Program in Neuroscience, University of Fribourg, Switzerland
Dr. Reinhard F. Stocker
Department of Biology
University of Fribourg
1700 FRIBOURG
SWITZERLAND
phone +41-26-300 8875
email Reinhard.Stocker@unifr.ch
The fruit-fly Drosophila as a model system in olfactory research
In order to fully comprehend the function of the nervous system, we need to understand not only the functions of individual neurones, but also how the neuronal circuits are assembled and which genes are involved in this process. An ideal model for studying these issues should have the attributes of simplicity and accessibility to genetic and non-genetic manipulations, as well as be of general interest. The olfactory system of the fruit-fly Drosophila melanogaster meets these requirements: the network implicated comprises but few neurones, and the fly detects a wide range of odors and responds to these stimuli by displaying well-characterized behavioural patterns. Thanks to advances in molecular genetics, it is now possible to study olfaction from the molecular to the behavioural level in this species. Most importantly, a growing body of evidence is revealing the existence of surprising parallels in the organization of insect and vertebrate olfactory systems.
Our major research tools are Drosophila lines manifesting different patterns of reporter-transgene expression, depending upon the genomic context of the transgene insertion. Not only are these lines excellent markers for the different neural elements of the olfactory system, but they can also be used for the expression of any gene of interest in these neurones, even foreign ones. For example, expression of toxin genes leads to a selective inactivation of these nerve cells. Observation of such flies in behavioural assays permits us to explore in-vivo the role of these neurones in the detection of odorants. Toxin-induced cellular ablation can be used to study developmental interactions between nerve cells. Transgenic lines also facilitate the cloning and analysis of Drosophila genes in the neighbourhood of the transgene insertion and permit the recovery of mutations therein. By using Drosophila as our model system, we hope to improve our knowledge and understanding of the neuronal networks involved in, and of the mechanisms underlying, animal olfaction, and to pinpoint the genes implicated in this process. Apart from genetic and behavioural methodologies, our research also depends upon a number of other techniques, including immunocytochemistry, molecular biology, neuroanatomy and three-dimensional reconstruction.
Selected publications
Stocker R.F. The organization of the chemosensory system in Drosophila melanogaster: a review. Cell Tiss. Res. 275: 3-26, 1994
Ferveur J.F., Stoertkuhl K.F., Stocker R.F. & Greenspan R.J. Genetic feminization of brain structures and changed sexual orientation in male Drosophila melanogaster. Science 267: 902-905, 1995
Stocker R.F., Heimbeck G., Gendre N. & de Belle J.S. Neuroblast ablation in Drosophila P[GAL4] lines reveals origins of olfactory interneurons. J. Neurobiol. 32: 443-456, 1997