The research, to be published in the Nov. 8, 2011 issue of Current Biology, clarifies the role of key chromosomal regions called centromeres in the formation of a structure known as the synaptonemal complex (SC). "Understanding this and other mechanisms involved in meiosis is important because of the crucial role meiosis plays in normal reproduction—and the dire consequences of meiosis gone awry," says R. Scott Hawley, Ph.D., who led the research at Stowers.
"Failure of the meiotic division is probably the most common cause of spontaneous abortion and causes a number of birth defects such Down syndrome," Hawley says.
Meiosis reduces the number of chromosomes carried by an individual's regular cells by half, allocating precisely one copy of each chromosome to each egg or sperm cell and thus ensuring that the proper number of chromosomes is passed from parent to offspring. And because chromosomes come in pairs—23 sets in humans—the chromosomes must be properly matched up before they can be divvied up.
"Chromosome 1 from your dad has to be paired with chromosome 1 from your mom, chromosome 2 from your dad with chromosome 2 from your mom, and so on," Hawley explains, "and that's a real trick. There's no room for error; the first step of pairing is the most critical part of the meiotic process. You get that part wrong, and everything else is going to fail."
The task is something like trying to find your mate in a big box store. It helps if you remember what they are wearing and what parts of the store they usually frequent (for example, movies or big-screen TVs). Similarly, chromosomes can pair up more easily if they're able to recognize their partners and find them at a specific place.
"Once they've identified each other at some place, they'll begin the process we call synapsis, which involves building this beautiful structure—the synaptonemal complex—and using it to form an intimate association that runs the entire length of each pair of chromosomes," Hawley explains.
"So even though the study of meiosis began in Drosophila, we really haven't had any idea how chromosomes initiate synapsis in Drosophila," Hawley says. "Now, we show that instead of clustering their chromosome ends, flies cluster their centromeres—highly organized structures that chromosomes use to move during cell division. From there, the biology works pretty much as you would expect: synapsis is initiated at the centromeres, and it appears to spread out along the arms of the chromosomes."
The ramifications of the findings extend beyond fruit flies, as there's some evidence that synapsis starts at centromeres in other organisms. In addition, Hawley and coauthors found that centromere clustering may play a role later in meiosis, when chromosomes separate from their partners.
"There's reason to believe that some parts of that process will be at least explorable and potentially applicable to humans," Hawley said.
The work also is notable as an example of discovery-based science, Hawley said. "We didn't actually set out to study the initiation of meiosis; we were simply interested in characterizing the basic biology of early meiosis."
But postdoctoral researcher and first author Satomi Takeo, Ph.D., noticed that centromere clustering and synaptonemal complex initiation occurred in concert, and her continued observations revealed the role of centromeres in initiating synapsis.
"I was staring with tired eyes at the cells that I was analyzing," Takeo recalls. "Somehow I started looking at the spots I had previously ignored—probably because I thought they were just background noise—until I saw the connection between centromere clustering and synapsis initiation. After going through many images, I wrote an email to Scott, saying, 'This is really important, isn't it??' With that finding, everything else started to make sense."
In addition to Hawley and Takeo, the paper's authors include Cathleen M. Lake at the Stowers Institute for Medical Research and Eurico Morais-de-Sá and Cláudio D. Sunkel at Universidade do Porto in Porto, Portugal, who provided information on the earliest stages of the process.
About the Stowers Institute for Medical Research
The Stowers Institute for Medical Research is a non-profit, basic biomedical research organization dedicated to improving human health by studying the fundamental processes of life. Jim Stowers, founder of American Century Investments, and his wife Virginia opened the Institute in 2000. Since then, the Institute has spent over 800 million dollars in pursuit of its mission.
Currently the Institute is home to nearly 500 researchers and support personnel; over 20 independent research programs; and more than a dozen technology development and core facilities. Learn more about the Institute at www.stowers.org.
Gina Kirchweger | EurekAlert!
The Secret of the Rock Drawings
24.05.2019 | Max-Planck-Institut für Chemie
Chemical juggling with three particles
24.05.2019 | Rheinische Friedrich-Wilhelms-Universität Bonn
A new assessment of NASA's record of global temperatures revealed that the agency's estimate of Earth's long-term temperature rise in recent decades is accurate to within less than a tenth of a degree Fahrenheit, providing confidence that past and future research is correctly capturing rising surface temperatures.
The most complete assessment ever of statistical uncertainty within the GISS Surface Temperature Analysis (GISTEMP) data product shows that the annual values...
Physicists at the University of Basel are able to show for the first time how a single electron looks in an artificial atom. A newly developed method enables them to show the probability of an electron being present in a space. This allows improved control of electron spins, which could serve as the smallest information unit in a future quantum computer. The experiments were published in Physical Review Letters and the related theory in Physical Review B.
The spin of an electron is a promising candidate for use as the smallest information unit (qubit) of a quantum computer. Controlling and switching this spin or...
Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...
With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.
Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...
'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.
However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...
29.04.2019 | Event News
17.04.2019 | Event News
15.04.2019 | Event News
24.05.2019 | Physics and Astronomy
24.05.2019 | Medical Engineering
24.05.2019 | Life Sciences