Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers divide enzyme to conquer genetic puzzle

15.03.2013
Rice University scientists find split, mutant protein serves as building block for synthetic biological circuits
Rice University researchers have found a way to divide and modify enzymes to create what amounts to a genetic logic gate.

Biochemist Matthew Bennett and graduate student David Shis created a library of AND gates by mutating a protein from a bacterial virus. The well-understood protein known as T7 RNA polymerase (RNAP) is a strong driver of transcription in cells.

Their discovery should help overcome a bottleneck in the development of synthetic gene networks that mimic digital circuitry. These networks could become diagnostic systems that look for signs of disease and, perhaps, gene therapies to find and treat disease in one step.

The research appeared online this week in the Proceedings of the National Academy of Sciences.

“AND logic gates are normally found in electronics: You have a circuit with two inputs and one output,” said Bennett, an assistant professor of biochemistry and cell biology. “In an AND gate, if the two wires leading to the gate are both on, then the output is also on. If either one or both are off, then the output is turned off.”

Few options have been available to researchers seeking reliable and flexible components for their synthetic circuits. The library of AND gates created at Rice should add significantly to the toolbox available to build larger and more complex gene circuits, Bennett said.

In its native, full-length state, T7 RNAP turns on genes that have a specific “promoter,” or target DNA sequence. The Rice researchers found they could program DNA to express the RNAP in two pieces, which could be manipulated via point mutations to target different promoters in a host cell. “The two pieces of the RNAP might even be made in different parts of the cell and they’ll still find each other,” Bennett said. “They have an affinity for each other, and once they combine, they’ll work together as if they hadn’t been split.”

The enzyme carried out its function only when both halves of the split RNAP were present. Bennett and Shis modified the bacterium E. coli to produce the RNAP segments in response to specific sugar molecules found in the environment. One half of the RNAP is produced only in the presence of arabinose and the other in the presence of lactose. When both sugars were found, their proof-of-concept polymerase would turn on a target gene, in this case a reporter gene that encodes a green fluorescent protein.

Better yet, the RNAP was orthogonal; that is, it didn’t fraternize with the E. coli’s native protein pathways. “This special T7 RNAP will not turn on any other gene but its specific target,” Bennett said. “In that way, it’s transparent to the host. This gives us an easy way to determine whether or not it’s working.”

The researchers found that while split T7 RNAP was not as active in expressing protein products as the full-length polymerase, the pieces were more stable and less prone to mutations that could affect a gene circuit’s function.

Bennett said the next step would be to test the split RNAP in hosts other than E. coli. “We want to port this into more complicated organisms: eukaryotes like yeast or zebrafish or mammalian cells. It will take a little bit of engineering to get them to work in more complicated organisms.”

He sees advanced diagnostics as a reasonable goal for gene circuits using AND gates. “The two inputs can be programmed to respond to separate conditions, whether they’re environment factors outside the organism or tissue-specific markers within a multicellular organism,” Bennett said.

“For instance, your inputs could be cancer markers that would trigger a fluorescent reporter gene for diagnosis or tumor suppressors for treatment,” he said. In addition, multiple gates from the library could be combined and layered to create more complicated circuits that simultaneously monitor many variables. “This means you could build circuits that turn on only in very specific conditions, which is important if you want to kill tumor cells without harming healthy tissue.”

The National Institutes of Health, the National Science Foundation and the Welch Foundation supported the research.

Read the abstract at http://dx.doi.org/10.1073/pnas.1220157110

This news release can be found online at http://news.rice.edu/2013/03/14/researchers-divide-enzyme-to-conquer-genetic-puzzle/

Follow Rice News and Media Relations via Twitter @RiceUNews.

Jeff Falk | EurekAlert!
Further information:
http://www.rice.edu

More articles from Life Sciences:

nachricht Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz

nachricht Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>