Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Slicing mitotic spindle with lasers, nanosurgeons unravel old pole-to-pole theory: Quantitative research shows key organelle of cell division to be more complex than previously thought

The top shows a series of fluorescent images of a spindle taken before the cut and at 5 seconds and 10 seconds after the cut. Scale bar, 10 µm. The bottom shows a graphical representation of the cut microtubules. The cut generates new 'plus' ends (red) and new 'minus' ends (green). The newly generated minus ends remain stable, whereas the new plus ends depolymerize, which creates two depolymerization fronts of opposed polarity.

Credit: Jan Brugués, Harvard School of Engineering and Applied Sciences.
The top shows a series of fluorescent images of a spindle taken before the cut and at 5 seconds and 10 seconds after the cut. Scale bar, 10 µm. The bottom shows a graphical representation of the cut microtubules. The cut generates new 'plus' ends (red) and new 'minus' ends (green). The newly generated minus ends remain stable, whereas the new plus ends depolymerize, which creates two depolymerization fronts of opposed polarity.

Credit: Jan Brugués, Harvard School of Engineering and Applied Sciences.

Abstract:
The mitotic spindle, an apparatus that segregates chromosomes during cell division, may be more complex than the standard textbook picture suggests, according to researchers at the Harvard School of Engineering and Applied Sciences (SEAS).

Slicing mitotic spindle with lasers, nanosurgeons unravel old pole-to-pole theory: Quantitative research shows key organelle of cell division to be more complex than previously thought

Cambridge, MA | Posted on April 26th, 2012

The findings, which result from quantitative measurements of the mitotic spindle, will appear tomorrow in the journal Cell.

The researchers used a femtosecond laser to slice through the strands of the organelle and then performed a mathematical analysis to infer the microscopic structure of the spindle from its response to this damage.

"We've been using this nanosurgery technique to understand the architecture and assembly of the spindle in a way that was never possible before," says Eric Mazur, Balkanski Professor of Physics and Applied Physics at Harvard, who co-authored the study. "It's very exciting."

The spindle, which is made of protein strands called microtubules, forms during cell division and segregates chromosomes into the daughter cells. It was previously unclear how microtubules are organized in the spindles of animal cells, and it was often assumed that the microtubules stretch along the length of the entire structure, pole to pole.

Mazur and his colleagues demonstrated that the microtubules can begin to form throughout the spindle. They also vary in length, with the shortest ones close to the poles.

"We wondered whether this size difference might result from a gradient of microtubule stabilization across the spindle, but it actually results from transport," says lead author Jan Brugués, a postdoctoral fellow at SEAS. "The microtubules generally nucleate and grow from the center of the spindle, from which point they are transported towards the poles. They disassemble over the course of their lifespan, resulting in long, young microtubules close to the midline and older, short microtubules closer to the poles."

"This research provides concrete evidence for something that we've only been able to estimate until now," Brugués adds.

Mazur and Brugués worked with Daniel Needleman, Assistant Professor of Applied Physics and Molecular and Cellular Biology at Harvard, and Valeria Nuzzo, a former postdoctoral fellow in Mazur's lab at SEAS, to bring the tools of applied physics to bear on a biological question.

The team used a femtosecond laser to make two small slices perpendicular to the plane of growth of the spindle apparatus in egg extracts of the frog species Xenopus laevis.

They were then able to collect quantitative data on the reconstruction of the spindle following this disruption and precisely determine the length and polarity of individual microtubules. Observing the speed and extent of depolymerization (unraveling) of the spindle, the team worked backwards to compile a complete picture of the beginning and end points of each microtubule. Finally, additional experiments and a numerical model confirmed the role of transport.

"The laser allowed us to make precise cuts and perform experiments that simply were not possible using previous techniques," says Mazur.

With further inquiries into spindle architecture, the researchers hope that scientists will one day have a complete understanding, and possibly even control over, the formation of the spindle.

"Understanding the spindle means understanding cell division," notes Brugués. "With a better understanding of how the spindle is supposed to operate, we have more hope of tackling the range of conditions—from cancer to birth defects—that result from disruptions to the cell cycle or from improper chromosomal segregation."

The research was supported by the National Science Foundation and by a fellowship from the Human Frontiers Science Program.

####

For more information, please click here

Contacts:
Caroline Perry

617-496-1351

Copyright © Harvard University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Researchers printed graphene-like materials with inkjet August 17th, 2017

Candy cane supercapacitor could enable fast charging of mobile phones August 17th, 2017

Freeze-dried foam soaks up carbon dioxide: Rice University scientists lead effort to make novel 3-D material August 16th, 2017

Gold shines through properties of nano biosensors: Researchers discover that fluorescence in ligand-protected gold nanoclusters is an intrinsic property of the gold particles themselves August 16th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Researchers printed graphene-like materials with inkjet August 17th, 2017

Freeze-dried foam soaks up carbon dioxide: Rice University scientists lead effort to make novel 3-D material August 16th, 2017

2-faced 2-D material is a first at Rice: Rice University materials scientists create flat sandwich of sulfur, molybdenum and selenium August 14th, 2017

Engineers pioneer platinum shell formation process – and achieve first-ever observation August 11th, 2017

Nanomedicine

Freeze-dried foam soaks up carbon dioxide: Rice University scientists lead effort to make novel 3-D material August 16th, 2017

Gold shines through properties of nano biosensors: Researchers discover that fluorescence in ligand-protected gold nanoclusters is an intrinsic property of the gold particles themselves August 16th, 2017

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

JPK reports on how the University of Glasgow is using their NanoWizard® AFM and CellHesion module to study how cells interact with their surroundings August 2nd, 2017

Discoveries

Researchers printed graphene-like materials with inkjet August 17th, 2017

Candy cane supercapacitor could enable fast charging of mobile phones August 17th, 2017

Freeze-dried foam soaks up carbon dioxide: Rice University scientists lead effort to make novel 3-D material August 16th, 2017

Gold shines through properties of nano biosensors: Researchers discover that fluorescence in ligand-protected gold nanoclusters is an intrinsic property of the gold particles themselves August 16th, 2017

Announcements

Researchers printed graphene-like materials with inkjet August 17th, 2017

Candy cane supercapacitor could enable fast charging of mobile phones August 17th, 2017

Freeze-dried foam soaks up carbon dioxide: Rice University scientists lead effort to make novel 3-D material August 16th, 2017

Gold shines through properties of nano biosensors: Researchers discover that fluorescence in ligand-protected gold nanoclusters is an intrinsic property of the gold particles themselves August 16th, 2017

Grants/Sponsored Research/Awards/Scholarships/Gifts/Contests/Honors/Records

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

2-faced 2-D material is a first at Rice: Rice University materials scientists create flat sandwich of sulfur, molybdenum and selenium August 14th, 2017

Moving at the Speed of Light: University of Arizona selected for high-impact, industrial demonstration of new integrated photonic cryogenic datalink for focal plane arrays: Program is major milestone for AIM Photonics August 10th, 2017

Landscapes give latitude to 2-D material designers: Rice University, Oak Ridge scientists show growing atom-thin sheets on cones allows control of defects August 9th, 2017

Nanobiotechnology

Freeze-dried foam soaks up carbon dioxide: Rice University scientists lead effort to make novel 3-D material August 16th, 2017

Gold shines through properties of nano biosensors: Researchers discover that fluorescence in ligand-protected gold nanoclusters is an intrinsic property of the gold particles themselves August 16th, 2017

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

JPK reports on how the University of Glasgow is using their NanoWizard® AFM and CellHesion module to study how cells interact with their surroundings August 2nd, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project