Polychaetoid controls patterning by modulating adhesion in the Drosophila pupal retina
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Updated: Jul 5, 2026
Dissection of the Drosophila Pupal Retina for Immunohistochemistry, Western Analysis, and RNA Isolation
Published on: March 15, 2019
Midori J Seppa1, Ruth I Johnson, Sujin Bao
1Department of Molecular Biology and Pharmacology, Washington University School of Medicine, 660 South Euclid Avenue, Saint Louis, MO 63110, USA.
Insights
Polychaetoid (Pyd) protein, a homolog of Zonula Occludens-1, is crucial for correct cellular patterning in the Drosophila pupal eye. Reduced Pyd function disrupts tissue development by affecting adherens junctions and cell adhesion.
Area of Science:
- Developmental Biology
- Cell Biology
- Genetics
Background:
- Correct cellular patterning is essential for tissue morphogenesis, but the precise role of epithelial junctions remains unclear.
- The Drosophila pupal eye offers a robust model for investigating junction-associated proteins during dynamic developmental processes.
Purpose of the Study:
- To elucidate the function of polychaetoid (Pyd), the Drosophila homolog of Zonula Occludens-1, in regulating cellular patterning within the developing pupal eye.
- To investigate the molecular mechanisms by which Pyd influences adherens junction dynamics and cell adhesion.
Main Methods:
- Utilized the Drosophila pupal eye as a model system to study gene function during development.
- Generated mutations and performed gene knockdown of polychaetoid (pyd) to assess its role in cellular patterning.
- Analyzed protein localization and expression levels of key junctional proteins, including Roughest and DE-Cadherin, using immunofluorescence.
Main Results:
- Pyd protein localizes to adherens junctions in the developing pupal retina.
- Reduction of Pyd function leads to mis-patterning of interommatidial cells and impaired cone cell contact switching.
- Decreased Pyd levels result in elevated expression of Roughest, DE-Cadherin, and other adherens junction proteins at the cell membrane.
- Overexpression or mutation of other junction-associated proteins exacerbates Pyd-related patterning defects.
Conclusions:
- Pyd plays a critical role in maintaining proper cellular organization within the Drosophila pupal eye.
- Pyd modulates adherens junction stability and influences Roughest-mediated cell adhesion.
- These findings highlight the importance of Pyd in coordinating cell-cell interactions during tissue development.
Abstract:
Correct cellular patterning is central to tissue morphogenesis, but the role of epithelial junctions in this process is not well-understood. The Drosophila pupal eye provides a sensitive and accessible model for testing the role of junction-associated proteins in cells that undergo dynamic and coordinated movements during development. Mutations in polychaetoid (pyd), the Drosophila homologue of Zonula Occludens-1, are characterized by two phenotypes visible in the adult fly: increased sensory bristle number and the formation of a rough eye produced by poorly arranged ommatidia. We found that Pyd was localized to the adherens junction in cells of the developing pupal retina. Reducing Pyd function in the pupal eye resulted in mis-patterning of the interommatidial cells and a failure to consistently switch cone cell contacts from an anterior-posterior to an equatorial-polar orientation. Levels of Roughest, DE-Cadherin and several other adherens junction-associated proteins were increased at the membrane when Pyd protein was reduced. Further, both over-expression and mutations in several junction-associated proteins greatly enhanced the patterning defects caused by reduction of Pyd. Our results suggest that Pyd modulates adherens junction strength and Roughest-mediated preferential cell adhesion.
