The research about to be published in the journal Current Biology shows that BubR1- a gene recently shown to affect cell division – maintains the cohesion of paired chromosomes (until their time to divide) during the production of reproductive cells. Because BubR1 mutations can result in cells with abnormal numbers of chromosomes, the research has potential implications for human disorders resulting from loss or gain of chromosomes such as Down Syndrome, a disease caused by an extra copy of chromosome 21.
Deletion of the BubR1 gene has been shown to disturb chromosome separation during meiosis - the process by which the reproductive cells, sperm and eggs, are formed - although how this happens is not clear. Following the discovery of a non-lethal BubR1 mutation in fruit flies Nicolas Malmanche, Claudio E. Sunkel and colleagues– which have had a long time interest in cell division - decided to try and identify the molecular role of this gene in meiosis. Fruit flies are particularly advantageous in this case as males and females of the species use different molecular mechanisms for the distribution of chromosomes between cells during meiosis, allowing a more detailed analysis of the effects of the BubR1 mutation and consequently also of BubR1 normal role.
Cells normally have two sets of each chromosome (called homologue chromosomes) where one set has come from the father and the other set of the mother. Meiosis - the specialised cell division that produces the sperm and eggs - starts with the duplication of all the chromosomes in the cell – that at this stage stay linked and are called (sister) chromatids - followed by two sets of divisions. During the first division homologues chromosomes are separated with each of the two daughter cells receiving one, while in the second division it is the sister chromatids that are separated with each sex cell receiving one from each pair.
It was by analysing and comparing mutated BubR1 and normal flies throughout these processes that Malmanche, Sunkel and colleagues were able to discover that the BubR1 gene is essential to maintain sister chromatids’ linked throughout meiosis, assuring in this way a correct distribution of the genetic material in the produced sex cells. The researchers also saw that in BubR1 mutated females, a complex structure called Synaptonemal Complex (SC), which binds homologue chromosomes during the first division of the meiosis and allows recombination (exchange of genetic material between homologous chromosomes, which is essential for generation of diversity) was also disrupted. Accordingly, detailed analysis of this process of recombination in BubR1 mutant cells revealed significant alterations in its frequency and distribution.
Malmanche, Sunkel and colleagues’ discoveries reveal BubR1 gene as crucial for a proper distribution of the genetic material during eggs and sperm formation in fruit flies. But because BubR1 is conserved throughout species and also exist in humans the research have potential implications for the study of human diseases caused by abnormal chromosomal distribution such as Down’s syndrome, which incidence increases with the mother’s age and can affect as much as 4% of the births in women over 45 years old.
Most significantly Down Syndrome individuals are known to have abnormal patterns of recombination and loss of cohesion between sister chromatids exactly like the defects observed in fruit flies with a mutant BubR1gene. As Claudio Sunkel says, “our observations suggest for the first time that inappropriate or reduced function of a gene like BubR1 might be at the heart of age-related chromosome imbalance observed in humans”.
Piece researched and written by Catarina.Amorim at linacre.ox.ac.uk
Catarina Amorin | alfa
Cancer diagnosis: no more needles?
25.05.2018 | Christian-Albrechts-Universität zu Kiel
Less is more? Gene switch for healthy aging found
25.05.2018 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences