Alternative translation initiation site in the DA strain of Theiler's murine encephalomyelitis virus.
Polyprotein processing studies of Theiler's murine encephalomyelitis virus (TMEV), a group of mouse picornaviruses, demonstrated synthesis of a protein we have called l during in vitro translations from the RNA of DA, a demyelinating strain of TMEV, but not GDVII, an acute neurovirulent strain. We have proposed that l is synthesized from an alternative initiation site in the DA leader (L) coding area out of phase with the polyprotein reading frame (R. P. Roos, W.-P. Kong, B. L. Semler, J. Virol. 63:5344-5353, 1989). We now provide support for this proposal from experiments involving in vitro translation of three separate mutations of an infectious DA cDNA clone: DA"l"-1, which contains a base mismatch at the putative initiation codon of l, DAL-1, which contains a base mismatch at the presumed authentic initiation site of L at the beginning of the polyprotein; and DAL:NheI, which contains nucleotides coding for a four-amino-acid insertion in the L coding area with a termination codon in the l reading frame. Our results demonstrate that the DA strain uses an alternative initiation site and reading frame to in vitro synthesize l. l may have a role in the biological activity of the virus.
Kong
W P
WP
Department of Neurology, University of Chicago, Illinois 60637.
Roos
R P
RP
D001483:Base Sequence; D016384:Consensus Sequence; D004279:DNA, Viral / Q000737:chemistry; D004680:Maus Elberfeld virus / Q000235:genetics*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D014176:Protein Biosynthesis; D014764:Viral Proteins / Q000096:biosynthesis / Q000235:genetics*
D004279:DNA, Viral; D014764:Viral Proteins