Understanding How Tiny Bacteria Control Mosquito Sperm Development to Stop Disease Spread

What is it about?

Controlling harmful animals by the use of microorganisms is an innovative biological way to advance human health prospects in the future. The deadliest animal in the world is the mosquito that kills a million people per year by spreading diseases like dengue, Zika, and Chikungunya viruses. A symbiotic bacterium called Wolbachia can control mosquito-borne diseases by not only stopping these viruses from growing inside them, but also making it hard for mosquito eggs to survive if the male mosquito carries Wolbachia and female does not. This combination helps to control the number of mosquitoes carrying diseases. However, if females harbor Wolbachia, the eggs survive to spread and replace the population with Wolbachia-carrying mosquitoes that reduce the virus transmission. Here, we investigated the mechanism of how Wolbachia affects sperm development in male mosquitoes that negatively impacts survival of the egg. We discovered that two proteins produced by a phage of Wolbachia, called CifA and CifB, target mosquito sperm DNA and severely affect how it is packaged. Mispackaging of sperm has deleterious impacts including infertility and errors in embryo development after fertilization. In particular, male chromosomes fail to synchronize with female chromosomes, resulting in arrested egg development.

Featured Image

Photo by National Institute of Allergy and Infectious Diseases on Unsplash

Photo by National Institute of Allergy and Infectious Diseases on Unsplash

Why is it important?

Learning how Wolbachia affect mosquito sperm is important for developing better ways to control disease transmission, especially in vectors and/or pest species that either do not get infected with Wolbachia or in which Wolbachia lack the capacity to induce sperm changes.