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A study of regional gut endoderm potency by analysis of Cdx2 null mutant chimaeric mice
Felix Beck1, Kallayanee Chawengsaksophak, Jenni Luckett
1Department of Biochemistry, University of Leicester, University Road, Leicester, LE1 7RH, UK. fb22@le.ac.uk
Abstract:
Inactivation of Cdx2 by homologous recombination results in the development of forestomach epithelium at ectopic sites in pericaecal areas of the midgut of heterozygote mice. Local factors subsequently result in the secondary induction of tissues exhibiting an orderly sequence of tissue types between the ectopic forestomach tissue and the surrounding colon. Clonal analysis of this secondarily generated tissue using Y chromosome painting in chimaeric mice indicates that once differentiated to express Cdx2, host colonic epithelium can only form small intestinal-type epithelium, while Cdx2 mutant cells give rise to a succession of gastric-type tissue but never to a small intestine morphology. Our results indicate a difference in potency between forestomach and midgut precursor endodermal cells.
Insights
Inactivating the Cdx2 gene in mice causes forestomach tissue to grow in the midgut. This study reveals distinct developmental potentials between forestomach and midgut precursor cells.
Area of Science:
- Developmental biology
- Genetics
- Gastrointestinal biology
Background:
- The gene Cdx2 plays a crucial role in intestinal development.
- Understanding cell potency is key to tissue regeneration and disease research.
Purpose of the Study:
- To investigate the role of Cdx2 in forestomach and midgut development.
- To determine the differentiation potential of Cdx2-expressing versus Cdx2-mutant cells.
Main Methods:
- Homologous recombination was used to inactivate the Cdx2 gene in mice.
- Chimeric mice and Y chromosome painting were employed for clonal analysis.
- Ectopic tissue development was observed in pericaecal areas.
Main Results:
- Cdx2 inactivation led to ectopic forestomach epithelium in the midgut.
- Secondary induction of tissues occurred between ectopic forestomach and colon.
- Cdx2-expressing cells formed small intestinal epithelium, while Cdx2-mutant cells formed gastric-type tissue.
Conclusions:
- Cdx2 is essential for specifying small intestinal fate.
- Forestomach and midgut precursor cells exhibit different developmental potencies.
- Local factors influence secondary tissue induction.