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Cellular analysis of limb development in the mouse mutant hypodactyly
K E Robertson1, M H Chapman, A Adams
1Department of Anatomy and Developmental Biology, University College London, United Kingdom.
Developmental Genetics
|January 1, 1996
Summary
The Hypodactyly (Hd) mutation in mice causes severe limb defects, affecting distal structures. This study reveals increased cell death and altered mesenchyme cell behavior in mutant limb buds, leading to reduced digit formation.
Area of Science:
- Developmental biology
- Genetics
- Mouse models
Background:
- The Hypodactyly (Hd) mutation in mice leads to defects in distal limb development.
- Heterozygous (Hd/+) mice exhibit partial or complete absence of distal phalanges and terminal claws in hindlimbs.
- Homozygous (Hd/Hd) mice display a single digit on each limb.
Purpose of the Study:
- To investigate the developmental basis of limb malformations in Hypodactyly (Hd) mutant mice.
- To identify the cellular and morphological changes occurring during limb development in Hd mutants.
Main Methods:
- Comparative morphological analysis of wild-type and Hd mutant mouse embryos.
- In vitro culture of mesenchyme cells from Hd/Hd mutants.
- Assessment of cell death and differentiation in developing limb buds.
Main Results:
- Limb bud morphology changes later in development, with Hd/Hd buds becoming pointed.
- Increased anterior cell death in Hd/+ hindlimbs and anterior/posterior cell death in Hd/Hd fore- and hindlimbs.
- Mesenchyme cells from Hd/Hd mutants exhibit cell-autonomous changes and reduced cartilage differentiation.
Conclusions:
- The Hypodactyly mutation disrupts normal limb development through increased apoptosis and altered mesenchyme cell behavior.
- These cellular changes lead to the observed distal limb defects in Hd mutant mice.
- The apical ectodermal ridge remains prominent even in severely malformed Hd/Hd limb buds.