Effects of the brachyury (T) mutation on mitotic activity in the neural tube.

Mitotic activity in the neural tube was examined in +/+, $\text{T}\text{+}$ and $\text{T}\text{T}$ mouse embryos. The number of mitotic figures per unit area of ependymal layer (area index) was higher in $\text{T}\text{+}$ embryos than in +/+ embryos. In +/+ embryos, area index was higher in the dorsal part of the neural tube than in the ventral part, whereas this pattern is disordered in $\text{T}\text{+}$ embryos. In $\text{T}\text{T}$ embryos, these values fluctuate. The process of nuclear migration accompanying cell division seems to be normal in the neural tube of $\text{T}\text{+}$ and $\text{T}\text{T}$ embryos.