Dresden 2017 – scientific programme
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BP: Fachverband Biologische Physik
BP 59: Multi-Cellular-Systems
BP 59.4: Talk
Friday, March 24, 2017, 10:30–10:45, HÜL 386
Active T1 transitions in the developing wing imaginal disc — •Marko Popovic1, Natalie Dye2, Guillaume Salbreux3, Suzanne Eaton2, and Frank Julicher1 — 1Max Planck Institute for Physics of Complex Systems — 2Max Planck Institute of Molecular Cell Biology and Genetics — 3Francis Crick Institute
The adult wing of the fruit fly develops from a precursor tissue called imaginal disk. We study the wing pouch region of the wing imaginal disk, a single layer epithelium from which the adult wing blade forms. Observing the two-dimensional network of cells in the wing pouch projected on a plane reveals a radially symmetric pattern of elongated cell shapes. Peripheral cells have larger apical area and are more elongated tangentially than central ones. How does this cell shape pattern emerge and how is it related to mechanical forces in the tissue?
We study this process in third instar larval wing disks growing in culture over 13 hours. We track individual cells in time and space and identify different cellular processes: divisions, extrusions and neighbor exchanges. We calculate contributions of these cellular processes to the tissue shape changes. We use a hydrodynamic theory to relate tissue stresses to tissue deformations and cell shape changes [Etournay et al. eLife e07090; Etournay et al. eLife e14334; Merkel et al., arXiv:1607.00357; Popovic et al., arXiv:1607.03304].
We find that the tangential elongation of cell shapes increases over time in the cultured discs. We further find that active radially oriented T1 transitions contribute to tissue shape change. We solve the hydrodynamic equations for a radially symmetric tissue to investigate how active T1 transitions can influence mechanical stresses in the tissue.