A microRNA from infectious spleen and kidney necrosis virus modulates expression of the virus-mock basement membrane component VP08R

•A novel microRNA, temporarily named ISKNV-miR-1, was identified from ISKNV.•ISKNV-miR-1 targets VP08R gene encoding a component of virus-mock basement membrane.•ISKNV-miR-1 modulates VP08R expression through reducing VP08R mRNA.

Infectious spleen and kidney necrosis virus (ISKNV) is the type species of the genus Megalocytivirus, family Iridoviridae. Infection of ISKNV is characterized by a unique pathological phenomenon in that the infected cells are attached by lymphatic endothelial cells (LECs). ISKNV mediates the formation of a virus-mock basement membrane (VMBM) structure on the surface of infected cells to provide attaching sites for LECs. The viral protein VP08R is an important component of VMBM. In this study, a novel ISKNV-encoded microRNA, temporarily named ISKNV-miR-1, was identified. ISKNV-miR-1 is complementary to the VP08R-coding sequence and can modulate VP08R expression through reducing its mRNA level. This suggests that formation of VMBM may be under fine regulation by ISKNV.