Deborah Andrew is a professor of cell biology at the Johns Hopkins University School of Medicine. She studies the genetic basis of the formation of salivary glands in fruit flies and mosquitoes. Recently, her lab discovered that, despite the fact that mosquitoes transmit malaria, their salivary glands don’t actually allow that many parasites to flow into the bite victim, potentially opening new doors to blocking malaria transmission entirely.
Andrew answered the following questions about her recent findings.
What got you interested in studying fruit fly salivary glands?
I’m interested in organ morphogenesis — in other words, how different organs in the body are first formed. We know that there are around 200 different cell types in the human body. What we still don’t clearly understand is how all these different cells form, and how they assemble together in a precise way to create the different organs in our body. Fruit flies are much simpler organisms, with many fewer cell types and fewer genes. We can ask the same fundamental questions in these insects and apply some of the principles of what we learn about how cells, tissues and organs form to higher organisms, including humans. In my lab, as a model for development, we study the genetic mechanisms that program cells in a fruit fly embryo to become mature salivary glands.
How did you move from fruit flies to mosquitoes? Why did you decide to also study mosquito spit glands?
Mosquitoes are the number one transmitters of disease in humans. When mosquitoes gulp down blood from their victims, they also transfer disease-causing parasites. These parasites have to go through the salivary gland to get into humans. If the mosquito salivary glands are the gateway organs for disease transmission, they are probably also the organs that should be targeted to block disease transmission. We have recently shown that mosquito salivary glands create many roadblocks for parasites, preventing them from escaping. We think that by enhancing these barriers that the glands naturally have for transmission, we might be able to completely block the spread of mosquito-borne diseases.
What are the challenges to working with mosquitoes?
Many of the experimental tools that are well established for fruit flies haven’t been developed for mosquitoes yet. Also, the genetics of fruit flies is much more developed compared with mosquitoes. Maintaining and managing different strains of genetically modified mosquitoes poses difficulties as well. Although there are many more challenges with working with mosquitoes, that doesn’t keep us from studying them. It just means that what would be a trivial experiment in fruit flies is more of a herculean task in mosquitoes.
What is the most rewarding part of being a researcher?
There are many. But figuring out something new definitely tops the list. I remember when we first dissected out the mosquito salivary glands, it took us forever to figure out the architecture of these organs. But then once it makes sense, even if it is after months of continuously staring at it, then the “aha” moment feels great; you can then move on to the next step and begin to think about more complex biological questions. It’s also fun to work with people and interact with talented students and postdocs.