Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

An easier way to manipulate malaria genes

12.08.2014

New approach to knocking out parasite's genes could make it easier to identify drug targets

Plasmodium falciparum, the parasite that causes malaria, has proven notoriously resistant to scientists' efforts to study its genetics. It can take up to a year to determine the function of a single gene, which has slowed efforts to develop new, more targeted drugs and vaccines.

MIT biological engineers have now demonstrated that a new genome-editing technique, called CRISPR, can disrupt a single parasite gene with a success rate of up to 100 percent — in a matter of weeks. This approach could enable much more rapid gene analysis and boost drug-development efforts, says Jacquin Niles, an associate professor of biological engineering at MIT.

"Even though we've sequenced the entire genome of Plasmodium falciparum, half of it still remains functionally uncharacterized. That's about 2,500 genes that if only we knew what they did, we could think about novel therapeutics, whether it's drugs or vaccines," says Niles, the senior author of a paper describing the technique in the Aug. 10 online edition of Nature Methods.

The paper's lead author is Jeffrey Wagner, a recent PhD recipient and current MIT postdoc in biological engineering. Graduate student Randall Platt, recent PhD recipient Stephen Goldfless, and Feng Zhang, the W.M. Keck Career Development Assistant Professor in Biomedical Engineering, also contributed to the research.

Plasmodium falciparum, a blood-borne parasite carried by mosquitoes, is responsible for most of the estimated 219 million cases, and 655,000 deaths, from malaria per year. Treatments include chloroquine and artemisin, but the parasite is becoming more resistant to these drugs.

There is an urgent need to develop new drugs, but potential genetic targets are hard to identify. In animals such as mice, it is fairly routine to study gene functions by deleting a target gene or replacing it with an artificial piece of DNA. However, in Plasmodium falciparum, this approach can take up to a year because it relies on homologous recombination, a type of genetic swapping that cells use to repair broken DNA strands. This occurs very rarely in the genome of the malaria parasite.

"You have to rely on this really inefficient process that occurs only if you have spontaneous DNA strand breaks that happen to fall within your region of interest," Niles says.

Using this time-consuming approach, scientists have been able to identify functions for some of the genes necessary for the parasite to invade red blood cells, as well as some of the genes required for the parasite to later erupt from blood cells. More recently, researchers have successfully used enzymes called zinc finger nucleases to cut out specific genes, but this approach is costly because it requires a new nuclease to be designed for each gene target.

CRISPR, a gene-editing system devised within the past several years, exploits a set of bacterial proteins that protect microbes from viral infection. The system includes a DNA-cutting enzyme, Cas9, bound to a short RNA guide strand that is programmed to bind to a specific genome sequence, telling Cas9 where to make its cut. This approach allows scientists to target and delete any gene by simply changing the RNA guide strand sequence.

As soon as researchers successfully demonstrated that this system could work in cells other than bacteria, Niles started to think about using it to manipulate Plasmodium falciparum. To test this approach, he and his colleagues tried using CRISPR to disrupt two genes, kahrp and eba-175, that had previously been knocked out in malaria using traditional approaches.

The kahrp gene produces a protein that causes red blood cells, which are normally smooth, to develop a knobby appearance when infected with malaria. Niles' team was able to disrupt this gene in 100 percent of parasites treated with the CRISPR system; red blood cells infected by those parasites remained smooth.

With eba-175, which codes for a protein that binds to red blood cell receptors and helps the parasite get into the cells, the researchers disrupted this gene in 50 to 80 percent of parasites manipulated with the CRISPR system. "We consider this to be a win," Niles says. "Compared to the efficiency with which P. falciparum genetics have been done in the past, even 50 percent is pretty substantial."

For both targets, the researchers demonstrated that they could insert a gene for the protein luciferase, which emits light, in addition to turning off the existing genes.

Now that CRISPR technology has been validated in Plasmodium falciparum, Niles expects that many scientists will adopt it for genetic studies of the parasite. Such efforts could reveal more about how the parasite invades red blood cells and replicates inside cells, which could generate new drug and vaccine targets.

"I think the impact could be quite huge," Niles says. "It lowers the barrier to really being more imaginative in terms of how we do experiments and the kinds of questions that we can ask."

The research was funded by the National Institute of General Medical Sciences, the National Institute of Environmental Health Sciences, the National Science Foundation, the National Institutes of Health, and the Bill and Melinda Gates Foundation.

Abby Abazorius | Eurek Alert!
Further information:
http://www.mit.edu

Further reports about: CRISPR DNA MIT Massachusetts Plasmodium blood develop drugs falciparum genes parasite parasites technique

More articles from Life Sciences:

nachricht Surprising similarity in fly and mouse motion vision
30.07.2015 | Max Planck Institute of Neurobiology, Martinsried

nachricht Intracellular microlasers could allow precise labeling of a trillion individual cells
30.07.2015 | Massachusetts General Hospital

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: On the crest of the wave: Electronics on a time scale shorter than a cycle of light

Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.

The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...

Im Focus: Superfast fluorescence sets new speed record

Plasmonic device has speed and efficiency to serve optical computers

Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.

Im Focus: Unlocking the rice immune system

Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight

A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...

Im Focus: Smarter window materials can control light and energy

Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.

By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...

Im Focus: Simulations lead to design of near-frictionless material

Argonne scientists used Mira to identify and improve a new mechanism for eliminating friction, which fed into the development of a hybrid material that exhibited superlubricity at the macroscale for the first time. Argonne Leadership Computing Facility (ALCF) researchers helped enable the groundbreaking simulations by overcoming a performance bottleneck that doubled the speed of the team's code.

While reviewing the simulation results of a promising new lubricant material, Argonne researcher Sanket Deshmukh stumbled upon a phenomenon that had never been...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Euro Bio-inspired - International Conference and Exhibition on Bio-inspired Materials

23.07.2015 | Event News

Clash of Realities – International Conference on the Art, Technology and Theory of Digital Games

10.07.2015 | Event News

World Conference on Regenerative Medicine in Leipzig: Last chance to submit abstracts until 2 July

25.06.2015 | Event News

 
Latest News

Surprising similarity in fly and mouse motion vision

30.07.2015 | Life Sciences

Efficient Infrared Heat Saves Time and Energy in the Manufacture of Motor Vehicle Carpets

30.07.2015 | Trade Fair News

Roentgen prize goes to Dr Eleftherios Goulielmakis

30.07.2015 | Awards Funding

VideoLinks
B2B-VideoLinks
More VideoLinks >>>