Stop or Go: With Doctor Norton Zinder

After joining the faculty of The Rockefeller University in 1952, Zinder and Tim Loeb, his first student, isolated bacteriophages that could grow only on strains carrying the F (fertility) factor responsible for bacterial sex. Thus was the first phage with an RNA genome (f2) identified. Access to large quantities of a homogeneous RNA opened the door to many fundamental questions, which Norton and his students attacked with vigor. Always there were mutants—and, once they knew that the genome was the message, biochemistry—that revealed the nature of nonsense suppressors and how protein synthesis initiates and terminates. In the late 1960s, a NOVA television program, “Stop or Go,” explained some of these discoveries. Norton and his lab members reenacted their search for conditional-lethal f2 mutants, their elation at finding them, and the experiments that led them to suppressor tRNAs, the n-formyl methionine that initiates protein synthesis, and translation stop codons.