Compaction and self-association of megabase-sized chromatin are induced by anionic protein crowding

Highly compacted chromatin, a complex of DNA with cationic histone proteins, is found in the nucleus of eukaryotic cells in an environment with a high concentration of macromolecular species, many of which possess a negative charge. In the majority of previous studies, however, these crowding condit...

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Main Authors: Zinchenko, Anatoly, Chen, Qinming, Berezhnoy, Nikolay V., Wang, Sai, Nordenskiöld, Lars
Other Authors: School of Biological Sciences
Format: Article
Language:English
Published: 2020
Subjects:
DNA
Online Access:https://hdl.handle.net/10356/144055
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1440552023-02-28T17:01:05Z Compaction and self-association of megabase-sized chromatin are induced by anionic protein crowding Zinchenko, Anatoly Chen, Qinming Berezhnoy, Nikolay V. Wang, Sai Nordenskiöld, Lars School of Biological Sciences Singapore Centre for Environmental Life Sciences and Engineering Science::Biological sciences::Molecular biology Association Reactions DNA Highly compacted chromatin, a complex of DNA with cationic histone proteins, is found in the nucleus of eukaryotic cells in an environment with a high concentration of macromolecular species, many of which possess a negative charge. In the majority of previous studies, however, these crowding conditions were experimentally modelled using neutral synthetic macromolecules such as polyethylene glycol (PEG). Despite the importance of the crowding agent charge in the condensation process of chromatin, to the best of our knowledge, the behavior of chromatin under conditions of anionic protein crowding has not been studied. Here, compaction of nearly megabase-long chromatin in the presence of the anionic globular protein BSA was investigated by single-molecule fluorescent microscopy (FM). We demonstrate different effects of anionic macromolecular crowders (MMCs) on DNA and chromatin, compared to neutral MMCs. While DNA molecules undergo gradual compaction into a globular form in the presence of ca. 20% w/v of BSA, chromatin fibres complete coil to globule transition at a much lower concentration of BSA (ca. 5% w/v). Furthermore, at higher concentrations of BSA in solution (>5% w/v), chromatin fibres self-associate and form large spherical or fibrillar supramolecular microstructures characterized by a high colloidal stability and dynamic intermolecular fluctuations. Formation of such self-organized colloids from chromatin is universal and characteristic of chromatin fibres of various lengths. Our results highlight the hitherto underappreciated effect of anionic MMC environment on chromatin higher-order structures that may play an important role in self-organization of chromatin in vivo. Ministry of Education (MOE) Accepted version This work was supported by a Singapore Ministry of Education (MOE) Academic Research Fund Tier 1 grant (2018-T1-001-114) and KAKENHI grant 17K05611 from Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT). 2020-10-12T02:13:06Z 2020-10-12T02:13:06Z 2020 Journal Article Zinchenko, A., Chen, Q., Berezhnoy, N. V., Wang, S., & Nordenskiöld, L. (2020). Compaction and self-association of megabase-sized chromatin are induced by anionic protein crowding. Soft Matter, 18(16), 4366-4372. doi:10.1039/d0sm00162g 1744-6848 https://hdl.handle.net/10356/144055 10.1039/d0sm00162g 32253414 18 16 4366 4372 en Soft Matter © 2020 The Author(s) (Royal Society of Chemistry). This paper was published in Soft Matter and is made available with permission of The Author(s) (Royal Society of Chemistry). application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Science::Biological sciences::Molecular biology
Association Reactions
DNA
spellingShingle Science::Biological sciences::Molecular biology
Association Reactions
DNA
Zinchenko, Anatoly
Chen, Qinming
Berezhnoy, Nikolay V.
Wang, Sai
Nordenskiöld, Lars
Compaction and self-association of megabase-sized chromatin are induced by anionic protein crowding
description Highly compacted chromatin, a complex of DNA with cationic histone proteins, is found in the nucleus of eukaryotic cells in an environment with a high concentration of macromolecular species, many of which possess a negative charge. In the majority of previous studies, however, these crowding conditions were experimentally modelled using neutral synthetic macromolecules such as polyethylene glycol (PEG). Despite the importance of the crowding agent charge in the condensation process of chromatin, to the best of our knowledge, the behavior of chromatin under conditions of anionic protein crowding has not been studied. Here, compaction of nearly megabase-long chromatin in the presence of the anionic globular protein BSA was investigated by single-molecule fluorescent microscopy (FM). We demonstrate different effects of anionic macromolecular crowders (MMCs) on DNA and chromatin, compared to neutral MMCs. While DNA molecules undergo gradual compaction into a globular form in the presence of ca. 20% w/v of BSA, chromatin fibres complete coil to globule transition at a much lower concentration of BSA (ca. 5% w/v). Furthermore, at higher concentrations of BSA in solution (>5% w/v), chromatin fibres self-associate and form large spherical or fibrillar supramolecular microstructures characterized by a high colloidal stability and dynamic intermolecular fluctuations. Formation of such self-organized colloids from chromatin is universal and characteristic of chromatin fibres of various lengths. Our results highlight the hitherto underappreciated effect of anionic MMC environment on chromatin higher-order structures that may play an important role in self-organization of chromatin in vivo.
author2 School of Biological Sciences
author_facet School of Biological Sciences
Zinchenko, Anatoly
Chen, Qinming
Berezhnoy, Nikolay V.
Wang, Sai
Nordenskiöld, Lars
format Article
author Zinchenko, Anatoly
Chen, Qinming
Berezhnoy, Nikolay V.
Wang, Sai
Nordenskiöld, Lars
author_sort Zinchenko, Anatoly
title Compaction and self-association of megabase-sized chromatin are induced by anionic protein crowding
title_short Compaction and self-association of megabase-sized chromatin are induced by anionic protein crowding
title_full Compaction and self-association of megabase-sized chromatin are induced by anionic protein crowding
title_fullStr Compaction and self-association of megabase-sized chromatin are induced by anionic protein crowding
title_full_unstemmed Compaction and self-association of megabase-sized chromatin are induced by anionic protein crowding
title_sort compaction and self-association of megabase-sized chromatin are induced by anionic protein crowding
publishDate 2020
url https://hdl.handle.net/10356/144055
_version_ 1759853187461808128