@misc{LeeBobkovaGieretal.2019, author = {Lee, Jin-Ho and Bobkova, Elizaveta and Gier, Theresa and Gote, Martin and Schmidt-kaler, Fanz and Brieger, Emily and Maus, Emanuel and Krufczik, Matthias and Chojowski, Robert and Korn, Friederike and Sarah, Schumann and Scherthan, Harry and Falkova, Iva and Falk, Martin and Hausmann, Michael and Hildenbrand, Georg}, title = {Mechanisms and Challenges for Understanding Radiation Induced Changes in Chromatin Nanoarchitecture}, series = {DRO 2018}, journal = {DRO 2018}, doi = {https://doi.org/10.13140/RG.2.2.31391.20647}, year = {2019}, abstract = {The three-dimensional architecture of genomes acts as an additional level of mode for fundamental biological processes such as DNA damage response. In this context, nanoprobing and super-resolution microscopy are powerful methods for structural analyses of genomic targets in native chromatin of single cells at resolutions of single antibodies, proteins, histones, short DNA stretches, etc. We used multi-color chromatin nanoprobing and single molecule localization microscopy of established DNA damage and chromatin markers in 3D-conserved nuclei of different cell types exposed to various types and doses of ionizing radiation. Similarly, effect of gold nanoparticles on extent and direction of cellular radiation response was assessed. Our studies revealed the nanoarchitecture of damage foci with respect to γH2AX, Mre11 or 53BP1 and their molecular rearrangements during repair processes. Nanoscopy of genomic Alu resulted in linear-quadratic dose-effects for low to higher dose ranges and in changes of H3K9me3 distribution around Alu clusters upon radiation exposure. Preliminary results show post-irradiation time dependent changes in Alu chromatin. Moreover, gold nanoparticles incorporated into cells seem to act by an interplay of radiation enhancement and chromatin remodeling leading to altered radiosensitivity. Our results contribute to the understanding of cellular radiation responses, thereby laying the basis for improved biological dosimetry and radiotherapies in future.}, subject = {Genom}, language = {en} } @article{KrufczikSieversHausmannetal.2017, author = {Krufczik, Matthias and Sievers, Aaron and Hausmann, Annkathrin and Lee, Jin-Ho and Hildenbrand, Georg and Schaufler, Wladimir and Hausmann, Michael}, title = {Combining Low Temperature Fluorescence DNA-Hybridization, Immunostaining, and Super-Resolution Localization Microscopy for Nano-Structure Analysis of ALU Elements and Their Influence on Chromatin Structure}, series = {International Journal of Molecular Sciences}, volume = {18}, journal = {International Journal of Molecular Sciences}, number = {5}, publisher = {MDPI AG}, issn = {1422-0067}, doi = {https://doi.org/10.3390/ijms18051005}, year = {2017}, abstract = {Immunostaining and fluorescence in situ hybridization (FISH) are well established methods for specific labelling of chromatin in the cell nucleus. COMBO-FISH (combinatorial oligonucleotide fluorescence in situ hybridization) is a FISH method using computer designed oligonucleotide probes specifically co-localizing at given target sites. In combination with super resolution microscopy which achieves spatial resolution far beyond the Abbe Limit, it allows new insights into the nano-scaled structure and organization of the chromatin of the nucleus. To avoid nano-structural changes of the chromatin, the COMBO-FISH labelling protocol was optimized omitting heat treatment for denaturation of the target. As an example, this protocol was applied to ALU elements—dispersed short stretches of DNA which appear in different kinds in large numbers in primate genomes. These ALU elements seem to be involved in gene regulation, genomic diversity, disease induction, DNA repair, etc. By computer search, we developed a unique COMBO-FISH probe which specifically binds to ALU consensus elements and combined this DNA-DNA labelling procedure with heterochromatin immunostainings in formaldehyde-fixed cell specimens. By localization microscopy, the chromatin network-like arrangements of ALU oligonucleotide repeats and heterochromatin antibody labelling sites were simultaneously visualized and quantified. This novel approach which simultaneously combines COMBO-FISH and immunostaining was applied to chromatin analysis on the nanoscale after low-linear-energy-transfer (LET) radiation exposure at different doses. Dose-correlated curves were obtained from the amount of ALU representing signals, and the chromatin re-arrangements during DNA repair after irradiation were quantitatively studied on the nano-scale. Beyond applications in radiation research, the labelling strategy of immunostaining and COMBO-FISH with localization microscopy will also offer new potentials for analyses of subcellular elements in combination with other specific chromatin targets.}, subject = {Genom}, language = {en} } @incollection{HausmannLeeSieversetal.2020, author = {Hausmann, Michael and Lee, Jin-Ho and Sievers, Aaron and Krufczik, Matthias and Hildenbrand, Georg}, title = {COMBinatorial Oligonucleotide FISH (COMBO-FISH) with Uniquely Binding Repetitive DNA Probes}, series = {The Nucleus}, booktitle = {The Nucleus}, publisher = {Springer US}, address = {New York, NY}, isbn = {9781071607626}, issn = {1064-3745}, doi = {https://doi.org/10.1007/978-1-0716-0763-3_6}, pages = {65 -- 77}, year = {2020}, subject = {Genom}, language = {en} }