Figure 1.

The development of the Tlx mutant LGE is compromised. A, C, At E12.5 (A) and E14.5 (C), Ki67, which marks cells in all stages of the cell cycle, is expressed in the LGE VZ and SVZ. B, At E12.5, there appears to be no significant differences between the Tlx mutant and wild-type LGE with respect to size as well as Ki67 expression. D, However, at E14.5, there is both an obvious reduction in size and the number of Ki67-expressing cells in the LGE. E-G, Also, after a 2 hr BrdU pulse, fewer BrdU-positive cells are detected in the E14.5 Tlx mutant LGE, particularly in the SVZ. E, We counted BrdU-positive cells in the LGE using four square-shaped bins placed adjacent to each other along the ventriculo-pial axis of the ventral LGE. The first bin extended from the ventricular lumen to the end of the ventricular zone in a wild-type LGE. G, Whereas the number of BrdU-positive cells in the first bin was not significantly different between wild-type and Tlx mutant embryos, the number of BrdU-positive cells in the three other bins were. KO, Knock-out; Se, septum; Stm, striatum. ^*p ≤ 0.01; Student's unpaired t test between wild-type and Tlx mutants.