The mouse node is the structural equivalent of Spemann's Organizer. The transcription factor Foxa2 (HNF3beta) is required for node and notochord specification and its enhancer has been characterized to a 500bp element that drives the expression of a reporter gene to the node and notochord in transgenic embryos. / The aim of the study was to identify sequence elements, within this enhancer, required to drive node/notochord specific-expression. Since, in the Xenopus organizer, Siamois activates organizer-specific gene expression, it was tested whether this factor could activate expression from the Foxa2 node-specific enhancer. Using deletion analysis, the response element was mapped to a 33bp region and it was shown that this element was both necessary and sufficient for reporter gene activation by X-Siamois . Furthermore, it was shown that X-Siamois can bind this DNA element and two sequence motifs required for binding and transactivation by X-Siamois were identified. Preliminary results suggest that the 33bp element, within the 500bp enhancer, is required for the maintenance of expression in the notochord of transgenic mice.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.78388 |
| Date | January 2003 |
| Creators | Islam, Ayesha |
| Contributors | Dufort, Daniel (advisor), Clarke, Hugh (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Biology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001984948, proquestno: AAIMQ88223, Theses scanned by UMI/ProQuest. |
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