Structure and function of enzyme complexes involved in post-transcriptional gene regulation

Many proteins in human cells function as part of high molecular weight multi-subunit assemblies. The structure and function of such large molecular machines is often difficult to characterise due to their complexity, low abundance and structural dynamics. Many of these problems can be addressed by using cryo-electron microscopy (cryo-EM), which currently brings about a revolution in structural biology (Nobel Prize in Chemistry, 2017).

This project will focus on a protein assembly involved in eukaryotic mRNA degradation, which plays a pivotal role in post-transcriptional gene regulation. The Ccr4-Not complex is a key component involved in regulated RNA degradation induced by microRNAs and regulatory RNA binding proteins. Understanding the biological and biochemical activities of the Ccr4-Not complex is relevant for a fundamental understanding of gene regulation as well as the mode of action of RNA therapeutics, such as small RNAs (such as siRNA) and the emerging class of mRNA therapeutics.

To understand the structure of the Ccr4-Not complex, active sub-modules of the Ccr4-Not deadenylase as well as the complete protein complex will be obtained by expression and purification of recombinant proteins involving bacterial and insect cell co-expression systems. Following successful expression and purification, active complexes will be characterised using biochemical assays. Subsequently, a variety of biophysical and structural methods will be employed, including negative stain EM, before single protein particle analysis will be carried out.

This project provides opportunities to obtain experience with a range of techniques that are an excellent preparation for a variety of careers in academia or industry.

This project is open for self-funded students only. If you are a student from the EU or other parts of the world, please get in touch at an early stage to discuss possible funding opportunities.