build a model system, using engineered E. coli, to understand how regulatory dynamics can produce pattern scaling without the need for a morphogen gradient.
As expected for a morphogen molecule, the system is very sensitive to the levels of Nodal.
The boundary conditions of the system are (1b) D ∂C (0, t ) ∂x + J = 0, (1c) D ∂C (L, t ) ∂x = 0, which states that at x=0 there is a source of morphogen responsible for a morphogen influx, J, while at x= L (the length of the system) the morphogen cannot leave the system.
It was this motivation that really got us thinking about how you combine the gradient and the affinity for a morphogen effector with a transcriptional network.
Surprising candidate for a second ring: None.
Typically, diffusion is thought to be the mechanism responsible for building a morphogen gradient.
DOI: http://dx.doi.org/10.7554/eLife.07048.002 Regulatory interactions between transcriptional factors play important roles for interpreting a morphogen gradient as positional information (Balaskas et al., 2012).
In root hair cells, the inactive and active states of ROPs are good candidates for possible Turing morphogens on account that their diffusivities are likely to be strongly affected by post-translational modifications, especially the S-acylation of active ROP [26].
Such a mechanism accounting for the conversion of a graded signal into discrete all or none changes in gene expression is essential for the function of a morphogen.
Here we studied and identified a facilitatory role for Sonic hedgehog protein (Shh), a morphogen that influences motor neuron floor plate architecture, during adult peripheral neuron regeneration.
