Fig. 1: CXCL12+ cells emerge in the hypoxic apical papilla at the onset of tooth root formation.
From: Wnt-directed CXCL12-expressing apical papilla progenitor cells drive tooth root formation
a–c HIF1α expression. Mandibular first molar (M1) sections at P0 (a) and P6 (b). a’, b’ High magnification. Yellow: HIF1α, gray: DIC/DAPI. c Quantification of HIF1α expression (mean intensity) from P0 to P15, n = 3 mice each time point. d–h Cxcl12-GFP expression. M1 sections of Cxcl12GFP/+ mandibles at P0 (d), P3 (e), P6 (f, g). Green: Cxcl12-GFP, cyan: E11, gray: DIC/DAPI. (h): Quantification of Cxcl12-GFP+ DP cells from P0 to P25, n = 3 mice each time point. i–n Short chase analysis of Cxcl12-creER+ cells. i M1 sections of Cxcl12GFP/+; Cxcl12-creER; R26RtdTomato mandibles at P5 (pulsed at P3). i’ High magnification of distal M1. j Flow cytometry analysis of P5 CD45neg tooth bud cells isolated from Cxcl12GFP/+; Cxcl12-creER; R26RtdTomato mice (pulsed at P3). k M1 sections of Gli1GFP/+; Cxcl12-creER; R26RtdTomato mandibles at P5 (pulsed at P3). l–n Immunostaining for CK5 (l), PDGFRα (m), SOX9 (n) in distal M1 of Cxcl12-creER; R26RtdTomato at P5 (pulsed at P3). Green: Cxcl12-GFP (i), Gli1-GFP (k), red: Cxcl12CE-tdT, cyan: CK5/PDGFRα/SOX9, gray: DIC/DAPI. o Cell proliferation. EdU was administered twice (6 and 3 h) to Cxcl12-creER; R26RtdTomato mice (pulsed at P3) before analysis at P8. Arrowheads: EdU+Cxcl12CE-tdT+ AP cells. Scale bar: 500 μm (a, b, d, e, f, i, k, o), 50 μm (d’, e’, f’, i’, k’, l, m, n, o’), 20 μm (a’, b’, g). M1: mandibular first molar, DP: dental papilla, DF: dental follicle, HERS: Hertwig’s epithelial root sheath. All data are mean ± SD. Representative images of at least three independent biological samples are shown in the figures. Source data are provided as a Source Data file.
