Fig 1: Bmp2 gene deletion in Sp7+ (Osterix+) cells leads to disorganized periodontal ligaments, decreased periostin and Nfic expression, and decrease VegfA expression in the periodontium and root odontoblasts region. (a, b) van Gieson stain for collagen bundles and fibers of control and Bmp2-cKOSp7-Cre-EGFP periodontium region, respectively, at ×400. The yellow line denotes the width of the periodontium. Black arrows, bundles of periodontal ligament collagen type 1-rich fibers in the periodontium, with disorganized Sharpey's fibers in the Bmp2-cKOSp7-Cre-EGFP mice. (c, d) Picrosirius Red stain for collagen shows highly disorganized Sharpey's fibers (white arrows) in the Bmp2-cKOSp7-Cre-EGFPmice (d), compared to the control (c) at ×200. (e, f) In situ hybridization of periostin at ×200. (g, h) Immunohistochemistry of periostin in control and Bmp2-cKOSp7Cre-EGFP of PDL at ×100. a–h are from 1.5-month-old mice. (i, j) Immunohistochemistry of Nfic in control and Bmp2-cKOSp7Cre-EGFP of the second molars at ×200. (k, l) Immunohistochemistry of VEGF-A in control and Bmp2-cKOSp7Cre-EGFP of the second molars at ×200. i–l are from 1-month-old mice, the second molars. Blue arrow points to periodontium and purple arrow points to root odontoblasts. Bmp2, bone morphogenetic protein-2; Nfic, nuclear factor IC; VEGF, vascular endothelial growth factor A.