THE NEURAL CREST

The Neural Crest

Table of Contents

1. Introduction3

1.1. Aim and Objective5

2. Induction6

2.1. Inductive Signals7

2.2. Neural Plate Border Specifiers11

2.3. Neural Crest Specifiers14

2.4. Neural Crest Effector Genes18

3. Initiation of migration19

4. Development of Entric Nervous System21

4.1 Neural crest cells: Origin of the ENS22

5. Neural crest cell origin for intrinsic ganglia of the developing chicken lung27

5.1 Coordinated development of ENS, smooth muscle, and ICC31

5.2 Defects in ENS development result in Hirschsprung's disease34

6. Intestinal motility and its control during fetal and postnatal life36

6.1 Mature intestinal motility patterns36

7. Development of intestinal motility and its control: Studies of laboratory animals41

7.1 Mice41

7.2 Development of intestinal motility in humans45

7.2.1. Intestinal motility before birth46

7.2.2. Intestinal motility shortly after birth47

7.2.3. Pediatric intestinal motility disorders47

7.2.4. Changes in properties of intestinal contents during development48

8. Conclusions50

References52

The Neural Crest

1. Introduction

Neural crest cells are induced at the dorsolateral edge of the neural plate; from there, they delaminate and migrate along specific routes to many destinations in the vertebrate embryo. These cells differentiate into a wide variety of cell types, including neurons and glial cells of the peripheral nervous system, melanocytes, smooth muscle, and cartilagenous and skeletal elements in the head (Le Douarin, Kalcheim, 2009). The remarkable migratory behaviour and diversity of cell types that the neural crest forms raises the challenge of identifying the mechanisms that underlie their induction, migration and guidance, and that control their differentiation at appropriate locations. In this review, we will discuss progress in the identification of molecular mechanisms that control neural crest development, focusing on advances that have been made subsequent to excellent reviews published in 2009 (Garcia-Castro, Bronner-Fraser, 2009).

Fig; Neural Crest Cell Origin



Fig; Neural Crest Formation

Fig; Neural Crest Cells

1.1. Aim and Objective

AIM

To determine that whether neural crest cell that enter foregut have the developmental potential to colonise the gut and or lung

OBJECTIVE

To carry out chick greenflorescent protein -chick grafts to fluorecently label neural crest cell

Carry out back transplantion experiments ,to reintroduce gfp-labelled ncc into early migration pathway.

Analyse the fate of backtransplanted gfp neural crest cells.

2. Induction

The induction of neural crest is a multistep process, starting at the early gastrula stage and continuing until neural tube closure. Neural crest induction can be monitored by the differentiation of pigment cells, which can be easily identified macroscopically, or by the expression of neural crest-specific genes. These genes include several families of transcriptional regulators (reviewed by Gammill and Bronner-fraser, 2003), among which the zinc finger transcription factor Slug, has become one of the most reliable markers for premigratory neural crest cells in chick and amphibian embryos (Mayor et al., 2005 and Nieto et al., 1994).

At the time of its induction the neural crest is flanked by the neural plate on one side and the non-neural ectoderm on the other side and is overlaying the paraxial mesoderm (Fig. 1). Because of their position relative to the neural crest each one of these tissues has been proposed as a source of inducer of neural crest fate.

Transplantation experiments in amphibian embryos have established that interactions between the neural plate and the surrounding non-neural ectoderm are involved in ...