Navigation Links
Slicing chromosomes leads to new insights into cell division
Date:5/29/2009

ANN ARBOR, Mich.By using ultrafast laser pulses to slice off pieces of chromosomes and observe how the chromosomes behave, biomedical engineers at the University of Michigan have gained pivotal insights into mitosis, the process of cell division.

Their findings could help scientists better understand genetic diseases, aging and cancer.

Cells in plants, fungi, and animalsincluding those in the human bodydivide through mitosis, during which the DNA-containing chromosomes separate between the resulting daughter cells. Forces in a structure called the mitotic spindle guide the replicated chromosomes to opposing sides as one cell eventually becomes two.

"Each cell needs the right number of chromosomes. It's central to life in general and very important in terms of disease," said Alan Hunt, an associate professor in the Department of Biomedical Engineering and an author of a paper describing these findings published in Current Biology.

"One of the really important fundamental questions in biology is how do chromosomes get properly segregated when cells divide. What are the forces that move chromosomes around during this process? Where do they come from and what guides the movements?"

Hunt's results validate the theory that "polar ejection forces" are at play. Scientists had hypothesized that the direction and magnitude of these forces might provide physical cues guiding chromosome movements. In this capacity, polar ejection forces would play a central role separating chromosomes in dividing cells, but no one had established a direct link until now.

Polar ejection forces are thought to arise out of the interaction between protein motors on the arms of chromosomes that push against cells' microtubules. Microtubules are long, thin tubes that form a central component of the cytoskeleton and the mitotic spindle. They serve as intracellular structural supports and as railways along which molecular motors move cargoes such as chromosomes.

Hunt's group hypothesized that polar ejection forces should be proportional to the chromosome's size, and therefore could be predictably changed by altering the size of the chromosomes. Using newts as a model organism, they cut off pieces of the chromosomes' arms.

"We asked what the relationship is between the size of the fragment we removed and the direction the chromosome moved," Hunt said. "Not only did we observe a relationship, we established that polar ejection forces were in fact a direct cue that guided chromosomal movements in mitosis."

To achieve this, Hunt performed "nanoscale surgery," as he calls it, taking advantage of the unprecedented precision of femtosecond pulses of laser light. A femtosecond is one billionth of one millionth of a second. The chromosomes he altered were only micrometers long, and the slices across the chromosomes were only nanometers thick. A nanometer is one-billionth of a meter, about a million times thinner than a human hair.

Understanding how chromosome guidance occurs allows scientists to determine how failures lead to genetic diseases, aging and cancer. When cells don't properly divide, they usually die. But survival can cause cancer or aging-related disorders. Likewise, genetic diseases such as Down's syndrome result from improper chromosome segregation.

Mitosis, Hunt says, is one of the most important targets of chemotherapy.

"By knowing how chromosomes move, we can better understand how these drugs interfere with those movements and we can design experiments to screen for new drugs," Hunt said. "It will also allow us to have a better handle on what makes these drugs work. There are a lot of drugs that interfere with mitosis, but only a few are good for cancer therapy."


'/>"/>

Contact: Nicole Casal Moore
ncmoore@umich.edu
734-647-1838
University of Michigan
Source:Eurekalert

Related biology news :

1. Slicing solar power costs
2. Grant supports study of abnormal ring-shaped chromosomes
3. Fungi can tell us about the origin of sex chromosomes
4. Cold Spring Harbor Protocols features classic approaches for analyzing chromosomes
5. UGA researchers discover mechanism that explains how cancer enzyme winds up on ends of chromosomes
6. Exploding chromosomes fuel research about evolution of genetic storage
7. Keeping chromosomes from cuddling up
8. How chromosomes meet in the dark -- Switch that turns on X chromosome matchmaking
9. Evolutionary origin of bacterial chromosomes revealed
10. Meth exposure in young adults leads to long-term behavioral consequences
11. Seattle Childrens Hospital leads $23.7 million NIH grant to study gene repair
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/6/2017)... LONDON , April 6, 2017 ... Control, RFID, ANPR, Document Readers, by End-Use (Transportation & ... Energy Facility, Oil, Gas & Fossil Generation Facility, Nuclear ... Healthcare, Educational, Other) Are you looking for ... Authentication sector? ...
(Date:4/4/2017)... April 4, 2017   EyeLock LLC , a ... the United States Patent and Trademark Office (USPTO) has ... the linking of an iris image with a face ... represents the company,s 45 th issued patent. ... very timely given the multi-modal biometric capabilities that have ...
(Date:3/30/2017)... NEW YORK , March 30, 2017 ... by type (physiological and behavioral), by technology (fingerprint, AFIS, ... recognition, voice recognition, and others), by end use industry ... travel and immigration, financial and banking, and others), and ... Europe , Asia Pacific ...
Breaking Biology News(10 mins):
(Date:10/10/2017)... 10, 2017 SomaGenics announced the receipt of ... develop RealSeq®-SC (Single Cell), expected to be the first ... (including microRNAs) from single cells using NGS methods. The ... to accelerate development of approaches to analyze the heterogeneity ... "New techniques for measuring levels of mRNAs in individual ...
(Date:10/9/2017)... ... October 09, 2017 , ... The award-winning American Farmer television series ... 2018. American Farmer airs Tuesdays at 8:30aET on RFD-TV. , With global population ... challenge of how to continue to feed a growing nation. At the same time, ...
(Date:10/7/2017)... ... October 06, 2017 , ... ... and applications consulting for microscopy and surface analysis, Nanoscience Instruments is now ... Analytical offers a broad range of contract analysis services for advanced applications. ...
(Date:10/6/2017)... ... October 06, 2017 , ... On ... and webinar on INSIGhT, the first-ever adaptive clinical trial for glioblastoma (GBM). The ... The event is free and open to the public, but registration is required. ...
Breaking Biology Technology: