Endoderm-specific deletion of Tbx1 reveals an FGF-independent role for Tbx1 in pharyngeal apparatus morphogenesis
Version of Record online: 12 JUN 2014
Copyright © 2014 Wiley Periodicals, Inc.
Volume 243, Issue 9, pages 1143–1151, September 2014
How to Cite
Jackson, A., Kasah, S., Mansour, S. L., Morrow, B. and Basson, M. A. (2014), Endoderm-specific deletion of Tbx1 reveals an FGF-independent role for Tbx1 in pharyngeal apparatus morphogenesis. Dev. Dyn., 243: 1143–1151. doi: 10.1002/dvdy.24147
- Issue online: 20 AUG 2014
- Version of Record online: 12 JUN 2014
- Accepted manuscript online: 9 MAY 2014 01:01AM EST
- Manuscript Accepted: 20 APR 2014
- Manuscript Revised: 1 APR 2014
- Manuscript Received: 23 NOV 2013
- Medical Research Council . Grant Number: G0601104
- NIH . Grant Number: R01DC04185
- pharyngeal endoderm;
Background: The T-box transcription factor Tbx1, is essential for the normal development of multiple organ systems in the embryo. One of the most striking phenotypes in Tbx1−/− embryos is the failure of the caudal pharyngeal pouches to evaginate from the foregut endoderm. Despite considerable interest in the role of Tbx1 in development, the mechanisms whereby Tbx1 controls caudal pouch formation have remained elusive. In particular, the question as to how Tbx1 expression in the pharyngeal endoderm regulates pharyngeal pouch morphogenesis in the mouse embryo is not known. Results: To address this question, we produced mouse embryos in which Tbx1 was specifically deleted from the pharyngeal endoderm and, as expected, embryos failed to form caudal pharyngeal pouches. To determine the molecular mechanism, we examined expression of Fgf3 and Fgf8 ligands and downstream effectors. Although Fgf8 expression is greatly reduced in Tbx1-deficient endoderm, FGF signaling levels are unaffected. Furthermore, pouch morphogenesis is only partially perturbed by the loss of both Fgf3 and Fgf8 from the endoderm, indicating that neither are required for pouch formation. Conclusions: Tbx1 deletion from the pharyngeal endoderm is sufficient to cause caudal pharyngeal arch segmentation defects by FGF-independent effectors that remain to be identified. Developmental Dynamics 243:1143–1151, 2014. © 2014 Wiley Periodicals, Inc.