Nature | News
Technique demonstrated in E. coli suggests ways to record key events in a cell’s life.
Internet users have a variety of format options in which to store their movies, and biologists have now joined the party. Researchers have used the microbial immune system CRISPR–Cas to encode a movie into the genome of the bacterium Escherichia coli.
The technical achievement, reported on 12 July in Nature1, is a step towards creating cellular recording systems that are capable of encoding a series of events, says Seth Shipman, a synthetic biologist at Harvard Medical School in Boston, Massachusetts. While studying brain development, Shipman became frustrated by the lack of a technique to capture how cells in the brain take on distinct identities. This inspired him to explore the possibility of making cellular recorders.
“Cells have this privileged access to all sorts of information,” he says. “I would like to have these molecular recordings functioning in the developing nervous system and recording information.”
To develop such a system, however, his team would need to establish a method for recording hundreds of events in a cell. Shipman and his colleagues, including Harvard geneticist George Church, harnessed the CRISPR–Cas immune system best known for enabling researchers to alter genomes with relative ease and accuracy.
Shipman’s team exploited the ability to capture snippets of DNA from invading viruses and store them in an organized array in the host genome. In nature, those snippets then target an enzyme to slice up the invader’s DNA. (It is typically this targeted DNA cutting that geneticists harness for gene editing.)
The team designed its system so that these snippets corresponded to pixels in an image. The researchers encoded the shading of each pixel — along with a barcode that indicated its position in the image — into 33 DNA letters. Each frame of the movie consisted of 104 of these DNA fragments.