Fig. 2.

SOX2⁺ progenitors have limited potential to generate TRC-replete organoids. (A) Procedure to generate organoids from CVP progenitors from Lgr5^EGFP or Sox2^GFP mice. See Materials and Methods for details. (B) Type I (Entpd2 and Kcnj1), II (Gnat3 and Pou2f3) and III (Car4 and Pkd2l1) TRC marker gene expression is significantly lower in SOX2- versus LGR5 organoids. (C,D) Most LGR5 organoids contain type I (NTPDase2⁺, green), II (gustducin⁺, green) and III (CAR4, green) TRCs, but most SOX2 organoids do not. Most TRCs in SOX2 organoids lack conventional taste cell morphology (yellow arrows). Images are maximum projections of confocal z-stacks of whole organoids. In D, n values (in brackets) indicate organoid number analyzed per condition from three independently derived organoid experiments. (E) LGR5 organoids have higher Kcnq1 (TRC marker) and Krt14 (progenitor marker) levels but similar Krt13 (non-taste epithelium marker) levels compared with SOX2 organoids. (F) In LGR5 organoids, KRT14⁺ cells (green) are basal/external and KRT8⁺ TRCs (magenta) (yellow dashed outline) are internal and surrounded by KRT13⁺ non-taste cells (cyan). (G) SOX2 organoids contain mostly KRT13⁺ cells (cyan); KRT8 (magenta) and KRT14 (green) are often co-expressed. Images are optical sections of immunostained organoids. DAPI nuclear counterstain is blue in C and white in F,G. Scale bars: 100 µm in C; 50 µm in F,G. Data are mean±s.e.m., *P<0.05, **P<0.01, ***P<0.001 (two-way ANOVA).