Nucleolin/Nsr1p binds to the 3' noncoding region of the tombusvirus RNA and inhibits replication.
Previous genome-wide screens identified >100 host genes affecting tombusvirus replication using yeast model host. One of those factors was Nsr1p (nucleolin), which is an abundant RNA-binding shuttle protein involved in rRNA maturation and ribosome assembly. We find that overexpression of Nsr1p in yeast or in Nicotiana benthamiana inhibited the accumulation of tombusvirus RNA by approximately 10-fold. Regulated overexpression of Nsr1p revealed that Nsr1p should be present at the beginning of viral replication for efficient inhibition, suggesting that Nsr1p inhibits an early step in the replication process. In vitro experiments revealed that Nsr1p binds preferably to the 3' UTR in the viral RNA. The purified recombinant Nsr1p inhibited the in vitro replication of the viral RNA in a yeast cell-free assay when preincubated with the viral RNA before the assay. These data support the model that Nsr1p/nucleolin inhibits tombusvirus replication by interfering with the recruitment of the viral RNA for replication.
Jiang
Yi
Y
Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, Lexington, KY 40546, USA.
Li
Zhenghe
Z
Nagy
Peter D
PD
D020413:3' Untranslated Regions; D001483:Base Sequence; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000502:physiology*; D010750:Phosphoproteins / Q000502:physiology*; D012367:RNA, Viral / Q000096:biosynthesis; D016601:RNA-Binding Proteins / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D014026:Nicotiana / Q000821:virology; D017864:Tombusvirus / Q000235:genetics / Q000502:physiology*; D014779:Virus Replication; D000097796:Nucleolin
D020413:3' Untranslated Regions; D009687:Nuclear Proteins; D010750:Phosphoproteins; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D000097796:Nucleolin; C068036:NSR1 protein, S cerevisiae