PUBLICATION

Control of her1 expression during zebrafish somitogenesis by a Delta-dependent oscillator and an independent wave-front activity

Authors
Holley, S.A., Geisler, R., and Nüsslein-Volhard, C.
ID
ZDB-PUB-000803-3
Date
2000
Source
Genes & Development   14(13): 1678-1690 (Journal)
Registered Authors
Geisler, Robert, Holley, Scott, Nüsslein-Volhard, Christiane
Keywords
Somitogenesis; Delta; her1 oscillator; wave front; zebrafish
MeSH Terms
  • Animals
  • Gene Expression Regulation, Developmental*
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins/physiology*
  • Somites*
  • Zebrafish/embryology*
  • Zebrafish/genetics
PubMed
10887161 Full text @ Genes & Dev.
Abstract
Somitogenesis has been linked both to a molecular clock that controls the oscillation of gene expression in the presomitic mesoderm (PSM) and to Notch pathway signaling. The oscillator, or clock, is thought to create a prepattern of stripes of gene expression that regulates the activity of the Notch pathway that subsequently directs somite border formation. Here, we report that the zebrafish gene after eight (aei) that is required for both somitogenesis and neurogenesis encodes the Notch ligand DeltaD. Additional analysis revealed that stripes of her1 expression oscillate within the PSM and that aei/DeltaD signaling is required for this oscillation. aei/DeltaD expression does not oscillate, indicating that the activity of the Notch pathway upstream of her1 may function within the oscillator itself. Moreover, we found that her1 stripes are expressed in the anlage of consecutive somites, indicating that its expression pattern is not pair-rule. Analysis of her1 expression in aei/DeltaD, fused somites (fss), and aei;fss embryos uncovered a wave-front activity that is capable of continually inducing her1 expression de novo in the anterior PSM in the absence of the oscillation of her1. The wave-front activity, in reference to the clock and wave-front model, is defined as such because it interacts with the oscillator-derived pattern in the anterior PSM and is required for somite morphogenesis. This wave-front activity is blocked in embryos mutant for fss but not aei/DeltaD. Thus, our analysis indicates that the smooth sequence of formation, refinement, and fading of her1 stripes in the PSM is governed by two separate activities.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping