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Updated: May 5, 2026
Modeling Paracrine Noncanonical Wnt Signaling In Vitro
Published on: December 10, 2021
Canonical Wnt/β-catenin signalling is essential for optic cup formation
Anna-Carin Hägglund1, Anna Berghard, Leif Carlsson
1Umeå Center for Molecular Medicine, Umeå University, Umeå, Sweden.
Abstract:
A multitude of signalling pathways are involved in the process of forming an eye. Here we demonstrate that β-catenin is essential for eye development as inactivation of β-catenin prior to cellular specification in the optic vesicle caused anophthalmia in mice. By achieving this early and tissue-specific β-catenin inactivation we find that retinal pigment epithelium (RPE) commitment was blocked and eye development was arrested prior to optic cup formation due to a loss of canonical Wnt signalling in the dorsal optic vesicle. Thus, these results show that Wnt/β-catenin signalling is required earlier and play a more central role in eye development than previous studies have indicated. In our genetic model system a few RPE cells could escape β-catenin inactivation leading to the formation of a small optic rudiment. The optic rudiment contained several neural retinal cell classes surrounded by an RPE. Unlike the RPE cells, the neural retinal cells could be β-catenin-negative revealing that differentiation of the neural retinal cell classes is β-catenin-independent. Moreover, although dorsoventral patterning is initiated in the mutant optic vesicle, the neural retinal cells in the optic rudiment displayed almost exclusively ventral identity. Thus, β-catenin is required for optic cup formation, commitment to RPE cells and maintenance of dorsal identity of the retina.
Insights
Early inactivation of beta-catenin (a key protein) in mice caused anophthalmia (no eyes) by blocking retinal pigment epithelium commitment and disrupting Wnt signaling, highlighting its crucial role in eye development.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- Eye development involves complex signaling pathways.
- The precise role of beta-catenin in early eye formation is not fully understood.
Purpose of the Study:
- To investigate the essential role of beta-catenin in early eye development.
- To determine the impact of early, tissue-specific beta-catenin inactivation on eye formation.
Main Methods:
- Utilized a genetic mouse model for early and tissue-specific inactivation of beta-catenin in the optic vesicle.
- Analyzed the effects on retinal pigment epithelium commitment, optic cup formation, and cell differentiation.
Main Results:
- Inactivation of beta-catenin led to anophthalmia, blocking retinal pigment epithelium commitment and arresting eye development before optic cup formation.
- Canonical Wnt signaling was lost in the dorsal optic vesicle, indicating its early requirement.
- Neural retinal cell differentiation was beta-catenin-independent, but cells adopted predominantly ventral identities, suggesting beta-catenin's role in dorsal identity maintenance.
Conclusions:
- Wnt/beta-catenin signaling is crucial for early eye development, optic cup formation, and retinal pigment epithelium commitment.
- Beta-catenin is essential for maintaining dorsal identity within the developing retina.
- These findings reveal a more central and earlier role for Wnt/beta-catenin signaling in eye development than previously recognized.
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