Epitope-Tagged L* Protein of Theiler's Murine Encephalomyelitis Virus Is Expressed in the Central Nervous System in the Acute Phase of Infection

Abstract

ABSTRACT TO subgroup strains of Theiler's murine encephalomyelitis virus (TMEV) synthesize L* protein from an alternative initiation codon. We first demonstrated L* expression in the central nervous system (CNS) of TMEV-infected mice during the acute phase of infection by immunoprecipitation and immunoblotting with anti-L* antibody. In addition, we generated mutant viruses which synthesize FLAG or 3xFLAG epitope-tagged L* protein. With a mutant virus expressing 3xFLAG epitope-tagged L*, designated DA/3xFLAGL*, we investigated L* in the CNS in the acute phase of infection. DA/3xFLAGL* did not change the virus tropism in comparison with wild-type virus, and L* was clearly identified in the CNS in both susceptible and resistant strains of mice. Double immunolabeling studies showed that L* is colocalized with TMEV polyprotein and exclusively expressed in neurons.