title: The G-protein gamma-subunit G gamma 8 is expressed in the developing axons of olfactory and vomeronasal neurons.
abstract: The tissue localization of the G-protein gamma-subunit, G gamma 8, that is specifically expressed in the olfactory and vomeronasal neurons, was studied in rats at different ages: embryonic day 16, postnatal days 1, 7, 14 and 35, and adult. G8 appears to be a specific marker of the immature olfactory and vomeronasal neurons. Its distribution differs from that of Golf alpha, a G-protein alpha-subunit which is predominantly expressed in mature olfactory neurons. G8 immunoreactivity indicates that an undifferentiated organization of the olfactory epithelium persists up to 3 weeks of age, though neonates possess a functional sense of smell. G gamma 8 accumulates at the highest levels in the axons of the developing olfactory neurons 2 weeks after birth (postnatal day 14). Moreover, up to postnatal day 14, G gamma 8-positive neurons are present in the region of the olfactory and vomeronasal epithelium, where they are not observed in later life. In the olfactory epithelium and in the bulb, G gamma 8 expression becomes weaker and patchy with increasing age, suggesting that the process of continuous regeneration of olfactory neurons occurs in discrete areas. G8-enhanced expression following axotomy indicates that this system is potentially active throughout life. Conversely, in the vomeronasal epithelium G gamma 8 expression persists virtually unmodified in the adult. This indicates that the degree of differentiation may differ between olfactory and vomeronasal neurons.
authors.affiliation: Istituto di Fisiologia Umana, Università di Parma, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Tirindelli
authors.forename: N J
authors.initials: NJ
authors.lastname: Ryba
mesh_terms: D000375:Aging / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies; D001369:Axons / Q000502:physiology*; D004622:Embryo, Mammalian; D019204:GTP-Binding Proteins / Q000096:biosynthesis* / Q000737:chemistry; D018507:Gene Expression Regulation, Developmental; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009474:Neurons / Q000502:physiology*; D009831:Olfactory Mucosa / Q000254:growth & development / Q000294:innervation* / Q000378:metabolism*; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry / Q000276:immunology; D051381:Rats; D017208:Rats, Wistar; D019147:Vomeronasal Organ / Q000254:growth & development / Q000294:innervation*
chemical_list: D000906:Antibodies; D046911:Macromolecular Substances; D010446:Peptide Fragments; D019204:GTP-Binding Proteins