CHARACTERIZATION OF NUCLEAR RECEPTOR-DNA INTERACTIONS ON THEIR NATIVE PROMOTERS

Abstract

Nuclear receptors are a class of proteins that are responsible for sensing metabolic and systemic hormonal signals. They regulate transcription of genes that control various cellular processes such as cell proliferation, growth, differentiation and metabolism. This work focuses on nuclear receptors namely the vitamin D (VDR), pregnane X (PXR), and the constitutive androstane receptors (CAR), which are grouped in the same family based on their domain architecture and sequence conservation. In this project, the interaction of DNA-binding domain of these receptor domains with DR3- and DR4-type response elements located in the promoters of CYP24A1, CYP3A4, CYP2B6 genes has been studied with the main aim to understand and characterize the interaction of these complexes and identify the structural determinants for their recognition and interaction. The obtained results are important for understanding the crosstalk between these three receptors in cellular signalling with application for the mechanisms of drug-drug interactions linked to gene regulation. Several approaches have been applied to achieve the goal of this work, including in silico methods such as homology modelling and molecular dynamics simulation. Results of the molecular dynamics studies suggest that VDR, PXR and CAR mostly prefer to bind DR4 elements, although they can also form quite stable complexes with DR3 elements. Further studies using the full-length receptors are needed to fully understand their interaction. Additionally, in vitro experiments will help to confirm the results obtained in silico.