Engineered DNA device could make cells differentiate or die on demand

LONDON - Biologists have constructed a programmable genetic ‘circuit’ that can rewire cells to respond on demand to just about any signal desired - it could coax cells to differentiate - or die.

The technique could have a wide range of uses, for example coaxing stem cells to transform into different tissues once inside the body or making plants activate a defence programme in response to low nutrients, reports Nature.

Christina Smolke, a bioengineer at Stanford University in California, constructed a stretch of DNA that acts as genetic circuit. When inserted into cells and transcribed into RNA, the circuit encodes its protein product only when it senses the presence or absence of a particular target protein inside the cell.

One version of the circuit makes human cells susceptible to an antiviral drug - but only if they are making abnormal amounts of a protein implicated in cancer.

To test their circuit, the researchers stimulated human cells to produce extra beta-catenin - as if they were cancer cells - then treated them with ganciclovir. Cells that contained the circuits were killed by the drug.

By tweaking the ‘wiring’ of such circuits, they could make cells respond to either the presence or absence of a desired protein, said Smolke.

Cell-hacking circuits are years away from the clinic, but Smolke thinks they could eventually be combined with other experimental treatments to control where and when they act within the body.

If we got good at gene therapy, then you could imagine these sophisticated sensing systems that would only deliver the kill or the gene when it’s in the exact right location,” said Adam Arkin, a systems and synthetic biologist at Lawrence Berkeley National Laboratory in California.

The study is published in Science. (ANI)