Engineering iridoviruses: development of reverse genetics and virus rescue systems

Area of Science:

• Virology
• Molecular Biology
• Aquaculture Health

Background:

• Iridoviruses, particularly Ranaviruses, cause significant mortality in fish and amphibians, impacting aquaculture and conservation efforts.
• The lack of reverse genetics systems has historically limited the study of iridovirus biology and the development of countermeasures.
• Frog virus 3 (FV3) is a widely studied iridovirus with a broad host range, making it a key target for research.

Purpose of the Study:

• To develop and characterize a functional reverse genetics system for frog virus 3 (FV3).
• To establish a novel method for virus rescue from genomic DNA using a helper virus.
• To facilitate genetic manipulation of the FV3 genome for functional studies and potential vaccine development.

Main Methods:

• Construction and characterization of a synthetic clone of frog virus 3 (FV3) for propagation in yeast and bacteria.
• Rescue of infectious virus from the synthetic FV3 clone.
• Development of a heterologous iridovirus-based system for reconstituting FV3 from naked DNA.

Main Results:

• A functional reverse genetics system for FV3 was successfully established, yielding rescued virus with identical properties to the parental isolate.
• A novel and facile method for virus reconstitution from purified FV3 DNA using a helper virus was demonstrated.
• The developed systems allow for efficient genetic manipulation of the FV3 genome.

Conclusions:

• The developed reverse genetics and rescue systems are essential tools for advancing iridovirus research and understanding virus-helminth interactions.
• These systems will enable detailed functional analysis of iridovirus genes.
• The FV3 system holds potential as a platform for developing modified live virus vaccines for various aquatic species.