René St-Arnaud

Genetics Unit, Shriners Hospital, and Departments of Surgery and Human Genetics, McGill University, Montréal (Québec) Canada H3G 1A6

PREFACE

Bone development requires a complex series of events involving three cell types: the chondrocytes, which form cartilage; the osteoblasts, or bone-forming cells; and the osteoclasts, the bone-resorbing cells. The functions of the skeleton, which include a structural role to support weight and muscles, and an endocrine role as a reservoir for minerals, require interactive cellular activity regulated by a variety of biochemical and mechanical factors. There has been tremendous progress in our understanding of the molecular determinants of bone cell differentiation and function.

This special issue of Frontiers in Bioscience explores some of the recent molecular mechanisms that have been unraveled, starting at the cellular surface with articles describing integrin receptors, G-protein-coupled receptors, fibroblast growth factors (FGF) receptors, and the receptor of Parathyroid Hormone related Peptide (PTHrP). Downstream signaling is described in a text reviewing Mitogen Activated Protein (MAP) kinases. As expected, the signals converge on the nucleus and transcriptional regulation is covered in depth with articles reviewing the role of several classes of transcriptional regulatory molecules, including the vitamin D receptor (VDR), the Core binding factor alpha 1 (Cbfa1), and transcriptional coactivators. As the nucleus is not an inert cellular organelle, the role of the nuclear matrix in the control of gene expression in bone cells is reviewed.

The articles are very up-to-date and the innovative platform provided by the journal will allow the authors, which are experts in their respective fields, to update their manuscripts when advancement on their topic warrants revision. Thus, the reader can turn to Frontiers in Bioscience to find the latest developments on signal transduction in bone cells.