A Transient Rise in Free Mg2+ Ions Released from ATP-Mg Hydrolysis Contributes to Mitotic Chromosome Condensation

Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved..

For cell division, negatively charged chromatin, in which nucleosome fibers (10 nm fibers) are irregularly folded [1-5], must be condensed into chromosomes and segregated. While condensin and other proteins are critical for organizing chromatin into the appropriate chromosome shape [6-17], free divalent cations such as Mg2+ and Ca2+, which condense chromatin or chromosomes in vitro [18-28], have long been considered important, especially for local condensation, because the nucleosome fiber has a net negative charge and is by itself stretched like "beads on a string" by electrostatic repulsion. For further folding, other positively charged factors are required to decrease the charge and repulsion [29]. However, technical limitations to measure intracellular free divalent cations, but not total cations [30], especially Mg2+, have prevented us from elucidating their function. Here, we developed a Förster resonance energy transfer (FRET)-based Mg2+ indicator that monitors free Mg2+ dynamics throughout the cell cycle. By combining this indicator with Ca2+ [31] and adenosine triphosphate (ATP) [32] indicators, we demonstrate that the levels of free Mg2+, but not Ca2+, increase during mitosis. The Mg2+ increase is coupled with a decrease in ATP, which is normally bound to Mg2+ in the cell [33]. ATP inhibited Mg2+-dependent chromatin condensation in vitro. Chelating Mg2+ induced mitotic cell arrest and chromosome decondensation, while ATP reduction had the opposite effect. Our results suggest that ATP-bound Mg2+ is released by ATP hydrolysis and contributes to mitotic chromosome condensation with increased rigidity, suggesting a novel regulatory mechanism for higher-order chromatin organization by the intracellular Mg2+-ATP balance.

Errataetall:

CommentIn: Curr Biol. 2018 Feb 5;28(3):R117-R119. - PMID 29408258

Medienart:

E-Artikel

Erscheinungsjahr:

2018

Erschienen:

2018

Enthalten in:

Zur Gesamtaufnahme - volume:28

Enthalten in:

Current biology : CB - 28(2018), 3 vom: 05. Feb., Seite 444-451.e6

Sprache:

Englisch

Beteiligte Personen:

Maeshima, Kazuhiro [VerfasserIn]
Matsuda, Tomoki [VerfasserIn]
Shindo, Yutaka [VerfasserIn]
Imamura, Hiromi [VerfasserIn]
Tamura, Sachiko [VerfasserIn]
Imai, Ryosuke [VerfasserIn]
Kawakami, Syoji [VerfasserIn]
Nagashima, Ryosuke [VerfasserIn]
Soga, Tomoyoshi [VerfasserIn]
Noji, Hiroyuki [VerfasserIn]
Oka, Kotaro [VerfasserIn]
Nagai, Takeharu [VerfasserIn]

Links:

Volltext

Themen:

8L70Q75FXE
ATP
Adenosine Triphosphate
Ca(2+)
Chromosome condensation
Condensin
FRET
I38ZP9992A
Indicator
Ions
Journal Article
Live-cell imaging
Magnesium
Mg(2+)
Mitotic chromosome
Nucleosome
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 03.07.2019

Date Revised 03.07.2019

published: Print-Electronic

CommentIn: Curr Biol. 2018 Feb 5;28(3):R117-R119. - PMID 29408258

Citation Status MEDLINE

doi:

10.1016/j.cub.2017.12.035

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM280197187