title: Genetic tracing of the gustatory neural pathway originating from Pkd1l3-expressing type III taste cells in circumvallate and foliate papillae.
abstract: Polycystic kidney disease 1-like 3 (Pkd1l3) is expressed specifically in sour-sensing type III taste cells that have synaptic contacts with afferent nerve fibers in circumvallate (CvP) and foliate papillae (FoP) located in the posterior region of the tongue, although not in fungiform papillae (FuP) or the palate. To visualize the gustatory neural pathways that originate from type III taste cells in CvP and FoP, we established transgenic mouse lines that express the transneuronal tracer wheat germ agglutinin (WGA) under the control of the mouse Pkd1l3 gene promoter/enhancer. The WGA transgene was accurately expressed in Pkd1l3-expressing type III taste cells in CvP and FoP. Punctate WGA protein signals appeared to be detected specifically in type III taste cells but not in other types of taste cells. WGA protein was transferred primarily to a subset of neurons located in close proximity to the glossopharyngeal (GL) nerve bundles in the nodose/petrosal ganglion (NPG). WGA signals were also observed in a small population of neurons in the geniculate ganglion (GG). This result demonstrates the anatomical connection between taste receptor cells (TRCs) in the FoP and the chorda tympani (CT) nerves. WGA protein was further conveyed to neurons in a rostro-central subdivision of the nucleus of the solitary tract (NST). These findings demonstrate that the approximately 10 kb 5'-flanking region of the mouse Pkd1l3 gene functions as a type III taste cell-specific promoter/enhancer. In addition, experiments using the pkd1l3-WGA transgenic mice reveal a sour gustatory pathway that originates from TRCs in the posterior region of the tongue.
authors: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors: Kurumi
authors: K
authors: Yamamoto
authors: Yoshiro
authors: Y
authors: Ishimaru
authors: Makoto
authors: M
authors: Ohmoto
authors: Ichiro
authors: I
authors: Matsumoto
authors: Tomiko
authors: T
authors: Asakura
authors: Keiko
authors: K
authors: Abe
mesh_terms: D000818:Animals; D015220:Calcium Channels; D018507:Gene Expression Regulation, Developmental; D005830:Geniculate Ganglion / Q000737:chemistry / Q000166:cytology / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009434:Neural Pathways / Q000737:chemistry / Q000166:cytology / Q000502:physiology; D009620:Nodose Ganglion / Q000737:chemistry / Q000166:cytology / Q000502:physiology; D050396:TRPP Cation Channels / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D013649:Taste / Q000235:genetics*; D013650:Taste Buds / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism*; D014059:Tongue / Q000737:chemistry / Q000166:cytology* / Q000502:physiology*; D014909:Wheat Germ Agglutinins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics
chemical_list: D015220:Calcium Channels; C512453:PKD1L3 protein, mouse; D050396:TRPP Cation Channels; D014909:Wheat Germ Agglutinins