19. Hedgehog & Wnt signalling Flashcards
what type of structure is a denticle
a bristle like structure
where are denticles present in drosophila
present on the anterior half - posterior half is smooth
who identified segment polarity mutants
Volhard & Wieschaus
describe segment polarity mutants in drosophila
a group of mutants that affected the patterning within segments of the drosophila body
what do hedgehog genes do
produces hedgehog proteins that are morphogens - signalling proteins involved in embryonic development
how many types of hedgehog proteins in drosophila
1
how many types of hedgehog proteins in vertebrates
3
name the hedgehog proteins found in vertebratea
sonic, indian, desert
what modifies hedgehog proteins
cleavage and addition of cholesterol
define morphogen
signalling proteins involved in embryonic development
what is the purpose of cholesterol in relation to hedgehog
embeds hedgehog in the in the cell membrane
what is the role of wingless
switch on expression of hedgehog in the adjacent stripe
how are drosophila embryo segments marked out
alternating expression of wingless (black) and hedgehog (red)
= red and black stripes
what is the boundary between the wingless and hedgehog stripes called
the parasegment boundary
what does hedgehog do in its segment
induces diffusible wingless in the adjacent cell
what happens if hedgehog lacks cholesterol
it is capable to diffuse - this means it can switch on wingless in more cells
describe the hedgehog receptor
patches
= 12 transmembrane domain
how does patched work
the KO of patched activates the hedgehog response - involved smoothened (Smo) protein