title: T-Box transcription factor Tbx20 regulates a genetic program for cranial motor neuron cell body migration.
abstract: Members of the T-box transcription factor family (Tbx) are associated with several human syndromes during embryogenesis. Nevertheless, their functions within the developing CNS remain poorly characterized. Tbx20 is expressed by migrating branchiomotor/visceromotor (BM/VM) neurons within the hindbrain during neuronal circuit formation. We examined Tbx20 function in BM/VM cells using conditional Tbx20-null mutant mice to delete the gene in neurons. Hindbrain rhombomere patterning and the initial generation of post-mitotic BM/VM neurons were normal in Tbx20 mutants. However, Tbx20 was required for the tangential (caudal) migration of facial neurons, the lateral migration of trigeminal cells and the trans-median movement of vestibuloacoustic neurons. Facial cell soma migration defects were associated with the coordinate downregulation of multiple components of the planar cell polarity pathway including Fzd7, Wnt11, Prickle1, Vang1 and Vang2. Our study suggests that Tbx20 programs a variety of hindbrain motor neurons for migration, independent of directionality, and in facial neurons is a positive regulator of the non-canonical Wnt signaling pathway.
authors.affiliation: Gene Expression Laboratory, The Salk Institute, La Jolla, CA 92037, USA.
authors.forename: Mi-Ryoung
authors.initials: MR
authors.lastname: Song
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Shirasaki
authors.forename: Chen-Leng
authors.initials: CL
authors.lastname: Cai
authors.forename: Esmeralda C
authors.initials: EC
authors.lastname: Ruiz
authors.forename: Sylvia M
authors.initials: SM
authors.lastname: Evans
authors.forename: Soo-Kyung
authors.initials: SK
authors.lastname: Lee
authors.forename: Samuel L
authors.initials: SL
authors.lastname: Pfaff
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism; D002465:Cell Movement; D016764:Cell Polarity; D003391:Cranial Nerves / Q000166:cytology / Q000196:embryology*; D047108:Embryonic Development / Q000235:genetics; D005154:Facial Nerve / Q000166:cytology / Q000196:embryology; D020869:Gene Expression Profiling; D051379:Mice; D008822:Mice, Transgenic; D009046:Motor Neurons / Q000166:cytology* / Q000378:metabolism; D009154:Mutation; D015398:Signal Transduction; D020825:T-Box Domain Proteins / Q000235:genetics* / Q000378:metabolism*; D014276:Trigeminal Nerve / Q000166:cytology / Q000196:embryology; D000159:Vestibulocochlear Nerve / Q000166:cytology / Q000196:embryology; D051153:Wnt Proteins / Q000378:metabolism
chemical_list: D020825:T-Box Domain Proteins; C486013:Tbx20 protein, mouse; D051153:Wnt Proteins