Figure 3. Loss of Bhlhb5 Function Disrupts Chemoarchitecture in Somatosensory and Caudal Motor Cortices.

In situ hybridization for various area-specific genes on sagittal wild type and Bhlhb5^lacZ/lacZ (null) brain sections. Asterisks delineate area of gene expression change. In Bhlhb5-nulls, there is:

(A) Ectopic expression of Cadherin 8, in layers II/III of somatosensory cortex.

(B) Lack of COUP-TF1 expression in layer IV of somatosensory cortex.

(C) Decreased expression of ephrin-A5 in layers IV/V of somatosensory cortex.

(D) Lack of Lmo4 expression in layer IV of somatosensory cortex.

(E,F) Lack of RORβ expression in layer IV of caudal motor cortex (E), medially (M), but not laterally (L) in somatosensory cortex (F).

(G,H) Lack of Id2 expression in layer IV of caudal motor cortex (G), medially (G), but not laterally in somatosensory cortex (H).

(I) Lack of EphA7 expression in layer IV of occipital cortex.

Ages: P3 (A, C, E, F, G, H, I); P5 (B,D). For each gene, wt n=3; Bhlhb5-nulls n=3. Scale bars: 1 mm.