Morphogen gradient reconstitution reveals Hedgehog pathway design principles

Abstract

How to build a better morphogen gradient To translate insights in developmental biology into medical applications, techniques are needed to ensure correct cell localization. Morphogen gradients allow precise and highly reproducible pattern formation during development. Through in vitro experiments and modeling, Li et al. tested the effects of unusual properties of Hedgehog (HH) signaling. The HH morphogen's receptor, Patched (PTCH), sends an inhibitory signal when no ligand is bound, which is relieved by ligand binding. PTCH also regulates spatial distribution of the signal by sequestering the HH ligand. Furthermore, signaling through the receptor promotes synthesis of more inhibitory receptor. These characteristics help speed gradient formation and explain the robustness of the system to changes in the rate of morphogen production. Science , this issue p. 543