Mechanisms of lineage restriction in development and reprogramming. (360G-Wellcome-212253_Z_18_Z)

Mechanisms that lead to the establishment and maintenance of cell identity are paramount for organismal health. They also underpin successful cellular reprogramming for disease modelling and cell replacement therapies. We will investigate the roles played by the epigenome and co-factors in regulating lineage transcription factor-mediated establishment and stabilisation of cell fate in vivo and in vitro. Firstly, controlled activation and degradation of engineered transcription factors (TFs) will be used to challenge cell identity in developing frog embryos. We will compare transcriptional profiles and chromatin landscape in "permissive" tissues that respond to TF over-expression by undergoing full lineage reprogramming, and "non-permissive" tissues that resist reprogramming, as well as probing heterogeneity of transcriptional response in individual cells. Secondly, mechanisms responsible for differential response to TF will be identified through interference with the epigenome as well as via alteration of the co-factors repertoire present in embryonic tissue. Finally, we will explore mechanisms underlying lineage fidelity in mammalian ES cells that have been engineered to co-express TFs specifying conflicting lineages. Overall, this work will reveal how the response to lineage determining TFs is controlled by integration of epigenetic features and co-factor availability in both the developing embryo and in reprogrammed mammalian cells.