Nobel Prize in Medicine honors two pioneers of gene regulation by tiny RNAs
On Monday, October 7, the Nobel Committee honored a crucial mechanism in cell function: the control of gene activity by tiny molecules known as “microRNAs.” The Nobel Prize for Physiology or Medicine was awarded to two American biologists who pioneered the field, Victor Ambros, 70, and Gary Ruvkun, 72.
Both come from the Nobel incubator of the prestigious universities concentrated around Boston, Massachusetts. Ambros, currently at the University of Massachusetts Medical School, conducted his award-winning research at Harvard. Ruvkun, on the other hand, carried out his work at Massachusetts General Hospital and Harvard Medical School, where he is still a professor of genetics.
It is important to understand the fundamental importance of these processes that control gene activity. They are what enable our cells to perform their myriad specialized functions within the various tissues of our body. For example, the absorption of nutrients by cells lining the intestine, the “firing” of certain neurons in response to specific stimuli, the secretion of insulin by cells in the pancreas and the contraction of muscle cells.
Let us recall how a “classic” gene works – in other words, a gene that delivers the instructions for the cellular machinery to manufacture proteins, the elementary building blocks that form the structure of cells and ensure their functions. In the first stage, the DNA sequence inscribed in each gene serves as a mold for the production of a complementary molecule, messenger RNA (mRNA, a nucleic acid like DNA).
The second stage is just as crucial. Each messenger RNA is then “translated” into a specific protein, according to a genetic code that won the Nobel Prize for its three discoverers, Robert W. Holley, Har Gobind Khorana and Marshall W. Nirenberg, in 1968.
Model organization
“For a long time, it was thought that gene activity was essentially controlled during the transcription stage when messenger RNA is produced from the DNA sequence of genes,” said Marie-Anne Félix, CNRS research director at the Ecole Normale Supérieure in Paris. It will be to the credit of Ambros and Ruvkun, the duo rewarded today, to reveal the importance of a completely different pathway: that of microRNAs, which are also nucleic acids but very small in size – only around 20 chemical letters.
It all began in the 1990s, with the unlikely case of a tiny nematode, C. elegans (Caenorhabditis elegans). With its thousand or so cells and millimeter-long body, the small transparent worm serves as a model organism. In 2002, he already won the Nobel Prize for American geneticist Robert Horvitz, who discovered the genes in this nematode that control programmed cell death, or “cell suicide” (apoptosis), and subsequently demonstrated the existence of analogous genes in humans. The researcher from Cambridge (Massachusetts) was to set an example. Indeed, it was in his laboratory that the two winners of the 2024 Nobel Prize did their post-doctoral work.
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