Project Summary Abstract
Mosquitoes infect hundreds of millions of people with deadly pathogens every year. Since mosquitoes
identify humans and other important resources primarily via their sense of smell, the disruption of
mosquito olfactory systems has long been recognized as a potential strategy for controlling these
pathogens. For example, repellants that scramble or block the detection of odors may be used to push
mosquitoes away from humans and the areas where we live and work. Conversely, irresistibly attractive
blends of volatile chemicals may be deployed to pull mosquitoes into lethal traps. Despite some
advances in this area over the past decade, progress has been limited by the fact that the olfactory
systems of our most important vector mosquitoes remain largely uncharacterized. We know that
mosquitoes detect odors using tens to hundreds of ligand-specific olfactory receptors expressed in
approximately 60 different types of olfactory sensory neurons (OSNs) found on their antennae and
maxillary palps. But we don’t yet know exactly which neurons mosquitoes rely on for detecting humans,
flowers, and oviposition sites, nor which receptors are expressed in those neurons. Moreover, exciting
preliminary data from our lab and others indicates that the 1-to-1 matching between receptors and
sensory neurons observed in Drosophila vinegar flies does not apply in mosquitoes. Instead, mosquito
sensory neurons appear to express multiple, ligand-specific receptors. This means that the tuning of the
neurons that drive behavior cannot be equated to the tuning of individual receptors and thus helps to
explain why previous receptor-focused studies have largely failed to unlock the logic of mosquito host
attraction. Here, we propose to characterize the molecular and functional properties of all major OSN cell
types on the antennae of the arbovirus vector mosquito Aedes aegypti. In Aim 1, we will conduct single-
nucleus RNA sequencing of antennal neurons to identify putative OSN cell types and the receptors
expressed therein. In Aim 2, we will use CRISPR/Cas9 genome editing to generate OSN type-specific
expression drivers that can be used to match OSN types to their target glomeruli in the antennal lobe of
the brain. In Aim 3, we will use in vivo antennal lobe imaging to characterize the tuning of a subset of
OSN types to a panel of 200-300 biologically relevant odorants and natural blends. Taken together we
expect to generate a receptor-neuron-glomerulus map for this important disease vector and a library of
genetic tools with which to manipulate it—facilitating the identification of the neurons that drive behavior
and opening the door to the efficient and rational design of chemical repellants and attractants for use in
vector control.
