1 / 25

Tetrapod Limb Development

Tetrapod Limb Development. Revisiting Axis specification Limb Formation and Growth Digit Formation. The tetrapod limb. stylopod. zeugopod. autopod. Limb Development in 4 dimensions. Proximal-Distal axis Anterior Posterior axis Dorsal-Lateral axis Time. Limb bud Specification.

Download Presentation

Tetrapod Limb Development

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Tetrapod Limb Development • Revisiting Axis specification • Limb Formation and Growth • Digit Formation

  2. The tetrapod limb stylopod zeugopod autopod

  3. Limb Development in 4 dimensions • Proximal-Distal axis • Anterior Posterior axis • Dorsal-Lateral axis • Time

  4. Limb bud Specification • Limb bud fate mapping • Removal • Transplantation • Cell/Tissue tracking • Limb Field • Limb Bud formation • Hox genes: Hox 6 and Forelimb

  5. Limb Bud: Lateral plate mesoderm

  6. Multilimbs arise from dividing the bud

  7. Induction of limb bud formation • Fgf8 • Wnt2b/8c and Fgf10

  8. Induction of Limb Bud

  9. Forelimb or Hindlimb? • Tbx transcription factors: Tbx5 and Tbx4

  10. Genetic Regulation of early limb formation Hox6 Tbx5 Fgf10 For Forelimb

  11. Proximal-Distal Axis: Anterior ectodermal ridge

  12. AER and Limb bud development • AER major signaling center for forming Limb. • Ensures plasticity of mesenchyme • Maintains factors that determine A-P axis • Contacts A-P/D-V axis specifiers in order to inform cells how to differentiate • AER at distal margin of forming limb bud. • Makes direct contact with mesenchyme underneath (Progress zone-PZ).

  13. AER and Limb development

  14. Role of PZ in Limb growth/specification

  15. Limb Growth

  16. Reaction-diffusion model for proximal-distal limb specification

  17. A-P axis: Sonic Hedgehog • Zone of polarizing activity (ZPA) • Shh expressed in ZPA

  18. A-P axis: Sonic Hedgehog • Zone of polarizing activity (ZPA) • Shh expressed in ZPA

  19. Polydactyly: Shhoverexpression?

  20. Digit formation

  21. D-V axis: third and final axis • Wnt7a • Lim1-dorsal specification regulator

  22. Coordination of the 3 axes

  23. Sculpting the hand • BMPs initiate cell death in interdigital, interior, and anterior-posterior necrotic zones.

  24. Joint Formation

  25. Fgfs and dwarfism

More Related