PUBLICATION

Notch Signalling Synchronizes the Zebrafish Segmentation Clock but Is Not Needed To Create Somite Boundaries

Authors

Ozbudak, E.M., and Lewis, J.

ID

ZDB-PUB-080227-4

Date

2008

Source

PLoS Genetics 4(2): e15 (Journal)

Registered Authors

Lewis, Julian, Ozbudak, Ertugrul

Keywords

Notch signaling, Somites, Embryos, Genetic oscillators, Morphogenic segmentation, Gene expression, Zebrafish, Mathematical models

MeSH Terms

Heat-Shock Response/genetics
Heat-Shock Response/physiology
Genes, Reporter
Mutation
Transcription Factors/genetics
Transcription Factors/physiology
Intracellular Signaling Peptides and Proteins
Promoter Regions, Genetic
Body Patterning/genetics
Body Patterning/physiology
Gene Expression Regulation, Developmental
Mesoderm/embryology
Mesoderm/physiology
Models, Biological
Basic Helix-Loop-Helix Transcription Factors/genetics
Basic Helix-Loop-Helix Transcription Factors/physiology
Green Fluorescent Proteins/genetics
Receptors, Notch/genetics
Receptors, Notch/physiology*
Triglycerides/administration & dosage
Triglycerides/pharmacology
Membrane Proteins/genetics
Membrane Proteins/physiology
Animals
Signal Transduction/drug effects
Somites/drug effects
Somites/embryology
Somites/physiology
Zebrafish Proteins/genetics
Zebrafish Proteins/physiology*
Zebrafish/embryology*
Zebrafish/genetics
Zebrafish/physiology*
Animals, Genetically Modified
gamma-Aminobutyric Acid/administration & dosage
gamma-Aminobutyric Acid/analogs & derivatives
gamma-Aminobutyric Acid/pharmacology

PubMed

18248098 Full text @ PLoS Genet.

Abstract

Somite segmentation depends on a gene expression oscillator or clock in the posterior presomitic mesoderm (PSM) and on read-out machinery in the anterior PSM to convert the pattern of clock phases into a somite pattern. Notch pathway mutations disrupt somitogenesis, and previous studies have suggested that Notch signalling is required both for the oscillations and for the read-out mechanism. By blocking or overactivating the Notch pathway abruptly at different times, we show that Notch signalling has no essential function in the anterior PSM and is required only in the posterior PSM, where it keeps the oscillations of neighbouring cells synchronized. Using a GFP reporter for the oscillator gene her1, we measure the influence of Notch signalling on her1 expression and show by mathematical modelling that this is sufficient for synchronization. Our model, in which intracellular oscillations are generated by delayed autoinhibition of her1 and her7 and synchronized by Notch signalling, explains the observations fully, showing that there are no grounds to invoke any additional role for the Notch pathway in the patterning of somite boundaries in zebrafish.

Genes / Markers

Figures