Navigation Links
Genetic engineering alters mosquitoes' sense of smell
Date:5/29/2013

In one of the first successful attempts at genetically engineering mosquitoes, Howard Hughes Medical Institute (HHMI) researchers have altered the way the insects respond to odors, including the smell of humans and the insect repellant DEET. The research not only demonstrates that mosquitoes can be genetically manipulated using the latest research techniques, but paves the way to understanding why the insect is so attracted to humans, and how to block that attraction.

"The time has come now to do genetics in these important disease-vector insects. I think our new work is a great example that you can do it," says Leslie Vosshall, an HHMI investigator at Rockefeller University who led the new research, published May 29, 2013 in the journal Nature.

In 2007, scientists announced the completion of the full genome sequence of Aedes aegypti, the mosquito that transmits dengue and yellow fever. A year later, when Vosshall became an HHMI investigator, she shifted the focus of her lab from Drosophila flies to mosquitoes with the specific goal of genetically engineering the insects. Studying mosquitoes appealed to her because of their importance as disease carriers, as well as their unique attraction to humans.

Vosshall's first target: a gene called orco, which her lab had deleted in genetically engineered flies 10 years earlier.

"We knew this gene was important for flies to be able to respond to the odors they respond to," says Vosshall. "And we had some hints that mosquitoes interact with smells in their environment, so it was a good bet that something would interact with orco in mosquitoes."

Vosshall's team turned to a genetic engineering tool called zinc-finger nucleases to specifically mutate the orco gene in Aedes aegypti. They injected the targeted zinc-finger nucleases into mosquito embryos, waited for them to mature, identified mutant individuals, and generated mutant strains that allowed them to study the role of orco in mosquito biology. The engineered mosquitoes showed diminished activity in neurons linked to odor-sensing. Then, behavioral tests revealed more changes.

When given a choice between a human and any other animal, normal Aedes aegypti will reliably buzz toward the human. But the mosquitoes with orco mutations showed reduced preference for the smell of humans over guinea pigs, even in the presence of carbon dioxide, which is thought to help mosquitoes respond to human scent. "By disrupting a single gene, we can fundamentally confuse the mosquito from its task of seeking humans," says Vosshall. But they don't yet know whether the confusion stems from an inability to sense a "bad" smell coming from the guinea pig, a "good" smell from the human, or both.

Next, the team tested whether the mosquitoes with orco mutations responded differently to DEET. When exposed to two human armsone slathered in a solution containing 10 percent DEET, the active ingredient in many bug repellants, and the other untreatedthe mosquitoes flew equally toward both arms, suggesting they couldn't smell the DEET. But once they landed on the arms, they quickly flew away from the DEET-covered one. "This tells us that there are two totally different mechanisms that mosquitoes are using to sense DEET," explains Vosshall. "One is what's happening in the air, and the other only comes into action when the mosquito is touching the skin." Such dual mechanisms had been discussed but had never been shown before.

Vosshall and her collaborators next want to study in more detail how the orco protein interacts with the mosquitoes' odorant receptors to allow the insects to sense smells. "We want to know what it is about these mosquitoes that makes them so specialized for humans," she says. "And if we can also provide insights into how existing repellants are working, then we can start having some ideas about what a next-generation repellant would look like."


'/>"/>

Contact: Jim Keeley
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
Source:Eurekalert

Related biology news :

1. U of A medical researchers ID genetic marker for sporadic breast cancer
2. Family studies suggest rare genetic mutations team up to cause schizophrenia
3. Fast new, 1-step genetic engineering technology
4. Genetic predictors of postpartum depression uncovered by Hopkins researchers
5. Genetic risk for schizophrenia is connected to reduced IQ
6. European Society of Human Genetics urges caution over use of new genetic sequencing techniques
7. University of Maryland Medical Center launches genetic-testing program for cardiac patients
8. Penn Medicine researchers identify 4 new genetic risk factors for testicular cancer
9. Fred Hutch evolutionary geneticist Harmit Malik selected as an HHMI investigator
10. Genetic and clinical factors best to predict late recurrence in estrogen receptor POS breast cancer
11. Study examines effects of genetic variants for infants with neonatal abstinence syndrome
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/15/2016)... 15, 2016 --> ... Transparency Market Research "Digital Door Lock Systems Market - Global ... 2023," the global digital door lock systems market in terms ... and is forecast to grow at a CAGR of 31.8% ... and medium enterprises (MSMEs) across the world and high industrial ...
(Date:3/14/2016)... , March 14, 2016 NXTD ... growing mobile commerce market, announces the airing of a new ... starting the week of March 21 st .  The commercials ... including its popular Squawk on the Street show. --> ... on the growing mobile commerce market, announces the airing of ...
(Date:3/11/2016)... http://www.apimages.com ) - --> http://www.apimages.com ) - ... Images ( http://www.apimages.com ) - Germany . ... new refugee identity cards. DERMALOG will be unveiling this device, and ... Hanover next week.   --> Germany ... the new refugee identity cards. DERMALOG will be unveiling this device, ...
Breaking Biology News(10 mins):
(Date:4/28/2016)... 2016 Q BioMed Inc. ... CEO  was featured in an article he wrote ... Fear To Tread: http://www.lifescienceleader.com/doc/accelerators-enter-when-vcs-fear-to-tread-0001 ... is an essential business journal for life science ... to Big Pharmas. Their content is designed to ...
(Date:4/27/2016)... ... April 27, 2016 , ... Cambridge Semantics, the leading provider ... announced that it has been named to The Silicon Review’s “20 Fastest Growing Big ... markets, Cambridge Semantics serves the needs of end users facing some of the most ...
(Date:4/27/2016)... and RESEARCH TRIANGLE PARK, N.C. ... (NASDAQ: UTHR ) announced today that ... of United Therapeutics will provide an overview and update ... st Annual Health Care Conference. The ... at 10:00 a.m. Eastern Time, and can be accessed ...
(Date:4/27/2016)... ... ... Global Stem Cells Group CEO Benito Novas announced that Duncan ... affiliate Kimera Labs in Miami. , In 2004, Ross received his Ph.D. in Immunology ... disorders and the suppression of graft vs. host disease (GVHD) under UM Professor Robert ...
Breaking Biology Technology: