Mojica, Jorge Ricardo2013-11-072013-11-0720082008Source: Masters Abstracts International, Volume: 47-05, page: 2710.http://hdl.handle.net/10393/27717http://dx.doi.org/10.20381/ruor-12220C2C12 murine progenitors are a model for transdifferentiation. This project investigated signaling events that regulate this process in culture by monitoring specific markers for transdifferentiation (alkaline phosphatase [ALP] and myogenin for the osteoblastic and myoblaststic fates respectively) in the presence of inducers and inhibitors. Antibodies specific for proteins implicated in signaling were used to monitor the differentiation process. BMP-2 addition caused transdifferentiation to the osteoblastic fate except for a small fraction of cells that may represent the so-called MyoD negative cells or the side population (SP). The timing of short term commitment of C2C12 to osteoblastic transdifferentiation was between 6 to 24h under our culture conditions. BMP-2-induced ALP activity increase and the repression of myogenin expression were not simultaneous. Differentiation as measured by ALP activity may be dependent on the interaction of BMP-2/Smad, p38 MAPK and TGF-beta1 pathways. Smads 1, 5 and/or 8 were almost always found under their phosphorylated form (pSmads) and thus almost invariably located in nuclei suggesting fast nucleoplasmic shuttling from the cytoplasm and nuclear retention of the phosphorylated forms. Phosphorylated forms were also found in the nucleus under proliferative conditions without exogenous BMP-2. In this case, it is suggested that this phosphorylation of Smads may be triggered by the reported autocrine secretion of TGF-beta by the C2C12 cells or by the TGF-beta present in the culture serum.140 p.enBiology, Cell.Thesis