Once messenger RNA (mRNA) has done its job - conveying the information to produce the proteins necessary for a cell to function - it is no longer required and is degraded. Scientists have long thought that the decay started after translation was complete and that decaying RNA molecules provided little biological information.
Now a team from EMBL Heidelberg and Stanford University led by Lars Steinmetz has turned this on its head in an article published in Cell. The researchers have shown that one end of the mRNA begins to decay while the other is still serving as a template for protein production. Thus, studying the decaying mRNA also provides a snapshot of how proteins are produced.
The discovery was made almost by accident. As part of research into how DNA is transcribed into mRNA, co-researchers Vicent Pelechano and Wu Wei developed an in vivo method to count decaying mRNA molecules in the cell. mRNA has a protective 'cap' that prevents it from being degraded - once that cap is removed, the decay begins. The researchers spotted a pattern in the distribution of the 'cap-less' RNA that they didn't expect.
Vicent Pelechano, from the Steinmetz group at EMBL Heidelberg, explains: "The decaying RNA was thought to be of little interest biologically, so we were really surprised to see a pattern. We looked more deeply into it because it appeared to be linked to the genetic code, but we never expected it to lead to a completely new understanding of how mRNA and ribosomes interact."
Proteins are produced from mRNA by ribosomes - 'molecular machines' that pass successively along the mRNA to translate its nucleotides into amino acids. It was thought that the mRNA only started to decay once the final ribosome had left it and translation was complete. In fact, the researchers were able to determine that the protective 'cap' is removed and degradation begins even while ribosomes are still associated with the mRNA.
They demonstrated that the enzyme degrading mRNA follows closely behind the ribosome, pausing at set points along the mRNA, usually after each group of 3 nucleotides, the section of code that relates to one amino acid. The team believes that this shows the enzyme pausing while translation goes on - allowing the ribosome to do its work and move on - before starting to degrade the mRNA previously protected by the ribosome.
This novel approach also opens up new avenues to study ribosomes. "Researchers studying ribosome activity usually use drugs to stall the ribosomes in place. This can alter the way we perceive their activity. We are simply looking for the molecules remaining from mRNA decay and determining their distribution. We believe this shows a more accurate picture of what is happening to the mRNA and the ribosome than was previously possible," explains Wu Wei of Stanford University.
Isabelle Kling | EurekAlert!
Bare bones: Making bones transparent
27.04.2017 | California Institute of Technology
Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel
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...
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...
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...
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...
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...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
27.04.2017 | Life Sciences
27.04.2017 | Physics and Astronomy
27.04.2017 | Earth Sciences