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
New application for acoustics helps estimate marine life populations
16.01.2018 | University of California - San Diego
Unexpected environmental source of methane discovered
16.01.2018 | University of Washington Health Sciences/UW Medicine
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
16.01.2018 | Materials Sciences
16.01.2018 | Materials Sciences
16.01.2018 | Power and Electrical Engineering