Extended Data Figure 8: smFISH analysis of FGF target-gene regulation.
From: Luminal signalling links cell communication to tissue architecture during organogenesis
a, Pea3 smFISH on WT, 15 μM FGF inducer- and 4 μM FGF inhibitor-treated primordia (cldnb:lynGFP in green, DAPI staining in blue, pea3 mRNAs in white), Scale bar, 5 μm. Close-up view of the dashed boxes shown as raw image (middle) and segmented pea3 transcripts (right). Scale bar, 2 μm. b, Image of pea3 smFISH in WT primordium (above); profile plot shows pea3 transcripts per cell over distance from leading edge (below). c, Pea3 smFISH in an organ with single Fgf3–GFP-expressing cell. Number of pea3 transcripts assigned to each nucleus does not show increase towards the expressing cell. Scale bar, 5 μm. d, Colorimetric in situ hybridization of pea3 mRNA showing high expression levels upon Fgf3–GFP induction, visible after 1 h colour reaction (30 °C), whereas expression in WT is hardly detectable. However, increasing reaction time reveals pea3 mRNA signal in WT primordia. e, Colorimetric in situ hybridization (30 °C, 0.5 h) of pea3 RNA in mosaic Fgf3–GFP expression shows detectable pea3 only in the expressing organ. Scale bar, 100 µm.
