|
|
|
|||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
First published online 30 January 2008
doi: 10.1242/dev.010660
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Department of Organismal Biology and Anatomy, The University of Chicago, 1027 East 57th Street, Chicago, IL 60637, USA.
* Author for correspondence (e-mail: mkinkel{at}uchicago.edu)
Accepted 15 December 2007
Cdx transcription factors have crucial roles in anteroposterior patterning of the nervous system and mesoderm. Here we focus on the role of cdx4 in patterning the endoderm in zebrafish. We show that cdx4 has roles in determining pancreatic β-cell number, directing midline convergence of β-cells during early pancreatic islet formation, and specifying the anteroposterior location of foregut organs. Embryos deficient in cdx4 have a posteriorly shifted pancreas, liver and small intestine. The phenotype is more severe with knockdown of an additional Cdx factor, cdx1a. We show that cdx4 functions within the endoderm to localize the pancreas. Morpholino knockdown of cdx4 specifically in the endoderm recapitulates the posteriorly shifted pancreas observed in cdx4 mutants. Conversely, overexpression of cdx4 specifically in the endoderm is sufficient to shift the pancreas anteriorly. Together, these results suggest a model in which cdx4 confers posterior identity to the endoderm. Cdx4 might function to block pancreatic identity by preventing retinoic acid (RA) signal transduction in posterior endoderm. In support of this, we demonstrate that in cdx4-deficient embryos treated with RA, ectopic β-cells are located well posterior to the normal pancreatic domain.
Key words: Cdx4, Cdx1a, Retinoic acid, Pancreas, β-cell, AP patterning
![]()
CiteULike
Complore
Connotea
Del.icio.us
Digg
Reddit
Technorati
Twitter What's this?
This article has been cited by other articles:
![]() |
M. D. Kinkel, E. M. Sefton, Y. Kikuchi, T. Mizoguchi, A. B. Ward, and V. E. Prince Cyp26 enzymes function in endoderm to regulate pancreatic field size PNAS, May 12, 2009; 106(19): 7864 - 7869. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. F. Schilling Anterior-posterior patterning and segmentation of the vertebrate head Integr. Comp. Biol., November 1, 2008; 48(5): 658 - 667. [Abstract] [Full Text] [PDF] |
||||