April 10, 1927, is the birthdate of Marshall Warren Nirenberg, the soft-spoken biochemist who startled the scientific world in 1961 when he revealed that he had deciphered the code by which cells produce proteins, the basic building blocks of life. A few years earlier, James Watson and Francis Crick had discovered the existence of DNA, and its double-helical structure, but it was left to others to figure out the specific “language” by which DNA is translated to create proteins.

So unknown was Nirenberg when he first introduced his findings, at a biochemistry conference in Moscow in August 1961, that very few people showed up to hear him speak. It was only when one attendee alerted Francis Crick to the content of Nirenberg’s talk, and Crick asked the conference organizers to arrange for a repeat delivery, this time in a large auditorium filled with hundreds of primed scientists, that the news reverberated around the world.

By 1968, Nirenberg, then 41, was the co-recipient of the Nobel Prize for Physiology or Medicine.

Floridian wilds and the KKK

Marshall Warren Nirenberg was born in New York, and spent his early years in Brooklyn. His father, Harry Nirenberg, ran Lion Brand Shirts, a manufacturer that had been founded by his father, who had arrived from Odessa in 1888 and begun by sweeping the floor in a shirt factory. Before entering the family business, Harry had spent a year and a half in medical school.

Marshall’s mother was the former Minerva Bykowsky, whose family also hailed from the former Russian empire. She and Harry had been married at New York’s Plaza Hotel, and their wedding was announced in the New York Times.

When Marshall was about nine, he was pushed by another child into a pool of cold water. It was the dead of winter. He contracted rheumatic fever, at the time a life-threatening disease, and eventually, his parents decided to move the family to Florida, for its sub-tropical climate. Harry bought and began to operate a dairy farm outside Orlando, then a small city.

Marshall thrived as he explored the wilds that were in his backyard, learning a lot from the biologists brought to the area during World War II to train air force pilots doing survival courses in Florida before heading off to the Pacific.

In the mid-20th century, Orlando was the center of Florida’s actively anti-Semitic Ku Klux Klan. (The city was also the state’s most segregated city.) Nirenberg’s biographer, Franklin H. Portugal, suggests that this may have accounted for his subject’s later reticence to talk about his Jewish background, even though the family was very involved in Orlando’s small Jewish community. Of course, Nirenberg was shy and unassuming in general.

Nirenberg attended Orlando High School, and then the University of Florida, where he earned a B.Sc. in 1948, and an M.Sc. in zoology in 1952. He only began to shine, however, during his doctoral studies in biochemistry at the University of Michigan (Ph.D., 1957). From there he went to the National Institutes of Health, in Washington, D.C. – and never left.

How a gene becomes a protein

Together with visiting German biochemist Heinrich J. Matthaei, Nirenberg began exploring the relationship between DNA, RNA and protein in 1959.

It was already known that DNA was made of just four types of chemical bases, which in turn lined up in units of three, called codons. Using radioactive markers, Nirenberg and Matthaei discovered that when DNA is transcribed into RNA, the base thymine is translated into uracil, and that a codon of three uracil bases in the RNA molecule codes for the amino acid phenylalaline in proteins.

Open gallery view How a protein is born: DNA is transcribed into RNA which is translated into protein. Credit: Dreamstime.com

Once they announced that finding, a race was on to discover the code for the structure of the other 63 codons that were the formulas for other amino acids. In what became an unofficial but very serious competition, Nirenberg’s lab won out, completing that task by 1966. Two years later, he won the Nobel, sharing it with two other scientists, Robert W. Holley and Har Gobind Khorana, who were involved in other aspects of RNA research.

Nirenberg remained at NIH after 1968, but turned his attention to neurobiological research.

He was married to Perola Zaltzman, a chemist from Brazil, who died in 2001. Four years later, he married Myrna Weissman, a professor of epidemiology and psychiatry, becoming stepfather to her four children.

Marshall Nirenberg died of cancer on January 15, 2010, at the age of 82.