A newly identified microRNA in female Aedes aegypti mosquitoes when deactivated disrupts the mosquito's blood digestion and egg development, University of California researchers have explained.
The discovery could help control the spread of not only dengue and yellow fever but potentially all vector-borne diseases, according to researchers.
MicroRNAs do not code for protein products but play powerful regulatory roles in development and cell growth; their mis-regulation leads to defects, including cancer.
The researchers asked if microRNAs were involved in essential functions in female mosquitoes such as blood feeding and egg maturation. These functions are required not only for successful reproduction, but also serve as a foundation for the mosquito's ability to transmit pathogens of devastating human diseases.
In their experiments in the lab, the researchers were screening a number of microRNAs in female Aedes aegypti mosquitoes to study their behavior during blood feeding and reproduction, when they found one microRNA, "miR-275," was highly elevated during egg development.
Next, the researchers developed a method for specific deactivation of miR-275 in Aedes aegypti females and fed these mosquitoes with blood to analyze what effects occur when female mosquitoes no longer have this microRNA at their disposal.
They found that the blood these mosquitoes had fed on remained undigested in their guts. Further, the overall volume of the engorged blood was unusually large, suggesting that the mosquitoes' fluid excretory function had been impeded.
The researchers also found that in these mosquitoes, egg development, whose success is dependent on blood digestion, was severely inhibited.
"We can now knock down a series of events - starting with the digestion of blood and proceeding all the way to egg maturation - simply by eliminating this small molecule, miR-275," said Alexander Raikhel, whose lab led the study.he study was published in the Proceedings of the National Academy of Sciences.