Wendy Reeves and Rachel Thayer contributed equally to this work.
Patterns & Phenotypes
Anterior-posterior regionalized gene expression in the Ciona notochord
Article first published online: 27 DEC 2013
Copyright © 2013 Wiley Periodicals, Inc.
Volume 243, Issue 4, pages 612–620, April 2014
How to Cite
Reeves, W., Thayer, R. and Veeman, M. (2014), Anterior-posterior regionalized gene expression in the Ciona notochord. Dev. Dyn., 243: 612–620. doi: 10.1002/dvdy.24101
- Issue published online: 25 MAR 2014
- Article first published online: 27 DEC 2013
- Accepted manuscript online: 29 NOV 2013 04:08AM EST
- Manuscript Accepted: 20 NOV 2013
- Manuscript Revised: 19 NOV 2013
- Manuscript Received: 4 OCT 2013
- NIH . Grant Number: NIH P20 GM103418
- NSF . Grant Number: DBI-1156571
- differential expression;
Background: In the simple ascidian chordate Ciona, the signaling pathways and gene regulatory networks giving rise to initial notochord induction are largely understood and the mechanisms of notochord morphogenesis are being systematically elucidated. The notochord has generally been thought of as a non-compartmentalized or regionalized organ that is not finely patterned at the level of gene expression. Quantitative imaging methods have recently shown, however, that notochord cell size, shape, and behavior vary consistently along the anterior-posterior (AP) axis. Results: Here we screen candidate genes by whole mount in situ hybridization for potential AP asymmetry. We identify 4 genes that show non-uniform expression in the notochord. Ezrin/radixin/moesin (ERM) is expressed more strongly in the secondary notochord lineage than the primary. CTGF is expressed stochastically in a subset of notochord cells. A novel calmodulin-like gene (BCamL) is expressed more strongly at both the anterior and posterior tips of the notochord. A TGF-β ortholog is expressed in a gradient from posterior to anterior. The asymmetries in ERM, BCamL, and TGF-β expression are evident even before the notochord cells have intercalated into a single-file column. Conclusions: We conclude that the Ciona notochord is not a homogeneous tissue but instead shows distinct patterns of regionalized gene expression. Developmental Dynamics 243:612–620, 2014. © 2013 Wiley Periodicals, Inc.