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. 2002;8(5):400–410. doi: 10.1080/13550280260422703

The virulence of mouse hepatitis virus strain A59 is not dependent on efficient spike protein cleavage and cell-to-cell fusion

Susan T Hingley 1,✉, Isabelle Leparc-Goffart 1, Su-hun Seo 3, Jean C Tsai 3, Susan R Weiss 3
PMCID: PMC7095328  PMID: 12402166

Abstract

The cleavage and fusion properties of recombinant murine hepatitis viruses (MHV) were examined to assess the role of the cleavage signal in determining the extent of S protein cleavage, and the correlation between cleavage and induction of cell-to-cell fusion. Targeted recombination was used to introduce amino acid substitutions into the cleavage signal of the fusion glycoprotein (spike or S protein) of MHV strain A59. The recombinants were then used to address the question of the importance of S protein cleavage and viral-mediated cell-to-cell fusion on pathogenicity. Our data indicate that cleavage of spike is not solely determined by the amino acid sequence at the cleavage site, but may also depend on sequences removed from the cleavage site. In addition, efficient cell-to-cell fusion is not necessary for virulence.

Keywords: cell-to-cell fusion, coronavirus, fusion protein, murine hepatitis virus, pathogenicity, targeted recombination

Footnotes

This work was supported by Public Health Service grants NS-21954 and NS-30606 (SRW).

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