Neural Crest and Placodes (BIO361) PDF

Figure 15.1 Neural crest cell migration (Part 1) Figure 15.1 Neural crest cell migration (Part 2) Figure 15.1 Neural crest cell migration (Part 3) Table 15.1 Some derivatives of the neural crest Figure 15.2 Regions of the chick neural crest Cranial (Cephalic) 1. Cranial: Cartilage, bone, neu...

Figure 15.1 Neural crest cell migration (Part 1) Figure 15.1 Neural crest cell migration (Part 2) Figure 15.1 Neural crest cell migration (Part 3) Table 15.1 Some derivatives of the neural crest Figure 15.2 Regions of the chick neural crest Cranial (Cephalic) 1. Cranial: Cartilage, bone, neurons, melanocytes, connective tissue 2. Cardiac: Melanocytes, neurons, cartilage, connective tissue (especially arterial) 3. Trunk: Sympathetic ganglia, adrenal medulla (adrenalin), melanocytes, neurons 4. Vagal/Sacral: Parasympathetic ganglia (gut) Making a Multi-Colored Organism for Lineage Tracing Version 1.0 Version 1.1 Random Cre-Lox Excision Figure 15.3 Lineage tracing of trunk neural crest cells in mouse proves they are multipotent stem cells: The Confetti Mouse Figure 15.4 Model for neural crest lineage segregation and the heterogeneity of neural crest cells Time Irreversible Figure 15.5 Specification of neural crest cells Figure 15.6 The gene regulatory network for neural crest development Simplified version of a complex gene regulatory network for neural crest development Paracrine Factors Transcription Factors Collagen Transcription Factors Chondrocytes Melanocytes Neurons Figure 15.9 Neural crest delamination and migration by contact inhibition Figure 15.11 Migrating neural crest cells demonstrate contact inhibition of locomotion in a live zebrafish embryo Figure 15.11 Model of collective migration of neural crest cells Example 1: Cranial Neural Crest Figure 15.18 Cranial neural crest cell migration in the mammalian head (Part 1) Figure 15.18 Cranial neural crest cell migration in the mammalian head (Part 2) * * * * Pharyngeal pouches Pharyngeal pouches are endodermal derivatives that give rise to glandular primordia (Chapter 20) Tonsil Thyroid Glandular primordia  Parathyroid Thymus Figure 15.18 Cranial neural crest cell migration in the mammalian head (Part 3) Figure 15.18 Cranial neural crest cell migration in the mammalian head (Part 4) Figure 15.18 Cranial neural crest cell migration in the mammalian head (Part 2) * * * * Pharyngeal pouches  Another in vivo example An in vitro example How do these streams form and how are they kept from mixing? Figure 15.19 “Chase and run” model for chemotactic cell migration Answer: Chase and Run guided by PLACODES Figure 15.19 “Chase and run” model for chemotactic cell migration (Part 1) Figure 15.19 “Chase and run” model for chemotactic cell migration (Part 2) Figure 15.20 Cranial neural crest cells in embryonic mice, stained for b-galactosidase expression The cranial neural crest that forms the facial skeleton is also critical for the growth of the anterior region of the brain The cranial neural crest that forms the facial skeleton is also critical for the growth of the anterior region of the brain (Part 2) Fgf8 NCC The cranial neural crest that forms the facial skeleton is also critical for the growth of the anterior region of the brain (Part 1) Example 2: Trunk Neural Crest Figure 15.13 Neural crest cell migration in the trunk of the chick embryo Figure 15.13 Segmental restriction of neural crest cells and motor neurons by the ephrin proteins of the sclerotome Figure 15.14 Segmental restriction of neural crest cells and motor neurons by the ephrin proteins of the sclerotome (Part 1) Figure 15.14 Segmental restriction of neural crest cells and motor neurons by the ephrin proteins of the sclerotome (Part 2) Figure 15.13 Segmental restriction of neural crest cells and motor neurons by the ephrin proteins of the sclerotome (Part 4) Ephrin + EPHRIN - No EPHRIN Notice that cells bind more efficiently to regions of the plate with no EPHRIN Figure 15.16 Neural crest cell migration in the dorsolateral pathway through the skin Figure 15.17 Variable melanoblast migration, caused by different mutations Piebald Mutation (Autosomal Dominant) Mitf Endra KIT Kit  Vertebrate Placodes Anterior Ectodermal Placodes Neurogenic Placodes Neurogenic: refers to placodes that give rise to neurons (i.e., have neurogenic potential). They are located in the embryonic head and anterior trunk region.  Ectoderm Optic Vesicle Induction Inducer Responder Neural Ectoderm Lens Placode What are the inducers? Xenopus Mouse Zebrafish Retinal Homeobox (Rx) What are the inducers? What are the inducers? In what other context have we seen Otx2? Anterior-posterior axis specification: All about the brain Zebrafish  Pax6 – Paired box 6 transcription factor: regulation of lens formation Pax6 gene structure Zebrafish Crystallin gene Mouse Lens Pax6 – Paired box 6 transcription factor Mouse Pax6 vs Fly Eyeless Experiment: Is mouse Pax6 functional in Drosophila eye development? Experiment: Is mouse Pax6 functional in Drosophila eye development? Mouse Pax6 mRNA injected into leg imaginal disc of fly. ? Experiment: Is mouse Pax6 functional in Drosophila eye development? Mouse Pax6 mRNA injected into leg imaginal disc of fly produces an ectopic eye. Eye Leg A word about induction Induction observed – tissue is competent