New Insight into the Mitotic Chromosome Structure: Irregular Folding of Nucleosome Fibers Without 30-nm Chromatin Structure

2010 ◽  
Vol 75 (0) ◽  
pp. 439-444 ◽  
Author(s):  
K. Maeshima ◽  
S. Hihara ◽  
H. Takata
Keyword(s):  
Chromatin Structure ◽  
Mitotic Chromosome ◽  
Chromosome Structure ◽  
Insight Into

Micromechanics of chromatin and chromosomes

2003 ◽  
Vol 81 (3) ◽  
pp. 209-220 ◽  
Author(s):  
John F Marko ◽  
Michael G Poirier
Keyword(s):  
Mechanical Properties ◽  
Key Words ◽  
Mitotic Chromosome ◽  
Chromosome Structure ◽  
Higher Order ◽  
Chromatin Assembly ◽  
Key Words Dna ◽  
Structure And Dynamics ◽  
Insight Into ◽  
Dna Scaffold

The enzymes that transcribe, recombine, package, and duplicate the eukaryotic genome all are highly processive and capable of generating large forces. Understanding chromosome function therefore will require analysis of mechanics as well as biochemistry. Here we review development of new biophysical-biochemical techniques for studying the mechanical properties of isolated chromatin fibers and chromosomes. We also discuss microscopy-based experiments on cells that visualize chromosome structure and dynamics. Experiments on chromatin tell us about its flexibility and fluctuation, as well as quantifying the forces generated during chromatin assembly. Experiments on whole chromosomes provide insight into the higher-order organization of chromatin; for example, recent experiments have shown that the mitotic chromosome is held together by isolated chromatin-chromatin links and not a large, mechanically contiguous non-DNA "scaffold".Key words: DNA struture, chromatin, chromosomes, mitosis.

Nucleosome dynamics

2006 ◽  
Vol 73 ◽  
pp. 109-119 ◽  
Author(s):  
Chris Stockdale ◽  
Michael Bruno ◽  
Helder Ferreira ◽  
Elisa Garcia-Wilson ◽  
Nicola Wiechens ◽  
...  
Keyword(s):  
High Resolution ◽  
Chromatin Structure ◽  
Current Knowledge ◽  
Dynamic Properties ◽  
Structure And Dynamics ◽  
Nucleosome Dynamics ◽  
Sharp Focus ◽  
Recent Advances ◽  
Insight Into ◽  
Chromatin Structure And Dynamics

In the 30 years since the discovery of the nucleosome, our picture of it has come into sharp focus. The recent high-resolution structures have provided a wealth of insight into the function of the nucleosome, but they are inherently static. Our current knowledge of how nucleosomes can be reconfigured dynamically is at a much earlier stage. Here, recent advances in the understanding of chromatin structure and dynamics are highlighted. The ways in which different modes of nucleosome reconfiguration are likely to influence each other are discussed, and some of the factors likely to regulate the dynamic properties of nucleosomes are considered.

scholarly journals Coupling chromatin structure and dynamics by live super-resolution imaging

2020 ◽  
Vol 6 (27) ◽  
pp. eaaz2196 ◽  
Author(s):  
R. Barth ◽  
K. Bystricky ◽  
H. A. Shaban
Keyword(s):  
Chromatin Structure ◽  
Cell Function ◽  
Super Resolution ◽  
Motion Reconstruction ◽  
Chromatin Dynamics ◽  
Structure And Dynamics ◽  
Photoactivated Localization Microscopy ◽  
Resolution Imaging ◽  
Insight Into ◽  
Chromatin Structure And Dynamics

Chromatin conformation regulates gene expression and thus, constant remodeling of chromatin structure is essential to guarantee proper cell function. To gain insight into the spatiotemporal organization of the genome, we use high-density photoactivated localization microscopy and deep learning to obtain temporally resolved super-resolution images of chromatin in living cells. In combination with high-resolution dense motion reconstruction, we find elongated ~45- to 90-nm-wide chromatin “blobs.” A computational chromatin model suggests that these blobs are dynamically associating chromatin fragments in close physical and genomic proximity and adopt topologically associated domain–like interactions in the time-average limit. Experimentally, we found that chromatin exhibits a spatiotemporal correlation over ~4 μm in space and tens of seconds in time, while chromatin dynamics are correlated over ~6 μm and last 40 s. Notably, chromatin structure and dynamics are closely related, which may constitute a mechanism to grant access to regions with high local chromatin concentration.

