Fig. 4.

Expression of Tbx20 in the CNS of mouse and Ciona. (A–D) Sections through the hindbrain of an embryonic-day-16.5 mouse embryo hybridized with a Tbx20 probe showing expression restricted to branchial and visceral motor nuclei: the trigeminal nucleus (nV) (A), the facial nucleus (nVII) (B), the nucleus ambiguus (nA) (C), the dorsal motor nucleus of the vagus nerve (dmnX) (D), and the accessory nucleus (nXI) (E), to the exclusion of somatic ones such as the hypoglossal (nXII in D) and abducens (data not shown). (F) (Left) Section through Ciona's cerebral ganglion hybridized with CiTbx20. (Right) Magnification of boxed area. The sense probe gave no signal (data not shown). (Scale bar, 100 μm.)