Researchers at IMBA – Institute of Molecular Biotechnology of the Austrian Academy of Sciences have identified a protein that disperses chromosomes during cell division, as Nature reports.
Billions of your cells divide every day. Cell division fuels growth and also replaces short-lived cells in some organs, like your skin, blood, and gut.
The surface of chromosomes is covered with surfactant-like proteins during cell division. These proteins act similar to soap to disperse chromosomes and prevent them from clustering together.
Dividing cells cycle through different stages. During most of this cycle, cells are at work expressing genes. At this stage chromosomes are spread out as a network of long threads that fill the entire volume of the cell nucleus.
As the cell prepares to divide, the chromosomes replicate and undergo a dramatic metamorphosis. They compact into iconic X-shaped bodies which can move around independently to transport one copy of the genome to each of the daughter cells. But what enables this “individualization” of chromosomes in dividing cells has been a mystery.
A team led by Daniel Gerlich at IMBA discovered that the protein Ki-67 prevents
chromosomes from sticking together in dividing cells. Ki-67 is a well-known marker of proliferating cells and is used in cancer diagnostics to measure erratic cell division. But the function of Ki-67 in the cell was unclear. Their findings, published in the current issue of Nature, show that the chromosomes can still compact without Ki-67, but they merge into a single mass and are essentially immobile. As a consequence, cells lacking Ki-67 divide more slowly.
The team set out to determine how Ki-67 disperses chromosomes in dividing cells. Sara Cuylen, first author of the study, explains: “one end of the Ki-67 protein is attracted to chromosomes, whereas the other end extends away from them.
As a result, Ki-67 forms elongated brush-like structures at the chromosome surface – essentially a barrier that keeps them apart.” These properties of Ki-67 are reminiscent of surface-active agents (surfactants) like soap – which we use daily to break up dirt and grease. That proteins can function as surfactants inside the cell was completely unexpected.
Daniel Gerlich points out that a surfactant mechanism might also control the spatial arrangement of other cell organelles: “The cell contains many other compartments that are not confined by membranes and it was previously unknown how these compartments maintain spatial separation. It will be exciting to search for other proteins with surfactant-like properties, and to study their potential role in cellular organization”.
Original publication: Cuylen, S., Blaukopf, C., Politi, A.Z., Müller-Reichert, T., Neumann, B., Poser, I., Ellenberg, J., Hyman, A.A., Gerlich, D.W. (2016), Ki-67 acts as a biological surfactant to disperse mitotic chromosomes. Nature DOI: 10.1038/nature18610
Dr. Bohr Gasse 3, 1030 Vienna, Austria
Tel.: +43 664 80847 – 3628
Mag. Ines Méhu-Blantar | idw - Informationsdienst Wissenschaft
Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory
Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine