Navigation Links
Protein abundant in cancerous cells causes DNA 'supercoiling'

A team of USC 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 proteinknown 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.

Contact: Robert Perkins
University of Southern California

Related biology news :

1. Selectively manipulating protein modifications
2. Specialised germanium surface as universal protein adapter
3. A cancer-promoting protein is found to also suppress cell growth
4. Age-related dementia may begin with neurons inability to dispose of unwanted proteins
5. Stressed proteins can cause blood clots for hours
6. Adding to the list of disease-causing proteins in brain disorders
7. Analytical trick accelerates protein studies
8. Antibacterial proteins molecular workings revealed
9. Nano-machines for bionic proteins
10. Bridges experimental and bioinformatics perspectives to delineate protein-DNA interactions
11. Discovering cell surface proteins behavior
Post Your Comments:
(Date:4/17/2017)... , April 17, 2017 NXT-ID, Inc. (NASDAQ: ... announces the filing of its 2016 Annual Report on Form 10-K ... Commission. ... 10-K is available in the Investor Relations section of the Company,s ... the SEC,s website at . 2016 Year ...
(Date:4/11/2017)... BROOKLYN, N.Y. , April 11, 2017 /PRNewswire-USNewswire/ ... identical fingerprints, but researchers at the New York ... University College of Engineering have found that partial ... fingerprint-based security systems used in mobile phones and ... previously thought. The vulnerability lies in ...
(Date:4/5/2017)... , April 4, 2017 KEY FINDINGS ... to expand at a CAGR of 25.76% during the ... is the primary factor for the growth of the ... MARKET INSIGHTS The global stem ... technology, application, and geography. The stem cell market of ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... ... October 11, 2017 , ... ... President Andi Purple announced Dr. Suneel I. Sheikh, the co-founder, CEO and chief ... ), Inc. has been selected for membership in ARCS Alumni Hall of ...
(Date:10/11/2017)... ... ... a basic first aid supply for any work environment, but most personal eye wash can ... a dangerous substance enters both eyes? It’s one less decision, and likely quicker response time ... , “Whether its dirt and debris, or an acid or alkali, getting anything in your ...
(Date:10/11/2017)... ... October 11, 2017 , ... Proscia Inc ., ... a Webinar titled, “Pathology is going digital. Is your lab ready?” with Dr. ... best practices and how Proscia improves lab economics and realizes an increase in ...
(Date:10/11/2017)... and LAGUNA HILLS, Calif. , Oct. ... Cancer Research, London (ICR) and University ... SKY92, SkylineDx,s prognostic tool to risk-stratify patients with multiple myeloma ... MUK nine . The University of Leeds ... partly funded by Myeloma UK, and ICR will perform the ...
Breaking Biology Technology: