| The Src associated substrate in mitosis of 68kDa (Sam68) is a KH-type RNA binding protein that has been shown to regulate several aspects of RNA metabolism, but the physiological role of this RNA binding protein has been unknown. The primary goal of the work presented in this thesis is to characterize the phenotype of Sam68 deficient mice. Since mesenchymal stem cells (MSCs) can give rise to adipocytes and osteoblasts, we explored the differentiation capacity of MSCs. First we showed that these mice are protected from age related bone loss due to enhanced osteoblast formation. Adipogenesis is defective in mouse embryo fibroblasts generated from Sam68-/- mice. Also, Sam68-/- mice show lower body and adipose tissue weights. These mice are protected against dietary obesity and diabetes owing to deregulation in lipid metabolism associated with adipogenesis defects. Taken together, the work presented here suggests a novel role for Sam68 as a positive adipocyte and a negative osteoblast differentiation factor. |
