Featured Research

from universities, journals, and other organizations

Protein abundant in cancerous cells causes DNA 'supercoiling'

Date:
March 11, 2013
Source:
University of Southern California
Summary:
A team of scientists has identified a protein that can change DNA topology, making DNA twist up into a so-called "supercoil." The finding provides new insight about the role of the protein -- known as mini-chromosome maintenance (MCM) -- in cancer cells, which have high levels of MCM.

A team of USC scientists has identified a protein that can change DNA topology, making DNA twist up into a so-called "supercoil."

Related Articles


The finding provides new insight about the role of the protein -- known as mini-chromosome maintenance (MCM) -- in cancer cells, which have high levels of MCM.

Think about twisting one end of a rubber band while holding the other end still. After a few turns, it forms a neatly twisted rope. But if you keep on turning, the twisted band will twist back upon itself into an increasingly coiled-up knot. Similarly, a DNA molecule can be twisted and coiled to varying extents to form different "supercoiled" structures.

Chromosomal DNA forms different supercoiled structures to enable a number of important processes. It turns on or off some genes, while tuning up or down other genes. The study suggests that an overabundance of MCM in a cell may allow certain genes to be overexpressed, and tune down or turn off other important genes, causing the cell to grow out of control and become cancerous.

Chromosomal DNA structure is very important for regulating gene expression of a cell, and thus the physiological status of the cell. Changing DNA topology is one effective way of controlling chromosomal DNA structure. The discovery of MCM's ability to change DNA topology offers a totally new perspective to MCM's role in gene regulation and cancer," said Xiaojiang Chen, professor of molecular biology at the USC Dornsife College of Letters, Arts and Sciences, and corresponding author of the study.

Chen worked with fellow USC professor Susan Forsburg and USC graduate students Ian M. Slaymaker, Yang Fu and Nimna Ranatunga; as well as Daniel B. Toso and Z. Hong Zhou of UCLA and Aaron Brewster of UC Berkeley. Their study was published online by Nucleic Acids Research on Jan. 29.

Chen and his team found that MCM proteins form a filament that looks much like a wide tube, through which the DNA strand spirals its way along the inner tube wall. Inside of the tube is a wide spiral path that has a strong positive electrical charge.

"Such a striking feature is unusual," said Chen. Who is also a member of the USC Norris Cancer Center. "When you see that, you know it must have a special function." Indeed, it turns out that the positively charged spiral path attracts and binds to the DNA strand, which has a negatively charged phosphate backbone.

Holding the DNA tightly to the spiral path inside the helical filament tube causes the DNA double-helix to change structure, creating supercoils. Future research by the team will explore how the DNA topology changes caused by MCM impacts cancer cell formation as well as its utility in cancer therapy.

This research was funded by the National Institutes of Health, grant numbers GM080338, AI055926, GM071940 and GM059321.


Story Source:

The above story is based on materials provided by University of Southern California. Note: Materials may be edited for content and length.


Journal Reference:

  1. I. M. Slaymaker, Y. Fu, D. B. Toso, N. Ranatunga, A. Brewster, S. L. Forsburg, Z. H. Zhou, X. S. Chen. Mini-chromosome maintenance complexes form a filament to remodel DNA structure and topology. Nucleic Acids Research, 2013; DOI: 10.1093/nar/gkt022

Cite This Page:

University of Southern California. "Protein abundant in cancerous cells causes DNA 'supercoiling'." ScienceDaily. ScienceDaily, 11 March 2013. <www.sciencedaily.com/releases/2013/03/130311151250.htm>.
University of Southern California. (2013, March 11). Protein abundant in cancerous cells causes DNA 'supercoiling'. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2013/03/130311151250.htm
University of Southern California. "Protein abundant in cancerous cells causes DNA 'supercoiling'." ScienceDaily. www.sciencedaily.com/releases/2013/03/130311151250.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Pet Dogs to Be Used in Anti-Ageing Trial

Pet Dogs to Be Used in Anti-Ageing Trial

Reuters - Innovations Video Online (Nov. 26, 2014) Researchers in the United States are preparing to discover whether a drug commonly used in human organ transplants can extend the lifespan and health quality of pet dogs. Video provided by Reuters
Powered by NewsLook.com
Today's Prostheses Are More Capable Than Ever

Today's Prostheses Are More Capable Than Ever

Newsy (Nov. 26, 2014) Advances in prosthetics are making replacement body parts stronger and more lifelike than they’ve ever been. Video provided by Newsy
Powered by NewsLook.com
From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

Newsy (Nov. 25, 2014) The US FDA is announcing new calorie rules on Tuesday that will require everywhere from theaters to vending machines to include calorie counts. Video provided by Newsy
Powered by NewsLook.com
Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Newsy (Nov. 25, 2014) Need another reason to eat yogurt every day? Researchers now say it could reduce a person's risk of developing type 2 diabetes. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins