Figure 6.

Neutralization of TGF-β in the developing chicken embryo from E2 to E7 does not interfere with the organization of floor plate and the expression of Shh. A, B, Nonradioactive in situ hybridization was performed using a digoxigenin-labeled Shh probe on complete serial cryostat sections of E7 chicken brain. Shh expression in the floor plate does not show significant differences between control (A) and treated (B) embryos, in which TGF-β function was blocked by a neutralizing antibody. C, D, Radial glial structure of the ventral midline is not altered in the absence of functional TGF-β signaling. A specific antibody (3CB2) was used to detect an intermediate filament associated protein selectively labeling radial glial cells at this age of development. v, Ventricle of the mesencephalon; fp, floor plate. Black arrows point to the ventral midline radial glia. Scale bar, 50 μm.