TorsionAtLamina · TWISTING THE BOUNDARIES: ROLE OF TOPOISOMERASE 1 AT THE NUCLEAR LAMINA
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2020-09-01 → 2022-08-31
- EU contribution
- €175,572
- Participants
- 1
- Scheme
- MSCA-IF
Lines connect the coordinator with its partners.
Results in brief
TWISTING THE BOUNDARIES: ROLE OF TOPOISOMERASE 1 AT THE NUCLEAR LAMINA
The DNA contained in one single cellular nucleus is 2 meters longs when stretched on a linear scale. Thus, fitting in a nucleus that is usually not bigger than 2 micrometers, requires that DNA has a high degree of compaction (1000000 times!!) and to achieve this the genome needs to be organized at several levels inside the nucleus. A correct genome organization is crucial to guarantee its proper function and stability. One crucial aspect of genome organization is anchoring of DNA to the nuclear lamina (NL), a scaffold that provides mechanical sustain to the nucleus. What controls the interaction between DNA and the NL is still a mystery. Among several proteins proposed to have a role in genome organization DNA topoisomerases have recently received particular attention. These enzymes can promote the relaxation of DNA that usually undergoes to substantial torsional stress during physiological processes inside the nucleus. By removing torsion from DNA, Topoisomerases can also control high order chromatin structures and favor and disfavor DNA compaction. DNA Topoisomerases are currently targeted in chemotherapy, thus understanding its biological function and interaction partners, especially in the context of 3D genome organization is very important to guarantee the development of new therapeutical approaches and identify potential additional targets to achieve more effective combinatorial therapies. The goal of this project was to understand the relationship between DNA Topoisomerases and genome interaction with the nuclear lamina. DNA Topoisomerases were investigated for a potential role in controlling DNA-NL interaction using a specific technique called pA-DamID. I also tried to directly measure the torsional stress on chromatin, identifying the effects of both local and genome wide chromatin context in modulation of torsional stress and DNA structures that are topology dependent.
Data: CORDIS, © European Union
Project objective
When DNA is transcribed or replicated, torsional stress accumulates on the double helix. This tension must be dissipated by spreading it along the DNA fiber, or it must be removed altogether. One of the main factors responsible for the removal of such stress is DNA Topoisomerase I (Top1), an important target of cancer chemotherapy. When Top1 activity is lost, torsional stress accumulates on transcriptionally active genes and can lead to the formation of non-canonical DNA/RNA hybrid structures called R loops. These structures are emerging as important regulators of genome function and stability. By genome-wide mapping of R loops in human cells, I recently found that depletion of Top1 leads to a marked R loop stabilization, specifically on genes that are anchored to the nuclear lamina. This strongly suggests that attachment of DNA to the nuclear lamina may prevent dissipation of torsional stress, but how this works is still largely unclear. I propose to investigate the causal relationships between torsonal stress, Top1, R-loops and nuclear lamina attachment, taking advantage of a suite of unique genomics techniques developed in the host lab. Specifically, I will: 1) Develop two novel reporter assays to probe the effects of chromatin context (in particular lamina associated chromatin) and Top1 on torsional stress and R loop formation, at thousands of locations in the human genome. 2) Investigate if and how Top1 regulates DNA/nuclear lamina contacts by by means of a novel version of the powerful genome-wide DamID mapping method with much-improved time resolution. My expertise in Top1, R-loops and DNA topology combined with the unique genomics methodologies in the host lab, as well as their expertise in lamina-associated DNA, will lead to a unique synergy that should result in new insights into the relationship between nuclear organization, torsional stress and R loop formation. Moreover, it will yield new methods that will boost scientific progress in this field.
Original text from CORDIS.
Participants
- STICHTING HET NEDERLANDS KANKER INSTITUUT-ANTONI VAN LEEUWENHOEK ZIEKENHUIS · AmsterdamCoordinatorNetherlands
Links
Data: CORDIS, © European Union