Dedicated to the acceptance, medical treatment, & legal protection of individuals in the process of correcting the misalignment of their anatomical sex, & supporting their transition into society.
Washington, DC, USA. A fundamental mechanism inhibits gene expression during translation or hinders the transcription of specific genes. Called RNA interference (RNAi), it targets RNA that is significant ...
New Haven, CT, USA. The mouse is commonly used as a model organism in biomedical research. For example, a great deal of work has been done to figure out what a particular gene does in an organism. Scientists c...
Cambridge, MA, USA. The genome contains a lot of data that has to be collected, cleaned, normalized, processed, and analyzed in a manner. This has to be done in a manner that enhances understanding and ca...
San Antonio, TX, USA. Repair mechanisms exist throughout the human body, but what happens when DNA is broken? The genome itself is the source of our body and any unrepaired — or poorly repaired — breaks can ha...
Tokyo, Japan. Scientists in Japan have made a micro-sized sewing machine to sew long threads of DNA into shape. Their work demonstrates a unique way to manipulate delicate DNA chains without breaking them. This is a serious contribution to solving an ongoing problem often confronted by researchers: tangled up DNA.
Scientists can diagnose genetic disorders such as Down's syndrome by using gene markers, or "probes", which bind to only highly similar chains of DNA. Once bound, the probe's location can be easily detected by fluorescence, and this gives information about the gene problem.
Detecting these probes is often a slow and difficult process, however, as the chains become tightly coiled. The new method presented by Kyohei Terao from Kyoto University, and colleagues from the University of Tokyo, uses micron-sized hooks controlled by lasers to catch and straighten a DNA strand with excellent precision and care.
"When a DNA molecule is manipulated and straightened by microhooks and bobbins, the gene location can be determined easily with high-spatial resolution," says Terao. The research team's findings appear in the journal Lab on a Chip, published by the Royal Society of Chemistry (RSC).
Maneuvering DNA. Using miniaturised hooks and bobbins, single DNA strands can be maneuvered without breakage.
The team use optical tweezers - tightly focused laser beams - to control the Z-shaped micro hook and pick up a single DNA "thread". The hook is barbed like an arrow, so the thread can't escape. When caught on the hook, the DNA can be accurately moved around by refocusing the lasers to new positions.
But just like thread in a sewing machine, a long DNA chain can be unwieldy - so the researchers built micro "bobbins" to wind the chain around. The lasers move one bobbin around another, winding the DNA thread onto a manageable spindle.
It is "an excellent idea to fabricate unique microtools that enables us to manipulate a single giant DNA molecule", says Yoshinobu Baba, who researches biologically useful microdevices at Nagoya University, Japan. The technology will also be useful for a number of other applications including DNA sequencing and molecular electronics, he adds.
On-site manipulation of single chromosomal DNA molecules by using optically driven microstructures. Kyohei Terao, Masao Washizu and Hidehiro Oana. Lab Chip 2008. doi: 10.1039 / b803753a [ Download PDF ]
Abstract
We report a novel method for manipulation of single giant DNA molecules under a video microscope. Using optically driven microstructures, we manipulated chromosomal DNA of length in the order of millimetres, extended by electroosmotic flow without DNA breakage in aqueous solution: we picked up DNA, using microfabricated hooks and wound it around microfabricated bobbins.
Conclusions
In conclusion, we have demonstrated the method and device for on-site single-molecule manipulation of giant DNA molecules, using optically driven microstructures for picking up and separating a DNA fibers from a bundle. We used a microfabricated hook together with winding/unwinding of the DNA fiber onto microfabricated bobbins. This method enables the manipulation of DNA molecules in the order of mega base pairs under a microscope without fragmentation. The method is purely mechanical, and requires no chemical modifications; moreover, it can manipulate any desired part of the targeted DNA in the microscope view. This method will create avenues for space-resolved single molecule assays of large chromosomal DNA, along with its applications in gene location and epigenetic studies.
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