Mapping the interactomes of localized mRNAs by proximity biotinylation

• Applicant: Professor Dr. Ralf-Peter Jansen
• Subject Area: General Genetics and Functional Genome Biology ; Biochemistry ; Cell Biology
• Term: from 2015 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 270067186

Transcripts destined for their cytoplasmic localization are specifically tethered via cis-acting localization elements to their transport complexes and translationally arrested during transport. The localization of ASH1 mRNA and 30 other transcripts by the SHE machinery in budding yeast has been particularly useful to dissect the molecular principles of RNA localization. Although several localization elements have been identified in yeast, almost no similarities have been found between them. Furthermore, their role in translational regulation is poorly understood. We aim to precisely map all SHE-related localization elements in yeast and assess their structural and functional properties. These insights shall for the first time disclose how RNA elements without obvious sequence and secondary-structure similarities fulfill the same function as localization elements. For an assessment of translational control of ASH1 we will establish a cell-free translation system from yeast to determine the exact contribution of all five RNA-binding proteins (RBPs) of ASH1 as well as of its localization elements. Since some translational repressors only appear to bind to a subset of the known 30 localizing mRNAs, we expect that not all RNAs will follow the same regulatory principles suggested for the ASH1 mRNA. We will therefore also assess the translational regulation of such other mRNAs and of newly identified transcripts in the cell-free system and in vivo. A detailed understanding of the regulation of localized mRNAs in yeast will help to gain general insight into translation regulation of transported mRNAs. It will also offer working models to be tested in more complex messenger ribonucleoprotein particles (mRNPs) of metazoans.

• DFG Programme: Research Units
• Subproject of: FOR 2333: Macromolecular Complexes in mRNA translocation