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The Sox2 high mobility group transcription factor inhibits mature osteoblast function in transgenic mice

Greg Holmes1, Timothy G Bromage, Claudio Basilico

  • 1Department of Microbiology, New York University School of Medicine, 550 1st Ave, New York, NY 10016, USA.

Bone
|June 28, 2011
PubMed

Insights

Sox2 acts as a negative regulator of osteoblast maturation. Overexpressing Sox2 in bone disrupts bone development, leading to porous, undermineralized bone and altered gene expression in osteoblasts.

Area of Science:

  • Bone Biology
  • Developmental Biology
  • Genetics

Background:

  • Sox2 is induced by Fgfs in osteoblasts, inhibiting Wnt signaling and differentiation.
  • Conditional deletion of Sox2 in osteoblasts leads to osteopenia and senescence.
  • Understanding Sox2's role in osteoblast development is crucial for bone health.

Purpose of the Study:

  • To investigate the in vivo role of Sox2 in osteoblast maturation.
  • To examine the effects of Sox2 overexpression in bone using a Col1α1 promoter.

Main Methods:

  • Generation of transgenic mice with Sox2 overexpression driven by the Col1α1 promoter.
  • Analysis of long bone and calvarial bone phenotypes.
  • Microarray analysis to assess gene expression changes in osteoblasts.

Main Results:

  • Overexpression of Sox2 delayed trabecular cartilage remodeling and disrupted the endochondral to cortical bone transition.
  • Resulting cortical bone was porous and undermineralized, with disorganized collagen deposition and altered osteoclast activity.
  • Calvarial bones were thinner, and parietal bones lacked diploic space; microarray revealed downregulation of mature osteoblast genes.

Conclusions:

  • Sox2 functions as a negative regulator of osteoblast maturation in vivo.
  • Altered Sox2 levels significantly impact bone structure, mineralization, and extracellular matrix gene expression.

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