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. 2016 Apr 12;7:11277. doi: 10.1038/ncomms11277

Figure 4. Tooth root formation requires PPR in osterix-lineage cells.

Figure 4

(a–f) Mandibular first molar (M1) sections of (a,d) Control (PPRfl/+fl/fl), (b,e) Osx-PPR conditional Het (Osx-cre; PPRfl/+) and (c,f) Osx-PPR conditional KO (Osx-cre; PPRfl/fl) mice at P3 (a–c) and P7 (d–f) were stained for hematoxylin and eosin. Lower panels: magnified views of the dotted areas. Asterisks: dental follicle, sharp: malformed crown on the mesial portion. Am: ameloblasts, arrowheads: dental papilla and follicle cells around HERS. Scale bars: 500 μm (upper panels) and 50 μm (lower panels). (g–i) Sections of (g) Control, (h) Osx-PPR conditional Het and (i) Osx-PPR conditional KO molars at P7 were stained for nuclei, EdU and Osx-GFP. EdU was administered twice (6 and 3 h) prior to analysis. Green: GFP-Alexa488, red: EdU-Alexa555, grey: DAPI. Yellow dotted lines: HERS, blue arrowheads: GFP+EdU+ dental follicle cells. Scale bars: 50 μm. (j–l) Stereoscopic images of (j) Control, (k) Osx-PPR conditional Het and (l) Osx-PPR conditional KO molars at P18 are shown. Red arrowheads: crowns of M1 and M2. Scale bars: 1 mm. (m–o) M1 sections of (m) Control, (n) Osx-PPR conditional Het and (o) Osx-PPR conditional KO molars at P18 were stained for hematoxylin and eosin. Lower panels: magnified views of the dotted areas. Arrows: irregular cementum, arrowheads: ankylosis of cementum to bone. Scale bars: 500 μm (upper panels) and 50 μm (lower panels). (p,q) Shown is quantification of EdU+ cells in dental papilla (p) and dental follicle (q) around HERS at P7. Blue bars: Control, green bars: Osx-PPR conditional Het, red bars: Osx-PPR conditional KO, n=5 per group, *P<0.05, Mann–Whitney's U-test. (r) Shown is quantification of M1 distal root length at P18. Blue bars: Control, green bars: Osx-PPR conditional Het, red bars: Osx-PPR conditional KO. n=4 per group, *P<0.05, Mann–Whitney's U-test All data are represented as mean±s.d.