Deleting a single gene from mosquitoes can make them highly resistant to the malaria parasite and thus much less likely to transmit the parasite to humans, according to a new paper from scientists at Johns Hopkins Bloomberg School of Public Health’s Malaria Research Institute.
The scientists used the new CRISPR/Cas9 system, which permits precise DNA editing, to delete a gene called FREP1 from the genome of Anopheles gambiae mosquitoes, the chief transmitters of malaria to humans. Within the modified mosquitoes, malaria parasites were much less likely to survive and multiply. The CRISPR/Cas9 system used in this study was developed by Eric Marois, research scientist at the University of Strasbourg.
The study, published March 8 in PLoS Pathogens, is the first to show that deleting a gene from mosquitoes can make them resistant to malaria parasites. It also underscores the potential of this strategy to modify wild mosquito populations and thereby reduce malaria transmission to humans.
The CRISPR/Cas9 system is a set of DNA-editing molecules implicated in bacterial defense mechanism against viruses. In recent years, biologists have adapted it as a precise tool for genetic engineering — in scientific experiments, and in prospective genetic-modification strategies against diseases such as malaria.
“Our study shows that we can use this new CRISPR/Cas9 gene-editing technology to render mosquitoes malaria-resistant by removing a so-called host factor gene,” says study senior author Dr. George Dimopoulos, professor in the Bloomberg School’s department of molecular microbiology and immunology. “This gives us a good technological platform for developing advanced malaria-control strategies, based on genetically modified mosquitoes unable to transmit the disease, and for studying the biology of malaria parasites in their mosquito hosts.”