Question

4) Identify four different chemoattractants that drive neural crest migration. What are the

receptors the molecules bind? How are the signals transduced? And what is the effect on cell

physiology? Which varieties of neural crest do they attract? What are the cell types these

neural crest become?

Answer 1

A. Four chemoattarants are: 1. Bone Morphogenetic Protein (BMP), 2. Wnt, 3. Fibroblast Growth Factor (FGF), 4. Retonoic acid and Notch Signals.

B. These molecules induce several transcription factors that control the expression of genes responsible for neural crest development. These molecules have a nuclear localization signal that helps them translocate to the nucleus. In the nucleus, they bind to enhancers, which increase gene expression and transcription of particular genes.

C. Steps for signal transduction through transcription factors: 1. Activator Proteins bind DNA segments called enhancers, 2. Other transcription proteins join the activator proteins forming a complex that brings them closer to the promoter region, 3. The protein complex allows RNA polymerase to bind the promoter region which induces gene transcription.

D. With the help of chemoattractant signals, neural crest cells differentiate into various cell lineages such as enteric cells, cardiac cells, cephalic cells, and truncal (PNS) neural crest cells.

E. Neural crest derivatives include: 1. Smooth Muscle Cells, 2. Sensory Neurons, 3. Cartilage and bones of face and skull, 4. Cranial Nerve Ganglia, 5. Thyroid gland larafollicular cells, 6. Conotruncal septum of heart, 7. Odontoblasts, 8. Dermis of face and neck, 9. Dorsal Root Ganglia, 10. Autonomic Nervous System, 11. Adrenal Medulla, 12. Schwann Cells, 13. Glial cells, 14. Meninges, 15. Melanocytes.