Flashcards in Lect. 25 - Limb Devpt I Deck (18):
Result of experiment removing half of the limb
Remaining half will form a complete limb
Role of Tbx5 in initiation of limb development
Initiates future forelimb
Role of Tbx4 and Pitx-1 in limb development
Initiates future hindlimb
What are the initial initiators of limb development?
Tbx4 and Tbx5
Role of Gli3 and Hand2 in initiation of limb development
Gli3 (anterior) and Hand2 (posterior) fix AP axis
Role of FGF-10 in initiation of limb development
Mesoderm to ectoderm
Role of FGF-8 in initiation of limb development
Ectoderm to mesoderm
What are the 3 axes that define the vertebrate limb?
Dorsoventral; anterior-posterior axis; and proximodistal axis
Determine position of ZPA via its highest concentration; expression is induced by RA
Signal produced by ZPA; also maintains structure and function of AER; induces expression of gremlin
Inhibits BMP-2 which inhibits FGF-4 in AER and inhibits Gli-3 in posterior part of limb bud
In anterior part of limb bud; inhibits expression of shh in anterior part of limb bud
Interactions of AER and limb bud mesoderm
Interacts w/ underlying limb bud mesoderm and promotes continued outgrowth of limb bud
Role of Hox genes in limb patterning
Pattern formation in the proximodistal limb axis
Relationship of Msx expression to the distal mesenchyme
Cells in the distal limb bud express Msx-1
What factors makes up the outgrowth-promoting signal?
FGFs (8, 4, 9, 17) and Wnts
What is the role of apoptosis in limb development?
It's a mechanism for morphogenesis; posterior necrotic zone (will become the axilla) and areas b/w future digits