Allantois / placenta

Figure 2.22 The Amniote Chick Egg, Showing the Membranes Enfolding the 7-Day EmbryoChick Embryo

Chick Embryo

Human Embryo

Human Embryo

Human Embryo

Human Embryo

NOW-Signaling in patterning in other systems

VERTEBRATE…+

Figure 10.22(1) Summary of Experiments by Nieuwkoop and by Nakamura and Takasaki, Showing Mesodermal Induction by Vegetal Endoderm

Figure 10.23 The Regional Specificity of Mesoderm Iinduction Can Be Demonstrated by Recombining Blastomeres of 32-Cell Xenopus Embryos

Figure 10.22(2) Summary of Experiments by Nieuwkoop and by Nakamura and Takasaki, Showing Mesodermal Induction by Vegetal Endoderm

Figure 10.24 The Role of Wnt Pathway Proteins in Dorsal-Ventral Axis Specification

InjectDominant

Inactive GSK-3

No

Active

No

Figure 10.25(1) Model of the Mechanism by which the Disheveled Protein Stabilizesb-catenin in the Dorsal Portion of the Amphibian Egg

Figure 10.25(2) Model of the Mechanism by which the Disheveled Protein Stabilizesb-catenin in the Dorsal Portion of the Amphibian Egg

No

Active

No

Beta-catenin signal on dorsal, not ventral side of embryo

Figure 23.13 Three Modifications of the Wnt Pathway

Overlap of TGF-beta signal and Beta-catenin signal specifies Nieuwkoop center

Figure 10.26 Events Hypothesized to Bring about the Induction of theOrganizer in the Dorsal Mesoderm

In organizer

Figure 10.27 Mesoderm Induction and Organizer Formation by the Interaction of b-catenin And TGF-b Proteins

The Organizer:

Figure 4.16(1) Microarray Analysis of Those Genes Whose Expression in the Early Xenopus Embryo Is Caused by the Activin-Like Protein Nodal-Related 1 (Xnr1)

Figure 4.16(2) Microarray Analysis of Those Genes Whose Expression in the Early Xenopus Embryo Is Caused by the Activin-Like Protein Nodal-Related 1 (Xnr1)

Figure 10.28 Ability of goosecoid mRNA to Induce a New Axis

Figure 10.31 Localization of Noggin mRNA in the Organizer Tissue,Shown by In Situ Hybridization

Noggin is secretedprotein, interacts with BMPs

Figure 10.30 Rescue of Dorsal Structures by Noggin Protein

Figure 10.32 Localization of Chordin mRNA

Chordin protein also interacts with BMPs

Figure 10.34 Cerberus mRNA injected into a Single D4 Blastomere of a 32-Cell Xenopus Embryo Induces Head Structures as Well as a Duplicated Heart and Liver

Cerebrus also interacts with BMPs

Figure 10.33 Model for the Action of the Organizer

Figure 23.14 Homologous Pathways Specifying Neural Ectoderm in Protostomes (Drosophila) and Deuterostomes (Xenopus)

Figure 10.35 Paracrine Factors From the Organizer are Able to BlockCertain Other Paracrine Factors

Figure 10.36 Xwnt8 Is Capable of Ventralizing the Mesoderm and PreventingAnterior Head Formation in the Ectoderm

Figure 10.37 Frzb Expression and Function

Figure 10.39 Ectodermal Bias Toward Neurulation

Figure 10.40 Regional Specificity of Induction can be Demonstrated by Implanting Different Regions (Color) of the Archenteron Roof into Early Triturus Gastrulae

Figure 10.41 Regionally Specific Inducing Action of the Dorsal Blastopore Lip

Figure 10.42(3) The Wnt Signaling Pathway and Posteriorization of the Neural Tube

Figure 10.44 Organizer Function and Axis Specification in the Xenopus Gastrula

Beta-catenin NON-FROG

Figure 8.11 Ability of the Micromeres to Induce Presumptive EctodermalCells to Acquire Other Fates

Figure 8.12(1) The Role of b-catenin in Specifying the VegetalCells of the Sea Urchin Embryo

Figure 8.12(2) The Role of b-catenin in Specifying the VegetalCells of the Sea Urchin Embryo

Figure 8.12(3) The Role of b-catenin in Specifying the VegetalCells of the Sea Urchin Embryo

Figure 8.13 The Micromere Regulatory Network Proposed byDavidson and Colleagues (2002)

Figure 8.14(1) A Model of Endoderm Specification

Figure 8.14(2) A Model of Endoderm Specification

Figure 8.14(3) A Model of Endoderm Specification

Figure 11.9 Axis formation in the Zebrafish Embryo

Figure 11.8 The Embryonic Shield as Organizer in the Fish Embryo

SonicHedgehogIn ventralmidline

Figure 11.10 B-Catenin Activates Organizer Genes in the Zebrafish

Figure 11.18 Formation of the Nieuwkoop Center in Frogs And Chicks

Figure 11.19 Formation of Hensen’s Node From Koller’s Sickle

Figure 8.39 Autonomous Specification by a Morphogenetic Factor

Figure 8.40 Antibody Staining of b-catenin Protein ShowsIts Involvement with Endoderm Formation

Figure 4.17 In Situ Hybridization Showing the Expression of the Pax6 Gene in the Developing Mouse Eye

EYE

Figure 4.17 In Situ Hybridization Showing the Expression of the Pax6 Gene in the Developing Mouse Eye

Figure 4.18(1) Whole-Mount In Situ Hybridization Localizing Pax6 mRNAin Early Chick Embryos

Figure 4.18(2) Whole-Mount In Situ Hybridization Localizing Pax6 mRNAin Early Chick Embryos

Figure 5.7 Regulatory Regions of the Mouse Pax6 Gene

Figure 5.15 The Enhancer Trap Technique

Figure 5.16 Targeted Expression of the Pax6 Gene in a Drosophila Non-eye Imaginal Disc

Figure 6.1 Ectodermal Competence and the Ability to Respond to the Optic Vesicle Inducer in Xenopus

Figure 6.2 Induction of Optic and Nasal Structures by Pax6 in the Rat Embryo

Figure 6.3 Recombination Experiments with Pax6-Deficient Rats

Figure 6.4(1) Lens Induction in Amphibians

Figure 6.4(2) Lens Induction in Amphibians

Figure 6.4(3) Lens Induction in Amphibians

Figure 6.5(3) Schematic Diagram of the Induction of the Mouse Lens