Many patterns of cell and tissue organization are
specified during development by gradients of morphogens,
substances that assign different cell fates at
different concentrations. Gradients form by morphogen
transport from a localized site, but whether this
occurs by simple diffusion or by more elaborate mechanisms is
unclear. We attempt to resolve this controversy by
analysis and computations of ligand-receptor models of the system.
In addition we examine recent experimental data in
ways that appropriately capture the complexity of the systems
in which transport, receptor interaction, endo- and exocytosis,
and degradation occur together.
We find that diffusive mechanisms of morphogen transport
are much more plausible- and nondiffusive mechanisms much
less plausible-than has generally been argued.
At the end of the talk,
I will discuss the applications of the ligand-receptor
model to other tissue patterning problems.
Copyright. All Rights Reserved.