Analysis of FGF2 5UTR mRNPs in the control of alternative translation initiation site choice

• Applicant: Privatdozent Dr. Jan Medenbach
• Subject Area: General Genetics and Functional Genome Biology ; Biochemistry
• Term: from 2013 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 241756384

The regulation of translation presents an important and critical layer of gene expression control in eukaryotic organisms allowing for spatio-temporal regulation of protein synthesis. It can affect both the amount of protein and the isoform synthesized (quantitative vs. qualitative control of translation). While we are slowly beginning to unravel the principles underlying quantitative regulation of translation, qualitative control still remains mostly enigmatic.Already in the 1980ies it was discovered that alternative translation initiation was employed by a number of mRNAs to produce different protein isoforms from a single RNA species (such as e.g. FGF2, C-MYC, VEGF). Certain cellular conditions can trigger the translation of N-terminally extended protein isoforms which exhibit markedly different activities compared to their smaller counterparts. Exemplarily, in contrast to the small protein isoform, high molecular weight (HMW) fibroblast growth factor 2 (FGF2) proteins are not secreted from the cell but translocate into the nucleus where they exhibit immortalizing activities. Despite the clinical importance of the various FGF2 peptides it remains unknown how production of the individual protein isoforms is controlled. Recent technological advances now allow us to examine ribonucleoproteins (RNPs) in a highly parallel fashion, probing simultaneously for a multitude of protein-RNA interactions. By further developing, adapting and applying these high throughput techniques to FGF2 mRNA (and a panel of additional RNAs of interest) I plan to interrogate RNP dynamics under different cellular conditions in unprecedented detail. Combining these high throughput approaches with reductionist, mechanistic experimentation will allow novel insights into the regulation of translation initiation and start codon choice on FGF2 mRNA, a truly important but yet poorly understood process in biology.

• DFG Programme: Research Grants