Section on Growth and Development
Jeff Baron, Section Head
Our group has continued to investigate the cellular and molecular mechanisms governing longitudinal bone growth in childhood. This process, which occurs at the growth plate, requires chondrocytes to undergo a two-step differentiation program – from stem-like cells in the resting zone into the rapidly dividing chondrocytes of the proliferative zone and then into the terminally differentiated chondrocytes of the hypertrophic zone. This section developed a novel technique that allows quantitative assessment of gene expression within individual zones of the growth plate. This approach, combined with functional studies, has provided evidence that a bone morphogenetic signaling gradient across the growth plate provides a key mechanism responsible for chondrocyte differentiation. Analogous studies have provided insight into the roles of fibroblast growth factor and insulin-like growth factor signaling in the spatial and temporal regulation of growth plate chondrogenesis.