Charles Yanofsky (April 17, 1925 – March 16, 2018) was an American geneticist on the faculty of Stanford University who contributed to the establishment of the one gene-one enzyme hypothesis and discovered attenuation, a riboswitch mechanism in which messenger RNA changes shape in response to a small molecule and thus alters its binding ability for the regulatory region of a gene or operon.
Early life and education
Charles Yanofsky was born on April 17, 1925, in New York. He was one of the earliest graduates of the Bronx High School of Science, then studied at the City College of New York and completed his degree in biochemistry in spite of having had his education interrupted by military service in World War II including participation in the Battle of the Bulge. His doctoral dissertation, A study of tryptophan-niacin metabolism in Neurospora, examined amino acid biosynthesis in fungi. Yanofsky showed that changes in DNA sequence can produce changes in protein sequence at corresponding positions. His work is considered the best evidence in favor of the one gene-one enzyme hypothesis.
His graduate student Iwona Stroynowski and Mitzi Kuroda discovered the process of attenuation of expression based on regulated binding ability of the five-prime untranslated region of the messenger RNA for the bacterial tryptophan operon. They had thus discovered the first regulatory riboswitch, although that terminology was not used until later. Yanofsky and his other collaborators then extended this work showing how mRNAs responded allosterically to a small molecule signal by changing shape and therefore changing ability to bind to the regulatory region of each operon. They showed that this mechanism applied to other amino acid biosynthesis and degradation operons of bacteria and to animal cell genes.
In 1980, Yanofsky and other Stanford scientists founded DNAX, a Palo Alto–based research institute subsequently acquired by Schering-Plough. Yanofsky was awarded the Selman A. Waksman Award in Microbiology from the National Academy of Sciences in 1972 and was co-recipient of the Louisa Gross Horwitz Prize from Columbia University in 1976 with Seymour Benzer. Yanofsky was elected a foreign member of the Royal Society in 1985 and was one of the recipients of the 2003 National Medal of Science awards.