Extended Data Fig. 8: Postnatal cartilage-specific Tsc1 ablation does not promote hypertrophic differentiation in the resting zone.
From: A radical switch in clonality reveals a stem cell niche in the epiphyseal growth plate
All Col2-creERT:R26R-Confetti:Tsc1 mice were injected with tamoxifen on P3 and analysed either on P28 (a, b, h) or P40 (c–g, i). The central sections of the tibial growth plates of Col2-creERT:R26R-Confetti:Tsc1fl/+ (Tsc1+/−, left) and Col2-creERT:R26R-Confetti:Tsc1fl/fl (Tsc1−/−, right) mice were imaged on P28 (a) and the clonal size of round cells above the columnar zone quantified with Imaris (b; mean ± s.e.m.; n = 3 (Tsc1−/+) and 6 (Tsc1−/−), unpaired two-tailed t-test). c, d, Haemotoxylin and eosin staining of the sections depicted in Fig. 3a, b. Arrowheads indicate typical clusters in the resting zone of Tsc1−/− mice. e–g, In situ hybridization for ColX (e) and Ihh (f), and immunostaining for Shh/Ihh (g). Insets in e and f show a magnified view of the outlined area in the resting zone, showing absence of staining. h, In situ hybridization for Gli2. i, Immunostaining for phosphorylated S6 (readout for mTORC1 activity). Typical positive cells in g–i are indicated by arrowheads. The dashed lines demarcate the growth plate. The SOC, the resting (R), proliferating (P), and hypertrophic (H) zones are labelled for orientation. Data in a, b and i derive from 2 independent experiments, whereas c–h represent one experiment with several mice stained at least twice.
