Regulation of MyoD-induced myogenesis in P19 cells.
|Title:||Regulation of MyoD-induced myogenesis in P19 cells.|
|Abstract:||MyoD is a member of the myogenic regulatory family of transcription factors which play a pivotal role in the formation of skeletal muscle. Stable expression of MyoD in the P19 embryonal carcinoma cell line leads to enhanced muscle formation only after aggregation of these cells. To study how MyoD and cell aggregation cooperate to affect muscle differentiation, a myc epitope tagged version of the protein was generated which functioned like the native MyoD protein. The production of an expression construct containing an internal ribosome entry site (IRES) was required to achieve efficient expression of mycMyoD using a drug resistance gene. With this expression construct it was determined that the level of mycMyoD protein did not increase after aggregation. Similarly no changes in cellular localization were observed as MycMyoD was located in the nucleus both before and after aggregation. There was no apparent change in dimerization partners upon aggregation as mycMyoD was found bound to E2A proteins in both the non-aggregated and aggregated cells. In a DNA binding assay mycMyoD from both cell types was able to bind to an E-box containing oligonucleotide. Thus, the effect of cell aggregation is not upon mycMyoD but rather is believed to be either at the point of DNA accessibility by mycMyoD:E2A protein heterodimers or at the stage of transcriptional activation. In vivo, these means of regulation are likely to ensure that myogenesis occurs only when proper cell contacts are achieved.|
|Collection||Thèses, 1910 - 2010 // Theses, 1910 - 2010|