UNIVERSITY PARK, Pa. — A virus that infects a species of malaria-transmitting mosquito could help scientists gain a better understanding of mosquito biology and eventually could lead to methods for stopping or slowing the spread of the disease, according to a researcher in Penn State's College of Agricultural Sciences.
Jason Rasgon, professor of entomology, has received a grant of $1.9 million from the National Institutes of Health to study the virus, called AgDNV. The goal of the five-year project is to develop a toolset that would enable researchers to genetically modify mosquitoes more easily, with an eye toward examining the influence of specific genes on mosquito phenotypes and developing malaria-control strategies.
"This project involves Anopheles gambiae, the main mosquito vector of malaria in Africa," Rasgon said. "Routine genetic manipulation of this species has proven challenging, so the development of novel tools for genetic modification is critical for both applied strategies for malaria control and for basic research into this mosquito's genetics and host-pathogen interactions."
To prove the feasibility of this concept, the research team will insert specific genes into a densonucleosis virus — known as a "densovirus" — which will infect the mosquito's tissues and express those genes.
"This virus is distantly related to the virus used in human gene therapy," Rasgon said. "So it's almost like gene therapy in the mosquito."
He explained that the densovirus is a tiny virus — it contains only three genes and about 4,100 nucleotides — and its entire genome can be synthesized artificially and placed into a plasmid, which is a circular piece of DNA.
"Once in that form, we easily can manipulate it and transfect it into insect cells in a dish, where it will make live, infectious virus that will have whatever genetic modifications we've put into it," said Rasgon.
Researchers then can infect mosquitoes either by putting the virus into water with mosquito larvae or by injecting it into adult mosquitoes. The virus then will infect them, and whatever gene was inserted will be expressed.