Victor Ambros and Gary Ruvkun won the 2024 Nobel Prize in Medicine for their discoveries about microRNA, a class of small RNA molecules that play a key role in gene regulation. In the 1990s, they studied the organism Caenorhabditis elegans, a small worm, to understand how cells develop.
It was then that Ambros discovered that the lin-4 gene produced a very short RNA molecule that did not code for proteins, but regulated the production of other proteins by interacting with the mRNA of another gene, lin-14. Ruvkun, in turn, confirmed that this small molecule, the microRNA, blocked the production of the lin-14 protein, inaugurating a new concept of genetic regulation.
MicroRNAs are like “switches” that turn genes on and off, controlling when and how proteins are produced. They do not code for proteins directly, but they affect the production of proteins by binding to mRNA, interrupting its translation process. The research revealed that these small RNAs play a crucial role in physiological processes, development, and behavior and may be associated with diseases such as cancer.
Today, it is known that the human genome contains thousands of genes that encode microRNAs, making this discovery one of the most important in modern molecular biology.
Genes for microRNA are as much a part of the human genome as genes that code for proteins. Cells produce microRNA using a process that resembles the early steps in protein synthesis. The microRNA gene is activated, the DNA strand unwinds, and the gene is copied, or transcribed, as RNA.
1- The initial transcript of the gene is called primary miRNA (pri-miRNA)
2- In the cell nucleus, these hairpin molecules are cut to form double-stranded precursor miRNA (pre-miRNA)
3- The pre-miRNA is transported to the cytoplasm. There, it is cut to form a functional mature miRNA (mature miRNA molecules are about 22 nucleotides long).
4- The mature miRNA first binds to a molecule called the RNA interference silencing complex, or RISC
5- The miRNA then binds to its target messenger RNA (mRNA), thereby blocking its translation or causing its degradation
The field of microRNAs is still growing, and researchers are exploring their potential to treat diseases, although finding effective ways to deliver them into cells is a major challenge. Ambros and Ruvkun’s discovery has opened the door to a new understanding of how genes are regulated, which could have huge implications for treating complex medical conditions.
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