Every October 11th, the Nobel Foundation announces that year’s winners. The prize awarded to the winners is called the Nobel Prize, one of the most prestigious awards in the world. Since the Nobel Prize attracts a lot of attention, the winners and their findings also receive significant public attention. Victor Ambros, an American biologist, is one of this year’s winners. When the news of this award was announced, his discovery, microRNA, received widespread attention.
MicroRNA was discovered by Victor Ambros and his colleagues in 1993. They published a paper about the lin-4 gene, which regulates the growth of Caenorhabditis elegans larvae. They found that when they separated the lin-4 miRNA gene, instead of producing the protein-coding mRNA—a type of RNA that acts as a blueprint for producing chemically coded proteins—it produced non-coding RNA. RNA is a molecule that delivers DNA instructions to other places to form proteins, and unlike DNA, it is very unstable. This mysterious finding included 22 types of nucleotide sequences that were partially complementary to lin-14, a nuclear protein controlling developmental timing in cells. This complementarity blocked the translation of lin-14 mRNA into RNA protein. At the time, scientists believed this was one of the unique characteristics of lin-14.
Victor Ambros studied two worms to identify the genes controlling the timing of activations among different genes. He observed two mutant worms that exhibited defects in the timing of development due to genetic issues. His goal was to prove the functions of these genes. However, he could not demonstrate how lin-14 activity was inhibited.
Ambros did not stop there. He established a laboratory dedicated to researching lin-14. He discovered that the lin-4 miRNA gene produced significantly shorter RNA molecules that were incapable of producing proteins. This led Ambros to conclude that the small RNA from lin-4 was responsible for inhibiting lin-14.
In 2000, another characteristic of RNA was revealed. It suggested that let-7 RNA, which suppresses lin-14 to ensure proper growth timing in Caenorhabditis elegans larvae, and additional small RNAs might regulate and control the timing of development in animals, including humans.
A year later, lin-4 and let-7 RNAs were discovered to constitute a significant portion of small RNAs in human cells. These RNAs were found to be very similar to lin-4 and let-7. That same year, biologists named these molecules “microRNAs.”
The main characteristic of microRNA in plants is its ability to pair with other RNAs, creating gene repression through cleavage of target transcripts.
In addition, microRNA is an important discovery for humanity. Gene regulation by microRNAs, discovered by Ambros and Gary Ruvkun, has been functioning for hundreds of millions of years. This regulation enabled the evolution of complex organisms. Cells and genes cannot develop properly without microRNAs. Without the regulation provided by microRNAs, organisms would not grow as we expect. Furthermore, abnormal regulation of microRNAs increases the risk of cancer, and mutations in genes coding for microRNAs can cause significant health issues such as hair loss, eye disorders, and serious skeletal abnormalities.
Without microRNA, humans would not develop successfully as we know.
MicroRNA is essential for every organism. Victor Ambros’s discovery was unexpected; however, it provided a new perspective on genes and explained the complexity of organisms.
Word Cited
Hong, Y., Lee, R. C., & Ambros, V. (2000b, March 20). Structure and function analysis of LIN-14, a temporal regulator of postembryonic developmental events in Caenorhabditis elegans. Molecular and cellular biology. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC110844/
The nobel prize in physiology or medicine 2024. NobelPrize.org. (2024, October 7). https://www.nobelprize.org/prizes/medicine/2024/press-release/
https://www.nature.com/articles/d41586-024-03212-9
By. Seunghu Chi