Featured Research

from universities, journals, and other organizations

Protein Discovery Tied To DNA Master Switch

Date:
December 21, 2001
Source:
University Of North Carolina School Of Medicine
Summary:
A new cellular protein discovered by scientists at the University of North Carolina at Chapel Hill appears to be a crucial molecular component of a master switch that turns genes on and off.

CHAPEL HILL - A new cellular protein discovered by scientists at the University of North Carolina at Chapel Hill appears to be a crucial molecular component of a master switch that turns genes on and off.

The new molecule may prove critical to the regulation of gene expression. If so, it could eventually lead to new treatments for diseases and provide information vital to research aimed at using stem cells to generate organs.

The discovery of the new molecule, SET7, was headed by Dr. Yi Zhang, assistant professor of biochemistry at UNC-CH School of Medicine and a member of the UNC Lineberger Comprehensive Cancer Center. A report of the research is published in the December 21 issue of the journal Molecular Cell.

All gene expression must be tightly controlled, Zhang said. "When we talk about genes, we're talking about DNA in the cell nucleus that's complexed with several basic proteins called histones. The basic structure is like 'beads on a string' which can be further packaged into a high order structure called chromatin," he explained.

"This chromatin packaging allows for efficient storage of genetic information. But it also impedes access to DNA by transcription factors, proteins that regulate gene expression."

Zhang and his colleagues believe their discovery to be part of the mechanism that dynamically changes the chromatin structure, its loosening or tightening. They focused their attention on a particular covalent modification -- methylation, addition of a methyl group to lysine, one of the amino acids that comprise the tail domain of the histone molecules.

Why lysine? Because recent research had linked gene silencing, or deactivation, to methylation of a particular lysine site (lysine 9) on the tail of the histone H3.

As it turns out, modifications of amino acids by methylation mainly occur on lysine. "We've known for three decades that histone can be methylated, but nobody knew the identity of the enzymes responsible for this modification until a year ago when the first lysine 9-specific histone methyltransferase was identified," Zhang said. "The new enzyme we identified, SET7, specifically modifies lysine 4, a different residue on the histone H3 N-terminal tail. It's the first protein ever identified from higher eukaryotes [including all mammals] that methylates histone H3 at lysine 4."

"By methylating H3-lysine 4, SET7 makes the chromatin structure more open, so other proteins can access the gene." The study team also determined that methylation of histone H3 at lysine 4 and lysine 9 inhibit each other. Thus, the findings suggest that methylation of either lysine 4 or 9 could determine gene activation or silencing.

Still, the situation is more complex than that. Among the possibilities, SET7 could have functioning partners yet to be identified. "We know the enzyme modifies lysine 4. After it's modified, we don't know exactly how the gene turns on," Zhang said. Study co-author Dr. Christoph Borchers, assistant professor of biochemistry at the medical school, used mass spectrometry to help identify the protein by measuring the atomic masses of its fragments.

Zhang is currently studying the possible importance of SET7 in embryogenesis, development at the very beginnings of life.

The research was supported with funds from the National Institute of General Medicine at NIH and the American Cancer Society. Zhang's UNC co-authors along with Borchers are Dr. Hengbin Wang; Ru Cao, doctoral student; Li Xia, technician. Drs. Hdiye Erdjument-Bromage and Paul Tempest were co-authors from Memorial Sloan Kettering Cancer Center in New York.


Story Source:

The above story is based on materials provided by University Of North Carolina School Of Medicine. Note: Materials may be edited for content and length.


Cite This Page:

University Of North Carolina School Of Medicine. "Protein Discovery Tied To DNA Master Switch." ScienceDaily. ScienceDaily, 21 December 2001. <www.sciencedaily.com/releases/2001/12/011221081457.htm>.
University Of North Carolina School Of Medicine. (2001, December 21). Protein Discovery Tied To DNA Master Switch. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2001/12/011221081457.htm
University Of North Carolina School Of Medicine. "Protein Discovery Tied To DNA Master Switch." ScienceDaily. www.sciencedaily.com/releases/2001/12/011221081457.htm (accessed October 21, 2014).

Share This



More Health & Medicine News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

CDC Revamps Ebola Guidelines After Criticism

CDC Revamps Ebola Guidelines After Criticism

Newsy (Oct. 21, 2014) The Centers for Disease Control and Prevention have issued new protocols for healthcare workers interacting with Ebola patients. Video provided by Newsy
Powered by NewsLook.com
First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

Newsy (Oct. 21, 2014) A medical team has for the first time given a man the ability to walk again after transplanting cells from his brain onto his severed spinal cord. Video provided by Newsy
Powered by NewsLook.com
CDC Issues New Ebola Guidelines for Health Workers

CDC Issues New Ebola Guidelines for Health Workers

Reuters - US Online Video (Oct. 21, 2014) The U.S. Centers for Disease Control and Prevention has set up new guidelines for health workers taking care of patients infected with Ebola. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
'Cadaver Dog' Sniffs out Human Remains

'Cadaver Dog' Sniffs out Human Remains

AP (Oct. 21, 2014) Where's a body buried? Buster's nose can often tell you. He's a cadaver dog, specially trained to find human remains and increasingly being used by law enforcement and accepted in courts. These dogs are helping solve even decades-old mysteries. (Oct. 21) Video provided by AP
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