Transcribing and replicating particles in a double-stranded RNA virus from Leishmania

Reitha S. Weeks, Jean L. Patterson, Ken Stuart, Giovanni Widmer

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


During the replicative cycle of many double-stranded RNA viruses, transcription of particles with a double-stranded RNA genome alternates with replication of particles containing a single-stranded genome. In virions infecting some strains of Leishmania guyanensis the putative transcriptase and replicase activities of the RNA-dependent RNA polymerase were previously detected in vitro. Northern hybridization to RNA of known polarity demonstrates that the single-stranded RNA products are of positive polarity and, by definition, are the products of the viral transcriptase. Re-evaluation of previously published data in the light of these findings suggests that transcription in Leishmania viruses is conservative. Sedimentation in sucrose gradients revealed two types of viral particles; single-stranded RNA particles comprised a small fraction of the virus population and sedimented more slowly than the peak of double-stranded RNA particles. In agreement with the replicative model of other dsRNA viruses, these single-stranded particles co-purified with the viral replicase activity that resulted in double-stranded RNA synthesis. In virus-infected promastigote extracts replicase activity decreased with increasing parasite density in culture, suggesting a correlation between cell division and viral replication.

Original languageEnglish (US)
Pages (from-to)207-213
Number of pages7
JournalMolecular and Biochemical Parasitology
Issue number2
StatePublished - Jun 1992
Externally publishedYes


  • Double-stranded RNA virus
  • Leishmania
  • RNA-dependent RNA polymerase
  • Replicase
  • Transcriptase

ASJC Scopus subject areas

  • Parasitology
  • Molecular Biology


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