Floor Plate Cues

A candidate guidance cue for postcommissural axons.

Floor plate cues. When axons arrive at the floor plate short range guidance cues take over. In the mouse floor plate several wnts particularly wnt4 and wnt7b are expressed in a rostral high to caudal low gradient. A canonical example of a critical inter mediate target is the floor plate fp which resides at. 15 16 the loss in sensitivity results from a direct inhibitory interaction between the slit receptor roundabout robo and dcc.

Summarized by de ramon francàs et al 2017. Axons have been shown to enter the floor plate as a result of interactions between axonal contactin 2 also known as axonin and neuronal cell adhesion molecule nrcam in the floor plate stoeckli and landmesser 1995. The floor plate is a structure integral to the developing nervous system of vertebrate organisms. The floor plate repels cultures of longitudinal axons in vitro tamada et al 1995 while certain longitudinal axon bundles wander into the midline in zebrafish lacking floor plate hatta 1992.

Xenopus spinal neurons lose their attraction to netrin 1 following exposure to slit a guidance cue that like netrin 1 is secreted by the floor plate. Was more compact and closest to the floor plate and therefore most likely to be influenced by floor plate cues. Cues are additionally presented at intermediate points that lie along the axonal trajectory effectively partition ing the pathway of a developing axon into a series of intermediate targets that orchestrate axonal arrival and departure 3. In agreement with this expression pattern wnts are chemoattractive cues in the longitudinal axis of the spinal cord lyuksyutova et al 2003 this attractive response is mediated by the wnt receptor frizzled3 fzd3 since commissural axons of fzd3 mice wang.

Same floor plate cues albeit resulting in distinct trajectories. These cells partition the distance traveled by growing axons into shorter intervals by serving as intermediate targets orchestrating the arrival and departure of axons by providing attractive and repulsive guidance cues. 15 the response to a netrin 1 gradient in vitro also depends. Additional floor plate signals dictate the direction of turns after crossing bourikas et al 2005.

These experiments suggest that the ability of longitudinal axons to remain. We decided to screen for differentially expressed floor plate genes as candidate guidance cues directing commissural axons along the. Longitudinal axons project through the same environment and thus are potentially influenced by the same floor plate cues albeit resulting in distinct trajectories.