Theiler's Murine Encephalomyelitis Virus Leader Protein Amino Acid Residue 57 Regulates Subgroup-Specific Virus Growth on BHK-21 Cells

Abstract

ABSTRACT Strains of Theiler's murine encephalomyelitis virus (TMEV) are divided into two subgroups, TO and GDVII. TMEV strains show subgroup-specific virus growth and cell tropism and induce subgroup-specific diseases. Using site-directed mutagenesis, we demonstrated that the amino acid at position 57 of the leader protein (L 57 ), which is located at the most N-terminal part of the polyprotein, regulates subgroup-specific virus growth on BHK-21 cells. Further study suggested that L 57 may regulate viral RNA encapsidation, although it does not affect the synthesis of viral proteins or the assembly of viral intermediates.