Mechanisms of Wnt8 function in zebrafish mesoderm patterning /

Bibliographic Details
Main Author: Ramel, Marie-Christine, 1977-
Other Authors: Lekven, Arne C. (Thesis advisor)
Format: Thesis eBook
Language:English
Published: [College Station, Tex.] : [Texas A&M University], [2006]
Subjects:
Online Access:Link to OAK Trust copy

MARC

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100 1 |a Ramel, Marie-Christine,  |d 1977- 
245 1 0 |a Mechanisms of Wnt8 function in zebrafish mesoderm patterning /  |c by Marie-Christine Ramel. 
264 1 |a [College Station, Tex.] :  |b [Texas A&M University],  |c [2006] 
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500 |a "Major Subject: Biology" 
500 |a Title from author supplied metadata (automated record created on Sep. 15, 2006.) 
500 |a Vita. 
500 |a Abstract. 
502 |b Ph. D.  |c Texas A&M University  |d 2005. 
504 |a Includes bibliographical references. 
516 |a Text (Dissertation). 
520 3 |a In vertebrate embryonic development, correct specification of tissue fates along the dorsoventral (D/V) axis is known to require the secreted signaling ligand Wnt8. Wnt8 signaling promotes ventral fates and antagonizes the expansion of the dorsal domain known as the organizer. Maintenance of the organizer is critical for proper development as this tissue is known to produce inhibitors of Wnt and BMP (Bone Morphogenetic Protein) family ligands; BMPs are also known to play a major role in promoting ventral fates. In order to understand how Wnt8 antagonizes the organizer, we analyzed the epistatic relationship between Wnt8 and the transcriptional repressors Vent and Vox using zebrafish as a model organism. We found that Wnt8/[Beta]-catenin signaling directly regulates the transcriptional levels of vent and vox so that they can repress the transcription of dorsal genes on the ventral side of the embryo. To understand the contribution of Wnt8 towards ventral fate specification, we carefully analyzed its relationship with BMP signaling during gastrula stages. We found that bmp expression in the mesoderm is under the control of Wnt8 at mid-gastrulation and that regulation of bmp explains many of the ventral defects observed in wnt8 mutants. Antagonism of the expression of organizer-derived BMP inhibitors by Wnt8 also indirectly allows timely BMP signaling. Analysis of wnt8; bmp double mutants revealed an early unsuspected function of BMP in the antagonism of the organizer. Further, we uncovered a mechanism through which regulation of vent, vox and a related-gene ved expression by both Wnt8 and BMP antagonizes dorsal/axial mesoderm identity to preserve the integrityof ventral/non-axial tissues. In summary, we have revealed some of the mechanisms of Wnt8 function in D/V mesoderm patterning: it restricts the organizer domain by regulating vent and vox, it allows BMP induced differentiation through its inhibition of BMP antagonists derived from the organizer and it co-regulates vent, vox, and ved with BMP signaling to allow maintenance of the non-axial domain. 
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538 |a System requirements: World Wide Web access and Adobe Acrobat Reader. 
500 |a Electronic resource. 
650 4 |a Major Biology. 
653 |a mesoderm 
653 |a BMP 
653 |a zebrafish 
653 |a Wnt8 
700 1 |a Lekven, Arne C.,  |e thesis advisor. 
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