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Otx2 and HNF3beta genetically interact in anterior patterning.
1Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
The International Journal of Developmental Biology
|April 9, 2001
Summary
Genetic interaction between Otx2 and HNF3beta is crucial for mouse nervous system development. Double heterozygous mutants exhibit severe anterior patterning defects, impacting survival.
Area of Science:
- Developmental Biology
- Genetics
- Neuroscience
Background:
- Mouse nervous system patterning relies on signals from the anterior visceral endoderm (AVE) and the node.
- Mutations in HNF3beta affect the node, while Otx2 mutations impact head structures via the AVE.
Purpose of the Study:
- To investigate potential genetic interactions between Otx2 and HNF3beta in early mouse development.
- To understand their roles in establishing anterior patterning and signaling centers.
Main Methods:
- Crossed Otx2+/- and HNF3beta+/- mice to generate double heterozygous mutants.
- Analyzed embryonic development and forebrain patterning using regional marker analysis.
Main Results:
- Double heterozygous Otx2+/-;HNF3beta+/- mutants showed high postnatal mortality due to severe anterior patterning defects.
- Phenotypes included holoprosencephaly, cyclopia, and forebrain truncations, with ventral forebrain most affected.
- Absence of Shh expression in anterior regions of mutants indicated a genetic interaction regulating anterior midline signaling.
Conclusions:
- Otx2 and HNF3beta genetically interact to regulate Shh expression in the anterior midline.
- Both genes are involved in anterior patterning, likely through overlapping expression in the AVE and/or prechordal mesoderm.