Figure 1.

Schematic representation of osteoblasticlineage commitment and differentiationfrom mesenchymal progenitors andthe models developed ingenetically engineered murine models.A) Normal osteoblast development from mesenchymal stem cells. Genes associated with the commitment and differentiation of osteoblasts are listed along with an approximation of the developmental state of the osteoblastic cells. B) Using the differentiation schematic, the different Cre lines that have been described are in bold with an approximation of the putative cells expressing the Cre. The alleles that are disrupted (loss of function for p53 and pRb; over-expression for SV40TAg) are shown on the arrows. Other tumour types associated with the different models are also highlighted. For further information on these alleles see Table 2.