scholarly journals Condensed Mitotic Chromosome Structure at Nanometer Resolution Using PALM and EGFP- Histones

PLoS ONE ◽  
2010 ◽  
Vol 5 (9) ◽  
pp. e12768 ◽  
Author(s):  
Atsushi Matsuda ◽  
Lin Shao ◽  
Jerome Boulanger ◽  
Charles Kervrann ◽  
Peter M. Carlton ◽  
...  
Keyword(s):  
Mitotic Chromosome ◽  
Chromosome Structure ◽  
Nanometer Resolution

scholarly journals The tropical coral Pocillopora acuta displays an unusual chromatin structure and shows histone H3 clipping plasticity upon bleaching

2021 ◽  
Vol 6 ◽  
pp. 195
Author(s):  
David Roquis ◽  
Céline Cosseau ◽  
Kelly Brener Raffalli ◽  
Pascal Romans ◽  
Patrick Masanet ◽  
...  
Keyword(s):  
Western Blot ◽  
Histone Modifications ◽  
Chromatin Structure ◽  
Histone H3 ◽  
Micrococcal Nuclease ◽  
Coral Host ◽  
Mutualistic Symbiosis ◽  
Ecological Importance ◽  
Endosymbiotic Algae ◽  
Insight Into

Background: Pocillopora acuta is a hermatypic coral with strong ecological importance. Anthropogenic disturbances and global warming are major threats that can induce coral bleaching, the disruption of the mutualistic symbiosis between the coral host and its endosymbiotic algae. Previous works have shown that somaclonal colonies display different levels of survival depending on the environmental conditions they previously faced. Epigenetic mechanisms are good candidates to explain this phenomenon. However, almost no work had been published on the P. acuta epigenome, especially on histone modifications. In this study, we aim at providing the first insight into chromatin structure of this species. Methods: We aligned the amino acid sequence of P. acuta core histones with histone sequences from various phyla. We developed a centri-filtration on sucrose gradient to separate chromatin from the host and the symbiont. The presence of histone H3 protein and specific histone modifications were then detected by western blot performed on histone extraction done from bleached and healthy corals. Finally, micrococcal nuclease (MNase) digestions were undertaken to study nucleosomal organization. Results: The centri-filtration enabled coral chromatin isolation with less than 2% of contamination by endosymbiont material. Histone sequences alignments with other species show that P. acuta displays on average ~90% of sequence similarities with mice and ~96% with other corals. H3 detection by western blot showed that H3 is clipped in healthy corals while it appeared to be intact in bleached corals. MNase treatment failed to provide the usual mononucleosomal digestion, a feature shared with some cnidarian, but not all; suggesting an unusual chromatin structure. Conclusions: These results provide a first insight into the chromatin, nucleosome and histone structure of P. acuta. The unusual patterns highlighted in this study and partly shared with other cnidarian will need to be further studied to better understand its role in corals.

scholarly journals Contribution of advanced fluorescence nano microscopy towards revealing mitotic chromosome structure

2021 ◽  
Author(s):  
S. W. Botchway ◽  
S. Farooq ◽  
A. Sajid ◽  
I. K. Robinson ◽  
M. Yusuf
Keyword(s):  
Fluorescence Imaging ◽  
Mitotic Chromosome ◽  
New Technologies ◽  
Chromosome Structure ◽  
Super Resolution ◽  
Condensation Process ◽  
Fluorescence Lifetime Imaging ◽  
Chromosome Research ◽  
Disease States ◽  
20 Nm

AbstractThe organization of chromatin into higher-order structures and its condensation process represent one of the key challenges in structural biology. This is important for elucidating several disease states. To address this long-standing problem, development of advanced imaging methods has played an essential role in providing understanding into mitotic chromosome structure and compaction. Amongst these are two fast evolving fluorescence imaging technologies, specifically fluorescence lifetime imaging (FLIM) and super-resolution microscopy (SRM). FLIM in particular has been lacking in the application of chromosome research while SRM has been successfully applied although not widely. Both these techniques are capable of providing fluorescence imaging with nanometer information. SRM or “nanoscopy” is capable of generating images of DNA with less than 50 nm resolution while FLIM when coupled with energy transfer may provide less than 20 nm information. Here, we discuss the advantages and limitations of both methods followed by their contribution to mitotic chromosome studies. Furthermore, we highlight the future prospects of how advancements in new technologies can contribute in the field of chromosome science.

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