Nuclear receptors function as DNA-bound ligand-inducible transcription factors that influence differentiation, proliferation, and development via regulation of target genes. A number of co-regulators (or: "mediators", "adaptors", "transcription intermediary factors (TlFs)") have been recently identified in the host institute and other laboratories which form complexes with nuclear receptors in a ligand dependent manner and are required for transmission of the pleiotropic signals to the basal transcription machinery and chromatin. However, the identity of complexes comprising nuclear receptors and cGregulators and their modes of action are yet unknown.
My goal is to (i) in vitro reassemble such complexes on biotinylated DNA using purified proteins and/or different nuclear extracts; (ii) characterise these complexes by using receptor mutants, artificial ligands and other means; (iii) test their activity in in vitro transcription assays using immobilised target promoters as templates; and (iv) analyse the effect of in vitro assembled chromatin on transcription from such promoters.
This study will allow us to understand the functioning of nuclear receptor co-regulator complexes in transcription, and to unravel the discrepancies between transcriptional regulation in vitro and in vivo.