10027/20045 EX Du EX Du XF Wang XF Wang WC Yang WC Yang D. Kaback D. Kaback SP Yee SP Yee CL Qin CL Qin A. George A. George JJ Hao JJ Hao Characterization of Fam20C expression in odontogenesis and osteogenesis using transgenic mice. University of Illinois at Chicago 2016 Fam20C green fluorescence protein green fluorescence protein report mouse promoter 2016-01-25 00:00:00 Journal contribution https://indigo.uic.edu/articles/journal_contribution/Characterization_of_Fam20C_expression_in_odontogenesis_and_osteogenesis_using_transgenic_mice_/10763345 Our previous studies have demonstrated that Fam20C promotes differentiation and mineralization of odontoblasts, ameloblasts, osteoblasts and osteocytes during tooth and bone development. Ablation of the Fam20C gene inhibits bone and tooth growth by increasing fibroblast growth factor 23 in serum and causing hypophosphatemia in conditional knockout mice. However, control and regulation of the expression of Fam20C are still unknown. In this study, we generated a transgenic reporter model which expresses green fluorescence protein (GFP) driven by the Fam20C promoter. Recombineering was used to insert a 16 kb fragment of the mouse Fam20C gene (containing the 15 kb promoter and 1.1 kb of exon 1) into a pBluescript SK vector with the topaz variant of GFP and a bovine growth hormone polyadenylation sequence. GFP expression was subsequently evaluated by histomorphometry on cryosections from E14 to adult mice. Fluorescence was evident in the bone and teeth as early as E17.5. The GFP signal was maintained stably in odontoblasts and osteoblasts until 4 weeks after birth. The expression of GFP was significantly reduced in teeth, alveolar bone and muscle by 8 weeks of age. We also observed colocalization of the GFP signal with the Fam20C antibody in postnatal 1- and 7-day-old animals. Successful generation of Fam20C-GFP transgenic mice will provide a unique model for studying Fam20C gene expression and the biological function of this gene during odontogenesis and osteogenesis.