Giant grouper nervous necrosis virus subgenomic RNA3 is transcribed by a premature termination mechanism via intragenomic RNA-RNA pairing | Virology Journal

Study Highlights GGNNV RNA Behavior and Gene Regulation

Research focused on the giant grouper nervous necrosis virus (GGNNV) has yielded insights into the virus’s genomic RNA replication and transcription mechanisms. In an experiment involving grouper brain (GB) cells infected with GGNNV, Northern blotting was utilized to track the expression of viral RNAs at different times post-infection. Results indicated that both positive and negative strands of viral RNA1, RNA2, and RNA3 started to appear at four hours post-infection, with expression levels stabilizing by 24 hours. A notable finding was the higher expression levels of RNA3 compared to RNA1 at early stages of infection.

The study also introduced a DNA-based reverse genetic platform, allowing for precise recovery of GGNNV from cDNA. This technique utilized a human cytomegalovirus (CMV) enhancer/promoter to regulate viral genome transcription. Subsequent experiments demonstrated that DNA constructs could facilitate the recovery of infectious recombinant GGNNV, achieving viral titers comparable to wild type.

In silico analyses and mutagenesis experiments further suggested an essential role for specific RNA structures in the transcription of RNA3, contributing to our understanding of the coordinated regulation among GGNNV RNAs. The results hold implications for virology by informing potential antiviral strategies.

• Why it matters: Findings could help in developing antiviral strategies targeting GGNNV, impacting aquaculture practices and virus management.
• The latest: Researchers successfully established high-titer recombinant GGNNV through a DNA-based reverse genetic vector.