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Investigation of Protein Recruitment to DNA Lesions Using 405 Nm Laser Micro-irradiation
Published on: March 20, 2018
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Radiation induced chromatin conformation changes analysed by fluorescent localization microscopy, statistical
Yang Zhang1, Gabriell Máté1, Patrick Müller2
1Institute for Theoretical Physics, Heidelberg University, Philosophenweg 19, 69120, Heidelberg, Germany.
Plos One
|June 5, 2015
Summary
Chromatin structure changes after ionizing radiation damage and repair. Heterochromatin relaxes post-irradiation and re-condenses during repair, while euchromatin remains largely unaffected, revealing dynamic nuclear organization.
Area of Science:
- Cell Biology
- Biophysics
- Radiation Biology
Background:
- Chromatin architecture is functionally correlated, not random.
- Ionizing radiation induces chromatin damage, triggering repair and structural changes.
- These changes may enhance repair complex accessibility to damaged DNA sites.
Purpose of the Study:
- To quantitatively describe chromatin structural changes following irradiation and during repair.
- To investigate histone protein positioning and chromatin rearrangements using high-resolution microscopy.
- To introduce novel analysis methods based on statistical physics and graph theory.
Main Methods:
- Utilized HeLa cells stably transfected with fluorescently labeled histones (H2B-GFP, H2A-YFP).
- Employed Spectral Position Determination Microscopy (SPDM) for high-resolution imaging.
- Applied statistical physics and graph theory (radial distribution, edge length distributions) for image analysis.
- Investigated antibody positioning for heterochromatin and euchromatin.
Main Results:
- Chromatin rearrangements detected by fluorescent nucleosomal patterns average out across the nucleus.
- Heterochromatic regions exhibit relaxation after irradiation and re-condensation during repair.
- Euchromatin appears unaffected or behaves oppositely to heterochromatin.
- SPDM combined with advanced analysis systematically elucidates sub-nuclear chromatin rearrangements.
Conclusions:
- SPDM and novel analysis techniques provide systematic insights into radiation-induced chromatin dynamics.
- Differential responses of heterochromatin and euchromatin to radiation and repair are quantitatively described.
- The study highlights the dynamic nature of nuclear organization in response to DNA damage.
