2018/01/19
National Institute of Genetics
Osaka University
Japan Science and Technology Agency
Kyoto University
Keio University
【Highlights of this research】
Developed a high-performance fluorescent magnesium sensor.
Successfully observed an increase in magnesium ion concentration during cell division using live-cell imaging.
The concentration increases as magnesium ions bound to ATP are released upon ATP consumption.
Proved for the first time that magnesium ions are involved in chromosome condensation within mitotic cells.
This research is expected to contribute to understanding diseases caused by abnormal chromosome formation.
◆Abstract
When a cell divides, the human genomic DNA, which can be up to two meters long, is compacted into bundles of DNA called "chromosomes," which are then accurately distributed to the two daughter cells. More than half a century ago, it was proposed that magnesium ions (Mg 2+ ), which are abundant in cells, could be key to genomic DNA condensation. However, at the time, there were no means to measure intracellular Mg 2+ concentration, so this hypothesis remained unproven and was forgotten.
A joint research group including Professor Kazuhiro Maeshima of the National Institute of Genetics, Professor Takeharu Nagai of Osaka University, Professor Kotaro Oka of Keio University, and Associate Professor Hiroomi Imamura of Kyoto University developed MARIO, a fluorescent sensor that uses fluorescent protein technology to sensitively detect changes in Mg 2+ concentration, and successfully visualized the intracellular Mg 2+ concentration in live cells via fluorescence imaging. They showed that the Mg 2+ concentration transiently increases during cell division, which weakens the repulsion between negatively charged DNA molecules and promotes chromosome condensation. This study has proven for the first time that Mg 2+ is actually involved in chromosome condensation within cells.
Failure in chromosome formation is thought to cause damage to genomic DNA, leading to various abnormalities in cells such as "cell death" and "canceration," and can even result in diseases. Furthermore, Mg 2+ , which is abundant in cells, assists the function of many proteins, and its deficiency is known to cause various cellular abnormalities. The development of this fluorescent sensor and the discovery of these biological insights are expected to contribute to elucidating the mechanisms by which such cellular abnormalities occur.
The results of this research will be published in "Current Biology" on Friday, January 19, 2018 (Japan Standard Time).
For the full press release, please see below.