PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

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

2013-09-12
(Press-News.org) 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 compatibility—that is, looking for the right match—to 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 kinetochore–microtubule attachments. Therefore, understanding how kinetochore–microtubule 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."

INFORMATION:

For more information about this study, please visit http://www.nature.com/nature/journal/vaop/ncurrent/full/nature12507.html.

This research was supported by grants from the National Institutes of Heath's (NIH) National Institute for General Medical Sciences (grant #s GM051542 and GM008704).

The Geisel School of Medicine at Dartmouth, founded in 1797, strives to improve the lives of the communities it serves through excellence in learning, discovery, and healing. The nation's fourth-oldest medical school, the Geisel School of Medicine has been home to many firsts in medical education, research and practice, including the discovery of the mechanism for how light resets biological clocks, creating the first multispecialty intensive care unit, the first comprehensive examination of U.S. health care variations (The Dartmouth Atlas), and helping establish the first Center for Health Care Delivery Science, which launched in 2010. As one of America's top medical schools, Dartmouth's Geisel School of Medicine is committed to training new generations of diverse health care leaders who will help solve our most vexing challenges in health care.

END



ELSE PRESS RELEASES FROM THIS DATE:

Climate change may speed up forests' life cycles

2013-09-12
DURHAM, N.C. -- Many climate studies have predicted that tree species will respond to global warming by migrating via seed dispersal to cooler climates. But a new study of 65 different species in 31 eastern states finds evidence of a different, unexpected response. Nearly 80 percent of the species aren't yet shifting their geographic distributions to higher latitudes. Instead, they're staying in place -- but speeding up their life cycles. The Duke University-led study, published online Wednesday in the peer-reviewed journal Global Change Biology, is the first to show ...

Crop-raiding elephants flee tiger growls

2013-09-12
Wild Asian elephants slink quietly away at the sound of a growling tiger, but trumpet and growl before retreating from leopard growls, researchers at the University of California, Davis, have found. The work, published Sept. 11 in the journal Biology Letters, could help Indian farmers protect their crops from marauding elephants and save the lives of both people and animals. "We noticed that the elephants were more scared of tigers than of leopards," said Vivek Thuppil, who carried out the work with Richard Coss, professor of psychology at UC Davis, as part of his Ph.D. ...

Who's got guts? Young infants expect animals to have insides

2013-09-12
CHAMPAIGN, Ill. — A team of researchers has shown that 8-month-old infants expect objects they identify as animals to have insides. The study appears in the Proceedings of the National Academy of Sciences. University of Illinois professor of psychology Renée Baillargeon, who led the new study with graduate student Peipei Setoh, said that many psychologists have theorized that babies are born with core physical and psychological frameworks that help them navigate the world. For instance, when babies see a self-propelled object, their core physical framework leads them ...

Researchers move endangered mussels to save them

2013-09-12
CHAMPAIGN, Ill. — Researchers have transported two endangered freshwater mussel species from Pennsylvania to Illinois in an attempt to re-establish their populations in the western part of the Ohio River Basin. The team of biologists, led by Jeremy Tiemann, of the Illinois Natural History Survey (INHS), traveled to the site of a bridge-replacement project on Pennsylvania's Allegheny River to collect northern riffleshell (Epioblasma rangiana) and clubshell (Pleurobema clava) mussels. The INHS is a division of the Prairie Research Institute at the University of Illinois. The ...

2 NASA satellites analyze Hurricane Humberto's clouds and rainfall

2013-09-12
VIDEO: In this satellite flyby animation, NASA's TRMM satellite passed over Humberto on Sept. 10 and measured rainfall rates of up to 2 inches/50 mm per hour (red) in the large... Click here for more information. Two NASA satellites passed over the hurricane in the Eastern Atlantic on Sept. 10 gathering information about the environment of Hurricane Humberto. NASA's Aqua satellite gathered infrared and visible data on Humberto's clouds while NASA's TRMM satellite measured ...

Plants in space: A novel method for fixing plant tissue samples maximizes time, resources, and data

2013-09-12
At work on the International Space Station, researchers studying plant and cell growth in space encountered a challenge. Imaging revealed interesting spaceflight-associated root morphologies. They needed to fix the tissues for further study back on Earth, but conventional fixation methods require separate fixatives depending on whether the sample is intended for molecular or morphological study. If the scientists wanted to study how spaceflight affected patterns of gene expression central to morphological patterns of cell growth, they needed a fixation method that would ...

