Chinese Giant Salamander Iridovirus 025L Is a Viral Essential Gene

Ranavirus is a large nucleocytoplasmic DNA virus. Chinese giant salamander iridovirus (CGSIV) belongs to the ranavirus genus, and its replication involves a series of essential viral genes. Viral PCNA is a gene closely associated with viral replication. CGSIV-025L also encodes PCNA-like genes. We have described the function of CGSIV-025L in virus replication. The promoter of CGSIV-025L is activated during viral infection, and it is an early (E) gene that can be effectively transcribed after viral infection. CGSIV-025L overexpression promoted viral replication and viral DNA replication. siRNA interfered with CGSIV-025L expression and attenuated viral replication and viral DNA replication. The Δ025L-CGSIV strain with the deletion of CGSIV-025L could not replicate normally and could be rescued by the replenishment of 025L. CGSIV-025L was proven to be an essential gene for CGSIV by overexpression, interference, and deletion mutation experiments. CGSIV-025L was found to interact with CGSIV-062L by yeast two-hybrid, CoIP, and GST pulldown. Thus, the current study demonstrated that CGSIV-025L is an essential gene of CGSIV, which may be involved in viral infection by participating in viral DNA replication and interacting with replication-related proteins.