Human Foamy Virus Replication: A Pathway Distinct from That of Retroviruses and Hepadnaviruses

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Science  15 Mar 1996:
Vol. 271, Issue 5255, pp. 1579-1582
DOI: 10.1126/science.271.5255.1579


Human foamy virus (HFV) is the prototype of the Spumavirus genus of Retroviridae. In all other retroviruses, the pol gene products, including reverse transcriptase, are synthesized as Gag-Pol fusion proteins and are cleaved to functional enzymes during viral budding or release. In contrast, the Pol protein of HFV is translated from a spliced messenger RNA and lacks Gag domains. Infectious HFV particles contain double-stranded DNA similar in size to full-length provirus, suggesting that reverse transcription has taken place in viral particles before new rounds of infection, reminiscent of hepadnaviruses. These data suggest that foamy viruses possess a replication pathway containing features of both retroviruses and hepadnaviruses but distinct from both.