting JEV replication. This study enriches the regulatory network between the JEV and host factors and lays the experimental foundation for further understanding of the function of the Rab4b protein.