The eyes have it

2013-09-12
More than one billion people worldwide rely on fish as an important source of animal protein, states the United Nations Food and Agriculture Organization. And while fish provide slightly over 7 per cent of animal protein in North America, in Asia they represent about 23 per cent of consumption. Humans consume low levels of methylmercury by eating fish and seafood. Methylmercury compounds specifically target the central nervous system, and among the many effects of their exposure are visual disturbances, which were previously thought to be solely due to methylmercury-induced ...

Study provides insights on protecting world's poor from climate change

2013-09-12
The worst impacts of climate change on the world's poorest fishing communities can likely be avoided by careful management of the local environment and investing in the diversification of options for local people, according to the Wildlife Conservation Society and James Cook University. Climate change is already putting pressure on fishers who depend on nature for their livelihoods. In a new study, scientists found large differences in the potential to adapt based on the local mixture of social and environmental characteristics, requiring a variety of management approaches ...

Health care safety net catches suburban poor

2013-09-12
CHICAGO --- A new study shows significant health benefits for uninsured people living under the federal poverty level in the suburbs when they receive access to primary care. Uninsured residents in a suburban collar county of Chicago reported a big improvement in their health status and increased their preventive care and screenings after one year of access to primary care, reports Northwestern Medicine research. The study illustrates the potential benefits of the Affordable Care Act (ACA) implementation and a promising solution to accessible health care for what are ...

Researchers identify ancient ancestor of tulip tree line

2013-09-12
BLOOMINGTON, Ind. -- The modern-day tulip tree, state tree of Indiana as well as Kentucky and Tennessee, can trace its lineage back to the time of the dinosaurs, according to newly published research by an Indiana University paleobotanist and a Russian botanist. The tulip tree, Liriodendron tulipfera, has been considered part of the magnolia family. But David Dilcher of Indiana University Bloomington and Mikhail S. Romanov of the N.V. Tsitsin Main Botanical Garden in Moscow show that it is closely related to fossil plant specimens from the Lower Cretaceous period. Their ...

LAST 30 PRESS RELEASES:

Are lifetimes of big appliances really shrinking?

Pink skies

Monkeys are world’s best yodellers - new research

Key differences between visual- and memory-led Alzheimer’s discovered

% weight loss targets in obesity management – is this the wrong objective?

An app can change how you see yourself at work

NYC speed cameras take six months to change driver behavior, effects vary by neighborhood, new study reveals

New research shows that propaganda is on the rise in China

Even the richest Americans face shorter lifespans than their European counterparts, study finds

Novel genes linked to rare childhood diarrhea

New computer model reveals how Bronze Age Scandinavians could have crossed the sea

Novel point-of-care technology delivers accurate HIV results in minutes

Researchers reveal key brain differences to explain why Ritalin helps improve focus in some more than others

Study finds nearly five-fold increase in hospitalizations for common cause of stroke

Study reveals how alcohol abuse damages cognition

Medicinal cannabis is linked to long-term benefits in health-related quality of life

Microplastics detected in cat placentas and fetuses during early pregnancy

Ancient amphibians as big as alligators died in mass mortality event in Triassic Wyoming

Scientists uncover the first clear evidence of air sacs in the fossilized bones of alvarezsaurian dinosaurs: the "hollow bones" which help modern day birds to fly

Alcohol makes male flies sexy

TB patients globally often incur "catastrophic costs" of up to $11,329 USD, despite many countries offering free treatment, with predominant drivers of cost being hospitalization and loss of income

Study links teen girls’ screen time to sleep disruptions and depression

Scientists unveil starfish-inspired wearable tech for heart monitoring

Footprints reveal prehistoric Scottish lagoons were stomping grounds for giant Jurassic dinosaurs

AI effectively predicts dementia risk in American Indian/Alaska Native elders

First guideline on newborn screening for cystic fibrosis calls for changes in practice to improve outcomes

Existing international law can help secure peace and security in outer space, study shows

Pinning down the process of West Nile virus transmission

UTA-backed research tackles health challenges across ages

In pancreatic cancer, a race against time

[Press-News.org] Discovery of cell division 'master controller' may improve understanding and treatment of cancer