Fig. 4

Her6 acts to genetically suppress neurog1. Analysis of ascl1a and irx1b, a pan-thalamic marker, at 30 hpf (A–D) and vglut2.1 and GAD65/67 at 48 hpf (E–H) in her6 and neurog1 morphant embryos. Knock-down of her6 leads to the down-regulation of ascl1a (45/61; A and B) as well as GAD65/67 (22/35; E and F) in the rTh (arrowheads) and in the PTh. Knock-down of neurog1 leads to an unaltered PTh but an increase in width in ascl1a expression (22/34; C) as well as GAD65/67 expression (12/21; G) in the rTh (yellow arrows). Compared to the her6 single knock-down, double knock-down of her6 and neurog1 rescues the prethalamic as well as the rostral thalamic expression domain (ascl1a: 17/22; GAD: 8/17; D and H). Analysis of the MDO in shh:GFP transgenic animals co-expressing ubiquitously the membrane-bound fluorophore mCherry (I–L): Down-regulation of her6 leads to disintegration of the Shh positive MDO (20/26; I and J; arrowheads). In embryos knocked-down for neurog1, the MDO seems unaltered in extension and width compared to the control (8/10; K, arrowhead). Double knock-down of her6 and neurog1 rescues the extend of the shh:GFP expression within the MDO (6/8; L, arrowhead). III, third ventricle; cTh, caudal thalamus; MDO, mid-diencephalic organizer; PTh, prethalamus; rTh, rostral thalamus.