BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Monthly Morphogenesis club talks - Sarah Robinson and Arnaud Ambro
 sini
DTSTART:20190730T120000Z
DTEND:20190730T130000Z
UID:TALK128419@talks.cam.ac.uk
CONTACT:Matt Benton
DESCRIPTION:Speaker 1: Sarah Robinson (Group leader\, Sainsbury Laboratory
 )\nTitle: Visualising hypocotyl elongation in response to stress-induced m
 icrotubule reorientation\nAbstract:\nMorphogenesis in plants is controlled
  by the spatial pattern of the mechanical properties across the tissue. Du
 ring growth\, internal mechanical stresses can develop and also serve as a
 n important determinant of plant development. To investigate the mechanica
 l properties and responses to mechanical stress in the developing tissues 
 of the model plant Arabidopsis we developed an automated confocal micro-ex
 tensometer (ACME). ACME enables forces to be applied to tissues\, while th
 ey are imaged with a confocal microscope. These images were analysed to ex
 tract 3D cellular strain measurements\; revealing spatial gradients in mec
 hanical properties that correlate with the pattern of growth. We also used
  ACME to investigate responses to mechanical stress. We imaged the cytoske
 leton in the different layers of the hypocotyl while mechanical stress was
  applied. The results were analysed by building a finite element model. We
  saw that when a relative compressive force was applied the pattern of tis
 sue stress changed\, leading to a reorientation of the microtubules in the
  epidermis but not the inner layers. As the epidermis usually restricts gr
 owth\, this reorientation led to growth increasing in these samples. This 
 may mimic the response of a seedling whose growth is restricted as it push
 es through the soil and responds with an increase in growth. \n\nSpeaker 2
 : Arnaud Ambrosini (postdoc soon joining Roepjer lab)\nTitle: Mechanical r
 ole of the nucleus during orthogonal force production within epithelium\nA
 bstract:\nMechanical forces are critical regulators of cell shape changes 
 and developmental morphogenetic processes. Forces generated along the epit
 helium apico-basal cell axis have recently emerged as essential for tissue
  remodeling in three dimensions. Yet the cellular machinery underlying tho
 se orthogonal forces remains poorly described. We found that during Drosop
 hila leg folding cells eventually committed to die produce apico-basal for
 ces through the formation of a dynamic actomyosin contractile tether conne
 cting the apical surface to a basally relocalized nucleus. We show that th
 e nucleus is anchored to basal adhesions by a basal F-actin network and co
 nstitutes an essential component of the force-producing machinery. Finally
 \, we demonstrate force transmission to the apical surface and the basal n
 ucleus by laser ablation. Thus\, this work reveals that the nucleus\, in a
 ddition to its role in genome protection\, actively participates in mechan
 ical force production and connects the contractile actomyosin cytoskeleton
  to basal adhesions. \n
LOCATION:Hodgkin Huxley Room\, Physiology Building\, Downing Site
END:VEVENT
END:VCALENDAR