Victor Ambros

Victor Ambros (born December 1, 1953, Hanover, New Hampshire, U.S.) is an American developmental biologist and molecular geneticist best known for his pioneering work in the discovery of microRNA (miRNA), a type of small RNA molecule that serves essential functions in regulating gene expression. Ambros’s contributions to the discovery of miRNA had a profound impact on scientific understanding of cell function and mechanisms underlying gene activity and disease and was particularly important for the fields of molecular biology and developmental biology. For his discoveries, he was awarded the 2024 Nobel Prize for Physiology or Medicine (shared with American molecular biologist and geneticist Gary Ruvkun).

Education and early research

Ambros spent his youth in Vermont, where his parents encouraged his interest in science. After graduating from high school, he attended the Massachusetts Institute of Technology (MIT), where he earned a bachelor’s degree in biology in 1975. He remained at MIT to pursue a Ph.D. in genetics, working under the guidance of American virologist and Nobelist David Baltimore while carrying out research aimed at better understanding the genomic structure and replication of poliovirus. In 1979 Ambros completed a Ph.D. and continued on at MIT as a postdoctoral researcher in the laboratory of biologist H. Robert Horvitz. There he later worked with Ruvkun, who was also a postdoctoral student with Horvitz, to investigate genetic factors dictating the timing of events in the development of the nematode Caenorhabditis elegans.

Lin-4 and miRNA

In the late 1980s, after joining the faculty at Harvard University, Ambros studied more deeply a strain of C. elegans that carries a mutation in a gene known as lin-4. Lin-4 exerts temporal control over developmental events in C. elegans larvae by negatively regulating LIN-14 protein. In the course of their investigations, Ambros and his team realized that lin-4 produces only a very short strand of RNA, which is not translated into protein, and that lin-4 interacts with a gene known as lin-14. Although it was apparent to Ambros and others that lin-4 somehow regulates lin-14 activity, the mechanism was a mystery.

In 1992, while still trying to elucidate lin-4 regulatory mechanisms, Ambros moved his laboratory to Dartmouth College. The following year his laboratory published its findings on the short RNA produced by lin-4. He and Ruvkun then compared their insights on lin-4 and lin-14, which Ruvkun’s laboratory had been investigating, and found that the short lin-4 RNA sequence was complementary to a segment of lin-14 messenger RNA (mRNA). They also showed that binding of lin-4 RNA to lin-14 mRNA blocks LIN-14 protein production. Following the publication of their work, it was recognized that they had discovered not only a novel RNA molecule—miRNA—but also a previously unknown mechanism of gene regulation. In 2008 Ambros joined the faculty at the University of Massachusetts Medical School, where his research continues to center on characterizing the role of miRNA in development.

Awards and honors

Ambros has received numerous awards and honors throughout his career, including the 2008 Lasker Award (shared with Ruvkun and David C. Baulcombe), the 2008 Gairdner International Award (shared with Ruvkun), and the 2014 Wolf Prize (shared with Ruvkun and Nahum Sonenberg). Ambros is a fellow of the American Academy of Arts and Sciences (2011) and the American Association for the Advancement of Science (2018).