To determine the role of BMP signalling in neural development I chose to make use of the REMI transgenic technique. I cloned the <I>Xenopus laevis</I> Pax-6 promoter and used it as a tool to drive the expression of BMP4 and the ΔXBMPR (a dominant negative BMP receptor) in the anterior neural plate, from the end of gastrulation. The main conclusion I draw from the misexpression of BMP4 in transgenic <I>Xenopus </I>F0 embryos is that developing neural tissue is still competent to respond to BMP4 signalling at neural plate stages. Furthermore, BMP4 continues to function as an inhibitor of the majority of neural genes expressed into the neural plate stages of development, though not all neural genes are affected by the ectopic expression of BMP4 equally. In addition, I present evidence to suggest that the inhibition of BMP signalling by the misexpression of a truncated form of the BMP receptor in transgenic F0 embryos perturbs neural development. I also present evidence that BMP4 signalling is required for specifying the anterior border of the neural plate in <I>Xenopus. </I>I show that BMP4 and BMP7 are present in the prechordal mesoderm, a region underlying the midline of the anterior neural plate, which could receive the signalling molecules. In sum, I suggest that BMP signalling is involved in the fine-tuning of patterning and development of the neural plate. To further our understanding of the role BMPs play in neural development and to advance our technical abilities to misexpress factors, I have developed the Gal4-UAS system in <I>Xenopus. </I>I show that given factors can be transactivated in a precise manner, by the cross-fertilisation of transgenic founder lines. Additionally, I show that transactivation by Gal4 can result in a predicted phenotype for the effector gene in question.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:603812 |
| Date | January 2001 |
| Creators | Hartley, K. |
| Publisher | University of Cambridge |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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