Developing organs must maintain their shape even as individual cells change dramatically. A study in Cell Reports reveals how the fruit fly retina accomplishes this - through a tissue-wide network of mechanical tension.
The Morphogenesis Problem
The fly retina is incredibly precise - hundreds of identical units (ommatidia) arranged in a perfect crystalline array. But during development, cells within each unit undergo complex shape changes. How does the tissue maintain its larger architecture?
The answer: mechanical forces coordinated across the entire tissue.
Organ-Scale Curvature
The researchers found that the developing retina acquires a specific curvature early in development. This curvature is maintained throughout subsequent morphogenesis, even as individual cells dramatically reshape themselves.
Disrupting the forces that maintain this curvature led to retinal disorganization.
Tension Through Adhesions
Interommatidial pigment cells (IOPCs) - the cells that sit between visual units - generate sustained actomyosin contractility through their apical adhesions. This creates a supracellular network of tension that spans the entire retina.
The tension isn't random. It's uniform and sustained, organized through the Rok (Rho kinase) pathway.
Coordination Across Scales
The findings reveal how local cellular mechanics aggregate to produce tissue-level properties. Individual cells generate tension; adhesions connect them into a network; the network maintains organ shape.
This principle may apply broadly to how complex tissues maintain form during the dramatic cellular rearrangements of development.
Reference: Bhattacharyya S, et al. (2025). Tension transmission across a supracellular network drives increased tissue rigidity in the Drosophila retina. Cell Reports. doi: 10.1016/j.celrep.2025.116355 | PMID: 41042671
Disclaimer: The image accompanying this article is for illustrative purposes only and does not depict actual experimental results, data, or biological mechanisms.