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
A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences