# Hbs and Rst adhesion molecules provide a regional code that regulates cell elimination during epithelial remodeling

## TL;DR

The study shows how Hibris and Roughest proteins control cell elimination in fruit fly tissue, shaping adult structures through adhesion and signaling.

## Contribution

The study identifies Hibris and Roughest as key regulators of cell elimination through a novel adhesive landscape during epithelial remodeling.

## Key findings

- Hbs and Rst are highly expressed in cell survival zones and low in cell pruning areas.
- Local suppression of Hbs/Rst in high-expression regions causes ectopic cell elimination.
- Hbs is regulated by mechano-sensitive EGFR signaling, linking mechanical and cell property cues.

## Abstract

Cellular interactions and mechanical forces are fundamental in shaping epithelial tissue architecture. In the Drosophila notum, tissue compression at the midline promotes epithelial cell elimination. Here, we conducted a multi-step RNAi screen and identified 47 diverse regulators of notum epithelial remodeling. We find that the two cell adhesion proteins Hibris (Hbs) and Roughest (Rst) show high expression in zones of cell survival versus low levels in areas of cell pruning. Notum-wide knock-down of hbs or rst or homogenous hbs overexpression disrupts cell death patterns and results in adult tissue malformations. Local suppression of Hbs and Rst in Hbshigh/Rsthigh territories triggers ectopic cell elimination indicating that Hbs/Rst can instruct cell removal. Interestingly, Hbs but not Rst is regulated by compaction-sensitive EGFR signaling, positioning Hbs as an integrator of both mechanical and cell property cues. These findings uncover a novel adhesive landscape that shapes the thorax midline and potentially other organs.

•Multi-step screen identifies new regulators of notum epithelial remodeling•Hibris and Roughest specify an adhesive landscape required for adult notum formation•Local changes in Hibris/Roughest expression can instruct cell elimination•Hibris, but not Roughest is regulated by mechano-sensitive EGFR signaling

Multi-step screen identifies new regulators of notum epithelial remodeling

Hibris and Roughest specify an adhesive landscape required for adult notum formation

Local changes in Hibris/Roughest expression can instruct cell elimination

Hibris, but not Roughest is regulated by mechano-sensitive EGFR signaling

Biological sciences; Cell biology; Molecular biology