Researchers have made bioluminescent “RNA lanterns” which make RNA glow.

Their lanterns, described in Nature Communications, could help to better understand how cells work – in everything from virus research to the human brain.

RNA, which transmits the information stored in DNA, plays a big role in the functioning of cells.

“The first step in saying something’s going to happen in a cell – the cell is going to grow, adapt, change or anything like that – underlying all of that is RNA,” says co-author Professor Andrej Lupták, a researcher at the University of California, Irvine, USA.

But RNA is hard to study in its natural environment – cells – because it’s very hard to track.

“It turns out it’s been really quite difficult to know in living cells, and especially in living organisms, when RNA is turned on and where it goes,” says Lupták.

“If you wanted to study the first 30 seconds or the first minute – nobody knows. But we provide a tool. You can now visualise it.”

Researchers have been using fluorescent tags to see proteins and other tiny biological features more closely for decades.

So far, it’s been tricky to do the same thing with RNA. Scientists had recently shown they could tag RNA with luciferase, the protein that gives fireflies and glow-worms their light. But they’d been yet to make it glow bright enough for a lot of useful imaging.

This team’s RNA lanterns tag each RNA molecule with a single copy of a section of luciferase, that still emits enough photons to be detected.

They could use it to image RNA movements in both cells, and live mice.

The researchers say their platform technology could be used to image RNA “from the micro to the macro scale”.

Co-author Professor Jennifer Prescher, also at UC Irvine, is interested in the tag’s use for understanding memories in the brain.

“There’s a lot of interesting biology that’s happening at the RNA level in neurons,” says Prescher.

“And being able to see early events and the transport of RNA from the cell body out to neural synapses where connections are being made to other neurons – that directly correlates with memory formation.

“If you have a way to watch that in real-time, that could tell you something fundamental about the brain and memory, which has been a holy grail in science for a long time.”