This paper has been prepared to commemorate the 70th anniversary of the Institute of Biophysics of the Czech Academy of Sciences (IBP CAS), which has a long-standing tradition in researching the biological effects of ionizing radiation (IR). Radiobiology has recently gained renewed importance due to several compelling factors. The demand for a better understanding of the biological effects of both low and high doses of various types of ionizing radiation, along with improved radiation protection, is increasing-particularly in the context of critical ongoing human activities such as medical diagnostics, radiotherapy, and the operation of nuclear power plants. This demand also extends to newly emerging scenarios, including the development of hadron and FLASH radiotherapy, as well as mixed radiation field exposures related to planned manned missions to Mars. Unfortunately, there is also an urgent need to address the heightened risk of nuclear materials and weapons misuse by terrorists or even rogue states. Additionally, nuclear energy is currently the only viable alternative that can provide efficient, sustainable, and ecological coverage for the dramatically increasing current and future energy demands. Understanding the risks of IR exposure necessitates exploring how different types of IR interact with living organisms at the most fundamental level of complexity, specifically at the level of molecules and their complexes. The rising interest in radiobiology is, therefore, also driven by new experimental opportunities that enable research at previously unimaginable levels of detail and complexity. In this manuscript, we will address the important questions in radiobiology, focusing specifically on the mechanisms of radiation-induced DNA damage and repair within the context of chromatin architecture. We will emphasize the differing effects of photon and high-LET particle radiation on chromatin and DNA. Both forms of IR are encountered on Earth but are particularly significant in space.

• Klíčová slova
• Biological effects of ionizing radiation, Chromatin architecture at micro- and nano-scale, DNA damage and repair, Densely ionizing (high-LET) particle radiation, Institute of biophysics of the Czech academy of sciences, Microscopy, Photon radiation, Radiobiological research, Single molecule localization microscopy (SMLM),
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Epigenetic modifications, such as acetylation, phosphorylation, methylation, ubiquitination, and ADP ribosylation, of the highly conserved core histones, H2A, H2B, H3, and H4, influence the genetic potential of DNA. The enormous regulatory potential of histone modification is illustrated in the vast array of epigenetic markers found throughout the genome. More than the other types of histone modification, acetylation and methylation of specific lysine residues on N-terminal histone tails are fundamental for the formation of chromatin domains, such as euchromatin, and facultative and constitutive heterochromatin. In addition, the modification of histones can cause a region of chromatin to undergo nuclear compartmentalization and, as such, specific epigenetic markers are non-randomly distributed within interphase nuclei. In this review, we summarize the principles behind epigenetic compartmentalization and the functional consequences of chromatin arrangement within interphase nuclei.

• MeSH
• acetylace MeSH
• buněčné jádro metabolismus   ultrastruktura   MeSH
• chromatin ultrastruktura   MeSH
• chromozomální proteiny, nehistonové fyziologie   MeSH
• epigeneze genetická MeSH
• exprese genu MeSH
• histony genetika   metabolismus   MeSH
• homolog proteinu s chromoboxem 5 MeSH
• inhibitory histondeacetylas MeSH
• interfáze MeSH
• lidé MeSH
• lidské chromozomy X metabolismus   MeSH
• metylace MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• chromatin MeSH
• chromozomální proteiny, nehistonové MeSH
• histony MeSH
• homolog proteinu s chromoboxem 5 MeSH
• inhibitory histondeacetylas MeSH

The spatial arrangement of some genetic elements relative to chromosome territories and in parallel with the cell nucleus was investigated in human lymphocytes. The structure of the chromosome territories was studied in chromosomes containing regions (clusters) of highly expressed genes (HSA 9, 17) and those without such clusters (HSA 8, 13). In chromosomes containing highly expressed regions, the elements pertaining to these regions were found close to the centre of the nucleus on the inner sides of chromosome territories; those pertaining to regions with low expression were localized close to the nuclear membrane on the opposite sides of the territories. In chromosomes with generally low expression (HSA 8, 13), the elements investigated were found symmetrically distributed over the territories. Based on the investigations of the chromosome structure, the following conclusions are suggested: (1) Chromosome territories have a non-random internal 3D structure with defined average mutual positions between elements. For example, RARalpha, TP53 and Iso-q of HSA 17 are nearer to each other than they are to the HSA 17 centromere. (2) The structure of a chromosome territory reflects the number and chromosome location of clusters of highly expressed genes. (3) Chromosome territories behave to some extent as solid bodies: if the territory is found closer to the nuclear centre, the individual genetic elements of this chromosome are also found, on average, closer the centre of the nucleus. (4) The positions of centromeres are, on average, nearer to the fluorescence weight centre of the territory (FWCT) than to genes. (5) Active genes are not found near the centromeres of their own territory. A simple model of the structure of chromosome territory is proposed.

• MeSH
• buněčné jádro genetika   MeSH
• centromera genetika   MeSH
• euchromatin genetika   MeSH
• geny MeSH
• heterochromatin genetika   MeSH
• hybridizace in situ fluorescenční MeSH
• jaderný obal genetika   MeSH
• kompartmentace buňky MeSH
• lidé MeSH
• lidské chromozomy, pár 17 ultrastruktura   MeSH
• lidské chromozomy ultrastruktura   MeSH
• lymfocyty diagnostické zobrazování   MeSH
• metoda Monte Carlo MeSH
• modely genetické MeSH
• počítačová simulace MeSH
• počítačové zpracování obrazu MeSH
• ultrasonografie MeSH
• zobrazování trojrozměrné * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• euchromatin MeSH
• heterochromatin MeSH