Sonic Hedgehog Expression At Floor Plate

To reach the myotome shh has to traverse the sclerotome and a reduction of sclerotomal shh affects myotome differentiation.

Sonic hedgehog expression at floor plate. To assay the range of direct shh action we developed a general method for blocking transduction of hedgehog hh signals through ectopic expression of a deleted form of the hh receptor patched ptc termed ptc δloop2 we validated this method in drosophila and used mouse ptc1 δloop2. At spinal cord levels shh produced by both the notochord and floor plate fp diffuses dorsally to organize patterned gene expression in dividing neural and glial progenitors. The floor plate expression is the result of the composite activities of ar b and ar d figs. Located on the ventral midline of the embryonic neural tube the floor plate is a specialized glial structure that spans the anteroposterior axis from the midbrain to the tail regions it has been shown that the floor plate is conserved among vertebrates such as zebrafish and mice with homologous.

Sonic hedgehog shh produced in the notochord and floor plate is necessary for both neural and mesodermal development. Cell pattern in the ventral neural tube is organized by sonic hedgehog shh secreted by floor plate cells. Despite the fact that two discrete sources of shh are involved in this process the individual contribution of the fp the. In vitro blocking of shh signaling using.

The spatial expression of these transcription factors in the neural tube and consequently the location of the pmn p3 and fp domains is regulated by the secreted signaling molecule sonic hedgehog shh dessaud et al. The morphogen sonic hedgehog shh is expressed by the notochord and later by cells of the floor plate where it plays a well described role in determining cell fate in the ventral neural tube. Intronic enhancers control expression of zebrafish sonic hedgehog in floor plate and notochord. Regulation of patched by sonic hedgehog in the developing neural tube.

The floor plate is a structure integral to the developing nervous system of vertebrate organisms. The pattern of ptc expression suggests that sonic hedgehog may play an inductive role in more dorsal regions of the neural tube than have been previously demonstrated. Similarly the other ar b containing transgenes also show expression in the posterior medial floor plate figs. 8 a recent study by.

Shh is secreted by the notochord ventralizes the neural tube inducing the floor plate and motor neurons. By investigating loss and gain of shh function and floor plate deletions we report that sclerotomal shh is also necessary for neural tube development. However ar c is dispensable for floor plate expression at this stage in contrast to the 3 somite stage fig. 1 institut de genetique et de biologie moleculaire et cellulaire cnrs inserm ulp bp 163 cu de strasbourg france.

7 the ventral to dorsal gradient of shh also places it in position to affect commissural axons approaching the midline floor plate. Müller f 1 chang b albert s fischer n tora l strähle u. Sonic hedgehog is the secreted protein which mediates signaling activities of the notochord and floor plate.