C-myc modulates the replication of RGNNV via glutamine-mediated ATP production in grouper fin cells

C-myc is a proto-oncogene that plays an important role in a variety of diseases. There were a lot of research on the correlation between C-myc and human viruses. However, the study about C-myc related to aquatic species virus is very limited. In the present study, the qRT-PCR, cellular immunofluorescence and western blotting determination data reported that C-myc and glutaminase (GLS) genes were significantly upregulated when grouper fin cells (GF-1) were infected with red grouper nervous necrosis virus (RGNNV). After knocking down the C-myc gene, the mRNA and protein levels of GLS, capsid protein (CP) and RNA polymerase (RdRp) of RGNNV were significantly reduced in RGNNV-infected GF-1 cells and the overexpression of the C-myc gene remarkably promoted these genes, which indicated that the replication of the virus and GLS gene were positively regulated by C-myc in RGNNV-infected GF-1 cells. In addition, supplementation of exogenous ATP can partially restore viral replication when RGNNV-infected GF-1 cells were cultured in glutamine-free medium, which confirmed that the glutamine was decomposed into ATP to provide energy for viral replication. Further studies confirmed that overexpression of C-myc can increase the content of ATP in normal cells. To sum up, these data suggested that activation of C-myc gene affected viral replication by regulating GLS expression to drive glutamine dissolution.