G(o) protein-dependent survival of primary accessory olfactory neurons.
Extensive G protein-coupled receptor families in both the main and accessory olfactory systems have been implicated in axonal targeting, sensory function, and cell survival. Although sensory function seems to be mediated by G proteins, axonal guidance and cell survival may be G protein-independent processes. In the accessory olfactory system, the G(o)-containing neurons in the basal vomeronasal organ (VNO) project to the posterior accessory olfactory bulb (AOB), whereas more apically located VNO neurons contain G(i2) and project to the anterior AOB. Herein, we investigate the organization of the accessory olfactory system in mice with a targeted deletion in the G(o)alpha gene. The accessory olfactory system seems normal at birth; however, postnatally, the number of G(o)-receptor-containing VNO neurons decreases by half, and apoptotic neurons are detected. The axons of VNO neurons remain restricted to the posterior AOB. The posterior AOB is reduced in size but contains a synaptophysin-positive layer with the normal number of glomeruli. The posterior AOB has reduced mitral cell c-Fos immunoreactivity, consistent with decreased sensory activation of G(o) protein-coupled VNO receptor neurons. Thus, in the accessory olfactory system, receptor-coupled G proteins are required for cell survival.
Tanaka
M
M
Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA.
Treloar
H
H
Kalb
R G
RG
Greer
C A
CA
Strittmatter
S M
SM
D000818:Animals; D017209:Apoptosis; D015816:Cell Adhesion Molecules, Neuronal / Q000096:biosynthesis; D002470:Cell Survival; D002478:Cells, Cultured; D005260:Female; D051960:GTP-Binding Protein alpha Subunit, Gi2; D044385:GTP-Binding Protein alpha Subunits; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D020962:Heterotrimeric GTP-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019006:Neural Cell Adhesion Molecules; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D051381:Rats; D016708:Synaptophysin / Q000096:biosynthesis; D019147:Vomeronasal Organ / Q000166:cytology / Q000378:metabolism*
D015816:Cell Adhesion Molecules, Neuronal; D044385:GTP-Binding Protein alpha Subunits; C108768:Ncam2 protein, mouse; D019006:Neural Cell Adhesion Molecules; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D016708:Synaptophysin; C084618:olfactory G protein subunit alpha olf; C498015:GNAI2 protein, human; D051960:GTP-Binding Protein alpha Subunit, Gi2; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; C498016:Gnai2 protein, mouse; C498017:Gnai2 protein, rat; D020962:Heterotrimeric GTP-Binding Proteins