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Dorsal cell fate specified by chick Lmx1 during vertebrate limb development
A Vogel1, C Rodriguez, W Warnken
1Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA.
Nature
|December 14, 1995
Summary
Chick Lmx1 (C-Lmx1), a LIM-homeodomain gene, specifies dorsal cell fate in developing chick limbs. Its expression in dorsal mesoderm is regulated by Wnt7a and influences limb axis development.
Area of Science:
- Developmental Biology
- Genetics
- Molecular Biology
Background:
- Limb development relies on positional cues along the dorsoventral axis.
- In Drosophila, the LIM-homeodomain gene apterous specifies dorsal cell fate in wing discs.
Purpose of the Study:
- To isolate and characterize a vertebrate LIM-homeodomain gene involved in chick limb development.
- To investigate the role of Chick Lmx1 (C-Lmx1) in establishing the dorsoventral axis of the chick limb.
Main Methods:
- Isolation of the Chick Lmx1 (C-Lmx1) gene.
- Analysis of C-Lmx1 expression patterns in developing chick limb buds.
- Investigating the regulatory relationship between Wnt7a and C-Lmx1.
- Studying the effects of C-Lmx1 misexpression on limb mesoderm development.
Main Results:
- C-Lmx1 transcripts are found in the presumptive and developing dorsal limb mesoderm.
- Wnt7a, localized in the overlying ectoderm, regulates C-Lmx1 expression.
- Wnt7a can induce ectopic C-Lmx1 expression in ventral mesoderm.
- Misexpression of C-Lmx1 leads to ventral-to-dorsal transformations in limb mesoderm.
Conclusions:
- C-Lmx1 is a key gene specifying dorsal cell fate in the developing chick limb.
- The Wnt7a-C-Lmx1 pathway is crucial for establishing the dorsoventral axis during chick limb development.