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• Posted February 16, 2022

Gene Editing on Ticks Promises Insights Into Disease Prevention

Scientists who conducted the first gene editing in ticks say this line of research could lead to new ways to reduce tick-borne diseases in humans.

Ticks can transmit a wide number of diseases to people -- including Lyme disease, babesiosis and Rocky Mountain spotted fever -- but genetic knowledge about ticks is currently limited.

That's in marked contrast to mosquitoes, researchers said in a new study. The findings were published Feb. 15 in the journal iScience.

"Despite their capacity to acquire and pass on an array of debilitating pathogens, research on ticks has lagged behind other arthropod vectors, such as mosquitoes, largely because of challenges in applying available genetic and molecular tools," said study co-author Monika Gulia-Nuss, a molecular biologist at the University of Nevada, Reno.

"Having genome-editing tools available will allow us to unlock some of the secrets of the tick genome and allow us to determine how these unique animals survive in the environment, how they interact with pathogens, and how we might prevent ticks from spreading diseases to humans and livestock," she explained in a journal news release.

The researchers used a technique called CRISPR-Cas9 to edit the genomes of the black-legged tick, which spreads Lyme disease. First, the scientists had to overcome a number of obstacles to conducting gene editing in tick embryos.

Tick eggs have high interior pressure, a hard outer shell and a wax layer outside the embryo that must be removed before injection for gene editing.

"We were able to carefully dissect [pregnant] female ticks to surgically remove the organ responsible for coating the eggs with wax, but still allowing the females to lay viable eggs. These wax-free eggs permitted injection of tick embryos with materials necessary for genome modification," Gulia-Nuss said.

"Another major challenge was understanding the timing of tick embryo development. So little is known about tick embryology that we needed to determine the precise time when to introduce CRISPR-Cas9 to ensure the greatest chance of inducing genetic changes," she said.

"We expect that the tools we developed here will open new research avenues that will dramatically accelerate our understanding of the molecular biology of this and related tick species," Gulia-Nuss said.

Ultimately, this may "inform the development and application of new approaches to tick-borne disease control," she added.

More information

For more on ticks, see the U.S. Centers for Disease Control and Prevention.

SOURCE: iScience, news release, Feb. 15, 2022