Nature | Health

Certain artificial genetic polymers, or 'XNAs,' could bind and inhibit proteins, including those involved in macular degeneration, or resemble Earth's earliest genetic molecules

April 19, 2012

By Helen Shen of Nature magazine

Nearly all organisms share a single genetic language: DNA. But scientists have now demonstrated that several lab-made variants of DNA can store and transmit information much like the genuine article.

Researchers led by Philipp Holliger, a synthetic biologist at the Medical Research Council Laboratory of Molecular Biology in Cambridge, UK, say that the alternative molecules could help others to develop new drugs and nanotechnologies. They publish their results today in Science.

DNA is made up of nucleic acid bases -- labeled A, C, G and T -- on a backbone made of phosphates and the sugar deoxyribose. The artificial polymers, dubbed XNAs, carry the normal genetic 'alphabet' on a backbone made using different sugars. Scientists have previously developed XNAs that recognize and bind genetic sequences for experimental and biomedical applications, but is it difficult to make them in large quantities.

"Any time you want another XNA molecule, you've got to make more, but you can't copy what you already made -- until now," says Gerald Joyce, a biochemist at the Scripps Research Institute in La Jolla, California.

Holliger and his team engineered enzymes that helped six types of XNA to assemble and replicate genetic messages. The enzymes transcribed DNA into the various XNAs, then back into new DNA strands -- with 95% accuracy or more.

"This is a huge step," says Eric Kool, a chemist at Stanford University in California. "I would have predicted this method would work to some extent. I just didn't know how well."

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Enzymes Grow Artificial DNA