Navigation Links
Discovery of cell division 'master controller' may improve understanding and treatment of cancer

Hanover, NH In a study to be published in the journal Nature, two Dartmouth researchers have found that the protein cyclin A plays an important but previously unknown role in the cell division process, acting as a master controller to ensure the faithful segregation of chromosomes during cell division.

Cell division is the process in which cells reproduce by splitting into two identical copies. This process happens trillions of times in an average person's lifetime. To generate two identical copies, cells must separate their chromosomes precisely, an event that relies on the bi-oriented attachment of chromosomes to spindle microtubules through specialized structures called kinetochores. In the early phases of division, there are numerous errors in how kinetochores bind to spindle microtubules. Normal cells efficiently correct these errors so that chromosomes segregate faithfully. However, cancer cells generally do not correct these errors, resulting in daughter cells with abnormal numbers of chromosomes, which may help these cancer cells develop resistance to chemotherapy treatments.

In their study, Dartmouth researchers Lilian Kabeche, PhD, and Duane Compton, PhD, show that microtubule attachments at kinetochores are very unstable in early phases of division. The unstable attachments promote the correction of errors by causing a constant detachment, realignment and reattachment of microtubules from kinetochores in the cells as they try to find the correct attachment. Their study found that the protein cyclin A governs this process by keeping the process going until the errors are eliminated.

"An analogy for this process could be dating," said Compton, Senior Associate Dean for Research and professor of biochemistry at Dartmouth's Geisel School of Medicine. "The chromosomes are testing the microtubules for compatibilitythat is, looking for the right matchto make sure there are correct attachments and no errors. The old view of this process held that chromosomes and microtubules pair up individually to find the correct attachment, like conventional dating. However, our results show that the system is more like speed dating. All the chromosomes have to try many connections with microtubules in a short amount of time. Then they all make their final choices at the same time. Cyclin A acts like a timekeeper or referee to make sure no one makes bad connections prematurely."

In normal cells, persistent cyclin A expression prevents the stabilization of microtubules bound to kinetochores even in cells with aligned chromosomes. As levels of cyclin A decline, microtubule attachments become stable, allowing the chromosomes to be divided correctly as cell division proceeds. In contrast, in cyclin A-deficient cells, microtubule attachments are prematurely stabilized. Consequently, these cells may fail to correct errors, leading to higher rates of chromosome mis-segregation.

"Many cancer cells continuously mis-segregate their chromosomes," says Kabeche. "The major cause is improper kinetochoremicrotubule attachments. Therefore, understanding how kinetochoremicrotubule attachments are regulated throughout cell division is important, not only for furthering our understanding of cell division, but also for allowing us to correct these problems in cancer cells."


Contact: Derik Hertel
The Geisel School of Medicine at Dartmouth

Related biology news :

1. Discovery of a molecule that initiates maturation of mammalian eggs can lead to more IVF pregnancies
2. Annual Drug Discovery Conferences Being Held in Boston MA, Spring 2012
3. Discovery provides blueprint for new drugs that can inhibit hepatitis C virus
4. Unexpected discovery reveals a new mechanism for how the cerebellum extracts signal from noise
5. Discovery offers insight into treating viral stomach flu
6. Breast cancer risk gene discovery fast tracked by new technology
7. Tales from the crypt lead researchers to cancer discovery
8. New discovery may lead to effective prevention and treatment of graft-versus-host dsease
9. Stomata development in plants unraveled -- a valuable discovery for environmental research
10. Discovery reveals chromosomes organize into yarns
11. Bacteria discovery could lead to antibiotics alternatives
Post Your Comments:
(Date:10/29/2015)... Va. , Oct. 29, 2015 Daon, ... today that it has released a new version of ... customers in North America have ... IdentityX v4.0 also includes a FIDO UAF certified ... are already preparing to activate FIDO features. These customers ...
(Date:10/27/2015)... -- In the present market scenario, security is one ... verticals such as banking, healthcare, defense, electronic gadgets, and ... secure & simplified access control and growing rate of ... bank accounts, misuse of users, , and so on. ... and smartphones are expected to provide potential opportunities for ...
(Date:10/26/2015)...  Delta ID Inc., a company focused on bringing ... devices, announced its ActiveIRIS® technology powers the iris recognition ... by NTT DOCOMO, INC in Japan ... to include iris recognition technology, after a very successful ... May 2015, world,s first smartphone to have this capability. ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... 2015 /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ:  AEZS; TSX: ... prospects remain fundamentally strong and highlights the following ... received DSMB recommendation to continue the ZoptEC Phase ... the final interim efficacy and safety data ... men with heavily pretreated castration- and Taxane-resistant prostate ...
(Date:11/25/2015)... ... November 25, 2015 , ... Jessica Richman and Zachary Apte, ... their initial angel funding process. Now, they are paying it forward to other ... stage investments in the microbiome space. In this, they join other successful ...
(Date:11/24/2015)... 2015 Halozyme Therapeutics, Inc. (NASDAQ: HALO ) will ... New York on Wednesday, December 2 at 9:30 a.m. ... and CEO, will provide a corporate overview. th ... at 1:00 p.m. ET/10:00 a.m. PT . Jim Mazzola ... a corporate overview. --> th Annual Oppenheimer Healthcare ...
(Date:11/24/2015)... Nov. 24, 2015 /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ: ... on behalf of the Toronto Stock Exchange, confirms that ... are no corporate developments that would cause the recent ... --> --> About Aeterna Zentaris Inc. ... --> Aeterna Zentaris is a specialty biopharmaceutical ...
Breaking Biology Technology: