Expression data with mouse osteoblast cell from wild-type and retinoblastoma tumor suppressor(Rb) knock-out.. Mus musculus

Here we report the characterization of a novel role for the retinoblastoma protein (pRb) as a regulator of osteoblast adhesion. Abrogation of pRb in osteoblasts resulted in aberrant cadherin expression and loss of adherens junctions. This produced defects suggestive of a transformed phenotype such as impaired cell-to-cell adhesion, loss of contact-dependent growth arrest, and the capacity to evade anoikis. This also resulted in profound abnormalities in bone structure. Consistent with this, microarray analyses showed that pRb regulates a wide repertoire of osteoblast cell adhesion genes. In addition, pRb loss also resulted in altered expression and function of several known regulators of cellular adhesion and adherens junction assembly, such as the Rho GTPase Rac1 and the merlin tumor suppressor. Taken together, our results show that pRb controls cell adhesion by regulating the expression and adherens junction components and by regulating the function of molecules involved in adherens junction assembly and stability. Microarray results helped us to portrait the overall influence on cell adhesion via both individual genes and pathway analysis. Overall design: MC3T3 cells were obtained from immortalizing primary cultured mouse osteoblast cells by using 3T3 protocol. There are 3 biological replicates for each group, 6 samples in total were analyzed.