PUBLICATION
Nodal signaling patterns the organizer
- Authors
- Gritsman, K., Talbot, W.S., and Schier, A.F.
- ID
- ZDB-PUB-000309-44
- Date
- 2000
- Source
- Development (Cambridge, England) 127(5): 921-932 (Journal)
- Registered Authors
- Gritsman, Kira, Schier, Alexander, Talbot, William S.
- Keywords
- none
- MeSH Terms
-
- Animals
- Blastocyst/physiology*
- Body Patterning/physiology*
- Crosses, Genetic
- Embryo, Nonmammalian/physiology*
- Gene Dosage
- Gene Expression Regulation, Developmental
- Goosecoid Protein
- Heterozygote
- Homeodomain Proteins/genetics*
- Homeodomain Proteins/metabolism
- Homeodomain Proteins/physiology
- Nodal Protein
- Notochord/physiology*
- Nucleolus Organizer Region/physiology*
- Repressor Proteins/genetics
- Signal Transduction
- Stem Cells/physiology
- Transcription Factors/genetics*
- Transcription Factors/physiology
- Transforming Growth Factor beta/genetics*
- Transforming Growth Factor beta/physiology
- Xenopus laevis/embryology
- Xenopus laevis/genetics
- Zebrafish Proteins*
- Zygote
- PubMed
- 10662632 Full text @ Development
Citation
Gritsman, K., Talbot, W.S., and Schier, A.F. (2000) Nodal signaling patterns the organizer. Development (Cambridge, England). 127(5):921-932.
Abstract
Spemann's organizer plays an essential role in patterning the vertebrate embryo. During gastrulation, organizer cells involute and form the prechordal plate anteriorly and the notochord more posteriorly. The fate mapping and gene expression analyses in zebrafish presented in this study reveal that this anteroposterior polarity is already initiated in the organizer before gastrulation. Prechordal plate progenitors reside close to the blastoderm margin and express the homeobox gene goosecoid, whereas notochord precursors are located further from the margin and express the homeobox gene floating head. The nodal-related genes cyclops and squint are expressed at the blastoderm margin and are required for prechordal plate and notochord formation. We show that differential activation of the Nodal signaling pathway is essential in establishing anteroposterior pattern in the organizer. First, overexpression of cyclops and squint at different doses leads to the induction of floating head at low doses and the induction of both goosecoid and floating head at higher doses. Second, decreasing Nodal signaling using different concentrations of the antagonist Antivin inhibits goosecoid expression at low doses and blocks expression of both goosecoid and floating head at higher doses. Third, attenuation of Nodal signaling in zygotic mutants for the EGF-CFC gene one-eyed pinhead, an essential cofactor for Nodal signaling, leads to the loss of goosecoid expression and expansion of floating head expression in the organizer. Concomitantly, cells normally fated to become prechordal plate are transformed into notochord progenitors. Finally, activation of Nodal signaling at different times suggests that prechordal plate specification requires sustained Nodal signaling, whereas transient signaling is sufficient for notochord development. Together, these results indicate that differential Nodal signaling patterns the organizer before gastrulation, with the highest level of activity required for anterior fates and lower activity essential for posterior fates.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping