Toscana virus NSs protein promotes degradation of double-stranded RNA-dependent protein kinase

Birte Kalveram, Tetsuro Ikegami

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


Toscana virus (TOSV), which is transmitted by Phlebotomus spp. sandflies, is a major etiologic agent of aseptic meningitis and encephalitis in the Mediterranean. Like other members of the genus Phlebovirus of the family Bunyaviridae, TOSV encodes a nonstructural protein (NSs) in its small RNA segment. Although the NSs of Rift Valley fever virus (RVFV) has been identified as an important virulence factor, which suppresses host general transcription, inhibits transcription from the beta interferon promoter, and promotes the proteasomal degradation of double-stranded RNA-dependent protein kinase (PKR), little is known about the functions of NSs proteins encoded by less-pathogenic members of this genus. In this study we report that TOSV is able to downregulate PKR with similar efficiency as RVFV, while infection with the other phleboviruses-i.e., Punta Toro virus, sandfly fever Sicilian virus, or Frijoles virus-has no effect on cellular PKR levels. In contrast to RVFV, however, cellular transcription remains unaffected during TOSV infection. TOSV NSs protein promotes the proteasome-dependent downregulation of PKR and is able to interact with kinase-inactive PKR in infected cells.

Original languageEnglish (US)
Pages (from-to)3710-3718
Number of pages9
JournalJournal of virology
Issue number7
StatePublished - Apr 2013

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology


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