HETEROTRIMERIC G-PROTEIN βγ SUBUNITS IN THE MOUSE PERIPHERAL OLFACTORY SYSTEM

G-protein coupled signaling cascades are involved in a variety of activities in the sensory neurons of the peripheral olfactory system in mice, such as odor transduction and axonal projection. While the roles of heterotrimeric G-protein α-subunits, such as the olfactory G-protein α subunit (Gαolf) are well documented, very little is known about Gβγ subunits in the nasal sensory epithelium. Contrastingly, many studies in other systems have yielded a surge of data documenting the diverse functions of the known five Gβ and twelve Gγ subunits. Lin et al. in 2007 characterized a subset of olfactory sensory neurons in the main olfactory epithelium expressing the ion channel transient receptor potential channel (TRPM5). In other systems such as taste receptor cells, TRPM5 is a necessary downstream component of the phospholipase C (PLC) pathway which is thought to be activated by Gβγ. The heterotrimeric G-protein γ subunit Gγ13 is present in the cilia of olfactory sensory neurons (OSNs) of the main olfactory epithelium (MOE). This suggests that as an obligate dimer, Gβγ could be serving a role in the function of olfactory sensory neurons. Although Gγ13 expression was found in the MOE, there was scattered and incomplete data regarding expression of other β and γ subunits in both MOE and the vomeronasal organ (VNO). In this work, using molecular techniques I provide a complete expression profile of the 5 different Gβ and 12 Gγ subunits in the MOE and VNO. I show that multiple Gβ and Gγ subunits are expressed in the MOE and VNO in a cell type specific fashion. Additionally, using molecular techniques and image analysis, I show that Gβ1 is dominant in both MOE and VNO. Finally, using molecular and physiological approaches, I demonstrate that Gβ1 is essential to proper function of OSNs and also for glomerular formation in the main olfactory bulb (MOB). My results demonstrate the heterotrimeric G-protein βγ subunits serve critical roles in olfaction