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Previous studies have shown that the reovirus lambda1 core protein harbors a putative nucleotide-binding motif and exhibits an affinity for nucleic acids. In addition, a nucleoside triphosphate phosphohydrolase activity present in reovirus cores has been recently assigned to lambda1 using gene reassortment analysis. In this study, it was demonstrated that(More)
The 5'-end of the flavivirus genome harbors a methylated (m7)GpppA(2'OMe) cap structure, which is generated by the virus-encoded RNA triphosphatase, RNA (guanine-N7) methyltransferase, nucleoside 2'-O-methyltransferase, and RNA guanylyltransferase. The presence of the flavivirus guanylyltransferase activity in NS5 has been suggested by several groups but(More)
It is believed that peach latent mosaic viroid (PLMVd) strands of both the plus and minus polarities fold into similar secondary and tertiary structures. In order to verify this hypothesis, the behavior of both strands in three biophysical assays was examined. PLMVd transcripts of plus and minus polarity were found to exhibit distinct electrophoretic(More)
The hepatitis C virus nonstructural 5B protein (NS5B) protein has been shown to require either magnesium or manganese for its RNA-dependent RNA polymerase activity. As a first step toward elucidating the nature and the role(s) of the metal ions in the reaction chemistry, we have utilized endogenous tryptophan fluorescence to quantitate the interactions of(More)
The RNA polymerase activity of the hepatitis C virus, a major human pathogen, has previously been shown to be supported by metal ions. In the present study, we report a systematic analysis of the effect of metal ion binding on the structural stability of the hepatitis C virus RNA polymerase. Chemical and thermal denaturation assays revealed that the(More)
BACKGROUND/AIMS Infection with hepatitis C virus (HCV) is associated with alterations in body iron homeostasis by poorly defined mechanisms. To seek for molecular links, we employed an established cell culture model for viral replication, and assessed how the expression of an HCV subgenomic replicon affects iron metabolism in host Huh7 hepatoma cells. (More)
Clinical data suggest that iron is a negative factor in chronic hepatitis C; however, the molecular mechanisms by which iron modulates the infectious cycle of hepatitis C virus (HCV) remain elusive. To explore this, we utilized cells expressing a HCV replicon as a well-established model for viral replication. We demonstrate that iron administration(More)
Peach latent mosaic viroid (PLMVd) is a small, single-stranded, circular RNA pathogen that infects Prunus persica trees. As with all other known viroids, the PLMVd genome does not encode any proteins. Consequently, it must interact with host cellular factors in order to ensure its life cycle. With the objective of identifying cellular proteins that interact(More)
Characterization of the phosphohydrolytic activities of recombinant reovirus lambda1 protein demonstrates that, in addition to the previously reported nucleoside triphosphate phosphohydrolase and helicase activities, the protein also possesses RNA 5'-triphosphatase activity. This activity was absolutely dependent on the presence of a divalent cation, Mg2+(More)