Featured Research

from universities, journals, and other organizations

Novel protein critical for cellular proliferation discovered

Date:
October 8, 2010
Source:
School of Molecular and Cellular Biology, University of Illinois, Urbana
Summary:
Researchers have identified a novel protein that is highly conserved in higher eukaryotes. They have shown that in human cells, this protein binds to heterochromatic structures, and plays an essential role in DNA replication.

Accurate duplication of genetic material and the faithful segregation of chromosomes are critical for cell survival. The initiation of DNA replication is linked both to cell cycle progression and chromatin organization. In plants, animals and other "eukaryotes," the assembly of a multi-protein complex called pre-replicative complex (preRC) is the first step in the initiation of DNA replication. As the name implies, origin recognition complex (ORC) proteins bind to origins of DNA replication. Subsequently, other components of preRC are assembled at these sites.

In addition to its role in DNA replication, ORC is also involved in gene silencing and organization of the tightly packed DNA, called heterochromatin. How ORC is brought to the DNA in human cells had previously remained a mystery.

Researchers at the University of Illinois, led by Professor Supriya Prasanth from the school of molecular and cellular biology, have identified a novel protein that is highly conserved in higher eukaryotes. They have shown that in human cells, this protein (once known as LRWD1 but renamed ORCA, for "ORC-associated" protein) associates with ORC and shows similar cell cycle dynamics to ORC. Along with ORC, this protein binds to heterochromatic structures, including centromeres and telomeres, which are important to cell division and chromosome maintenance.

The researchers further demonstrated that ORCA efficiently recruits ORC to chromatin, the DNA and proteins that make up the chromosome. Depletion of ORCA in human primary cells as well as in embryonic stem cells results in the loss of ORC binding to chromatin and subsequent arrest of cells in a vital phase of the cell cycle. Loss of ORCA results in defects in cellular proliferation, suggesting that a fine-tuned balance in the levels of ORCA is maintained in a normal cell. These results suggest that a novel protein, ORCA, is critical for initiation of DNA replication and heterochromatin organization in mammalian cells.

This work appears in the October 8, 2010 issue of the journal Molecular Cell.

"The discovery of this new protein is going to be revolutionary in the field of replication and cell cycle," Prasanth said. "We all know that diseases like cancer are caused by uncontrolled proliferation of cells, and our data demonstrates that ORCA controls proliferation of cells. This work is going to have important implications in cancer biology."

The study was spearheaded by Zhen Shen, a graduate student, with assistance from post-doctoral fellows Kizhakke M. Sathyan and Arindam Chakraborty. Other Illinois researchers on the study include Kannanganattu Prasanth, a professor in the department of cell and developmental biology; his graduate student Ruiping Zheng; Brian Freeman, a professor in the department of cell and developmental biology; Fei Wang, a professor in cell and developmental biology; and his graduate student Yejie Geng. The funding for this study was provided by National Science Foundation, and The Leukemia and Lymphoma Society, through a Special Fellow Award granted to Supriya Prasanth.


Story Source:

The above story is based on materials provided by School of Molecular and Cellular Biology, University of Illinois, Urbana. Note: Materials may be edited for content and length.


Journal Reference:

  1. Zhen Shen, Kizhakke M. Sathyan, Yijie Geng, Ruiping Zheng, Arindam Chakraborty, Brian Freeman, Fei Wang, Kannanganattu V. Prasanth, Supriya G. Prasanth. A WD-Repeat Protein Stabilizes ORC Binding to Chromatin. Molecular Cell, Volume 40, Issue 1, 99-111, 8 October 2010 DOI: 10.1016/j.molcel.2010.09.021

Cite This Page:

School of Molecular and Cellular Biology, University of Illinois, Urbana. "Novel protein critical for cellular proliferation discovered." ScienceDaily. ScienceDaily, 8 October 2010. <www.sciencedaily.com/releases/2010/10/101007123115.htm>.
School of Molecular and Cellular Biology, University of Illinois, Urbana. (2010, October 8). Novel protein critical for cellular proliferation discovered. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2010/10/101007123115.htm
School of Molecular and Cellular Biology, University of Illinois, Urbana. "Novel protein critical for cellular proliferation discovered." ScienceDaily. www.sciencedaily.com/releases/2010/10/101007123115.htm (accessed July 28, 2014).

Share This




More Health & Medicine News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
West Africa Gripped by Deadly Ebola Outbreak

West Africa Gripped by Deadly Ebola Outbreak

AFP (July 28, 2014) The worst-ever outbreak of the deadly Ebola epidemic grips west Africa, killing hundreds. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
Powered by NewsLook.com
Google's Next Frontier: The Human Body

Google's Next Frontier: The Human Body

Newsy (July 27, 2014) Google is collecting genetic and molecular information to paint a picture of the perfectly healthy human. 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:
from the past week

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