PLoS ONE (Jan 2013)

Attenuation of mouse hepatitis virus by deletion of the LLRKxGxKG region of Nsp1.

  • Lin Lei,
  • Sun Ying,
  • Luo Baojun,
  • Yang Yi,
  • He Xiang,
  • Su Wenli,
  • Sun Zounan,
  • Guo Deyin,
  • Zhu Qingyu,
  • Liu Jingmei,
  • Chang Guohui

DOI
https://doi.org/10.1371/journal.pone.0061166
Journal volume & issue
Vol. 8, no. 4
p. e61166

Abstract

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Coronaviruses are a family of large positive-sense RNA viruses that are responsible for a wide range of important veterinary and human diseases. Nsp1 has been shown to have an important role in the pathogenetic mechanisms of coronaviruses in vivo. To assess the function of a relatively conserved domain (LLRKxGxKG) of MHV nsp1, a mutant virus, MHV-nsp1-27D, with a 27 nts (LLRKxGxKG) deletion in nsp1, was constructed using a reverse genetic system with a vaccinia virus vector. The mutant virus had similar growth kinetics to MHV-A59 wild-type virus in 17CI-1 cells, but was highly attenuated in vivo. Moreover, the mutant virus completely protected C57BL/6 mice from a lethal MHV-A59 challenge. To further analyze the mechanism of the attenuation of the mutant virus, changes in reporter gene expression were measured in nsp1- or nsp1-27D-expressing cells; the results showed that nsp1 inhibited reporter gene expression controlled by different promoters, but that this inhibition was reduced for nsp1-27D. The research in vivo and in vitro suggests that the LLRKxGxKG region of nsp1 may play an important role in this process.