PUBLICATION
A revised model of Xenopus dorsal midline development: Differential and separable requirements for Notch and Shh signaling
- Authors
- Peyrot, S.M., Wallingford, J.B., and Harland, R.M.
- ID
- ZDB-PUB-110207-4
- Date
- 2011
- Source
- Developmental Biology 352(2): 254-266 (Journal)
- Registered Authors
- Harland, Richard
- Keywords
- Floor plate, Notochord, Hypochord, Dorsal midline, Notch, Shh
- MeSH Terms
-
- Animals
- Base Sequence
- Body Patterning/genetics
- Body Patterning/physiology*
- DNA Primers/genetics
- Gastrula/embryology
- Gene Expression Regulation, Developmental
- Hedgehog Proteins/genetics
- Hedgehog Proteins/physiology*
- Models, Biological*
- Models, Neurological
- Neural Plate/embryology
- Notochord/embryology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Notch/genetics
- Receptors, Notch/physiology*
- Signal Transduction
- Xenopus Proteins/genetics
- Xenopus Proteins/physiology*
- Xenopus laevis/embryology*
- Xenopus laevis/genetics
- Xenopus laevis/physiology*
- PubMed
- 21276789 Full text @ Dev. Biol.
Citation
Peyrot, S.M., Wallingford, J.B., and Harland, R.M. (2011) A revised model of Xenopus dorsal midline development: Differential and separable requirements for Notch and Shh signaling. Developmental Biology. 352(2):254-266.
Abstract
The development of the vertebrate dorsal midline (floor plate, notochord, and hypochord) has been an area of classical research and debate. Previous studies in vertebrates have led to contrasting models for the roles of Shh and Notch signaling in specification of the floor plate, by late inductive or early allocation mechanisms, respectively. Here, we show that Notch signaling plays an integral role in cell fate decisions in the dorsal midline of Xenopus laevis, similar to that observed in zebrafish and chick. Notch signaling promotes floor plate and hypochord fates over notochord, but has variable effects on Shh expression in the midline. In contrast to previous reports in frog, we find that Shh signaling is not required for floor plate vs. notochord decisions and plays a minor role in floor plate specification, where it acts in parallel to Notch signaling. As in zebrafish, Shh signaling is required for specification of the lateral floor plate in the frog. We also find that the medial floor plate in Xenopus comprises two distinct populations of cells, each dependent upon different signals for its specification. Using expression analysis of several midline markers, and dissection of functional relationships, we propose a revised allocation mechanism of dorsal midline specification in Xenopus. Our model is distinct from those proposed to date, and may serve as a guide for future studies in frog and other vertebrate organisms.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping