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SUMMARY:Modeling embryonic patterning with human embryonic stem cell colon
 ies - Eric Siggia\, Rockefeller University
DTSTART:20150603T131500Z
DTEND:20150603T141500Z
UID:TALK58740@talks.cam.ac.uk
CONTACT:Lucy Colwell
DESCRIPTION:Embryos allocate cells to the three germ layers in a spatially
  ordered sequence. Human embryonic stem cells (hESCs)\ncan generate the th
 ree germ layers in culture\; however\, differentiation is typically hetero
 geneous and spatially disordered. We show that geometric confinement is su
 fficient to trigger self-organized patterning in hESCs. \n\nIn response to
  BMP4\, colonies reproducibly differentiated to an outer trophectoderm-lik
 e ring\, an inner ectodermal circle and a ring of mesendoderm expressing p
 rimitive-streak markers in between. Fates were defined relative to the bou
 ndary with a fixed length scale: small colonies corresponded to the outer 
 layers of larger ones. Inhibitory signals limited the range of BMP4 signal
 ing to the colony edge and induced a gradient of Activin-nodal signaling t
 hat patterned mesendodermal fates. These results demonstrate that the intr
 insic tendency of stem cells to make patterns can be harnessed by controll
 ing colony geometries and provide a quantitative assay for studying paracr
 ine signaling in early development.
LOCATION:Todd Hamied Room\, Dept. of Chemistry
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