Entirely new class of biomolecule may be common to all forms of life

Scientists continue to make surprising discoveries in our own bodies. Stanford researchers have now discovered a new biomolecule hiding in plain sight, which may be common to most types of life and could play a role in autoimmune diseases in humans.

Dubbed glycoRNA, the new biomolecule is made up of sugar molecules attached to a section of RNA. These are formed through a process called glycosylation that, until now, was only thought to happen to proteins or lipids. The resulting biomolecules play a role in a range of biological processes in animal, plant and microbial cells, which suggests that the new glycoRNA molecules are doing something equally important.

“This is a stunning discovery of an entirely new class of biomolecules,” says Carolyn Bertozzi, senior author of the study. “It’s really a bombshell because the discovery suggests that there are biomolecular pathways in the cell that are completely unknown to us.”

The researchers say that glycoRNAs have eluded discovery for so long because the two components – glycans and RNA – operate in different parts of cells, so biologists assumed they didn’t come into contact with each other. But for the new study, the team investigated the possibility that there was some overlap.

Researcher Ryan Flynn noticed that an enzyme that glycosylates some proteins also binds to RNA, so he wondered whether it might also be glycosylating that RNA. He attached fluorescent tags to various glycans to keep track of what they’re binding to, and found a signal indicating RNA was a target for many of these sugar molecules.

The team identified the new glycoRNAs in cells in humans, mice, hamsters and zebrafish. That variety of animals indicates that these biomolecules must be performing an important role, and it must have arisen in the ancient past, before we all split off from our last common ancestor.

Exactly what glycoRNAs do in the body remains unknown, but scientists plan to investigate further. The team has a suspicion that they may be involved in autoimmune diseases, since some of the RNAs that are becoming glycosylated are known targets for the immune system in patients with lupus. Further studies could open up new potential treatment opportunities.

The research was published in the journal Cell.

Source: Stanford University