Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A New Connection between Metabolism and Regulation

22.12.2014

Heidelberg scientists discover modified ribonucleic acids in bacteria

In cells, ribonucleic acids (RNAs) are most commonly known as messengers or scaffold molecules, but they can also accelerate key biochemical reactions and regulate metabolic pathways. These regulatory RNAs were discovered just a few years ago.

In studies on bacteria, scientists from Heidelberg University have now found previously unknown modifications in the RNAs that contribute to their stability against the degradation mechanisms of the cell. Among other things, regulatory RNAs are associated with cancer development and bacterial infections. The findings of the research at the Institute of Pharmacy and Molecular Biotechnology were published in the journal “Nature”.

In bacteria, most of these regulatory RNAs act by binding other RNA molecules, e.g. messenger RNAs, thereby triggering the degradation of the resulting complexes. As a consequence, the bound RNAs are no longer available for the biosynthesis of proteins, Prof. Dr. Andres Jäschke of the Institute of Pharmacy and Molecular Biotechnology explains.

“So far, regulatory RNAs had been assumed to be composed of the four standard building blocks, the nucleotides A, C, G and U. We were now able to show that some regulatory RNAs in the gut bacterium Escherichia coli carry a particular modification at their ends that confers increased stability against the cell’s degradation machinery.” Furthermore, the team headed by Prof. Jäschke found an enzyme that can remove this modifying cap and release the previously protected RNA for degradation. According to Prof. Jäschke, the modifier is an “old acquaintance”, i.e. nicotinamide adenine dinucleotide (NAD), which assumes a key role in the metabolism of both bacteria and higher organisms.

These NAD-modified regulatory RNAs can be isolated by a novel method that was developed by chemist Dr. Hana Cahová and biotechnologist Dr. Marie-Luise Winz. In their approach, an enzyme from a marine mollusc and a technique known as “click chemistry” were used to label only the NAD-modified RNA molecules contained in a total RNA sample, while all others remained unaltered.

The labelled RNAs can thus be selectively isolated and identified by high-throughput sequencing and comparison with databases. “For many of the modified RNAs we identified, no biological function is known to date. Interestingly, others have been described in the context of cellular metabolism or associated with the bacterial response to ‘stress’ caused by extreme environmental conditions,” Andres Jäschke notes.

The scientists have now looked into the question why a bacterium modifies some of its regulatory RNAs with NAD. “As the chemical nature of the ends was known to be a key factor in the degradation of RNA by cellular enzymes, we assumed that the NAD modification might stabilize the RNA,” says biotechnologist Katharina Höfer. Together with biochemist Gabriele Nübel, she thus investigated several known degradation pathways.

The researchers could indeed demonstrate a significantly increased stabilisation against two modification and degradation enzymes. As it would be useful for the cell to cleave off the protective cap once its purpose is fulfilled, the scientists tested further enzymes and discovered what they were looking for yet again: one of the enzymes was able to remove NAD and thus initiate RNA degradation.

Andres Jäschke’s team suspect the attached NAD to have additional functions. “The nicotinamide adenine dinucleotide interacts with many proteins in a specific manner, so the NAD-RNAs might form protein complexes as well, which, in turn, might regulate various processes in the bacterium. In addition, NAD can occur in the cell in two different forms, namely in an oxidised and in a reduced one. The equilibrium between these two states may influence and modulate the biological function of NAD-RNAs,” Prof. Jäschke explains.

While protective caps at the ends of RNA have been known for decades in higher organisms, this is the first study to report a cap-like – but chemically different – structure in bacteria, according to the scientists. These investigations open up a new research area, as the biological functions and the mechanisms of this new modification now need to be clarified. “We are particularly interested to find out whether these NAD modifications are present in bacteria only or in higher organisms as well,” comments Andres Jäschke. “If this were a phenomenon specific to bacteria, it might provide clues for new antibacterial treatments.”

The research work was supported by fellowships from the Alexander von Humboldt Foundation and the Hartmut Hoffmann-Berling International Graduate School for Molecular and Cellular Biology (HBIGS) of Heidelberg University.

Original Publication:
Cahová, H., Winz, M.-L., Höfer, K., Nübel, K. & Jäschke, A.: NAD captureSeq indicates NAD as a bacterial cap for a subset of regulatory RNAs. Nature (22 December 2014), DOI 10.1038/nature14020

Internet information:
http://www.jaeschke.uni-hd.de

Contact:
Prof. Dr. Andres Jäschke
Institute of Pharmacy und Molecular Biotechnology
Phone +49 6221 54-4853
jaeschke@uni-hd.de

Marietta Fuhrmann-Koch | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-heidelberg.de

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>