FREP1 – BioQuakes

A new discovery has highlighted the positive effects that the revolutionary new gene editing tool, CRISPR-Cas9, can have. Scientists at the Johns Hopkins Bloomberg School of Public Health’s Malaria Research Institute have discovered that the deletion of a single gene from the Anopheles Gambiae mosquito, called the FREP1 gene, yields promising results in the eradication of the malaria disease.

Gene Editing

The FREP1 gene has been associated with being a malaria “host factor” gene because it helps the parasite live in the gut of the mosquitoes. However, the scientists, using the CRISPR-Cas9 gene editing procedures, have been able to delete the FREP1 gene from the mosquitoes and have seen significant decreases in the spread of malaria. Without the host factor gene, the parasite has difficulty surviving in the mosquito, which decreases the spread of the disease to other organisms.

The deletion of the FREP1 gene had other effects in addition to the resistance of the malaria parasites. In the mosquitoes where the gene was deleted, many showed no signs of sporozoite-stage parasites in their salivary glands, which can spread to humans through mosquito bites. George Dimopoulos, PhD, professor in the Bloomberg School’s Department of Molecular Microbiology and Immunology, commented on the study, saying that “if you could successfully replace ordinary, wild-type mosquitoes with these modified mosquitoes, it’s likely that there would be a significant impact on malaria transmission”.

Everybody hates mosquitoes. Not only are they annoying pests that bite us during the summertime, but they are also transmitters of the parasite that spreads malaria–Plasmodium. However, scientists believe that they have found a way to wipe out malaria for future generations. By using CRISPR in order to alter the fibrinogen-related protein 1 (FREP1), Plasmodium can be stopped from spreading amongst human beings. The alteration stops the plasmodium from reaching the mosquitoes’ salvatory glands, effectively halting transmission into the human bloodstream.

However, although CRISPR is a lot less drastic than simply wiping out the mosquito population, it does come with minor setbacks. The alteration made to the FREP1 gene causes the fertility of the mosquito as well as the egg-hatching rate to drop. These effects cause the reproduction rates of the altered mosquitoes to be significantly lower than that of other mosquitoes. If the modified mosquitoes are not able to reproduce, then the genetic modifications are unlikely to have any real effect on the transmission of malaria since they are not being passed on generationally.

The solution? Alter the female mosquitoes. Only female mosquitoes transmit malaria, so scientists have realized that altering the genetic code of female mosquitoes might be the way to solve the problem with reproduction. This way, the mosquitoes are able to maintain the genetic resistance to Plasmodium whilst avoiding the dramatic drop in reproduction.

Even though the alteration of mosquitoes’ genetics is definitely a scientific feat, there are no certainties when it comes to this attempt to stop malaria. Nobody is positive about whether or not CRISPR is the solution, but it is definitely a huge step in the right direction.

BioQuakes

AP Biology class blog for discussing current research in Biology

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