RT Journal Article
SR Electronic
T1 Emergence and patterning dynamics of mouse definitive endoderm
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 728642
DO 10.1101/728642
A1 Pour, Maayan
A1 Kumar, Abhishek Sampath
A1 Walther, Maria
A1 Wittler, Lars
A1 Meissner, Alexander
A1 Nachman, Iftach
YR 2019
UL http://biorxiv.org/content/early/2019/08/07/728642.abstract
AB The segregation of definitive endoderm (DE) from mesendoderm progenitors leads to the formation of two distinct germ layers. Dissecting DE onset has been challenging as it occurs within a narrow spatio-temporal window in the embryo. Here we employ a dual Bra-GFP, Sox17-RFP reporter cell line to study DE onset dynamics. We find Sox17 starts in a few isolated cells in vivo. Using 2D and 3D in vitro models, we show that DE cells emerge from mesendoderm progenitors at a temporally regular, but spatially stochastic pattern, which is subsequently arranged by self-sorting of Sox17+ cells. Self-sorting coincides with up-regulation of E-cadherin but is not necessary for DE differentiation or proliferation. A subpopulation of Bra-high cells commits to a Sox17+ fate independent of external Wnt signal. Our in vivo and in vitro results highlight basic rules governing DE onset and patterning through the commonalities and differences between these systems.