Cryo-electron microscopy and functional analysis of the yeast Ccr4-Not deadenylase complex

• Applicant: Dr. Katrin Wiederhold
• Subject Area: Structural Biology
• Term: from 2010 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 181453187

The poly(A) tail of mRNAs plays important roles in the mRNA export from the nucleus, in mRNA stability and in translation. Deadenylation is often the rate-limiting step of mRNA turnover as well as translational silencing and therefore serves as a key regulation step of gene expression. The Ccr4-Not complex is a multicomponent complex known to be involved in transcription as well as cytoplasmic mRNA degradation. The core complex probably consists of nine subunits in yeast and has a molecular weight of about 1 MDa. Although the Ccr4-Not complex seems to be involved in many regulatory processes in gene expression, to date very little is known about the structure of the Ccr4-Not complex or single subunits. This research project aims to gain insight into the function of the Ccr4-Not complex using structural, biochemical and biophysical techniques. The plan is to determine the three-dimensional structure of the yeast Ccr4-Not complex using single particle cryo-electron microscopy. Additionally, the subunit stoichiometry will be determined. Enzymatic activity assays and biophysical methods (e.g. calorimetry) will complement the project. Through my investigations into the architecture, composition and activity of the Ccr4-Not complex, I will gain insight into its fundamental roles in the regulation of gene expression.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Dr. Lori Passmore