Helical coiling of metaphase chromatids

0572694 - ÚEB 2024 RIV US eng J - Journal Article
Kubalová, I. - Câmara, A. S. - Cápal, Petr - Beseda, Tomáš - Rouillard, J.-M. - Krause, G. M. - Holušová, Kateřina - Toegelová, Helena - Himmelbach, A. - Stein, N. - Houben, A. - Doležel, Jaroslav - Mascher, M. - Šimková, Hana - Schubert, V.
Helical coiling of metaphase chromatids.
Nucleic Acids Research. Roč. 51, č. 6 (2023), s. 2641-2654. ISSN 0305-1048. E-ISSN 1362-4962
R&D Projects: GA ČR(CZ) GC18-14450J; GA MŠMT(CZ) EF16_019/0000827
Institutional support: RVO:61389030
Keywords : MITOTIC CHROMOSOME STRUCTURE * SPIRAL STRUCTURE * TRADESCANTIA-REFLEXA
OECD category: Plant sciences, botany
Impact factor: 14.9, year: 2022
Method of publishing: Open access
https://doi.org/10.1093/nar/gkad028

Chromatids of mitotic chromosomes were suggested to coil into a helix in early cytological studies and this assumption was recently supported by chromosome conformation capture (3C) sequencing. Still, direct differential visualization of a condensed chromatin fibre confirming the helical model was lacking. Here, we combined Hi-C analysis of purified metaphase chromosomes, biopolymer modelling and spatial structured illumination microscopy of large fluorescently labeled chromosome segments to reveal the chromonema-a helically-wound, 400 nm thick chromatin thread forming barley mitotic chromatids. Chromatin from adjacent turns of the helix intermingles due to the stochastic positioning of chromatin loops inside the chromonema. Helical turn size varies along chromosome length, correlating with chromatin density. Constraints on the observable dimensions of sister chromatid exchanges further supports the helical chromonema model.
Permanent Link: https://hdl.handle.net/11104/0343302