Hox genes control vertebrate body elongation by collinear Wnt repression
Abstract
In vertebrates, the total number of vertebrae is precisely defined. Vertebrae derive from embryonic somites which are continuously produced posteriorly from the presomitic mesoderm (PSM) during body formation. We show that in the chicken embryo, activation of posterior Hox genes (paralogs 9-13) in the tail-bud correlates with the slowing-down of axis elongation. Our data indicate that a subset of progressively more posterior Hox genes, which are collinearly activated in vertebral precursors, repress Wnt activity with increasing strength. This leads to a graded repression of the Brachyury/T transcription factor, reducing mesoderm ingression and slowing down the elongation process. Due to the continuation of somite formation, this mechanism leads to the progressive reduction of PSM size. This ultimately brings the retinoic acid (RA)-producing segmented region in close vicinity to the tail bud, potentially accounting for the termination of segmentation and axis elongation.
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Author details
Reviewing Editor
- Marianne E Bronner, California Institute of Technology, United States
Publication history
- Received: August 14, 2014
- Accepted: February 20, 2015
- Accepted Manuscript published: February 26, 2015 (version 1)
- Version of Record published: March 16, 2015 (version 2)
Copyright
© 2015, Denans et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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