Higher-order structure of barley chromosomes observed by electron tomography

Hayashida, Misa; Sartsanga, Channarong; Phengchat, Rinyaporn; Malac, Marek; Harada, Ken; Akashi, Takumi; Fukui, Kiichi; Ohmido, Nobuko

doi:10.1016/j.micron.2022.103328

Cited by 3 publications

(2 citation statements)

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“…Similarly, via transmission and scanning electron microscopy, helical chromatid organization was visualized in plants and animals containing large chromosomes, such as onion (Hao et al, 1990), barley (Hayashida et al, 2022) bean (D€ obel & Schubert, 1981), mouse (Rattner & Lin, 1985;Sumner, 1998), Chinese hamster (Ris, 1981), and human (Rattner & Lin, 1985;Utsumi, 1982). In addition, via electron diffraction and electron tomography, Phengchat et al (2019) and Hayashida et al (2021) revealed a helical chromatid scaffold in HeLa cells, which seems to organize chromatin loops.…”

Section: Light and Electron Microscopymentioning

confidence: 97%

Helical chromonema coiling is conserved in eukaryotes

Câmara,

Kubalová,

Schubert

2023

The Plant Journal

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SUMMARYEfficient chromatin condensation is required to transport chromosomes during mitosis and meiosis, forming daughter cells. While it is well accepted that these processes follow fundamental rules, there has been a controversial debate for more than 140 years on whether the higher‐order chromatin organization in chromosomes is evolutionarily conserved. Here, we summarize historical and recent investigations based on classical and modern methods. In particular, classical light microscopy observations based on living, fixed, and treated chromosomes covering a wide range of plant and animal species, and even in single‐cell eukaryotes suggest that the chromatids of large chromosomes are formed by a coiled chromatin thread, named the chromonema. More recently, these findings were confirmed by electron and super‐resolution microscopy, oligo‐FISH, molecular interaction data, and polymer simulation. Altogether, we describe common and divergent features of coiled chromonemata in different species. We hypothesize that chromonema coiling in large chromosomes is a fundamental feature established early during the evolution of eukaryotes to handle increasing genome sizes.

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Section: Light and Electron Microscopymentioning

confidence: 97%

Helical chromonema coiling is conserved in eukaryotes

Câmara,

Kubalová,

Schubert

2023

The Plant Journal

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“…Other authors (Grigoryev et al, 2016;Bascom and Schlick, 2017) suggested a hierarchical layering of loops to integrate the models based on a highly disordered chromatin filaments (Eltsov et al, 2008;Nishino et al, 2012) and results indicating a multilayer organization of chromatin in chromosomes. Electron diffraction analysis revealed a repetitive structure (100-200 nm) oriented perpendicular to the chromosome axis (Hayashida et al, 2021), which could correspond to clusters of stacked chromatin layers.…”

Section: Introductionmentioning

confidence: 99%

Hypothesis: The opposing pulling forces exerted by spindle microtubules can cause sliding of chromatin layers and facilitate sister chromatid resolution

Daban

2023

Front. Genet.

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Previous studies indicated that mitotic chromosome structure consists of many stacked layers formed by a mononucleosome sheet folded as a helicoid. This multilayer chromatin structure justifies the cylindrical shape of chromosomes and the transverse orientation of cytogenetic bands, and can explain chromosome duplication by the formation of a transient double helicoid that is split into two sister chromatids in mitosis. Here it is hypothesized that the bipolar pulling forces exerted by the mitotic spindle cause the sliding of the layers and facilitate sister chromatid resolution. This hypothesis is supported by three favorable conditions: i) There is no topological entanglement of DNA between adjacent layers; ii) The orientation (parallel to the stacked layers) of the bipolar kinetochore microtubules is adequate to produce layer sliding in opposite directions; iii) The viscous resistance to the sliding caused by the weak interactions between nucleosomes in adjacent layers can be overcome by the microtubule pulling forces.

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