# Harnessing the highly adaptable barnase-barstar system for genetic biocontrol of Aedes aegypti

## TL;DR

Researchers adapted the barnase-barstar system to control Aedes aegypti mosquitoes by using it as a toxin-antidote pair in gene drives.

## Contribution

The barnase-barstar system is demonstrated as a highly adaptable toxin-antidote pair for genetic biocontrol in mosquitoes.

## Key findings

- Ubiquitous expression of barnase in transgenic mosquitoes leads to up to 100% lethality.
- Tissue-specific barnase expression causes flightlessness or reduced fertility in female mosquitoes.
- Barstar can rescue barnase's effects when ubiquitously expressed but is less effective in tissue-specific cases.

## Abstract

Toxin-antidote pairs can be used in gene drive systems, providing powerful means to modify mosquito populations. Here we use the toxin-antidote pair, barnase and barstar, originally identified in Bacillus amyloliquefaciens, due to their high binding affinity, small size and lack of need for cofactors. In Ae. aegypti cell culture, we find that barnase can kill and barstar can rescue the effect. Ubiquitous expression of barnase in transgenic mosquitoes results in up to 100% lethality. Tissue specific expression results in flightless or reduced fertility in females and this could be partially rescued by ubiquitous expression of barstar likely due to insufficient expression of barstar in affected tissues. In conclusion, we show barnase-barstar to be a highly adaptable toxin-antidote pair, providing a basis for developing toxin-antidote gene drive systems.

The barnase-barstar pair is effective in Aedes aegypti as a basis for toxin-antidote gene drive systems, barnase is able to kill mosquitoes and cells and barstar rescues the effect in a ubiquitous or tissue-specific manner.