Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A key component of cell division comes to light

01.07.2014

A breakthrough at IRB Barcelona fills a knowledge gap in understanding how the cell division apparatus, the mitotic spindle, is formed.

The in vivo visualization and monitoring of the starting points of microtubules — filaments responsible for organising the mitotic spindle — provides novel insight into the dynamic architecture of this structure.


Microtubules in the mitotic spindle (Photo: N Lecland, IRB Barcelona)

The findings will also contribute to understanding how the mitotic spindle is perturbed by drugs that target microtubules and that are used in chemotherapy.

The division of a cell in two requires the assembly of the mitotic spindle, an extremely complex structure, which is the result of the coordinated action of a multitude of proteins and a finely tuned balance of their activities. A large part of the time that a cell requires to divide is devoted to assembling the mitotic spindle, which, superficially, resembles a ball of thread with the shape of a rugby ball.

The most abundant components of the spindle are the microtubules. “By labelling the ends of thousands of these fine filaments, which are indispensable and extremely dynamic and variable, we have finally been able to follow their distribution and movement during the assembly of the mitotic spindle,” explains Jens Lüders, a cell biologist from the Institute for Research in Biomedicine (IRB Barcelona). The breakthrough appeared yesterday in the advanced online edition of the journal Nature Cell Biology.

“For more than 10 years we have been able to track only the growing ends of microtubules but not the starting points. As a result, we lacked essential information in order to understand the dynamic architecture of the mitotic spindle and how it contributes to cell division,” says Lüders. Headed by the German scientist who runs the Microtubule Organisation group at IRB Barcelona, the study carries only two names, his own and that of the French researcher Nicolas Lecland, first author, who completed his PhD at IRB Barcelona through a “la Caixa” fellowship.

The scientists have demonstrated that the protein γ-tubulin localizes at the starting points of the microtubule filaments and is relatively stably associated with these structures. Using a version of γ-tubulin that carries a fluorescent label activated by laser light, the researchers were able to follow the movement of the starting points of microtubules within mitotic spindles by filming dividing human cells.

The Advanced Digital Microscopy Facility, a joint IRB Barcelona-Barcelona Science Park Facility run by the IRB physicist Julien Colombelli, has been crucial for setting up the technology required. “The success of this study is also the result of the technical know-how and cutting-edge technology available, without which we would never have been able to tackle this project,” emphasizes Lüders.

The researchers describe for the first time where most microtubules form inside the mitotic spindle, how they develop, and how their starting points are transported—with the help of three motor proteins—to opposite poles of the spindle, where they attach. Simultaneous to this process, the opposite ends of the filaments extend towards the cell centre, where they interact with chromosomes.

When the spindle is finally assembled, the microtubules pull the chromosomes to opposite poles and initiate the physical division of the cell. “We now have a more complete understanding of how the spindle assembles and functions and can use our novel marker for testing old and new hypotheses about underlying mechanisms,” says the scientist.

A new tool to study cancer

In addition, the breakthrough paves the way to “better” understanding the mode of action of drugs that inhibit microtubules and that are used in chemotherapy. These kinds of drugs impede the mitotic spindle, thus preventing cell division and interfering with tumour growth.

In spite of the many years of clinical success of these treatments against cancer, little is known about how they impair spindle architecture and function. Although these drugs are highly efficient, they do not show the specificity desirable as they also affect healthy dividing cells. In addition, they affect non-dividing cells such as neurons, in which microtubules also have important functions.

“A better understanding of the differences in spindle organisation between cancer and healthy cells and how they respond to microtubule-targeted drugs is essential in order to optimise treatments, for example by identifying more specific drugs or new targets. This tool could be useful to achieve these objectives,” states the researcher.

The study has been supported by structural funds from the Generalitat de Catalunya, a Marie Curie grant from the European Union, and the Plan Nacional, of the Ministry of Economy and Competitiveness.

Reference article:
The dynamics of microtubule minus ends in the human mitotic spindle
Nicolas Lecland and Jens Lüders
Nature Cell Biology (2014) Doi: http://dx.doi.org/10.1038/ncb2996

Sònia Armengou | Eurek Alert!

Further reports about: Cell IRB chemotherapy drugs filaments healthy microtubule microtubules movement spindle structure

More articles from Life Sciences:

nachricht How Invasive Plants Influence an Ecosystem
28.07.2016 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht Perseus translates proteomics data
27.07.2016 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Self-assembling nano inks form conductive and transparent grids during imprint

Transparent electronics devices are present in today’s thin film displays, solar cells, and touchscreens. The future will bring flexible versions of such devices. Their production requires printable materials that are transparent and remain highly conductive even when deformed. Researchers at INM – Leibniz Institute for New Materials have combined a new self-assembling nano ink with an imprint process to create flexible conductive grids with a resolution below one micrometer.

To print the grids, an ink of gold nanowires is applied to a substrate. A structured stamp is pressed on the substrate and forces the ink into a pattern. “The...

Im Focus: The Glowing Brain

A new Fraunhofer MEVIS method conveys medical interrelationships quickly and intuitively with innovative visualization technology

On the monitor, a brain spins slowly and can be examined from every angle. Suddenly, some sections start glowing, first on the side and then the entire back of...

Im Focus: Newly discovered material property may lead to high temp superconductivity

Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.

While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.

Im Focus: Mapping electromagnetic waveforms

Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.

Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...

Im Focus: Continental tug-of-war - until the rope snaps

Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases

Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

GROWING IN CITIES - Interdisciplinary Perspectives on Urban Gardening

15.07.2016 | Event News

SIGGRAPH2016 Computer Graphics Interactive Techniques, 24-28 July, Anaheim, California

15.07.2016 | Event News

Partner countries of FAIR accelerator meet in Darmstadt and approve developments

11.07.2016 | Event News

 
Latest News

World first demo of labyrinth magnetic-domain-optical Q-switched laser

28.07.2016 | Information Technology

New material could advance superconductivity

28.07.2016 | Materials Sciences

CO2 can be stored underground for 10 times the length needed to avoid climatic impact

28.07.2016 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>