The embryonic node functions as an instructive stem cell niche (scRNA-seq)

During development, the amniote organizer, Hensen's node, contributes cells to the developing axis in head-to-tail direction. However, some cells remain resident in the node and it has been suggested that these resident cells are stem cells. This study aimed to characterise single resident cells and their environment within the node. Using the chick as an amniote model, we generated transcriptomes of single resident cells (scRNA-seq of GFP cells that remained resident till stage-HH8 following a GFP-donor homotopic transplant into a non-GFP host) and of six node sub-regions (bulk RNA-seq of GFP-transgenic stage-HH8 node, but otherwise un-manipulated embryos). We also obtained transcriptomes of single cells with resident behaviour that would normally never enter the node, but were made to do so (scRNA-seq of cells that remained resident till HH8 following a GFP-donor heterotopic/heterochronic transplant into a non-GFP host).