An international collaboration of scientists has successfully inserted green fluorescent protein (GFP) into Anopheles stephensi mosquito embryos, creating the first transgenic Anopheles mosquito and raising hopes in the fight against malaria (Nature 405, 959–962, 2000). Transformation was made possible when researchers finally were able to prevent the hardening process of the mosquito embryo, which occurs immediately after the eggs are deposited, according to senior author Andrea Crisanti. The team tested a compound that inhibited the enzyme phenoloxidase and prevented the first steps of melanization. Treated embryos stayed soft and transparent for up to 3 h, allowing injection of the enhanced GFP gene. An average of 29% of the injected embryos survived, and half of them carried the marker gene to the larval stage. By inserting the marker gene using the transposon Minos, the researchers have shown they can alter the mosquito genome. The next step is to develop a malaria-resistant mosquito by inserting genes to disrupt the interaction between the mosquito and the malaria-causing parasite, or perhaps to direct malaria-infected mosquitoes to prey on animals rather than humans, Crisanti says.

Credit: © Imperial College