Infect mosquito, watch genes respond

IOWA STATE (US) — Researchers have turned the tables on a common mosquito, infecting it with pathogens to see which genes turn on in response.

Their findings are reported today in the journal Science.

The international project involved the common southern house mosquito (Culex quinquefasciatus) that is common to many areas of the United States and around the world. It feeds on blood from birds, livestock and humans, and transmits a wide variety of deadly and debilitating human and veterinary pathogens.

In addition to transmitting the West Nile virus, the mosquito can carry the St. Louis encephalitis and the microscopic roundworm that causes lymphatic filariasis—a debilitating tropical disease that affects up to 40 million people every year.

In the research, mosquitoes were infected with viruses, worms, and bacteria. The genes of the mosquitoes were monitored to see which changed during the response to infection and therefore could ward off disease.

“What we’re trying to do is broaden our understanding of infection response genes beyond those that we expect to be there,” says Lyric Bartholomay, a first author on the paper and assistant professor of entomology at Iowa State University.

“We took a two-pronged approach to understanding infection responses,” she adds. “First, we scoured the genome sequence looking for those immunity genes that the mosquitoes can use to respond to an infection. Then, we looked at what genes comprise broad spectrum and specific immune responses.

Bartholomay notes that the functions of many of the genes revealed in this analysis are still unknown, but as more is discovered about the functions of the genes, it could provide the first steps to controlling mosquito-borne diseases.

Bartholomay also worked with colleagues to analyze the mosquito’s genome, as reported in a companion paper that also will be published in the current issue of Science.

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