All living organisms consist of cells that have arisen from other living cells by the process of cell division. In order to ensure that the genetic material is equally and accurately distributed between the two daughter cells during cell division, the DNA fibers must remain in an orderly and closely-packed condition.
At the Max Planck Institute (MPI) of Biochemistry in Martinsried near Munich, scientists have now elucidated how this packaging process works in bacteria. Their studies showed that the SMC protein complex holds DNA together like a clip and thus keeps the genetic material in order.
In each human cell, about two meters of DNA must fit into a cell nucleus that has a diameter of only a few thousandths of a millimeter. Here, the DNA is organized in individual chromosomes. In order to ensure the DNA’s secure transport during cell division, the long and coiled DNA fibers must be tightly packed.
So far, scientists have only a sketchy understanding of this step: The SMC protein complexes play a key role in this process. They consist of two arms (SMC) and a bridge (kleisin). Together, they form a ring-like structure. “You can understand how important these protein complexes are when you look at their evolution,” explains Larissa Wilhelm, PhD student at the MPI of Biochemistry. “Structure and operating mode are quite similar in bacteria and humans.”
There are different possibilities as to how the SMC protein complex could pack up DNA. It could for example stick together the different DNA fibers. However, the Max Planck scientists were able to show in bacteria that the SMC protein arms embrace the DNA like a clip, thus enabling the connection of pieces of the DNA that lie wide apart from each other.
In a next step, the members of the research group “Chromosome Organization and Dynamics” want to find out whether the clip either opens for a short period of time in which it embraces already formed DNA loops, or whether the clip first binds to the DNA and then forms DNA loops itself by encasing the DNA.
“Our results could also help to better understand the complex organization of human chromosomes and hereby allow insights into the development of genetic defects such as Trisomy 21” says Stephan Gruber, group leader at the MPI of Biochemistry.
L. Wilhelm, F. Bürmann, A. Minnen, H.-C. Shin, C.P. Toseland, B.-H. Oh, S. Gruber: SMC condensin entraps chromosomal DNA by an ATP hydrolysis dependent loading mechanism in Bacillus subtilis. eLIFE, May 7, 2015.
Dr. Stephan Gruber
Chromosome Organization and Dynamics
Max Planck Institute of Biochemistry
Am Klopferspitz 18
Max Planck Institute of Biochemistry
Am Klopferspitz 18
Phone +49 89 8578-2824
http://www.biochem.mpg.de/en/news - More press release of the Max Planck Institute of Biochemistry
http://www.biochem.mpg.de/gruber - Website of the research group "Chromosome Organization and Dynamics" (Stephan Gruber)
Anja Konschak | Max-Planck-Institut für Biochemie
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy