What Is MicroRNA? The Discovery Behind the 2024 Medicine Nobel
Victor Ambros and Gary Ruvkun received the 2024 medicine prize for discovering microRNA and its role in post-transcriptional gene regulation.
Timeline
- 1993: Ambros and Ruvkun's groups described how the lin-4 small RNA regulates lin-14 in the worm C. elegans.
- 2000: Ruvkun's laboratory reported the conserved let-7 microRNA, helping show that the mechanism extended across animal species.
- October 7, 2024: The Nobel Assembly announced the joint physiology or medicine prize for Ambros and Ruvkun.
The 2024 Nobel Prize in Physiology or Medicine went jointly to Victor Ambros and Gary Ruvkun for discovering microRNA and its role in post-transcriptional gene regulation. Their work revealed that very short RNA molecules can control whether messenger RNA is translated into protein, adding a broadly used regulatory layer to the path from genetic information to cell function. [1][2]
A gene can be copied from DNA into messenger RNA, or mRNA, which carries instructions for building a protein. MicroRNAs do not usually encode proteins themselves. Instead, a microRNA can bind to complementary sequences in a target mRNA and reduce protein production, either by blocking translation or promoting breakdown of the message. [1][2]
Ambros and Ruvkun studied developmental timing in the small roundworm Caenorhabditis elegans. Ambros's group found that lin-4 produced an unusually short RNA rather than a protein. By comparing sequences, the researchers showed that lin-4 could pair with complementary sites in lin-14 messenger RNA and suppress production of the LIN-14 protein. [2]
At first, the mechanism seemed as though it might be a peculiarity of one worm. That view changed when Ruvkun's laboratory identified let-7, another microRNA involved in developmental timing, and showed that its sequence was conserved across many animal species, including humans. Researchers then discovered large numbers of microRNAs and many regulated targets. [1][2]
MicroRNA regulation helps cells with the same DNA develop different identities and adjust protein levels over time. Disrupted microRNA networks have been associated with cancer, developmental conditions and other diseases. Association does not mean every microRNA is a useful drug target, and moving from a regulatory mechanism to a safe therapy requires validation of delivery, specificity and unwanted effects. [2]
The discovery concerns regulation after an RNA message has been produced, which is why the Nobel citation uses the term post-transcriptional. It does not mean microRNAs rewrite the underlying DNA sequence. Their effect is more like adjusting how much protein is made from selected messages, often within a larger network that varies by cell type and developmental stage. [1][2]
The prize recognized a conceptual shift: small noncoding RNAs were not cellular debris but important regulators conserved through evolution. The lin-4 and let-7 discoveries supplied the first clear examples, and subsequent research established microRNA control as a fundamental feature of multicellular organisms. That mechanism, rather than one specific medical treatment, was the achievement honored in 2024. [1][2]
Sources
- Nobel Prize — 2024 physiology or medicine prize summary
- Nobel Assembly — 2024 medicine prize press release