Figure 2.

Transgenic vector for Cre-mediated overexpression of tumor necrosis factor–α (TNF-α). (A) Schematic for conditional overexpression of TNF-α in the odontoblasts of transgenic mice. A transgenic mouse line designated TNF-α^glo was generated, which requires Cre-mediated recombination to overexpress TNF-α. These TNF-α^glo mice were bred with a dentin matrix protein 1 (DMP1)–Cre line for overexpression of TNF-α in both the tooth pulp and bone. (B) The transgenic vector was first tested in the MO6-G3 odontoblast cell line. The MO6-G3 cells show decreased green fluorescent protein (GFP) expression when cotransfected with Cre versus an empty vector. (C) Supernatants from MO6-G3 cells cotransfected with Cre show higher levels of TNF-α by enzyme-linked immunosorbent assay (***P < 0.001). (D) When cotransfected with Cre, MO6-G3 cells show increased active TNF-α signaling via nuclear factor (NF)–κB phosphorylation and a concomitant decrease in GFP expression. β-Actin was used as loading control. EV, empty vector.