Limb Devolpment Flashcards
AER
Apical ectodermal ridge.
- initiates outworks growth of a limb as well as the PZ in anterior-poster and proximal-distal axes devolpment
ZPA
Zone of polarity.
Used in anterior-posterior axis formation. Contains high amounts of SHH
SHH
Sonic hedgehog
Prime signaling molecule in anterior- posterior limb formation
- high amounts of SHH = posterior component differentiation
- low amounts of SHH = anterior component differentiation
FGF
Fibroblast growth factor
Growth factor used to initae proliferation of cells.
Used in anterior-posterior (FGF10)
Used in proximal-distal (FGF8)
HOX genes
specific genes that control limb and appendage formation through apoptosis of of mesnechymal cells
- play key role in proximal-distal limb devolpment
BMP
Bone morphogenic protein
- used in seperation of digits by synergistic signals from SHH and BMP
Wnt7a
Used in ventral-dorsal axis formation.
Congregates around the dorsal ectoderm and generates dorsal differentiation
EN-1
Used in dorsal-ventral axis formation.
Aggregates along the ventral side and directly antagonizes Wnt to inhibit production.
Amelia
No limbs are devolved due to no initiation of ZPA
Polydactyly
Multiple appendages/phalanges due to improper SHH gradient production.
Brachydactyly
Shortened terminal phalanges due to HOXD13 mutation (ineffective)
Syndactyly
Webbing of phalanges due to improper BMP production.
Causes no/little apoptosis in mesnechymal between phalanges