Increased bone formation and osteosclerosis in mice overexpressing the transcription factor Fra-1 Academic Article uri icon


  • Bone formation by osteoblasts is essential for skeletal growth and remodeling. Fra-1 is a c-Fos-related protein belonging to the AP-1 family of transcription factors. Here we show that transgenic mice overexpressing Fra-1 in various organs develop a progressive increase in bone mass leading to osteosclerosis of the entire skeleton, which is due to a cell-autonomous increase in the number of mature osteoblasts. Moreover, osteoblast differentiation, but not proliferation, was enhanced and osteoclastogenesis was also elevated in vitro. These data indicate that, unlike c-Fos, which causes osteosarcomas, Fra-1 specifically enhances bone formation, which may be exploited to stimulate bone formation in pathological conditions.


  • Jochum, Wolfram
  • David, Jean-Pierre
  • Elliott, Candace
  • Wutz, Anton
  • Plenk, Hanns
  • Matsuo, Koichi
  • Wagner, Erwin F

publication date

  • September 2000