title: Local increases in mechanical tension shape compartment boundaries by biasing cell intercalations.
abstract: Mechanical forces play important roles during tissue organization in developing animals. Many tissues are organized into adjacent, nonmixing groups of cells termed compartments. Boundaries between compartments display a straight morphology and are associated with signaling centers that are important for tissue growth and patterning. Local increases in mechanical tension at cell junctions along compartment boundaries have recently been shown to prevent cell mixing and to maintain straight boundaries. The cellular mechanisms by which local increases in mechanical tension prevent cell mixing at compartment boundaries, however, remain poorly understood. Here, we have used live imaging and quantitative image analysis to determine cellular dynamics at and near the anteroposterior compartment boundaries of the Drosophila pupal abdominal epidermis. We show that cell mixing within compartments involves multiple cell intercalations. Frequency and orientation of cell intercalations are unchanged along the compartment boundaries; rather, an asymmetry in the shrinkage of junctions during intercalation is biased, resulting in cell rearrangements that suppress cell mixing. Simulations of tissue growth show that local increases in mechanical tension can account for this bias in junctional shrinkage. We conclude that local increases in mechanical tension maintain cell populations separate by influencing junctional rearrangements during cell intercalation.
authors: Institute of Genetics, Technische Universität Dresden, 01062 Dresden, Germany.
authors: Daiki
authors: D
authors: Umetsu
authors: Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
authors: Benoît
authors: B
authors: Aigouy
authors: Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany.
authors: Maryam
authors: M
authors: Aliee
authors: Institute of Genetics, Technische Universität Dresden, 01062 Dresden, Germany.
authors: Liyuan
authors: L
authors: Sui
authors: Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
authors: Suzanne
authors: S
authors: Eaton
authors: Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany.
authors: Frank
authors: F
authors: Jülicher
authors: Institute of Genetics, Technische Universität Dresden, 01062 Dresden, Germany. Electronic address: christian.dahmann@tu-dresden.de.
authors: Christian
authors: C
authors: Dahmann
mesh_terms: D000005:Abdomen / Q000254:growth & development; D000818:Animals; D004331:Drosophila melanogaster / Q000166:cytology* / Q000254:growth & development*; D000078404:Epidermal Cells; D004817:Epidermis / Q000254:growth & development; D007091:Image Processing, Computer-Assisted; D011679:Pupa / Q000166:cytology / Q000254:growth & development; D015398:Signal Transduction; D013314:Stress, Mechanical