Gene Editing

CRISPR-Cas9 and Nanoclew

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Getty Images: 1150397413
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Gene drives take over embryonic development in 4 generations. Image: physics.org

CRISPR technology was first derived from a bacterial immune response that uses RNA to protect itself against plasmids and viruses by breaking specific DNA sequences in the pathogen's genome. With the CRISPR technology, researchers have co-opted that system to edit any gene, allowing them to make precise genetic changes for a desired effect.

The gene drive mechanism may allow scientists to control malarial mosquitoes or pesticide-resistant pests, for example, by using CRISPR to introduce a mutation (allele) into a few individuals in a population and have that mutation quickly spread through the entire population. But researchers fear such gene drives could have unintended consequences, such as spreading into an unintended species.

physics.org article

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Nanoclew gene editing tool

The nanoclews are made of a single, tightly-wound strand of DNA. The DNA is engineered to partially complement the relevant CRISPR RNA it will carry, allowing the CRISPR-Cas9 complex - a CRISPR RNA bound to a Cas9 protein—to loosely attach itself to the nanoclew. "Multiple CRISPR-Cas complexes can be attached to a single nanoclew," says Wujin Sun, lead author of the study and Ph.D. student in Gu's lab.

When the nanoclew comes into contact with a cell, the cell absorbs the nanoclew completely - swallowing it and wrapping it in a protective sheath called an endosome. But the nanoclews are coated with a positively-charged polymer that breaks down the endosome, setting the nanoclew free inside the cell. The CRISPR-Cas9 complexes can then free themselves from the nanoclew to make their way to the nucleus. And once a CRISPR-Cas9 complex reaches the nucleus, gene editing begins.