Generating offspring is the evolutionary goal of all living organisms. The multiplication of individual cells is coordinated by the cell cycle. For the discovery of how this process is regulated in eukaryotes the Noble Prize was awarded in 2001.
The team of Prof. Urs Jenal at the Biozentrum of the University of Basel has now identified the central switch for reproduction in bacteria. While cell cycle progression in eukaryotes is regulated by small proteins called cyclins, in bacteria this role is adopted by a small signaling molecule, c-di-GMP. In the current issue of «Nature» the scientists describe the molecular details of this process.
Though very tiny, the molecule is vital for the survival of almost all bacteria. This signaling messenger – called c-di-GMP – controls behavioral processes in bacteria. For instance, it ensures that bacteria join together to form biofilms, which can cause chronic infections in humans.
The scientists working with Prof. Urs Jenal at the Biozentrum of the University of Basel have now demonstrated that c-di-GMP also plays a decisive role in bacterial reproduction. They discovered that oscillating levels of the messenger subsequently influence the activity of key regulatory proteins, thereby controlling cell cycle progression and proliferation of bacteria.
Signaling molecule sets traffic lights at check points
How do cells multiply? When cells divide, two daughter cells arise from one mother cell. Before this, however, the cell must go through several phases from growth, to the replication of its genetic information and finally to cell division.
This process is known as the cell cycle. In their study on the model bacterium Caulobacter crescentus the infection biologists show for the first time, that the signaling messenger c-di-GMP controls the cell cycle in a similar way as a traffic light works. In the absence of c-di-GMP in the cell, the light shows red.
This indicates that the cell will have to remain in the first phase of the cell cycle. If the c-di-GMP level increases, the light switches to green and the cell enters the next phase. The scientists have investigated what exactly occurs on the molecular level.
c-di-GMP controls an enzyme with two modes of action
The role of this traffic light is played by an enzyme that works in two different ways. “When c-di-GMP is lacking, it blocks the process which leads to replication of the genetic material,” explains Jenal. “However, as soon as c-di-GMP is produced, it binds to the enzyme, thus altering its structure and mode of action. Subsequently, this blockade is lifted and the bacterial chromosomes can be copied.”
This step marks the entry into the next phase of the cell cycle. The varying spatial distribution of the signaling molecule in the dividing mother cell also plays an important role in the behavior of the progeny.
Pathogens use the same signaling network
It is the first time that the researchers have been able to establish a direct connection between the two major regulatory networks of bacterial cells, – the small messenger and important regulatory enzymes called kinases. The insights gained provide an important basis for elucidating the much more complicated c-di-GMP networks of pathogens.
The signaling molecule is involved in virulence, persistence mechanisms and antibiotic resistance of pathogens. For instance, dangerous pathogens causing cholera or pneumonia use c-di-GMP signaling to survive in their human host. As a next step, the researchers want to figure out, whether this molecule acts in these pathogens in the same way as in the model bacterium C. crescentus.
Lori C, Ozaki S, Steiner S, Böhm R, Abel S, Dubey BN, Schirmer T, Hiller S, and Jenal U.
Cyclic di-GMP acts as a cell cycle oscillator to drive chromosome replication. Nature; published online 6th May 2015.
Prof. Urs Jenal, Biozentrum University of Basel, Tel: +41 61 267 21 35,
Christoph Dieffenbacher | Universität Basel
Atomic-level motion may drive bacteria's ability to evade immune system defenses
24.04.2017 | Indiana University
Two-dimensional melting of hard spheres experimentally unravelled after 60 years
24.04.2017 | University of Oxford
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
24.04.2017 | Physics and Astronomy
24.04.2017 | Materials Sciences
24.04.2017 | Life Sciences