
A REVOLUTIONARY technique is letting scientists peer into cells at the genetic level remarkable footage shows how — both imaging the cell and sequencing its DNA. Developed at the Broad Institute in the US the remarkable footage shows the cell’s genetic sequences. Instead of being light-based, DNA ‘bar codes’ are used to tag molecules in cells. A computer algorithm decodes the resulting genetic information into an image.
From readings of the complex interactions of these labels with the molecules and each other, a computer algorithm can work backward to reveal an image of the cell. DNA microscopy could find myriad applications — including helping scientists study immune cells and
The unorthodox imaging technique was developed by biophysicist Joshua Weinstein and colleagues at the Broad Institute in Cambridge, Massachusetts.
Unlike a traditional microscope that uses light to create an image, the new microscopy technique instead uses ‘bar codes’ of DNA that work to pinpoint the relative positions of molecules within a sample.
The approach can let scientists both assemble a picture of the cells they are studying while simultaneously revealing the cells genetic sequences.
‘This gives us another layer of biology that we haven’t been able to see,’ said
‘It’s an entirely new category of microscopy,’ said paper co-author and computational biologist Aviv Regev.
‘It’s not just a new technique, it’s a way of doing things that we haven’t ever considered doing before,’ she added.
The new imaging technique works by fixing cells into position in a reaction chamber and adding to them an assortment of DNA ‘bar codes’.
Once the tags latch on, they create more and more copies of each of the tagged molecules — hundreds in total — forming a growing pile which expands out from the original molecule’s starting position.
‘Picture every single molecule as a radio tower broadcasting its own signal outward,’
As the tagged molecule copies spread out, they eventually collide with other copies of tagged molecules — forcing them to link together to form distinctive paired genetic sequences that can be decoded using a DNA sequencer.
The closer the original molecules were to each other, the more likely their respective copies are to collide, resulting in more of their copies pairing.
In contrast, if the original molecules are further apart, then they ultimately produce less of the paired copies.
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Remarkable footage shows how a revolutionary technique is letting scientists peer into cells at the genetic level — both imaging the cell and sequencing
Remarkable footage shows how a revolutionary technique is letting scientists peer into cells at the genetic level — both imaging the cell and sequencing its DNA.
The DNA-sequencing process can take up to 30 hours to process a sample, producing around 50 million DNA letters in genetic sequence for the computer to translate into both an image and a sequence of the cell’s genome.
Because DNA can also attach to other molecules in cells beside DNA and RNA, the approach can also image and identify other cellular components including antibodies, receptors and even the molecules on
‘You’re basically able to reconstruct exactly what you see under a light microscope,’ said
In fact, he added, the two methods can be used to complement each other.
Whereas light-based microscopy can see molecules well even where they’re present in limited numbers, DNA microscopy works well when molecules are present in dense concentrations.
The new technique can even handle the imaging of molecules that are piled up on top of each other.
The strength of the DNA microscopy technique lies in how it can combine the kinds of information produced by the two existing types of microscopy.
Basic optical microscopes, first invented in the early 1600s, use light to illuminate samples — and have been adapted in various ways that replace visible light with other wavelengths or electrons, for
Either way, all optical microscopes work on the principle that the sample gives off photons or electrons which can then be detected.
The second type of microscope relies on dissecting samples at a series of predefined locations and then
While optical imaging can offer detailed portrayals of the structure and actions with a cell, dissection-style approaches can offer
DNA microscopy, however, does both — capturing
Concentrating on only one of these aspects, said
From readings of the complex interactions of these labels with the molecules and each other, a computer algorithm can work backward to reveal an image of the cell +3
From readings of the complex interactions of these labels with the molecules and each other, a computer algorithm can work backward to reveal an image of the cell
One potential application for DNA microscopy would be in accelerating the development of immunotherapy treatments that help patients to fight cancer.
Scientists might use the imaging method to identify the immune cells best suited for targeting a particular cancerous cell.
This could be achieved because every cell has a unique DNA
‘By capturing information directly from the molecules being studied, DNA microscopy opens up a new way of connecting genotype to phenotype,’ said paper author and biochemist Feng Zhang.
According to Weinstein, DNA microscopy is especially well suited to studying immune cells, in which both even single-letter DNA changes and
However, the possibilities for new research using this technique are broad and rich for exploration, Professor Regev said.
‘We hope that it sparks the imagination — that people will be inspired with great ideas that we’ve never thought about,’ she added.
The study was published in the Cell journal.
How DNA microscopy technique works
The new imaging technique works by fixing cells into position in a reaction chamber and adding to them an assortment of DNA ‘bar codes’.
Once the tags latch on, they create more and more copies of each of the tagged molecules — hundreds in total — forming a growing pile which expands out from the original molecule’s starting position.
As the tagged molecule copies spread out, they eventually collide with other copies of tagged molecules — forcing them to link together to form distinctive paired genetic sequences that can be decoded using a DNA sequencer.
— Internet