Photoswitch controls DNA duplex creation, separation

FEBRUARY 18, 2009--Researchers at Riken, one of Japan's largest research organizations, have developed a light-controlled switch to regulate the formation and separation of DNA duplexes. Their creation may have implications for numerous biological processes, including gene regulation.

Formation of nucleic acid complexes underlies many biological events. And hybridization of the nucleic acids, through base pairing, produces the intricate complexes responsible for the creation of DNA duplexes. The ability to control hybridization, and consequently biological events, has been a key goal for scientists. Shinzi Ogasawara and Mizuo Maeda of Riken's Advanced Science Institute (Wako, Japan) have described how the switch directs the formation and destabilization of a series of DNA duplexes in a paper published by Angewandte Chemie International Edition.

They designed the photoswitch, a photochromic nucleoside (PCN), with several fundamental properties and benefits. The switch can be easily incorporated into a DNA strand and its physical conformation can be altered reversibly when irradiated by an external light source. Change of the physical conformation, by isomerization, disrupts and destabilizes the hybridization of two DNA strands.

Another benefit of the PCN switch is that installing it into DNA has little influence on the structure of the duplex when it forms. Further, the PCN can be used as molecular trace label because it is fluorescent. This PCN photoswitch is therefore easy to track in the body and could be used in living cells without disruption.

The researchers irradiated a series of reaction mixtures containing PCN-modified DNA duplexes, which were fluorescent, with light at 370 nm for 5 minutes. After this time, only a slight fluorescence was seen. The PCN fragments had isomerized and the duplex broken. They then irradiated the mixtures at 254 nm for 2 minutes and the fluorescence returned, indicating a change back in conformation of the PCNs and importantly, hybridization to re-form the duplexes (Fig. 1). This switching showed good reversibility over two cycles.

Surprisingly, this easy switching system also works below room temperature. "There were no particular problems we had to overcome," says Ogasawara. However, the synthesis of the PCNs was not as straightforward as they would have liked.

Ogasawara and Maeda now want to build on the results of this current study. "We plan to apply this technology to gene regulation such as antigene, antisense and siRNA," says Ogasawara. "We think that this light-switching technique can be applied to nanotechnology, for example [using] light [to] control DNA nanomachines and architectures."

More information:
See the paper, Straightforward and reversible photoregulation of hybridization by using a photochromic nucleoside, in Angewandte Chemie International.

Posted by Barbara G. Goode, barbarag@pennwell.com, for BioOptics World.

Get All the BioOptics World News Delivered to Your Inbox

Subscribe to BioOptics World Magazine or email newsletter today at no cost and receive the latest news and information.

 Subscribe Now
Related Articles

NANOTECHNOLOGY/LIGHT ACTIVATION: IR light method turns blood clotting on (like drugs) and off (like nothing else)

Gold nanoparticles, controlled by infrared (IR) light from a pulsed femtosecond laser, promise to promote wound healing and help doctors control blood clotting in patients undergoing surgery.

Microscopy helps discover potential new drug target for cystic fibrosis

An international team of scientists, using automated microscopy and genetics, have discovered a promising potential drug target for cystic fibrosis.

Next-gen DNA sequencing helps provide new genetic clue to anorexia

The largest next-generation DNA sequencing study of anorexia nervosa to date has linked the eating disorder to variants in a gene coding for an enzyme that regulates cholesterol metabolism.

Synchrotron light identifies RNA double helix structure

Scientists at McGill University have crystallized a short RNA sequence, poly (rA)11, and used data collected at the Canadian Light Source (CLS) and the Cornell High Energy Synchrotron to confirm th...

BLOGS

Neuro15 exhibitors meet exacting demands: Part 2

Increasingly, neuroscientists are working with researchers in disciplines such as chemistry and p...

Why be free?

A successful career contributed to keeping OpticalRayTracer—an optical design software program—fr...

LASER Munich 2015 is bio-bent

LASER World of Photonics 2015 included the European Conferences on Biomedical Optics among its si...

White Papers

Understanding Optical Filters

Optical filters can be used to attenuate or enhance an image, transmit or reflect specific wavele...

How can I find the right digital camera for my microscopy application?

Nowadays, image processing is found in a wide range of optical microscopy applications. Examples ...

CONNECT WITH US

            

Twitter- BioOptics World

Copyright © 2007-2016. PennWell Corporation, Tulsa, OK. All Rights Reserved.PRIVACY POLICY | TERMS AND CONDITIONS