Genetic engineering is a complex field in which scientists use a range of molecular tools to make changes to DNA, the information center of cells. You might have heard of gene editing techniques such as CRISPR, TALENs, and even PRIME Editing.
But now researchers at Princeton University may have found a simple solution that can not just make DNA molecules bend and turn but also snap them together as desired.
Are chromosomes liquid or solid?
Ever since the discovery of the chromosome, researchers have wondered if the structure, made up of long strands of DNA coiled around proteins, behaves like a solid, liquid, or something in between.
This might seem like a question of curiosity alone. But delve a bit deeper into genetic disease and one realizes that the answer to how to treat them depends on knowing more about chromosome behavior.
Researchers at Princeton were keen to solve this mystery and developed a tool that could probe chromosomes to learn more about their mechanical properties.
Working with condensates
Some components inside the cell have distinct membranes that separate the contents inside them from those outside, much like soap bubbles. Condensates on the other hand are liquid-like droplets that can fuse together quite easily since they are not bound by any membrane. Inside the cell, condensates come together to perform a certain task and then disperse, when the task is complete.
Princeton researchers used lasers to direct the fusion of condensates inside the cell. When exposed to a certain wavelength of blue light, the condensates fused together to form larger droplets. Since the process is initiated by a protein that is also used in CRISPR, the researchers were also able to attach the droplet to a particular sequence of DNA and, hence, target specific genes of interest.
Using condensates (green), the researchers pulled two sections of a DNA strand together, enabling them to touch. Illustration by Wright Seneres
By switching the light on and off, the researchers have been able to perform a wide range of functions on the DNA, such as growing droplets stuck to different sequences, merging them, and even shrinking them, putting them together.
This gave them unprecedented control over DNA interactions, which could only have been achieved through random interactions before. What’s even more interesting is that the entire process takes just 10 minutes.
Like CRISPR but different
Now that the research team could move the DNA molecules around at will, they wanted to know if they could also change the DNA sequence, much like how CRISPR, TALENs and other techniques do.
Unlike CRISPR, the tool does not actually let researchers cut DNA and edit their sequence. However, it can be used to change the positioning of the DNA inside the nucleus so that a particular gene’s expression can be turned on or off.
The researchers plan to use the tool to map out cellular machinery to get a better picture of what is happening inside the cell, especially in cases such as cancer.
The research findings were published in Cell last month.
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