Quantitative analysis of ribonucleoprotein complexes at the interface between translation and mRNA degradation

The information contained in the genes of living cells has to be converted into cellular components that form structures and enable biochemical reactions to take place. This process is called gene expression and it is vital to all life. Gene expression comprises two main steps, called transcription and translation. In transcription, the information in the DNA sequences of the genes is converted into equivalent sequences in so-called messenger RNA (mRNA) molecules. In translation, the mRNA molecules are 'read' by a large molecular structure called the ribosome, which uses the information to dictate the synthesis of proteins. On the other hand, the mRNA templates for protein synthesis do not survive for ever in the cell, but rather are continually degraded and resynthesised. The degradation of an mRNA molecule is timed to follow a spell of activity in protein synthesis. We will study how this timing is controlled by examining the interactions between the cellular components that are responsible for making proteins from the mRNAs and the components that degrade the mRNA molecules. In this way, we will learn about the balance of synthetic and degradative forces in the cell.

The overall rate of synthesis of a protein from an mRNA template is related both to the steady state level of the mRNA in the cell, which is determined by the rates of transcription and of mRNA degradation, and to the efficiency of translation. The posttranscriptional processes of mRNA degradation and translation are accordingly of key importance to the control and regulation of gene expression. It has been known for some time that translation and mRNA degradation are intimately related, yet the mechanisms underlying this relationship are poorly understood, and there is minimal information on the principles of quantitative control governing the rates and mutual interactions of the two processes. In this project, we propose to advance our understanding of the underlying mechanisms of control by characterizing the interrelationships between the respective components of the translation and decay machineries using a combination of methods. We will use a combination of biochemical and biophysical techniques to study the interactions between the pathways of translation and decay. The experimental methods used will include the pull-down of complexes from the cell, competition analysis of RNA binding proteins, atomic force spectroscopy, high resolution imaging, surface plasmon resonance and resonant acoustic profiling.