Baltimore , David

(1938–) American molecular biologist

Baltimore was born in New York City and studied chemistry at Swarthmore College. He continued with postgraduate work at the Massachusetts Institute of Technology, and at Rockefeller University, where he obtained his PhD in 1964. After three years at the Salk Institute in California, he returned to MIT in 1968 where, in 1972, he became professor of biology.

Francis Crick had formulated what came to be known as the Central Dogma of molecular biology, namely, that information could flow from DNA to RNA to protein but could not flow backward from protein to either DNA or RNA. Although he had not actually excluded the passage of information from RNA to DNA it became widely assumed that such a flow was equally forbidden. In June 1970 Baltimore and, quite independently, Howard Temin announced the discovery of an enzyme later to be known as reverse transcriptase, which is capable of transcribing RNA into DNA. Apparently certain viruses, like the RNA tumor viruses used by Baltimore, could produce DNA from an RNA template. For this work Baltimore shared the 1975 Nobel Prize for physiology or medicine with Temin and Renato Dulbecco. A few years later their work took on an added significance when Gallo and Montagnier identified a retrovirus as the cause of AIDS.

Earlier (1968) Baltimore had done important work on the replication of the polio virus. He revealed that the RNA of the virus first constructed a ‘polyprotein’ (or giant protein molecule), which then split into a number of smaller protein molecules. Two of these polymerized further RNA while the remainder formed the protein coat of the new viral particles.

In 1982 Baltimore became founding director of the Whitehead Institute, Cambridge, Massachusetts, a research biomedical foundation backed by the industrialist E. C. Whitehead. While at Whitehead, in collaboration with D. Schatz, he identified two antibody genes, RAG-1 and RAG-2. In 1990 Baltimore was appointed president of Rockefeller University; it was not to prove a fruitful or happy time. Many staff opposed the appointment and Baltimore became involved in a bitter controversy. It had been claimed that a paper co-authored by Baltimore and published in 1986 in Cell was based on falsified data. Although Baltimore withdrew his name from the paper, the public controversy persisted in Congressional hearings and the correspondence columns of Nature. Baltimore resigned the presidency in 1992 and returned to MIT in 1994 as professor of molecular biology.