The genetic master plan of every living cell is contained within its DNA (deoxyribonucleic acid) and its subunits, the genes. In order to make use of the genetic information, copies are produced in the form of RNAs (ribonucleic acids) in a process called transcription. RNAs are very diverse molecules and can serve either as an instruction for the translation of the RNA into a protein as shown below, or RNAs can function as enzymatic, regulatory or structural molecules in their own right.
In the most common subtypes of MND, several thousands of RNA molecules are altered regarding levels or sequences, but the proportion or the identity of those RNAs that cause disease is unknown. Most alterations are likely to have occurred not as a cause but as a consequence of previous dysregulations. Thus, the challenge is to find which aberrant RNAs cause the disease. Hundreds of aberrant alternative splicing events were recently identified in several major subtypes of ALS (C9ORF72, SOD1, TARDBP/TBP-43, FUS), however functional consequences on cellular protein synthesis remain poorly understood. Therefore, it is crucial to comprehensively characterise protein factors causing disease onset and progression.
We study the effects of these dysregulated RNA molecules on protein synthesis in motor neurodegenerative disorders such as ALS. Our aim is to identify aberrant RNA molecules that cause disease in order to provide new targets for the development of novel therapies. Protein:RNA complexes are purified from cells using FPLC systems and RNAs are radioactively labelled and visualized to reveal RNA processing defects and changes in RNA levels.
Cellular mRNAs and example of RNA-binding protein (RBP) visualised by Fluorescence In Situ Hybridisation (panels A, B) together with immunofluorescence (panel C) microscopy studies respectively. Nuclei (dotted line) and cytoplasm surrounding nuclei (solid line) of human cells are highlighted. This shows that overexpression of this mutated RBP triggers mRNA nuclear accumulation.