Howard Martin Temin (February 10, 1934 – February 10, 1994) was an American geneticist and virologist renowned for his discovery of the enzyme reverse transcriptase, a finding that transformed the understanding of viral replication and earned him the 1975 Nobel Prize in Physiology or Medicine, shared with David Baltimore and Renato Dulbecco. His work laid foundational concepts for modern molecular biology, retrovirology, and the development of antiretroviral therapies.
Early life and education
- Born in Boston, Massachusetts, United States.
- Earned a Bachelor of Science in chemistry (1955) from the University of California, Berkeley.
- Completed a Master of Science (1957) and a Ph.D. in genetics (1960) at UC Berkeley, conducting his doctoral research under the supervision of Nobel laureate George Beadle.
Academic career
- 1960‑1965: Assistant professor of genetics, University of Wisconsin, Madison.
- 1965‑1970: Associate professor, later professor, of biology, Massachusetts Institute of Technology.
- 1970‑1972: Research associate at the Scripps Institution of Oceanography, La Jolla.
- 1972‑1994: Professor of biochemistry and molecular biology, University of California, San Diego (UCSD), where he remained until his death.
Research contributions
- Provirus hypothesis (1964): Temin proposed that RNA tumor viruses integrate a DNA copy of their genome into the host cell’s DNA, forming a “provirus.” This challenged the prevailing view of RNA viruses as purely cytoplasmic entities.
- Discovery of reverse transcriptase (1970): While investigating the provirus hypothesis, Temin, together with David Baltimore, independently identified an RNA‑dependent DNA polymerase activity in RNA tumor viruses. This enzyme, later termed reverse transcriptase, catalyzes the synthesis of DNA from an RNA template.
- Retroviral oncogenesis: Temin’s studies on Rous sarcoma virus and avian leukosis virus elucidated mechanisms by which retroviruses can induce cellular transformation, contributing to the broader understanding of oncogenes and tumor biology.
- Implications for HIV/AIDS research: The existence of reverse transcriptase became a critical target for antiretroviral drug development after the identification of human immunodeficiency virus (HIV) as a retrovirus.
Awards and honors
- Nobel Prize in Physiology or Medicine, 1975 (shared with David Baltimore and Renato Dulbecco).
- Lasker Award for Basic Medical Research, 1969 (shared).
- National Medal of Science, United States, 1979.
- Member, National Academy of Sciences (elected 1972).
- Member, American Academy of Arts and Sciences.
Personal life
Temin married twice and was the father of three children. He was known for his outspoken advocacy of scientific funding and education, as well as for his interest in the broader social implications of scientific research.
Legacy
Howard Temin’s elucidation of reverse transcription fundamentally altered the conceptual framework of molecular genetics and virology. The enzyme he helped discover remains a cornerstone of modern biotechnology, enabling techniques such as cDNA cloning, quantitative PCR, and the generation of synthetic genomes. His work directly informed the development of reverse transcriptase inhibitors, a class of drugs essential for treating HIV/AIDS. Temin’s scientific philosophy, emphasizing bold hypotheses tested through rigorous experimentation, continues to influence generations of molecular biologists and virologists.