Binding of encephalomyocarditis virus RNA polymerase to the 3'-noncoding region of the viral RNA is specific and requires the 3'-poly(A) tail.
An in vitro RNA bandshift assay has been developed to demonstrate the binding of purified recombinant encephalomyocarditis (EMC) virus RNA-dependent RNA polymerase (3Dpol) to the 3'-noncoding region (NCR) and 30 nucleotides of the adjacent 3'-terminal poly(A) tail (3'-NCR(A)) of EMC virus RNA. The binding of 3Dpol to the 3'-NCR(A) fragment was specific since four other unrelated proteins including an RNA polymerase did not bind, and unlabeled 3'-NCR(A), but not alpha-globin mRNA, tRNA, or pure poly(A), competed with radiolabeled 3'-NCR(A) for binding. Surprisingly, 3Dpol failed to bind to the 3'-NCR of EMC virus RNA lacking the poly(A) tail. The results together show that EMC virus RNA template specificity depends only on 3Dpol, the 3'-NCR, and the poly(A) tail. This suggests that 3'-poly(A) is essential for viral RNA template selection by the EMC virus RNA polymerase.
Cui
T
T
Institute of Molecular and Cell Biology, National University of Singapore.
Sankar
S
S
Porter
A G
AG
D001483:Base Sequence; D001665:Binding Sites; D017931:DNA Primers; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004686:Encephalomyocarditis virus / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D011061:Poly A / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012367:RNA, Viral / Q000096:biosynthesis / Q000378:metabolism*; D013698:Templates, Genetic
D017931:DNA Primers; D012333:RNA, Messenger; D012367:RNA, Viral; D011061:Poly A; D012321:DNA-Directed RNA Polymerases