Medical News
Health
12 June 2019
Current techniques are based on the CRISPR-Cas9 complexCARLOS CLARIVAN/SCIENCE PHOTO LIBRARY
By Michael Le PageCRISPR genome editing technology is revolutionising biology, but it could soon become even powerful. Two teams have developed new variants of the method based on “jumping genes” that might make it much easier to add pieces of DNA to cells.
“I think we will see a flurry of excitement around this,” says Samuel Sternberg of Columbia University in New York, who leads one of the teams.
For everything from treating many genetic diseases to creating genetically modified organisms, adding DNA to the genomes of cells is a key step. But none of the existing methods work particularly well.
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During gene therapy, for instance, viruses are typically used to deliver extra genes to cells to compensate for inherited mutations, but there’s no way to control where in the genome the extra DNA ends up. This can lead to harmful mutations and sometimes trigger cancer.
CRISPR enables researchers to insert DNA into a precise site in the genome. Unfortunately, existing CRISPR techniques typically work only 20 per cent of the time, and they don’t work at all for many types of cells.
But Sternberg’s team have now achieved efficiencies of 40 to 60 per cent for adding DNA in a precise spot using a new form of CRISPR based on transposons. Also known as jumping genes, transposons are selfish genetic parasites that do nothing but copy and paste themselves from one part of the genome to another.
Last week, a team led by Feng Zhang of the Massachusetts Institute of Technology reported efficiencies of up to 80 per cent using a very similar approach. But Zhang’s method inserts DNA in the target site only half the time, says Sternberg – on the other occasions the DNA was inserted in a random site. Sternberg says his method adds DNA to the right spot on 95 per cent of occasions.
However, both teams tested their techniques on the E. coli bacterium. It is not yet clear if this new form of CRISPR will work in plant or animal cells.
Journal reference: Nature, DOI: 10.1038/s41586-019-1323-z
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