CRISPR Cas13a used to reduce egg production in genetically modified mosquitos

New work demonstrated silencing of multiple genes in genetically modified A. gambiae and A. aegypti.

Scientists from New Mexico State University harnessed the power of type VI CRISPR system – Cas13a (CRISPR-associated protein 13a) derived from bacterium Leptotrichia wadeii. The platform is also known as CRISPRi, from CRISPR interference, as instead of editing the genome, it only binds to DNA and silences nearby genes.

Two mosquito species were efficiently changed in the study: Anopheles gambiae (from the middle Africa) and Aedes aegypti (more widespread, in most warm climate areas). Mosquitoes were first injected with Cas13 constructs, which established expression of the CRISPR-associated protein. Then, researchers administered crRNA targeting specific genes. They chose genes responsible for egg production, such as Vg. As a result, genetically modified mosquitos laid down less eggs – demonstrating an interesting case for possible population control, including gene drive technology if Cas13 and crRNA would be inserted into the genome.

Additionaly, a pair of genes Cactus and Caspar was simultaneously silenced to demonstrate parallel activity of Cas13a in mosquitoes.

The authors concluded:

The Cas13a-CRISPRi system as a new tool holds promise for robust and flexible programming to silence one or more genes simultaneously in mosquitoes, with potential applications in other arthropods.

Preprint: Aditi Kulkarni, Wanqin Yu, Alex S. Moon, Ashmita Pandey, Kathryn A. Hanley, Jiannong Xu. Programmable CRISPR interference for gene silencing using Cas13a in mosquitoes. doi:10.1101/846055.

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