PUBLICATION

her1, a zebrafish pair-rule like gene, acts downstream of notch signalling to control somite development

Authors
Takke, C. and Campos-Ortega, J.A.
ID
ZDB-PUB-990628-22
Date
1999
Source
Development (Cambridge, England)   126(13): 3005-3014 (Journal)
Registered Authors
Campos-Ortega, Jose
Keywords
her1; NOTCH signalling; somitogenesis; zebrafish
MeSH Terms
  • Animals
  • Basic Helix-Loop-Helix Transcription Factors
  • Caenorhabditis elegans Proteins*
  • Cell Differentiation
  • DNA-Binding Proteins/genetics
  • Gene Expression Regulation, Developmental
  • Helminth Proteins/genetics*
  • Membrane Proteins/genetics*
  • Muscles/embryology
  • Proteins/genetics*
  • RNA, Messenger/metabolism
  • Receptors, Notch
  • Repressor Proteins/genetics
  • Signal Transduction/genetics
  • Somites/cytology*
  • Somites/metabolism*
  • Zebrafish/embryology
  • Zebrafish/genetics*
  • Zebrafish Proteins*
PubMed
10357943 Full text @ Development
Abstract
During vertebrate embryonic development, the paraxial mesoderm becomes subdivided into metameric units known as somites. In the zebrafish embryo, genes encoding homologues of the proteins of the Drosophila Notch signalling pathway are expressed in the presomitic mesoderm and expression is maintained in a segmental pattern during somitogenesis. This expression pattern suggests a role for these genes during somite development. We misexpressed various zebrafish genes of this group by injecting mRNA into early embryos. RNA encoding a constitutively active form of notch1a (notch1a-intra) and a truncated variant of deltaD [deltaD(Pst)], as well as transcripts of deltaC and deltaD, the hairy-E(spl) homologues her1 and her4, and groucho2 were tested for their effects on somite formation, myogenesis and on the pattern of transcription of putative downstream genes. In embryos injected with any of these RNAs, with the exception of groucho2 RNA, the paraxial mesoderm differentiated normally into somitic tissue, but failed to segment correctly. Activation of notch results in ectopic activation of her1 and her4. This misregulation of the expression of her genes might be causally related to the observed mesodermal defects, as her1 and her4 mRNA injections led to effects similar to those seen with notch1a-intra. deltaC and deltaD seem to function after subdivision of the presomitic mesoderm, since the her gene transcription pattern in the presomitic mesoderm remains essentially normal after misexpression of δ genes. Whereas notch signalling alone apparently does not affect myogenesis, zebrafish groucho2 is involved in differentiation of mesodermal derivatives.
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