Fig. 7. Ciliogenesis and Shh signalling in Ftm^-/- cells in mice. (A) Upper part: immunohistochemistry on G₀ phase (left) and proliferating (right) MLCs. (Left panels) In G₀ phase, each wild-type and Ftm^-/- cell exhibits a single cilium, detected by acetylated -tubulin antibody (green staining). Ftm (stained in red) is present only in wild-type MLCs. (Right panels) In proliferating wild-type and Ftm^-/- MLCs, cilia are absent and the cytoplasm is enriched with cytoskeletal tubulins, marked by acetylated -tubulin antibody (green staining). Note that Ftm antibodies were not used in this staining. Lower part: Shh response in G₀-phase (left) and proliferating (right) wild-type and Ftm^-/- MLCs. G₀-phase wild-type MLCs show a strong induction of Gli1 and Ptc1 after incubation with recombinant Shh protein for 24 hours. In G₀-phase Ftm^-/- MLCs, the induction of Gli1 and Ptc1 is strongly reduced. Both, proliferating (non-ciliated) wild-type and Ftm^-/- MLCs show no induction of Shh target genes after stimulation. (B) Quantification of Ptc1-expression levels in G₀-phase (left panels) and proliferating (right panels) wild-type and Ftm^-/- MLCs after Shh stimulation. The quantification of Ptc1 induction reveals that G₀-phase wild-type MLCs show an increase of Ptc1 transcripts by a factor of 9.4, whereas G₀-phase Ftm^-/- MLCs show an increase of only a factor of 3.1. Proliferating (non-ciliated) wild-type and Ftm^-/- MLCs show no changes in the relative expression levels of Ptc1 upon treatment with Shh (wild-type MLCs 1.1; Ftm^-/- MLCs 0.8). Data represent the quantification of three independent experiments. wt, wild type.