On June 17, 1920—102 years ago—a Jewish merchant family in Nancy, France, welcomed a new baby who would later make significant contributions to life sciences. That baby was François Jacob, the French biologist and bacterial geneticist who proposed two important concepts: mRNA and the operon model.

In 1957, Francis Crick first proposed the Central Dogma: genetic information flows from DNA to RNA to protein. But DNA resides in the nucleus and cannot cross the nuclear membrane. How does the genetic code get to the cytoplasm? This is the job of mRNA.

In 1959, Arthur Pardee, François Jacob, and Jacques Monod (Pasteur Institute) inferred from the lactose operon experiment that an unstable, short-lived messenger molecule might exist. In 1961, they captured this messenger—an RNA molecule complementary to DNA—which they named messenger RNA. The operon model was a landmark achievement, with significance rivaling the discovery of the DNA double helix. Jacob, Monod, and André Lwoff received the 1965 Nobel Prize.

How Does mRNA Deliver the Message?

DNA is the "original" genetic information. During protein synthesis, its double helix unwinds, and one strand serves as a template to synthesize mRNA. mRNA contains sequences complementary to DNA, serving as the direct template for protein synthesis. Genetic information is stored in nucleotide sequences, with every three bases forming a codon that encodes a specific amino acid.

After transcription, mRNA leaves the nucleus, enters the cytoplasm, and binds to ribosomes—the protein assembly machines. With the help of tRNA as "porters," specific amino acids are delivered and matched to mRNA codons, building the polypeptide chain until completion.

Sixty years after mRNA's discovery, it has been used in COVID-19 vaccine development—an outcome unimaginable at the time.