Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NIH Scientists Determine How Environment Contributes to Several Human Diseases

27.11.2014

Using a new imaging technique, National Institutes of Health researchers have found that the biological machinery that builds DNA can insert molecules into the DNA strand that are damaged as a result of environmental exposures.

These damaged molecules trigger cell death that produces some human diseases, according to the researchers. The work, appearing online Nov. 17 in the journal Nature, provides a possible explanation for how one type of DNA damage may lead to cancer, diabetes, hypertension, cardiovascular and lung disease, and Alzheimer’s disease.


Bret Freudenthal, NIEHS

After the DNA polymerase (gray molecule in background) inserts a damaged nucleotide into DNA, the damaged nucleotide is unable to bond with its undamaged partner. As a result, the damaged nucleotide swings freely within the DNA, interfering with the repair function or causing double-strand breaks. These steps may ultimately lead to several human diseases.

Time-lapse crystallography was used by National Institute of Environmental Health Sciences (NIEHS) researchers to determine that DNA polymerase, the enzyme responsible for assembling the nucleotides or building blocks of DNA, incorporates nucleotides with a specific kind of damage into the DNA strand. Time-lapse crystallography is a technique that takes snapshots of biochemical reactions occurring in cells.

Samuel Wilson, M.D., senior NIEHS researcher on the team, explained that the damage is caused by oxidative stress, or the generation of free oxygen molecules, in response to environmental factors, such as ultraviolet exposure, diet, and chemical compounds in paints, plastics, and other consumer products. He said scientists suspected that the DNA polymerase was inserting nucleotides that were damaged by carrying an additional oxygen atom.

“When one of these oxidized nucleotides is placed into the DNA strand, it can’t pair with the opposing nucleotide as usual, which leaves a gap in the DNA,” Wilson said. “Until this paper, no one had actually seen how the polymerase did it or understood the downstream implications.”

Wilson and his colleagues saw the process in real time, by forming crystal complexes made of DNA, polymerase, and oxidized nucleotides, and capturing snapshots at different time points through time-lapse crystallography. The procedure not only uncovered the stages of nucleotide insertion, but indicated that the new DNA stopped the DNA repair machinery from sealing the gap. This fissure in the DNA prevented further DNA repair and replication, or caused an immediate double-strand break.

“The damaged nucleotide site is akin to a missing plank in a train track,” Wilson said. “When the engine hits it, the train jumps the track, and all of the box cars collide.”

Large numbers of these pileups and double-strand breaks are lethal to the cell, serving as a jumping off point for the development of disease. However, it can be a good thing if you are a researcher trying to destroy a cancer cell.

“One of the characteristics of cancer cells is that they tend to have more oxidative stress than normal cells,” said Bret Freudenthal, Ph.D., lead author of the paper and postdoctoral fellow in Wilson’s group. “Cancer cells address the issue by using an enzyme that removes oxidized nucleotides that otherwise would be inserted into the genome by DNA polymerases. Research performed by other groups determined if you inhibit this enzyme, you can preferentially kill cancer cells.”

Wilson and Freudenthal stressed that the quantities of oxidized nucleotides in the nucleotide pool are usually under tight control, but if they accumulate and start to outnumber undamaged nucleotides, the DNA polymerase adds more of them to the strand. Molecules that inhibit oxidation, known as antioxidants, reduce the level of oxidized nucleotides, and may help prevent some diseases.

Reference: Freudenthal BD, Beard WA, Perera L, Shock DD, Kim T, Schlick T, Wilson SH. 2014. Uncovering the polymerase-induced cytotoxicity of an oxidized nucleotide. Nature; doi:10.1038/nature13886 [Online 17 November 2014].

Grant numbers:
Z01ES050158
Z01ES050161
ZICES043010
U19CA105010

NIEHS supports research to understand the effects of the environment on human health and is part of NIH. For more information on environmental health topics, visit http://www.niehs.nih.gov . Subscribe to one or more of the NIEHS news lists (http://www.niehs.nih.gov/news/newslist/index.cfm ) to stay current on NIEHS news, press releases, grant opportunities, training, events, and publications.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov .

NIH...Turning Discovery Into Health ®

Robin Arnette | newswise

More articles from Life Sciences:

nachricht Cloud Formation: How Feldspar Acts as Ice Nucleus
09.12.2016 | Karlsruher Institut für Technologie

nachricht Closing the carbon loop
08.12.2016 | University of Pittsburgh

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>