Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

U of T researchers map role of Epstein-Barr virus in cancer

01.04.2005


Researchers at the University of Toronto have mapped the molecular details that show how a viral protein coded in the Epstein-Barr virus immortalizes cells and causes them to continuously grow, thereby predisposing people to certain types of cancer.



"Epstein-Barr virus (EBV) is one of the most common human viruses in the world and is strongly linked to certain b-cell cancers like Burkitt’s lymphoma as well as the epithelial cell cancer, nasopharyngeal carcinoma. EBNA1 is a protein coded in the Epstein-Barr virus and suspected to play a role in the development of cancer," says Lori Frappier, professor in medical genetics and microbiology at U of T and senior author of a paper in the April 1 issue of Molecular Cell.

"This research shows how EBNA1 interferes with natural cell growth regulation by binding to a particular protein in cells, causing them to continue growing and therefore increasing the risk of becoming cancerous."


Frappier explains that all cells contain the two proteins – p53 and USP7 – that work together to regulate cell growth. P53 is an important protein whose level in the cell determines whether cells will continue to proliferate or stop dividing and die. USP7 is a protein that binds to p53 and makes it stable. Under those conditions, cells stop growing and die, which is a natural state of cell regulation. Once EBNA1 is introduced to cells, however, this protein interferes with natural cell regulation by binding to USP7 and preventing its interaction with the p53 protein.

"Normally, p53 levels will increase in response to certain problems in the cell such as damaged DNA and this stops the cell from proliferating. Through binding USP7, EBNA1 keeps the p53 levels low so cells will continue to divide when they shouldn’t, which means they’re now more likely to develop into cancer," Frappier says.

"All viruses known to be able to cause cancer, like the human papillomavirus that causes cervical cancer for example, have been shown to work through this p53 protein, but up until now, no one’s ever found any regulation of p53 that’s associated with the Epstein-Barr virus. That was surprising because all other viruses that stimulate cell proliferation do it through p53. The question was why this one didn’t. What our research shows is that EBNA1 does actually impact on the p53 protein; it just does it in a different way than other viruses do."

Frappier, a Canada Research Chair in Molecular Virology, also conducted this research with Professor Aled Edwards, also of medical genetics and microbiology at U of T, and Professor Cheryl Arrowsmith, of medical biophysics at U of T and the Ontario Cancer Institute. Both Edwards and Arrowsmith are also from U of T’s Banting and Best Department of Medical Research and the Structural Genomics Consortium.

The researchers tested the effects of EBNA1 on human cells grown in culture. Frappier says the paper provides a structural explanation of this protein complex so scientists can see in molecular detail how the EBNA1 protein binds to USP7 and the resulting impact on cell growth. Once that level of detail is achieved, she says scientists can then design specific mutations in these proteins to see what happens to cells when the proteins don’t interact with one another. A better understanding of these molecular mechanisms will hopefully lead scientists and researchers to developing better methods of combating viruses like these which cause disease, says Frappier.

Lori Frappier | EurekAlert!
Further information:
http://www.utoronto.ca

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | 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: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>