Nobel Prize goes to microRNA researchers

The 2024 Nobel Prize in Physiology or Medicine was awarded to US scientists Victor Ambros and Gary Ruvkun for their work on microRNA.

Their discoveries help explain how complex life arose on Earth and how the human body is made up of a variety of different tissues.

MicroRNAs influence how genes – the instructions for life – are controlled in organisms, including us.

The winners will share prize money worth 11 million Swedish krona (£810,000).

Every cell in the human body contains the same raw genetic information locked in our DNA.

Although the cells of the human body have identical genetic information, they differ greatly in form and function.

The electrical impulses of nerve cells differ from the rhythmic beating of heart cells. The metabolic powerhouse of a liver cell is different from a kidney cell, which filters urea from the blood. The light-sensing abilities of cells in the retina differ in their abilities from those of white blood cells, which produce antibodies to fight infections.

Because of gene expression, so much diversity can arise from the same starting material.

The US scientists were the first to discover microRNAs and how they could control the differential expression of genes in different tissues.

The winners of the Medicine and Physiology Prizes are selected by the Nobel Assembly of the Swedish Karolinska Institute.

They said: “Their groundbreaking discovery revealed an entirely new principle of gene regulation that turned out to be essential for multicellular organisms, including humans.”

“It is now known that the human genome encodes over 1,000 microRNAs.”

Without the ability to control gene expression, every cell in an organism would be identical, so microRNAs helped enable the development of complex life forms.

Abnormal regulation by microRNAs can lead to cancer and some diseases, including congenital hearing loss and bone diseases.

A serious example is DICER1 syndrome, which leads to cancer in various tissues and is caused by mutations affecting microRNAs.

Prof. Ambros, 70, works at the University of Massachusetts Medical School and Prof. Ruvkun, 72, is a professor at Harvard Medical School.

Both of them conducted their research on the nematode worm – C. elegans.

They experimented with a mutated form of the worm that was unable to develop some cell types and eventually zeroed in on tiny pieces of genetic material, or microRNAs, that were essential to the worms' development.

This is how it works:

• A gene or genetic instruction is contained in our DNA
• Our cells make a copy called messenger RNA, or simply mRNA (you know this from Covid vaccines).
• This travels out of the cell nucleus and instructs the cell's protein factories to begin producing a specific protein
• But microRNAs interfere by sticking to the messenger RNA and preventing it from working
• Essentially, the mircoRNA prevented the gene from being expressed in the cell

Further work showed that this was not a process unique to worms, but a central part of life on Earth.

Prof Janosch Heller from Dublin City University said he was “delighted” that the prize had gone to Profs Ambros and Ruvkun.

“Their groundbreaking work on gene regulation by microRNAs paved the way for groundbreaking research into novel therapies for devastating diseases like epilepsy, but also opened our eyes to the wonderful machinery that tightly controls what happens inside our cells.”