Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mechanical forces could affect gene expression

03.02.2010
University of Michigan researchers have shown that tension on DNA molecules can affect gene expression---the process at the heart of biological function that tells a cell what to do.

Scientists understand the chemistry involved in gene expression, but they know little about the physics. The U-M group is believed to be the first to actually demonstrate a mechanical effect at work in this process. Their paper is published in the current edition of Physical Review Letters.

"We have shown that small forces can control the machinery that turns genes on and off. There's more to gene regulation than biochemistry. We have to look at mechanics too," said Jens-Christian Meiners, associate professor in the Department of Physics and director of the biophysics program.

A better understanding of how cells regulate themselves could lead to new insights into how the process could fail and lead to disease.

"When cells start to misinterpret regulatory signals, cardiac disease, birth defects, and cancer can result. In fact, mechanical signals have been implicated as a culprit in a variety of pathologies," said Joshua Milstein, a research fellow in the Department of Physics.

To perform their experiment, the scientists used custom "optical tweezers," or lasers, to pull on the ends of bacterial DNA strands with 200 femtonewtons of force, said Yih-Fan Chen, a doctoral student in the Department of Biomedical Engineering. Chen designed and built the tweezers.

The force they used corresponds roughly to the weight of one-billionth of a grain of rice.

In segments of DNA that were tethered to a microscope slide, the scientists observed a 10-fold decrease in the rate at which the strands looped in on themselves.

DNA looping prevents genes within the loops from being expressed. A common mechanism for gene regulation, it also occurs in complex organisms including humans. Specialized proteins act as buckles to connect distant points on the DNA to form the loops. That's the chemistry part. The challenge for physics is to understand how the DNA bends so those distant points can come together.

While this experiment was performed on free DNA, the scientists say forces as much as 100 times stronger are regularly created inside cells as contents shift and buffet each other.

"If we can basically shut this process down with the tiniest force, how could all these larger forces not have an impact on gene expression?" Milstein said.

Meiners and his team are striving for a quantitative understanding of this biological process. He likens the current state of our understanding of gene expression to a diagram. He is searching for equations, and these results begin to provide that.

"We can tell you how long you'll have to wait for a DNA loop to form based on how much force you apply to the DNA," Meiners said. "We're one step closer to understanding cells quantitatively."

The paper is called "Femtonewton Entropic Forces Can Control the Formation of Protein-Mediated DNA Loops."

This research is funded by the National Institutes of Health and the National Science Foundation.

For more information:

Jens-Christian Meiners: http://biop.lsa.umich.edu/meiners-jens-christian.aspx

Nicole Casal Moore | EurekAlert!
Further information:
http://www.umich.edu
http://prl.aps.org/abstract/PRL/v104/i4/e048301

More articles from Physics and Astronomy:

nachricht Seeing the quantum future... literally
16.01.2017 | University of Sydney

nachricht Airborne thermometer to measure Arctic temperatures
11.01.2017 | Moscow Institute of Physics and Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>