David Baltimore spent his career working with viruses. His research involved finding the relationship between cancer viruses and the DNA of the cells they infect. In 1975, Baltimore shared the Nobel Prize in Physiology or Medicine with Renato Dulbecco, an Italian-born virologist and Howard M. Temin, an American virologist. In 1965, Temin, an assistant professor of oncology at the University of Wisconsin, proposed for the first time a process called reverse transcription. During this process, viral RNA inserts its own genes into its host cell's DNA. At the Massachusetts Institute of Technology while studying Rauscher mouse-leukemia virus, Baltimore tested Temin's hypothesis and discovered an RNA viral enzyme that alters the host DNA. Temin also found a similar enzyme in the Rous-sarcoma virus. Viruses that alter host DNA in this manner are called retroviruses, and human immunodeficiency virus, the virus that causes AIDS is an example of a retrovirus. The enzyme involved in reverse transcription is known as reverse transcriptase. Baltimore and Temin's work on reverse transcriptase showed how a retrovirus disrupts a cell's replication mechanism and causes cancer. Their findings led to certain cancer treatments.
Born in New York City, Baltimore became interested in science as a child, particularly mathematics and biology. While in high school, he attended summer school at Jackson Memorial Laboratory, Bar Harbor, Maine, which sparked his interest in biological research. In 1956, Baltimore began as a biology major at Swarthmore College in Pennsylvania and later switched to chemistry. His interest in biochemistry developed after a summer at Cold Spring Harbor Laboratories working with George Streisinger. Baltimore graduated from Swarthmore in 1960 and received high honors in chemistry. He attended graduate school at the Massachusetts Institute of Technology in the field of biophysics, and then transferred to Rockefeller University in New York. There he worked on his thesis and continued his research in animal virology. In 1964 he received his Ph.D. from Rockefeller University. From 1964-1965, he studied virus-specific enzymes with Dr. Jerard Hurwitz at the Albert Einstein College of Medicine in New York.
Baltimore worked as a research associate from 1965-1968 at the Salk Institute for Biological Studies in California. His colleague, Renato Dulbecco, was studying the differences between normal cells and viral-induced tumor cells. He then joined the faculty at the Massachusetts Institute of Technology in 1968, and was named full professor in 1972. In 1974, Baltimore conducted research at the MIT Center for Cancer Research where Salvador Luria was the director. There he focused on the relationship between viruses and cancer.
In 1990, he was appointed president of Rockefeller University in New York, but was forced to resign the following year as a result of a paper written in 1986 containing data that his associate, Thereza Imanishi-Kari, a Tufts University professor, allegedly falsified. The NIH Office of Scientific Integrity investigated the scientific behavior of three of the authors. The case drew national attention and took on political overtones. Baltimore was never accused of falsifying data, but a committee from the House of Representatives found the fraud charges against Imanishi-Kari believable. Nevertheless, the prestigious name of David Baltimore and the questionable credibility of the Tufts graduate student who was the whistle blower in the case left the matter unresolved. Finally, in 1996, ten years after the paper's publication, a federal appeals panel rejected the fraud charges against Imanishi-Kari. David Baltimore continues to maintain the position of Professor of Biology at MIT. In 1998, he was appointed President of Caltech in California. He is also serves as a Professor of Microbiology for the American Cancer Society and Chairman of the AIDS Vaccine Research Committee of the National Institutes of Health.
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