Abstract
The Czech scientist Jan Svoboda was a pioneer of Rous sarcoma virus (RSV). In the 1960s, before the discovery of reverse transcriptase, he demonstrated the long-term persistence of the viral genome in non-productive mammalian cells, and he supported the DNA provirus hypothesis of Howard Temin. He showed how the virus can be rescued in the infectious form and elucidated the replication-competent nature of the Prague strain of RSV later used for the identification of the src oncogene. His studies straddled molecular oncology and virology, and he remained an active contributor to the field until his death last year. Throughout the 50 years that I was privileged to know Svoboda as my mentor and friend, I admired his depth of scientific inquiry and his steadfast integrity in the face of political oppression.
Highlights
The Czech scientist Jan Svoboda was a pioneer of Rous sarcoma virus (RSV)
Academy of Sciences as a foreign associate in 2015, he wrote a fascinating perspective on his long career, his scientific discoveries concerning Rous sarcoma virus (RSV), and the political tribulations he faced [2]
Svoboda found that the Prague [3] and Schmidt–Ruppin [18] strains replicate without the need of a helper virus, and he surmised that they contain both env and src as follows: avian leukosis virus (ALV)
Summary
Jan Svoboda’s life and achievements have been briefly reviewed in Jiři Hejnar’s excellent obituary [1]. Two papers published in 1960 by Temin [8] and Svoboda [6] became early landmarks in tumor virology They demonstrated that the virus carried a genetic determinant for malignant transformation and viral persistence in tumor cells. Temin further showed that the transforming activity could be separated from viral replication [12] These reports represented the first evidence of a transforming gene or oncogene in RSV. Svoboda’s short paper [6] showed that RSV was present in tumors that arose many months after virus inoculation and could be rescued in infectious form by inoculation of X-irradiated tumor cells into chickens. Svoboda continued to study this question into his later years [2] Another curious feature of RSV rescued from mammalian cells is that they are replication-competent. Svoboda found that the Prague [3] and Schmidt–Ruppin [18] strains replicate without the need of a helper virus, and he surmised that they contain both env and src as follows: ALV
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