Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Light games with DNA

13.12.2010
The toolbox for imaging DNA now comes with an artificial DNA fluorescent base that can be ‘switched off’

The diagnosis of hereditary diseases and the identification of genetic fingerprints hinge on high-sensitivity DNA imaging biotechnologies. These imaging tools detect specific genes in cells using fluorophores—fluorescent tags that can illuminate DNA structures—and quenchers that interact with these tags to prevent them from emitting light, effectively working as an ‘off switch’.

In a development that expands the detection toolbox and the genetic alphabet, a team led by Ichiro Hirao from the RIKEN Systems and Structural Biology Center, Yokohama, has now designed an artificial base pair between a fluorophore (Dss) and quenchers (Pn and Px)¹. This method incorporates the pair into complementary DNA strands using polymerases and demonstrates that either Pn or Px can decrease the fluorescence of Dss upon hybridization.

Hirao and his team previously developed artificial base pairs involving Dss because of its strong fluorescence, which could illuminate DNA and RNA structures. “This time, we can put out the candle lit by Dss using the quencher as its pairing partner at will,” he says.

Hirao notes that this ability is unique because fluorescent dye Dss and quencher Pn face each other on their respective ssDNA strand, forming an artificial DNA base pair that also works in biological systems. He says that this close proximity results in strong ‘contact quenching’ of the fluorophore.

Usually, researchers have attached fluorophores and quenchers to natural bases through a linker that mediates so-called fluorescence resonance energy transfer (FRET) between dyes. However, this process lacks efficiency compared to contact quenching. Also, according to Hirao, unlike the Dss–Pn system, typical fluorophore–quencher pairs cannot be introduced at specific positions in DNA strands using polymerases, limiting their applications.

After establishing that the pairs were compatible with natural DNA synthesis techniques, Hirao’s team integrated the Dss–Pn pair in the stem of molecular beacons—hairpin-shaped single-stranded DNA (ssDNA) structures that fluoresce upon hybridization with DNA targets. They found that the beacons detected the targets with high sensitivity and differentiated ssDNA containing one mismatched base.

Next, the researchers tested the performance of Dss–Px in polymerase chain reaction (PCR)—a powerful DNA amplification technique. Dss-bearing ssDNA fragments became less fluorescent upon assimilation of Px into synthesized DNA chains, allowing the team to monitor the amplification process in real time.

“One of our present tasks is to apply this system to in vivo cell experiments,” says Hirao. “If it is possible, we will be able see the on–off of a specific gene expression.”

The corresponding author for this highlight is based at the Nucleic Acid Synthetic Biology Research Team, RIKEN Systems and Structural Biology Center

Journal information

1. Kimoto, M., Mitsui, T. Yamashige, R., Sato, A., Yokoyama, S. & Hirao, I. A new unnatural base pair system between fluorophore and quencher base analogues for nucleic acid-based imaging technology. Journal of the American Chemical Society 132, 15418–15426 (2010).

gro-pr | Research asia research news
Further information:
http://www.riken.jp
http://www.researchsea.com

More articles from Life Sciences:

nachricht Cells communicate in a dynamic code
19.02.2018 | California Institute of Technology

nachricht Studying mitosis' structure to understand the inside of cancer cells
19.02.2018 | Biophysical Society

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Contacting the molecular world through graphene nanoribbons

19.02.2018 | Materials Sciences

When Proteins Shake Hands

19.02.2018 | Materials Sciences

Cells communicate in a dynamic code

19.02.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>