Temin's description of how tumor viruses act on the genetic material of the cell through reverse transcription was revolutionary. This upset the widely held belief at the time of a popularized version of the "Central Dogma" of molecular biology posited by Nobel laureate Francis Crick, one of the co-discoverers of the structure of DNA (along with James Watson and Rosalind Franklin). Crick had claimed only that sequence information cannot flow out of protein into DNA or RNA, but he was commonly interpreted as saying that information flows exclusively from DNA to RNA to protein. Temin showed that certain tumor viruses carried the enzymatic ability to reverse the flow of information from RNA back to DNA using reverse transcriptase. This phenomenon was also independently and simultaneously discovered by David Baltimore, with whom Temin shared the Nobel Prize.
The New York Times published the following obituary about Howard Temin:
Dr. Howard M. Temin, a cancer researcher who won the Nobel Prize for his role in discovering an enzyme that overturned a central tenet of molecular biology, died of lung cancer Wednesday at his home in Madison, Wis. He was 59.
The enzyme, reverse transcriptase, later played a crucial role in identifying the AIDS virus. It also became the underpinning of much of the biotechnology industry and was crucial to the genetic engineering that has produced drugs like human insulin and tpa, a clot-dissolving agent that stops heart attacks in progress.
The Nobel committee cited Dr. Temin for "discoveries concerning the interaction between tumor viruses and the genetic material of the cell." He shared the prize with his former professor, Dr. Renato Dulbecco, and another researcher, Dr. David Baltimore. Dr. Temin's award was for his role in discovering reverse transcriptase, the enzyme that helps certain viruses subvert the genetic machinery of the cells they infect. Dr. Temin found the enzyme in a virus that causes cancer in chickens, while Dr. Baltimore independently discovered reverse transcriptase in a virus that causes cancer in mice.
Dr. Temin's award came after a lonely battle to overcome derisive criticism from scientific leaders who refused to believe in his theory that some viruses carry their genetic information in the form of RNA, which is then copied into DNA in infected cells. This theory challenged what then was known as the "central dogma" in biology, that that deoxyribonucleic acid (DNA) always passed information on to ribonucleic acid (RNA) and never the other way around.
"The idea that RNA could make DNA was considered ludicrous," said Dr. Robin Weiss, a leading virologist in London, in an interview.
For six years Dr. Temin persisted against the criticism until he identified the enzyme, reverse transcriptase, that proved the theory.
Dr. J. Michael Bishop, who won a Nobel Prize in 1989, said Dr. Temin had "an exceptional, independent intellect and imagination that produces discoveries, and he produced them."
In an interview yesterday, Dr. Bishop recalled entering the field and watching "Howard go from a figure thought by some to be irresponsible and lax in interpreting data to be a lion overnight." He added: "It was quite a lesson for me in intellectual courage because he just toughed it. He was not adversarial and not strident. He was way ahead of the pack, carrying the banner and taking a lot of flak for it, and he was in a humbling position for quite a while."
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At the time, scientists knew there were RNA and DNA viruses. But unlike most other scientists, Dr. Temin was puzzled why RNA viruses were an exception to central dogma.
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Dr. June Osborn, a virologist who is now the dean of the University of Michigan School of Public Health in Ann Arbor, who said she became close friends with Dr. Temin over the 16 years that they had taught together in Madison, described him as "totally focused, he had incredible control that kept him from getting distracted."
She recalled walking into his office with another professor just hours after Dr. Temin learned that he had won the Nobel Prize. Though happy to see his friends, Dr. Temin complained that he could not get work done because of the sudden attention thrust on him.
[I have edited the original obituary.]