Neuroattenuation of an avirulent bunyavirus variant maps to the L RNA segment

M. J. Endres, C. Griot, F. Gonzalez-Scarano, N. Nathanson

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


The derivation and characterization of a neuroattenuated reassortant clone (RFC 25/B.5) of California serogroup bunyavirus was described previously (M. J. Endres, A. Valsamakis, F. Gonzalez-Scarano, and N. Nathanson, J. Virol. 64:1927-1933, 1990). To map the RNA segment responsible for this attenuation, a panel of reassortants was constructed between the attenuated clone B.5 (genotype TLL) and a virulent clone (B1-1a) of reciprocal genotype (LTT). Parent viruses and clones representing all of the six possible reassortants were examined for neurovirulence by intracerebral injection in adult mice. Reassortants bearing the large RNA segment from the virulent parent were almost as virulent as the virulent parent virus, while reassortants bearing the large RNA segment from the avirulent parent virus exhibited low or intermediate virulence. These results indicate that the large RNA segment is the major determinant of neuroattenuation of clone B.5. In addition to its neuroattenuation, clone B.5 was temperature sensitive and exhibited an altered plaque morphology. These phenotypes also segregated with the large RNA segment. The importance of the large RNA segment (which encodes the viral polymerase) in neurovirulence contrasts with prior studies which indicate that the ability to cause lethal encephalitis after peripheral injection of suckling mice (neuroinvasiveness) is primarily determined by the middle-sized RNA segment, which encodes the viral glycoproteins.

Original languageEnglish (US)
Pages (from-to)5465-5470
Number of pages6
JournalJournal of virology
Issue number10
StatePublished - 1991
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology


Dive into the research topics of 'Neuroattenuation of an avirulent bunyavirus variant maps to the L RNA segment'. Together they form a unique fingerprint.

Cite this