Gene editing about to get a lot more powerful

WASHINGTON( AP) — Scientists are altering a powerful gene-editing technology in hopes of the working day fighting diseases without inducing permanent changes to people’s DNA.

The trick: Edit RNA instead, the messenger that carries a gene’s instructions.

“If you edit RNA, you can have a reversible therapy, ” important in case of side effects, said Feng Zhang of the Broad Institute of MIT and Harvard, a gene-editing innovator whose team reported the new spin Wednesday in the publication Science.

A genome editing technique called CRISPR has revolutionized scientific research. It’s a biological cut-and-paste tool that lets researchers spot a gene defect inside living cells and use molecular “scissors” to snip that spot, either deleting, repairing or replacing the affected gene.

Researchers are using CRISPR to try to improve crops, develop malaria-resistant mosquitoes, grow transplantable organs inside animals, and develop therapies that one day may help genetic disease such as sickle cell or muscular dystrophy.

There are challenges for medical employ. Because a change to Dna is permanent, accidentally cutting the incorrect spot could lead to lasting side effects.

And DNA repair is harder to achieve in certain cells, such as brain and muscle cells, than in others, such as blood cells — so targeting RNA may offer an important alternative, said University of California, San Diego, prof Gene Yeo, who wasn’t to participate in Wednesday’s study. His squad is generating its own RN-Atargeting version of CRISPR.

Disease can occur when a genetic defect leaves cells making too little or too much of a specific protein, or not making it at all.

RNA, a cousin of DNA, carries the gene’s instructions to start the protein-making process. Editing RNA’s instructions should result in temporary fixings to abnormal protein production, Zhang explained. Because RNA degrades over day, the changes theoretically would last merely as long as the therapy was used.

To starting figuring out how, researchers returned to nature.

CRISPR was adapted for use in mammalian cells from a system that evolved in bacteria, and uses as its molecular scissors an enzyme named Cas9. Zhang’s team examined relatives in the Cas protein family and found one, Cas1 3, that could target RNA instead. The researchers engineered a Cas1 3 assortment so it sticks to RNA instead of cutting it. They then fused on another protein to edit that spot and tested it in lab dishes.

The research is in its earliest stages, involving more work before it even could be tested in animals.

But San Diego’s Yeo, who is using a different Cas approach to target RNA, praised the competing work.

“It actually tells us that many Cas proteins can truly bind RNA, ” he said. “The smart thing to do is to exam a lot of them.”

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