Fusing a TurboID tag with the Andrias davidianus ranavirus 2L reduced virus adsorption efficiency

Andrias davidianus ranavirus (ADRV) is a member of the genus ranavirus (family Iridoviridae). ADRV 2L is an envelope protein that could be essential in viral infection. In the present study, the function of ADRV 2L was investigated by fusion with the biotin ligase TurboID tag. A recombinant ADRV with a V5-TurboID tag fused in the N-terminal of 2L (ADRV_T-2L) and a recombinant ADRV expressing V5-TurboID (ADRV_T) were constructed, respectively. Infection of the recombinant viruses and wild-type ADRV (ADRV_WT) in the Chinese giant salamander thymus cell line (GSTC) showed that ADRV_T-2L had reduced cytopathic effect and lower virus titers than the other two viruses, indicating the fusion of a big tag affected ADRV infection. Analysis of the temporal expression profile showed that the expression of V5-TurboID-2L was delayed than wild-type 2L. However, electron microscopy found that the virion morphogenesis was not affected in ADRV_T-2L-infected cells. Furthermore, the virus binding assay revealed that the adsorption efficiency of ADRV_T-2L was considerably decreased compared to the other two viruses. Therefore, these data showed that linking the TurboID tag to ADRV 2L affected virus adsorption to the cell membrane, which suggested an important role of 2L in virus entry into cells.