The Nobel Prize in Physiology or Medicine for 2024 has been awarded to two American scientists, Victor Ambros and Gary Ruvkun, for their pioneering work on microRNA. Their discoveries have provided insights into how complex life forms emerged on Earth and how the human body consists of a vast array of different tissues, despite all cells carrying the same genetic information.
MicroRNAs, which are tiny molecules that regulate gene expression, play a vital role in determining how genes are controlled within organisms, including humans. Ambros and Ruvkun’s breakthrough findings laid the foundation for understanding how genetic instructions are differently expressed across various tissues, which helps explain the diversity of cells in the human body. The Nobel Assembly of Sweden’s Karolinska Institute, which selects the Nobel Prize winners, announced that the two scientists would share a prize fund of 11 million Swedish kronor, equivalent to about £810,000.
The genetic information in every cell of the human body is stored in DNA. Although every cell contains identical genetic material, the types of cells they become and their functions vary greatly. For example, the electrical impulses generated by nerve cells differ entirely from the rhythmic contractions of heart cells. Similarly, the metabolic activities of liver cells contrast with the function of kidney cells, which filter waste products from the blood. The retina’s light-sensing cells and white blood cells, which fight infections, are also strikingly different in their roles.
This vast diversity is made possible through a process called gene expression, which refers to how cells read and execute the instructions stored in DNA. Ambros and Ruvkun were the first to identify microRNAs, and their research showed how these molecules exert control over the way genes are expressed, resulting in different outcomes in various tissues.
The Nobel Assembly commended the two scientists, stating, “Their groundbreaking discovery revealed a completely new principle of gene regulation that turned out to be essential for multicellular organisms, including humans.” The Assembly also noted that the human genome contains more than 1,000 microRNAs, highlighting the importance of these molecules in regulating the genetic blueprint.
MicroRNAs have been crucial in allowing life to evolve into its complex forms. Without the precise control of gene expression that microRNAs provide, all cells within an organism would be identical. This ability to regulate genes is fundamental to the development of diverse cell types that serve different functions within the body. However, when microRNAs are not functioning correctly, they can contribute to a range of diseases. Abnormal regulation by microRNAs has been linked to cancers and various other conditions, including congenital hearing loss and bone disorders. A severe example of microRNA-related disease is DICER1 syndrome, which is caused by mutations affecting microRNAs and leads to the development of cancers in different tissues.
Victor Ambros, who is 70 years old, currently works at the University of Massachusetts Medical School, while Gary Ruvkun, aged 72, is a professor at Harvard Medical School. Both scientists conducted much of their research using a simple organism, the nematode worm known as *C. elegans*. Their research focused on a mutant form of the worm that failed to develop certain cell types. Through their experiments, they identified small pieces of genetic material—later identified as microRNAs—that were crucial for the worm’s development.
To understand how microRNAs function, it’s essential to first know how genes are expressed. A gene contains instructions that are stored in DNA. When a cell needs to make use of this genetic information, it first creates a copy of the gene in the form of messenger RNA (mRNA), which carries the instructions out of the nucleus to the cell’s machinery that produces proteins. Proteins are essential for the structure and function of the body’s tissues and organs. MicroRNAs, however, interfere with this process by attaching themselves to the messenger RNA, effectively stopping it from delivering its instructions. In doing so, the microRNAs prevent the gene from being expressed in the cell. Ambros and Ruvkun’s further research demonstrated that this regulatory mechanism is not unique to worms but is a fundamental process across all life forms on Earth.
Janosch Heller, a professor at Dublin City University, praised the Nobel recipients for their significant contributions to science. “I am delighted to hear that the prize has gone to Profs Ambros and Ruvkun,” Heller said. “Their pioneering work into gene regulation by microRNAs paved the way for groundbreaking research into novel therapies for devastating diseases such as epilepsy, but also opened our eyes to the wonderful machinery that is tightly controlling what is happening in our cells.”
The Nobel Prize for Physiology or Medicine has a long history of recognizing outstanding contributions to science. In recent years, several laureates have been honored for their groundbreaking discoveries:
– In 2023, Katalin Kariko and Drew Weissman received the award for developing the technology that led to the creation of mRNA-based COVID-19 vaccines.
– In 2022, Svante Paabo was recognized for his work on human evolution, specifically for decoding the genome of ancient human relatives.
– The 2021 Nobel Prize was awarded to David Julius and Ardem Patapoutian for their discoveries on how the human body senses touch and temperature.
– In 2020, Michael Houghton, Harvey Alter, and Charles Rice were honored for discovering the Hepatitis C virus, which has led to life-saving treatments for millions of people.
– In 2019, Sir Peter Ratcliffe, William Kaelin, and Gregg Semenza were awarded for their work in uncovering how cells sense and respond to varying oxygen levels in their environment.
– James P. Allison and Tasuku Honjo received the 2018 prize for their work on cancer immunotherapy, which harnesses the body’s immune system to fight cancer cells.
– In 2017, the prize went to Jeffrey Hall, Michael Rosbash, and Michael Young for their research on how the body’s internal clock, or circadian rhythm, is regulated.
– Yoshinori Ohsumi won the Nobel Prize in 2016 for discovering how cells maintain their health by recycling their internal components, a process known as autophagy.
The Nobel Prize in Physiology or Medicine continues to celebrate those who make remarkable strides in understanding the human body and the fundamental mechanisms that drive life. This year’s recognition of Victor Ambros and Gary Ruvkun for their work on microRNAs highlights the importance of gene regulation in the evolution of life and opens new doors for medical research and treatments for various diseases. Their discovery not only deepens our understanding of life but also holds the potential to transform how we approach some of the most challenging medical conditions.