Definition: In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.
Input: 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 viralmediated 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, ef cient cell-to-cell fusion is not necessary for virulence. Journal of NeuroVirology (2002) 8, 400-410.

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