MCD BIO 138 Lecture Notes - Lecture 17: Fgf10, Fgf8, Positive Feedback

• School: UCLA
• Department: Molecular, Cell, and Developmental Biology
• Course: MCD BIO 138
• Professor: karenlyons

Document Summary

Limb buds = lateral plate mesoderm + apical ectodermal ridge. Reciprocal interaction btwn limb mesenchyme and overlying ectoderm (aer) Thickened ridge of epithelium along a/p of limb bud. Develops prox/dist axis thru fgf 4 and 8. Removal of aer -> limb truncations (no distal structures) + cell death increase + decrease proliferation of mesenchyme (loss of pr activity) Middle of aer not maintained -> that area degenrates and cells in that area of pz die -> no digits in that region. Exp: transplant another pr -> mirror image, another axis develops. Exp: transplant small pr -> one digit develops instead of full axis. Exp: graft shh soaked bead -> same effects as grafting pr -> shh controls a/p identity. Amt of time in pz under fgf signals from aer determines identity. Transplant both pz and aer from early to late limb bud and late to early limb bud. Early to late -> duplicated structures, entire prox to distal limb develops.