Loss of Gbx2 disrupts the dorsal and posterior borders of the
thalamus. (A-F) After tamoxifen administration at E10.5, X-gal
staining of whole-mount (A,B) and sagittal brain sections of
Gbx2CreER/+ and Gbx2CreER/- embryos
(C-F) at different stages, as indicated. (G,H) Nissl analysis of
immediate adjacent sections of E and F, respectively. (I-P) After
tamoxifen administration at E10.25 (I-L) or E10.5 (M-P), X-gal analysis of
coronal brain sections of Gbx2CreER/+ and
Gbx2CreER/- embryos at E12.5 (I,J) and E18.5 (K-P). The
boxed area in M and N is magnified in O and P. (Q,R) Nissl
analysis of adjacent sections of O and P, respectively. The arrowheads
indicate the lineage-restriction boundaries; the asterisks indicate cells that
violate compartment boundaries; the red dashed line indicates the border
between the thalamus and lateral habenular nucleus; the arrow indicates marked
cells in the nucleus of Darkschewitsch (E) and the lateral habenlar nucleus
(O). Note that the HPT is enlarged in Gbx2 mutants (H and L), and
that the region under the pial surface contains sparse cells in the mutants
(bracket in P and R), probably due to abnormal accumulation of neuritis. ET,
epithalamus; HPT, habenular-peduncular tract; mb, midbrain; Ncx, neocortex;
PT, pretectum; PTh, prethalamus; TH, thalamus. Scale bars: 265 μm in C,D;
250 μm in E-H; 350 μm in I,J; 450 μm in K-N; 200 μm in O-R.