Floor Plate Roof Plate Neural Tube Release

In the embryo the ventral midline of the neural tube may be exposed to high levels of shh due to the close apposition of the notochord 12.

Floor plate roof plate neural tube release. After closure the neural tube forms a basal plate or floor plate and an alar plate or roof plate in response to the combined effects of shh and factors including bmp4 secreted by the roof plate. The floor plate responds to shh by producing its own shh and forming a gradient. The neural tube is from its very outset patterned in this axis as there is a roof plate floor plate and differing numbers and types of neuroblasts. The notochord expresses shh.

These neuroblasts develop into different types of neurons which express a different range of marker genes. The roof plate forms in the dorsal midline of the developing spinal cord shortly after neural tube closure as a result of induction by bmp4 and bmp7 both secreted by the. The floor plate is a structure integral to the developing nervous system of vertebrate organisms. The roof plate of the neural tube responds to those signals by expressing more bmp4 and other transforming growth factor beta tgf β signals to form a dorsal ventral gradient among the neural tube.

The alar plate. Just as the floor plate is important in ventral patterning the roof plate serves as an important organizing center for dorsal patterning along with the dorsal epidermis. They serve primarily as pathways for nerve fibers crossing from one side to the other. The roof plate is an embryonic organizing centre that occupies the dorsal midline of the vertebrate neural tube.

Similarly exposure of neural cells to shh protein in vitro results in floor plate induction suggesting that high levels of shh can act alone to induce the floor plate 10 11. In the spinal cord one of these axes dorsal ventral d v depends largely on signals produced by two specialized midline structures one at the ventral pole of the neural tube the floor plate yamada et al 1991 and the other at the dorsal pole the roof plate figure 58 2 b. The basal plate forms most of the ventral portion of the nervous system including the motor portion of the spinal cord and brain stem. Roof plate alar plate.

The dorsal and ventral midline portions of the neural tube known as the roof and floor plates respectively do not contain neuroblasts. Despite the importance of the roof plate for normal patterning and development of the neural tube not much was known about its development or function until recently.