Index
Abstract
1. Introduction
1.1 Early development of vertebrate eye
1.1.1 Morphogenesis of eye
1.1.2 Specification of eye field by eye field transcription factors (EFTFs) 1.1.3 Molecular mechanisms of vertebrate retina development
1.1.3.1 Patterning of retina
1.1.3.2 Specification of retinal cell types
1.2 Xenopus laevis as a vertebrate model organism in developmental biology
1.2.1 The advantages of this model organism 1.2.2 Animal cap embryonic stem (ACES) cells
1.3 BMP signaling and its antagonists
1.3.1 BMP signaling
1.3.2 BMP antagonists and neural induction
1.4 Neural induction and eye field specification
1.4.1 Noggin and eye field transcription factors
1.5 Retinal degenerative diseases and cell replacement therapy
1.6 Aims of this project
2. Materials and Methods
3. Results
3.1 In vitro analyses of ACES cells expressing different doses of noggin mRNA
3.1.1 High doses of noggin can effectively induce the expression of retinal cell type specific markers in ACES cells
3.1.2 ACES cells expressing high dose noggin mRNA effectively differentiate into retinal lineages
3.2 In vivo analyses of ACES cells expressing different doses of noggin mRNA
3.2.1 ACES cells transplantation assay and description of the resulting phenotypes 3.2.2 Analyses of the noggin-expressing ACES cells in the transplants
3.2.2.1 Histological analysis 3.2.2.2 Molecular analysis
3.3 Functional analyses of 20pg noggin-expressing ACES cells transplanted in the eye field
region
3.4 Combination, in ACES cells, of high doses of noggin with transcription factors that promote
specific retinal cell fate
3.4.1 In vitro and in vivo analyses of ACES cells co-injected with high dose noggin and Xotx5b
3.5 Comparison of activities of Noggin and tBR in ACES cells
3.5.1 Activities of tBR in Xenopus embryos
3.5.2Cell identities in the tBR-expressing ACES cells
3.6 Synergistic effects of Noggin and Shh signaling on the retinal cell fate induction
4. Discussion and Conclusions
4.1 ACES cells expressing high doses of noggin are directed to retinal lineages
4.2 ACES cells expressing high doses of noggin form eyes that are morphologically and
functionally identical to normal eyes
4.3 The possible mechanisms of Noggin action in ACES cells
4.3.1 Correlation between Noggin-mediated retinal induction and antagonism of BMP signaling 4.3.2 The correlation of Noggin and downstream secondary signalings
