Temin, Howard Martin

▪ 1995

      U.S. virologist (Dec. 10, 1934, Philadelphia, Pa.—Feb. 9, 1994, Madison, Wis.), won the 1975 Nobel Prize for Physiology or Medicine (with Renato Dulbecco and David Baltimore) for his role in discovering reverse transcriptase, an enzyme that transcribes RNA into DNA. Temin identified the enzyme while conducting research on a virus that causes cancer in chickens. Temin's groundbreaking finding dramatically illustrated the exception to one of the fundamental tenets of molecular biology—that the genetic instructions for protein synthesis flow uniquely from DNA to RNA. Temin's studies helped scientists determine that reverse transcriptase also has a role in the replication of such viruses as hepatitis B, cauliflower mosaic (a plant virus), and HIV, which causes AIDS. Temin's original 1964 theory that the DNA-into-RNA sequence could be reversed was derided in the scientific community, but he persevered for six years before proving his hypothesis. Temin graduated from Swarthmore (Pa.) College at the age of 18 and earned a Ph.D. (1959) at the California Institute of Technology. There, working under the tutelage of Dulbecco, he began his investigations into viruses and their role in animal cancers. Temin contended, however, that viruses probably did not play a central role in cancers in humans. An ardent antismoking crusader, he felt that the incidence of cancer could be reduced by the elimination of smoking. In 1960 Temin joined the staff of the University of Wisconsin, where he successively served as associate professor, full professor, Wisconsin Alumni Research Foundation professor of cancer research, and American Cancer Society professor of viral oncology and cell biology. Temin succumbed to lung cancer, but not a type associated with smoking.

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▪ American virologist

born Dec. 10, 1934, Philadelphia, Pa., U.S.

died Feb. 9, 1994, Madison, Wis.

      American virologist who in 1975 shared the Nobel Prize for Physiology or Medicine with his former professor Renato Dulbecco (Dulbecco, Renato) and another of Dulbecco's students, David Baltimore (Baltimore, David), for his codiscovery of the enzyme reverse transcriptase.

      While working toward his Ph.D. under Dulbecco at the California Institute of Technology, Temin began investigating how the Rous sarcoma virus causes animal cancers. One puzzling observation was that the virus, the essential component of which is ribonucleic acid (RNA) (RNA), could not infect the cell if the synthesis of deoxyribonucleic acid (DNA) (DNA) was stopped. Temin proposed in 1964 that the virus somehow translated its RNA into DNA, which then redirected the reproductive activity of the cell, transforming it into a cancer cell. The cell would reproduce this DNA along with its own DNA, producing more cancer cells.

      Skeptics pointed out that Temin's suggestion contradicted the contemporary tenet of molecular biology: that genetic information always passed from DNA to RNA, rather than the reverse. But in 1970 both Temin and Baltimore proved Temin's hypothesis correct. They identified an enzyme (reverse transcriptase) in the virus that synthesizes DNA that contains the information in the viral RNA.

      Temin obtained his Ph.D. in 1959, and after spending another year with Dulbecco, he joined the faculty of the University of Wisconsin in Madison, where he taught and conducted research until his death.

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