Bio-Computer Created Inside Living Cel
The new bio-computer consists of snippets of engineered RNA assembled inside a yeast cell.
RNA is a biological molecule similar to DNA, which encodes genetic information, such as how to make various proteins.
In engineering terms, the bio-computer's "inputs" are molecules floating around inside the cell. The "output" manifests as changes in protein production.
For example, an RNA computer may be able to bind with two different molecules. If both target molecules attach to it, they trigger the device to change shape.
The altered bio-computer is now the right shape to bind to DNA, where it can directly affect gene expression and ramp up or slow down the making of desired proteins.
Those proteins can affect the cell in various ways, such as killing it if it is cancerous.
Ehud Shapiro is a computer scientist and biologist at the Weizmann Institute of Science in Israel. He was not involved in the study.
Shapiro's team had previously created a bio-computer using DNA that worked inside a test tube and could perform simple calculations, such as determining whether a list of zeros and ones contained an even number of ones.
But unlike the new RNA computer, Shapiro's test tube bio-computer was "oblivious" to its surroundings and could not interact with or be affected by its environs in any meaningful way, he said.
"The work of Smolke shows a computer that can respond to molecules inside a cell," said Shapiro, who wrote a review of the new study for Science.
Shapiro looks forward to a day when RNA computers are replaced by more sophisticated devices made from proteins.
"Proteins are the most efficient natural devices we know of," he said. "We know how to evolve RNA to do simple tasks, but do not know yet how to engineer proteins."