Human genes corrected, Nature Biotechnology

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Human genes corrected, Nature Biotechnology

08 Apr 2005 Medical News Today

With a discovery published online this week in Nature that could

herald an alternative to gene therapy, Holmes and his

colleagues demonstrate a new way to correct disease-causing mutations

in human DNA.

Researchers have struggled to perfect gene therapy, in which they try

to compensate for defective genes by inserting a new working copy

into cells. Gene correction takes a different approach: repairing the

mistakes in DNA that cripple the gene.

Holmes' team fused a zinc-finger protein, which recognizes three to

four base pairs in DNA, to a nuclease, which cuts DNA at that

sequence. These 'zinc-finger nucleases' are known to trigger

homologous recombination, a process by which the surrounding segment

of DNA is replaced by a fresh copy.

The team designed a zinc-finger nuclease that recognizes the mutation

underlying X-linked severe combined immune deficiency (SCID) -

children with this condition can suffer life-threatening infections

soon after birth. Holmes and co-workers showed that the nuclease

prompted correction of the defect in a high frequency of T cells -

the cells affected by the disorder. The study offers the prospect

that zinc-finger nucleases could be engineered against any disease-

causing mutation in the human genome, and used to treat the disease.