Extended Data Fig. 9: Medially localised ALDH1A2 expression in somites is established by non-canonical Wnt signalling.

(a) Imaris-rendered surfaces showing regions of ALDH1A2 (purple) and UNCX (blue) expression by HCR within somites, relative to the position of the neural tube (pink), for both hTLS (left) and axioloid (right) structures made from ZO-1::mEGFP cells. A, anterior; P, posterior; M, medial; L, lateral. (b–e) Projected HCR images of whole mount 120 h and 144 h hTLS structures exposed to Wnt signalling inhibition. Scale bars, 100 μm (n = 5-8 per condition). (f) FACS gating strategy for single-cell sorting for the derivation of monoclonal transgenic cell lines, shown for FCI-GM25256. First, cells were gated based on size and granularity (SSC-A vs. FSC-A). From this population, singlets were identified using FSC-H vs. FSC-A. Finally, Cherry-positive cells were selected for sorting (gate P3). One Cherry-positive cell per well was sorted to establish monoclonal cell lines.