Periodic Reporting for period 1 - GSR (Genome surveillance by small non-coding RNAs)
Berichtszeitraum: 2017-01-01 bis 2018-12-31
The goal of the ""GsR"" project (Genome surveillance by small non-coding RNAs) was to investigate how molecules such as RNA partner with enzymes (proteins) to repair breaks that occurred in the DNA double-helix (known as DNA double-strand breaks). The project was inspired by recent evidence indicating that a category of small RNAs which do not carry genetic information (non-coding RNAs) participate in the repair of DNA double-strand breaks. Understanding how these tiny machines repair our DNA, at long term, will improve the way society manages diseases and healthcare.
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The second phase of the project consisted in taking a different approach to detect directly RNA molecules using microscopy (Work package 2). For that, we used a technique for detection of individual RNA molecules (single molecule) inside cells by hybridizing RNAs to fluorescent probes (fluorescence in situ hybridization, FISH). We set up an improved variant of this technique recently developed in France at the Centre National de la Recherche Scientifique, which is known as smiFISH (single-molecule inexpensive FISH). Using this method, we observed individual RNA molecules.
We suspected that the RNA molecules of interest are likely to interact with proteins, in particular with enzymes capable of unfolding RNA molecules, which are known as RNA helicases. In the final phase of the project, we used assays for measuring specific DNA repair activities inside cells to address the role of these RNA helicases in DNA double-strand break repair (Work package 3).
Surprisingly, our results diverged from previously published reports on small non-coding RNAs and DNA repair. Our data indicates that small RNA molecules may not have as general role in DNA repair as it had been anticipated. In the same time, we were able to show that RNA helicases are involved in DNA double-strand break repair through a mechanism which is still not completely clear.
We presented our results to a small part of the community at a workshop on the role of RNAs and proteins in DNA double-strand repair, which was organized in France, 2017. This meeting gave birth to new collaborations and revealed a great complexity of RNA-dependent DNA repair mechanisms. Future work will be necessary to fully understand how RNA molecules function in DNA repair.