Molecular analysys of the axon guidance process in chemosensory neurons of the olfactory system

• Grant number: 11/02343-7
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date until: May 01, 2011
• End date until: December 31, 2013
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Fabio Papes
• Grantee: Fábio Frangiotti Conte
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The mammalian olfactory system is capable of detecting a great variety of distinct chemical stimuli. Several olfactory subsystems participate in this process, each with sensory cells located in different places in the nasal cavity, with distinct molecular receptors, signaling mechanisms and projections to the brain. In mice, olfactory sensory neurons send axons to the olfactory bulb, the first relay of olfactory information in the brain. New olfactory neurons are formed in the sensory epithelium throughout adulthood, and its axons are directed to glomerular destinations in the bulb via the action of a series of factors, including attraction and repulsion molecules and neuronal activity level. The molecular receptors employed in odorant detection belong to a large family of proteins, and it seems that the receptors themselves play a fundamental direct role in the axonal targeting of olfactory sensory neurons.The phenomenon of axonal targeting in the olfactory system defines some essential properties in the functioning of such sensory system, since it results in the formation of the so-called 'glomerular map': sensory neurons expressing the same molecular receptor converge onto two specific glomeruli in the olfactory bulb. Thus, each glomerulus collects information coming from sensory neurons expressing one of the many odorant receptors, and different glomeruli exhibit distinct specificities, leading to a neural map of the decorrelated olfactory information.The main goal of this project is to study the molecular mechanisms underlying the process of axonal targeting of olfactory sensory neurons to the olfactory bulb in the brain, particularly the importance of the odorant receptors and their ligands. The study of the process of axonal targeting will, therefore, contribute substantially to a better comprehension of the olfactory system, a field of great interest in neurobiology since the Nobel Prize was handed to two researchers in the field in 2004. This knowledge will also increase our understanding of the process of axonal targeting in other areas of the brain, in both health and disease.