Identification of novel multicomponent protein complexes of the critical transcription factors Steroidogenic factor 1 and Liver Receptor Homolog 1 essential to embryonic stem cells and induced pluripotent stem cells

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Transcriptional regulation of the cellular gene expression plays an important role in both sickness and health. Most molecular events in controlling gene expression and cell programming require transient multi protein complexes that act in response to different physiological signals to interpret enhancers and promoters found in the DNA. Much progress is made in structure and function analyses of individual components of theses machines, but few detailed mechanisms are known for multi-component assemblies. I propose to work on this problem but limit the scope of research by focusing on the essential transcription factors Steroidogenic factor 1 (SF-1) and Liver Receptor Homolog 1 (LRH-1) and their co-regulators, which are critical to embryonic stem (ES) cells and to induced pluripotent stem (iPS) cells. The possibility to achieve stable transcriptional protein assemblies in vitro in the presence of appropriate DNA molecules or by the incorporation of posttranslational modifications (PTMs) will be evaluated with these transcription factors. The stability of full-length SF-1 and LRH-1 in the presence of optimized DNA fragments and co-regulating proteins is expected to improve and thus to gain access to structural studies. The introduction of PTMs can further increase protein stability and might help to identify novel protein binding partners. The remarkable advantage of the chosen semi-synthetic strategy to incorporate PTMs into proteins lies in the generation of homogeneously modified proteins that will allow crystallographic studies. The investigation of the resulting stabilized protein assemblies will provide necessary information for understanding the SF-1 and LRH-1 structure-function relationship and how one could design and use specific modulators to tune aberrant activities which underlie endocrine metabolic diseases and cancer.