Clustered cytoneme interactions contribute to peripheral nervous system patterning in Drosophila

The development of adult tissues in organisms depends on the precise communication between cells during their formation. In the fruit fly Drosophila melanogaster, the dorsal thoracic sensory bristles of the peripheral nervous system (PNS) rely on protrusions called cytonemes for this purpose. While the individual dynamics of cytonemes have been explored in experiments and theory, the interaction between cytonemes during PNS development is still not fully understood.

To investigate this, researchers employed in vivo and ex vivo imaging techniques alongside fly genetics. They discovered that cytonemes aggregate into clusters on the basal surface of the developing PNS. The formation of these clusters enhances the dynamics of individual cytonemes, suggesting a cooperative communication among cytonemes.

These clusters are dynamic and temporary structures that can be disrupted in experiments by aligning nanofibers. When this manipulation occurs, the typical PNS patterning is altered. The researchers found that the interaction between cytonemes via these clusters is facilitated by the cell adhesion molecule E-cadherin. Reducing the expression of E-cadherin leads to alterations in cluster dynamics, cytoneme length, and the overall PNS patterning.

Based on their findings, the researchers propose a model where complex interactions between cytonemes, mediated by clusters and enhanced through cell-cell communication, play a crucial role in promoting individual cytoneme dynamics. They suggest that the improved dynamics and stability provided by these increased interactions could support both the variety and intensity of local signaling events necessary for proper tissue patterning in the PNS.