Further characterization and determination of the single amino acid change in thetsI138reovirus thermosensitive mutant

Abstract

Many temperature-sensitive mutants have been isolated in early studies of mammalian reovirus. However, the biological properties and nature of the genetic alterations remain incompletely explored for most of these mutants. The mutation harbored by the tsI138 mutant was already assigned to the L3 gene encoding the λ1 protein. In the present study, this mutant was further studied as a possible tool to establish the role of the putative λ1 enzymatic activities in viral multiplication. It was observed that synthesis of viral proteins is only marginally reduced, while it was difficult to recover viral particles at the nonpermissive temperature. A single nucleotide substitution resulting in an amino acid change was found; the position of this amino acid is consistent with a probable defect in assembly of the inner capsid at the nonpermissive temperature.