NT4/5 mutant mice have deficiency in gustatory papillae and taste bud formation.
Neurotrophins are key determinants for controlling the survival of peripheral neurons during development. Brain-derived neurotrophic factor (BDNF) and neurotrophin-4/5 (NT4/5) exert their action through a common trkB receptor but independently support gustatory sensory neurons. To assess the role of NT4/5 during development, we examined the postnatal development and maintenance of fungiform taste buds in mice carrying a deletion of NT4/5. The absence of NT4/5 results in embryonic deficits in gustatory innervation and a reduced number of fungiform papillae at birth. No degenerative deficits of fungiform papillae were observed for the first 3 weeks of postnatal development. However, these remaining fungiform papillae were smaller in appearance and many did not contain taste pores. By postnatal day 60, there was 63% decrease in the number of fungiform papillae, and remaining papillae were smaller in size or modified into filiform-like spines. These papillae had either no taste bud or a taste bud with a reduced number of taste cells compared to controls. These findings demonstrate that the NT4/5 gene functions in the maintenance of fungiform gustatory papillae and raises the possibility for an earlier role in development.
Liebl
D J
DJ
Center for Developmental Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, Texas, 75235-9133, USA.
Mbiene
J P
JP
Parada
L F
LF
D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D005314:Embryonic and Fetal Development / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D051379:Mice; D008855:Microscopy, Electron, Scanning; D009154:Mutation; D009414:Nerve Growth Factors / Q000235:genetics*; D013650:Taste Buds / Q000196:embryology* / Q000502:physiology / Q000648:ultrastructure; D014059:Tongue / Q000196:embryology* / Q000294:innervation / Q000502:physiology / Q000648:ultrastructure
D019208:Brain-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; C071951:neurotrophin 5; C073922:neurotrophin 4