Imma Perfetto
Cosmos science journalist
The 2024 Nobel Prize in Physiology or Medicine has been jointly awarded to Victor Ambros and Gary Ruvkun for their discovery of microRNA – class of tiny RNA molecules governing how gene activity is regulated.
Ambros, now a professor at the University of Massachusetts Chan Medical School, and Ruvkun, a professor at Harvard Medical School and Massachusetts General Hospital, first discovered the new class of RNA in the small worm Caenorhabditis elegans in 1993.
Since then, scientists have learned that gene regulation by microRNA is universal among multicellular organisms, including humans.
Associate Professor Philip Gregory, who leads the Gene Regulation in Cancer Laboratory at the University of South Australia’s Centre for Cancer Biology and has worked in the microRNA field since the mid-2000s, told Cosmos the Nobel Prize award is both well-deserved and a little bit overdue.
“It’s quite a fundamental discovery,” he says. “It showed that there was this completely different way of controlling how cells function, which was not known before.
“And because of that, we can have a much better understanding of how organisms develop, how the [levels of gene expression] within organisms, particularly complex organisms … is very finely tuned.”
It’s estimated that there are almost 200 different cell types in an adult human body. They all contain the same DNA instructions but have wildly different specialised functions. So, how do they manage it?
The key lies in gene regulation, which allows each cell to not only express just the relevant genes, but to tune the level of that expression to adapt to changing conditions in our bodies and environment.
When genes are expressed, the information is converted from DNA to messenger RNA (mRNA) in a process called transcription. This mRNA is then then translated into proteins.
MicroRNA is not the same as mRNA.
“[MicroRNAs are], essentially, as the name suggests, a small RNA,” says Gregory.
“Unlike many other RNAs in our cells, they don’t do the job of making a protein. They have a very different role, and that’s in regulating other RNAs … and controlling the levels of proteins that get produced from those RNAs.”
According to Gregory, microRNAs are present in every cell of the human body and are essential for their everyday functioning.
“They can control how fast the cell grows, how it can move to different locations, how it can differentiate [into different cell types] – all sorts of different things,” he says.
“Higher organisms, including humans, of course, [are] very complex and we typically use a lot of microRNAs to specify the complex functions of all the different cell types that we have.
“Without micro RNAs, we really wouldn’t be able to develop into the complex organisms we are and function normally as we do.”
More than 30 years on from the initial discovery by Ambros and Ruvkun, scientists now know that there are more than 1,000 genes for microRNAs in humans. A single microRNA can regulate the expression of many different genes, and a single gene can be regulated by multiple microRNAs.
“In terms of my research, which is in the cancer space, there’s been a lot of interest in trying to understand how microRNAs might control how cancers progress and become more aggressive,” says Gregory.
“It turns out that there’s certain microRNAs which are important in this process and can essentially control whether a cancer cell will grow fast [and] can spread to other places in the body.
“A new area that’s being explored is the possibility that [microRNAs] might be able to be used as diagnostic tools. So, for example, people are taking specimens of blood or even saliva and measuring microRNAs in them as a potential diagnostic to inform of various diseases.
“It’s very widespread, the reach of research that’s come from that initial discovery.”
