The University Record, July 19, 1999

Michigan Great Nirenberg earned Nobel Prize for DNA work

Editor’s Note: This article is one in a series of profiles of alumni who have made significant and lasting contributions through their research, scholarship and creative activity. Expanded versions of these articles are available on the Web at www.research.umich.edu/research/news/michigangreats.html.


By Lee Katterman
Office of the Vice President for Research

Newman
“The last few decades of research have yielded an explosion of biological information,” noted the Life Sciences Commission in its February 1999 report. One of the early discoveries that ignited research in the life sciences was made by Marshall Nirenberg, a graduate of the Department of Biological Chemistry in the Medical School. In 1968, Nirenberg shared the Nobel Prize in Medicine for his work to “crack” the genetic code.

Born in New York City in 1927, Nirenberg’s interest in biology got a boost when his family moved in 1939 to Orlando, Fla.—then an agricultural area with lots of open space. When it came time for college, Nirenberg enrolled in the University of Florida in Gainesville, where he majored in zoology and botany.

While an undergraduate, he got involved in the relatively young field of biochemistry as a laboratory assistant in the school’s Nutrition Laboratory. This gave Nirenberg the chance to learn about the use of radioactive isotopes to follow the course of biochemical reactions—basic knowledge that he would put to good use later in the research that led to the Nobel Prize.

In 1948, Nirenberg received a bachelor’s degree and began work on his master’s degree. His thesis focused on the ecology and classification of the caddis fly, a freshwater insect. He continued his education at Michigan, where he enrolled in the biological chemistry Ph.D. program. The grades Nirenberg brought with him were not spectacular, so he was accepted on probationary status.

However, as Nirenberg became more deeply involved in research in the lab of Prof. James Hogg, things improved. He was very excited about his research project—a study of an enzyme system that facilitated sugar uptake by tumor cells—and spent many hours in the lab. Ultimately, he completed a fine thesis and graduated in 1957.

“The University should be quite proud for attracting a student as gifted as Nirenberg and for providing the research environment in which he could flourish,” notes Minor Coon, the Victor C. Vaughan Distinguished University Professor of Biological Chemistry, who was on the faculty when Nirenberg was studying here.

After graduation, Nirenberg received an American Cancer Society fellowship and went to work in the lab of DeWitt Stetten at the National Institutes of Health (NIH). In 1960, he was appointed to the regular research staff.

By the late 1950s, James Watson and Frances Crick had shown the world the double helix of DNA. Scientists also knew that the sequence of nucleotides in DNA was ultimately responsible for directing the synthesis of all proteins in the cell. In very simple terms, it is protein activity in cells that directs all biological function.

At the NIH, Nirenberg explored the relationship between DNA, RNA and protein synthesis. In 1961, he delivered a paper at an international scientific meeting in Moscow describing his success in synthesizing an artificial protein composed entirely of the amino acid phenylalanine. At first, his report got little attention. But before the meeting concluded, the significance of his finding led the organizers to invite Nirenberg to present his paper a second time at a special session. In short, Nirenberg had replicated the cellular mechanism that translated the information contained in DNA into a protein, a process mediated by RNA.

With Nirenberg’s report, the race was on to determine the precise code of nucleotides in DNA that specified the amino acids to be joined to form any particular protein. Initially, it appeared that researchers other than Nirenberg would be the first to publish the complete genetic code, but with help from a number of colleagues at NIH, Nirenberg was able to report many of the corresponding DNA-amino acid code sequences, thereby staking his claim for the Nobel Prize that was awarded in 1968.

Nirenberg shared the prize in medicine that year with Robert Holley of the Salk Institute and Gobind Khorana of the Massachusetts Institute of Technology, who simultaneously reported important findings to help decipher the genetic code.

Today, Nirenberg is chief of biomedical genetics at NIH’s National Heart, Lung, and Blood Institute, where he continues to work to understand how genetic information controls the development and metabolism of living organisms.