Osterix (Osx) is essential for both intramembranous or endochondral bone formation. Osteoblast-specific ablation of Osx using Col1α1-Cre resulted in osteopenia, because of impaired osteoblast differentiation in adult mice. Since Osx is also known to be expressed in chondrocytes, we evaluated the role of Osx expressed in chondrocytes by examining the skeletal phenotype of mice with conditional d...

INTRODUCTION: Insight into elucidating the transcriptional regulatory mechanisms underlying the successive events that mediate endochondral ossification is important in understanding possible mechanism of disease as well as cures to severe diseases ranging from skeletal dysplasia to fracture nonunion. The zinc finger-containing transcription factor Osterix (Osx) was demonstrated to be a key med...

We have identified a novel zinc finger-containing transcription factor, called Osterix (Osx), that is specifically expressed in all developing bones. In Osx null mice, no bone formation occurs. In endochondral skeletal elements of Osx null mice, mesenchymal cells, together with osteoclasts and blood vessels, invade the mineralized cartilage matrix. However, the mesenchymal cells do not deposit ...

K7M2 mouse osteosarcoma cells form lytic tumors and are deficient in osterix (Osx), a zinc finger-containing transcription factor required for osteoblast differentiation and bone formation. Our previous studies showed that replacement of Osx suppresses lytic bone destruction. Cytokines, including interleukin (IL)-1alpha, IL-6, IL-11, and prostaglandin E2, have been shown to stimulate osteoclast...

Tumor necrosis factor α (TNF-α) promotes bone loss and inhibits bone formation. Osterix (Osx, SP7) is a transcription factor required for osteoblast (OB) differentiation because deletion results in a cartilaginous skeleton. We previously described a TNF suppressor element in the Osx promoter that was used to isolate nuclear proteins mediating TNF inhibition of OB differentiation. Nuclear extrac...

Osterix (Osx), a transcriptional factor essential for osteogenesis, is also critical for in vivo cellular cementum formation. However, the molecular mechanism by which Osx regulates cementoblasts is largely unknown. In this study, we initially demonstrated that overexpression of Osx in a cementoblast cell line upregulated the expression of markers vital to cementogenesis such as osteopontin (OP...

Mouse genetic studies reveal that ascorbic acid (AA) is essential for osteoblast (OB) differentiation and that osterix (Osx) was a key downstream target of AA action in OBs. To determine the molecular pathways for AA regulation of Osx expression, we evaluated if AA regulates Osx expression by regulating production and/or actions of local growth factors and extracellular matrix (ECM) proteins. I...

Bone formation is a complex developmental process involving the differentiation of mesenchymal stem cells to osteoblasts. Osteoblast differentiation occurs through a multi-step molecular pathway regulated by different transcription factors and signaling proteins. Osx (also known as Sp7) is the only osteoblast-specific transcriptional factor identified so far which is required for osteoblast dif...

Both β-catenin (β-cat) and osterix (OSX) are known to be essential for embryonic and postnatal osteoblast differentiation and bone growth. In the present study, we explored the crosstalk between β-cat signaling and OSX, and assessed its effect on the osteoblastogenic differentiation of human pre-osteoblastic cells (MG-63) and bone marrow stromal cells (HS-27A). In the HS-27A and MG-63 cells, th...

The transcription factor Osterix (Osx) is required for osteoblast differentiation and bone formation during embryonic development, but it is not known whether Osx has an essential function in postnatal bone growth and in bone homeostasis. Conditional deletion of Osx at several time points postnatally revealed that Osx was essential for osteoblast differentiation and new bone formation in growin...