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SUMMARY:Shaping the fly wing - Dr Marko Popovic\, Max Planck Institute for
  the Physics of Complex Systems\, Dresden 
DTSTART:20161124T130000Z
DTEND:20161124T140000Z
UID:TALK69220@talks.cam.ac.uk
CONTACT:Guy Blanchard
DESCRIPTION:The fruit fly wing develops from an epithelium called the imag
 inal disc\, which grows continuously during fly larval development. At the
  start of the pupal development phase it everts and forms a double layered
  pupal wing. Large scale tissue flows reshape the pupal wing over ~16 hour
 s of pupal morphogenesis. How do cellular processes and mechanical stresse
 s lead to the proper reshaping of the wing and how does a shape defect ari
 se in a dumpy mutant wing?\n	We observe the dorsal wing layer during pupal
  morphogenesis in vivo. Imaging the tissue at cellular resolution allows u
 s to track individual cells in time and space and to identify different ce
 llular processes: cell division\, cell extrusion and T1 transitions. We ca
 lculate the contributions of these cellular processes to the overall tissu
 e shape changes using the Triangle Method. Furthermore\, we develop a hydr
 odynamic 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.\, https://arxiv.org/a
 bs/1607.03304].\n	We find that at the early times of pupal morphogenesis b
 lade cells elongate more than the blade tissue itself due to active T1 tra
 nsitions acting to increase the cell elongation. In the context of the hyd
 rodynamic theory we describe the shear flow contribution from the T1 trans
 itions as a linear function of cell elongation with an exponential memory 
 kernel. These memory effects produce a tissue rheology that differs from t
 he standard Maxwell viscoelastic material by an effective inertial element
  and can lead to damped oscillations in the tissue. Finally\, we construct
  a simple model of the pupal wing morphogenesis and we find that the missh
 aped dumpy mutant wing can be understood as the wild type wing tissue with
  compromised boundary attachments to the surrounding cuticle.
LOCATION:Bryan Matthews seminar room\, Physiology Dept.\, Downing site.
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