|PI of the laboratory: Prof Richard Benton |
Direct supervisor (assistant): Dr Michael Saina
Department: Center for Integrative Genomics
A combined microarray and RNAi screen for novel chemosensory genes
Description of project:
The overall goal of the research in our group is to understand how sensory information in the environment is detected and processed in the brain to evoke an appropriate behavioural response. We focus on the olfactory and gustatory systems of the fruit fly, Drosophila melanogaster, a model genetic organism that displays a sophisticated repertoire of chemosensory-driven behaviours under the control of neural circuits that have similar anatomical and functional properties to those of mammals but with significantly reduced complexity. Our group takes a multidisciplinary approach to this problem, combining bioinformatics, genetics, molecular cell biology, electrophysiology, neuronal imaging and behavioural analysis. We aim to gain insights into both a fundamental problem of neuroscience - how genes and circuits control behaviour – and the evolutionary mechanisms operating in animal nervous systems.
We recently discovered a novel family of chemosensory genes, named the Ionotropic Receptors (IRs) (Benton et al. Cell 2009). These genes encode proteins that are structurally related to ionotropic glutamate receptors, a conserved class of ligand-gated ion channel best studied for their roles in synaptic transmission. IRs, however, have highly divergent ligand binding domains that lack glutamate-interacting residues. IR genes are expressed in specific combinatorials in neurons in the antenna - the major olfactory organ - that are distinct from those that express the well-characterised Odorant Receptors (ORs). IRs localise to the ciliated endings of olfactory sensory dendrites and expression of an IR in an ectopic neuron is sufficient to confer novel odour responses, providing evidence for a direct role in odour recognition. The IRs are therefore likely to define a previously unappreciated second “nose” in Drosophila.
The proposed project will use cutting-edge genetics and genomics approaches to identify novel genes required for the development and function of the IR chemosensory circuits. First, microarray analysis will be used to identify genes selectively-expressed in these neuronal populations. Second, the function of these genes will be investigated by screening an available library of transgenic RNAi Drosophila lines for loss-of-function phenotypes. Functional assays may involve techniques such as immunofluorescence and confocal microscopy or in vivo electrophysiology, depending upon the interests of the student. Finally, more in-depth analysis is envisaged of one or a few of these genes in a specific process (e.g. axon guidance, chemosensory signal transduction) according to the obtained results.
Link to the group web site