Development of an improved reverse genetics system for Akabane bunyavirus

Area of Science:

• Veterinary Virology
• Molecular Biology
• Infectious Diseases

Background:

• Akabane disease, caused by Akabane virus (AKAV), results in significant fetal deformities and mortality in livestock.
• Economic losses due to Akabane disease are substantial in affected countries, including Japan.
• Effective control strategies and vaccines are crucial for mitigating these economic impacts.

Purpose of the Study:

• To establish a novel T7 RNA polymerase-based reverse genetics system for Akabane virus (AKAV).
• To utilize this system for reconstituting a live attenuated AKAV vaccine strain (rTTT).
• To generate and characterize an AKAV mutant lacking the NSs virulence factor (rTTTΔNSs).

Main Methods:

• Development of a reverse genetics system using three plasmids for antigenomic RNA transcription.
• Transfection of plasmids into cells stably expressing T7 polymerase.
• Reconstitution of the live attenuated vaccine strain (rTTT) and generation of the NSs-deficient mutant (rTTTΔNSs).

Main Results:

• Successful reconstitution of the live attenuated Akabane virus vaccine strain (rTTT).
• Generation of a gene-manipulated Akabane virus mutant (rTTTΔNSs) lacking the NSs virulence factor.
• Demonstrated significantly slower growth kinetics of the rTTTΔNSs mutant compared to the parental strains.

Conclusions:

• The established reverse genetics system is a powerful tool for Akabane virus (AKAV) research.
• This system facilitates studies on AKAV vaccine development.
• The system enables the generation of gene-manipulated AKAV for virulence factor analysis and vaccine research.