PUBLICATION

Multiple roles for Med12 in vertebrate endoderm development

Authors
Shin, C.H., Chung, W.S., Hong, S.K., Ober, E.A., Verkade, H., Field, H.A., Huisken, J., and Stainier, D.Y.
ID
ZDB-PUB-080414-12
Date
2008
Source
Developmental Biology   317(2): 467-479 (Journal)
Registered Authors
Chung, Won-Suk, Hong, Sung-Kook, Ober, Elke, Shin, Chong, Stainier, Didier, Verkade, Heather
Keywords
none
MeSH Terms
  • Animals
  • Base Sequence
  • Basic Helix-Loop-Helix Transcription Factors/metabolism*
  • Cell Differentiation/physiology*
  • Cell Line
  • DNA Primers/genetics
  • DNA-Binding Proteins/metabolism
  • Endoderm/embryology*
  • Endoderm/metabolism
  • Gene Expression Regulation, Developmental*
  • High Mobility Group Proteins/metabolism
  • In Situ Nick-End Labeling
  • Mediator Complex
  • Molecular Sequence Data
  • Mutagenesis
  • Phenotype*
  • Polymorphism, Restriction Fragment Length/genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • SOXF Transcription Factors
  • Sequence Analysis, DNA
  • Transcription Factors/genetics
  • Transcription Factors/metabolism*
  • Vertebrates/embryology*
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed
18394596 Full text @ Dev. Biol.
Abstract
In zebrafish, the endoderm originates at the blastula stage from the most marginal blastomeres. Through a series of complex morphogenetic movements and differentiation events, the endodermal germ layer gives rise to the epithelial lining of the digestive tract as well as its associated organs such as the liver, pancreas, and swim bladder. How endodermal cells differentiate into distinct cell types such as hepatocytes or endocrine and exocrine pancreatic cells remains a major question. In a forward genetic screen for genes regulating endodermal organ development, we identified mutations at the shiri locus that cause defects in the development of a number of endodermal organs including the liver and pancreas. Detailed phenotypic analyses indicate that these defects are partially due to a reduction in endodermal expression of the hairy/enhancer of split-related gene, her5, at mid to late gastrulation stages. Using the Tg(0.7her5:EGFP)(ne2067) line, we show that her5 is expressed in the endodermal precursors that populate the pharyngeal region as well as the organ-forming region. We also find that knocking down her5 recapitulates some of the endodermal phenotypes of shiri mutants, further revealing the role of her5 in endoderm development. Positional cloning reveals that shiri encodes Med12, a regulatory subunit of the transcriptional Mediator complex recently associated with two human syndromes. Additional studies indicate that Med12 modulates the ability of Casanova/Sox32 to induce sox17 expression. Thus, detailed phenotypic analyses of embryos defective in a component of the Mediator complex have revealed new insights into discrete aspects of vertebrate endoderm development, and provide possible explanations for the craniofacial and digestive system defects observed in humans with mutations in MED12.
Genes / Markers
Figures
Expression
Phenotype
Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping
Errata and Notes