Another protein glue usually makes it possible for our genes to be copied and kept together as parallel strands before neatly splitting into two batches of separate chromosomes to become the nucleus of new cells, according to research published in the current issue of the scientific journal Cell (November 24, 2010).
Human mitotic chromosomes, Cohesin dyed in blue
The action of the ‘sister’ glue called sororin may be the missing link in the way the main glue protein called cohesin allows identical DNA strands to bind together in such a stable way that all the chromosomes in a cell can line up and then divide into their two groups during cell division. It is this action which makes all sex possible, allowing genes from two different people, the parents, to mix together to make a new unique individual, their baby.
It is also the mechanism which most often goes wrong in embryo fertilisation in older mothers, leading to miscarriages during pregnancy or genetic abnormalities such as Down’s syndrome babies born with their characteristic facial features and mental retardation. Recent research has shown that as many as 35% of human eggs from women in their forties have either an extra or a missing chromosome. Now scientists have finally started to study the mechanism behind these mistakes made within our bodies.
“We believe that this second glue protein, sororin, is critical in understanding the way embryo cells make these mistakes when copying chromosomes”, says Jan-Michael Peters from the Institute of Molecular Pathology, Vienna, Austria, who led the new research.
The puzzle has been to find out how the glue protein, cohesin makes the two halves of each copied chromosome stick together until exactly the right moment when a cell divides. It has to stop itself being prematurely cut by other proteins in the cell nucleus which act as biological scissors when the cell separates.
Now the Austrian research team has discovered that the new glue protein sororin acts as a shield for the cohesin, protecting it from being removed from DNA too early, stopping the individual members of the pairs of chromosomes drifting free from each other.
“If the cohesion lets go too soon, the individual chromosome halves run the risk of ending up in the wrong cell nucleus, which could mean that a new egg cell has one too many or one too few chromosomes”, says Tomoko Nishiyama from the Peters research team. “This can lead to an unviable egg, an embryo that dies in the womb, a miscarriage, or a baby born with genetic abnormalities like Down’s syndrome”.
"While this work gives us a new and important bit of basic information about cell division, it also points us towards further research in understanding exactly what goes wrong with the missing and extra chromosomes which cause genetic diseases", Jan-Michael Peters adds.
The paper "Sororin Mediates Sister Chromatid Cohesion by Antagonizing Wapl" (Nishiyama et al.) is published in Cell on Wednesday, November 24, 2010.About the IMP
Dr. Heidemarie Hurtl | idw
Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel
Researchers develop eco-friendly, 4-in-1 catalyst
25.04.2017 | Brown University
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
26.04.2017 | Materials Sciences
26.04.2017 | Agricultural and Forestry Science
26.04.2017 | Physics and Astronomy