Marshall W(arren) Nirenberg - Research, Biography

Biochemist, born in New York City, New York, USA. He taught while a student at the University of Florida (1945–52), then joined the National Institutes of Health (1957). Beginning in 1960, knowing that the genetic code consists of 64 nucleotide base ‘triplets’ that code for 20 amino acids, he synthesized successions of nucleic acids with a known base sequence, then determined which amino acid each triplet represented. For his pioneering work in deciphering the genetic code, he shared the 1968 Nobel Prize for Physiology or Medicine. After this research, he concentrated on studies of cellular control, neuromuscular differentiation, and genetic evolution.

Research

By 1959, experiments by Oswald Avery, Francis Crick, James D. It was not known, however, how DNA was replicated, how DNA directed the expression of proteins, or what role RNA had in these processes. They produced RNA comprised solely of uracil, a nucleotide that only occurs in RNA. They then added this synthetic poly-uracil RNA into a cell-free extract of Escherichia coli which contained the DNA, RNA, ribosomes and other cellular machinery for protein synthesis. They added DNase, which breaks apart the DNA, so that no additional proteins would be produced other than that from their synthetic RNA. They then added 1 radioactively labeled amino acid, the building blocks of proteins, and 19 unlabeled amino acids to the extract, varying the labeled amino acid in each sample. They realized that they had found the genetic code for phenylalanine: UUU (three uracil bases in a row) on RNA. This was the first step in deciphering the codons of the genetic code and the first demonstration of messenger RNA (see Nirenberg and Matthaei experiment).

Nirenberg received great scientific attention for these experiments. Within a few years, his research team had performed similar experiments and found that three-base repeats of adenosine (AAA) produced the amino acid lysine, cytosine repeats (CCC) produced proline and guanine repeats (GGG) produced nothing at all. The next breakthrough came when Phillip Leder, a postdoctoral researcher in Nirenberg's lab, developed a method for determining the genetic code on pieces of tRNA (see Nirenberg and Leder experiment).

Nirenberg's later research focused on neuroscience, neural development, and the homeobox genes.

Biography

Nirenberg was born in New York City, the son of Harry and Minerva Nirenberg.

He began his postdoctoral work at the National Institutes of Health (NIH) in 1957 as a fellow of the American Cancer Society. In 1959 he began to study the steps that relate DNA, RNA and protein. Nirenberg's groundbreaking experiments advanced him to become the head of the Section of Biochemical Genetics in 1962.

Nirenberg was awarded the National Medal of Science in 1966 and the National Medal of Honor in 1968 by President Lyndon B.