Genetic tracing of the gustatory and trigeminal neural pathways originating from T1R3-expressing taste receptor cells and solitary chemoreceptor cells.
We established transgenic mouse lines expressing a transneuronal tracer, wheat germ agglutinin (WGA), under the control of mouse T1R3 gene promoter/enhancer. In the taste buds, WGA transgene was faithfully expressed in T1R3-positive sweet/umami taste receptor cells. WGA protein was transferred not laterally to the synapse-bearing, sour-responsive type III cells in the taste buds but directly to a subset of neurons in the geniculate and nodose/petrosal ganglia, and further conveyed to a rostro-central region of the nucleus of solitary tract. In addition, WGA was expressed in solitary chemoreceptor cells in the nasal epithelium and transferred along the trigeminal sensory pathway to the brainstem neurons. The solitary chemoreceptor cells endogenously expressed T1R3 together with bitter taste receptors T2Rs. This result shows an exceptional signature of receptor expression. Thus, the t1r3-WGA transgenic mice revealed the sweet/umami gustatory pathways from taste receptor cells and the trigeminal neural pathway from solitary chemoreceptor cells.
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Makoto
M
Ohmoto
Ichiro
I
Matsumoto
Akihito
A
Yasuoka
Yoshihiro
Y
Yoshihara
Keiko
K
Abe
D000595:Amino Acid Sequence; D000818:Animals; D002628:Chemoreceptor Cells / Q000166:cytology / Q000502:physiology*; D005786:Gene Expression Regulation / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009297:Nasal Mucosa / Q000166:cytology / Q000502:physiology; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology; D043562:Receptors, G-Protein-Coupled / Q000096:biosynthesis / Q000235:genetics*; D013649:Taste / Q000235:genetics*; D013650:Taste Buds / Q000166:cytology / Q000502:physiology*; D014276:Trigeminal Nerve / Q000166:cytology / Q000502:physiology*
D043562:Receptors, G-Protein-Coupled; C431926:taste receptors, type 1