MBG 3050 Lecture Notes - Lecture 15: Morphogen, Sonic Hedgehog, Smoothened

• School: University of Guelph
• Department: Molecular Biology and Genetics
• Course: MBG 3050
• Professor: Nina Jones

Document Summary

Paracrine signalling by morphogens: shh morphogen = a signaling molecule that acts directly on cells to produce speci c cellular responses depending on its local concentration diffusion of the morphogen causes a gradient different concentrations = different fates ex. Shh is important for embryo pattern formation, especially limb formation and neural differentiation. Shh protein is produced cholesterol is bound to signalling n-terminus, catalytic c-terminus is cleaved thought to help it diffuse undergoes further processing may diffuse over long distances. Shh binds to patched receptor and releases the inhibition on smoothened receptor relative amounts of gli activators and gli repressors determine how genes are expressed polarization from anterior to posterior regions polarization from proximal to distal regions. Gli3 concentration increases from posterior to anterior: digits 2 through 5 are all dependent on the shh gradient, digits 3 - 5 are also dependent on the time shh is expressed, the 1st digit is shh independent.