At the flick of an electronic switch, DNA replication can be turned on or off with the assistance of a nanopore just wide enough for a single DNA molecule to pass through.

Proteins that form molecular pores are important tools for manipulating and studying single molecules of DNA, as well as the polymerase enzymes that bind to DNA and drive its replication. Mark Akeson and his team at the University of California, Santa Cruz, have developed a nanopore system that measures and controls DNA replication as it happens.

The authors designed their system so that polymerase enzymes replicated DNA strands one after the other when the DNA was captured by the nanopore. Reversing the voltage across the pore activated this reaction by shifting the position of the DNA strand within the pore, exposing it to the enzymes. The researchers used their nanopores to measure the rate of replication for hundreds of DNA molecules on the millisecond timescale.

Nature Nanotechnol. doi:10.1038/nnano.2010.177 (2010)