Hsp90 interacts specifically with viral RNA and differentially regulates replication initiation of Bamboo mosaic virus and associated satellite RNA.
Host factors play crucial roles in the replication of plus-strand RNA viruses. In this report, a heat shock protein 90 homologue of Nicotiana benthamiana, NbHsp90, was identified in association with partially purified replicase complexes from BaMV-infected tissue, and shown to specifically interact with the 3' untranslated region (3' UTR) of BaMV genomic RNA, but not with the 3' UTR of BaMV-associated satellite RNA (satBaMV RNA) or that of genomic RNA of other viruses, such as Potato virus X (PVX) or Cucumber mosaic virus (CMV). Mutational analyses revealed that the interaction occurs between the middle domain of NbHsp90 and domain E of the BaMV 3' UTR. The knockdown or inhibition of NbHsp90 suppressed BaMV infectivity, but not that of satBaMV RNA, PVX, or CMV in N. benthamiana. Time-course analysis further revealed that the inhibitory effect of 17-AAG is significant only during the immediate early stages of BaMV replication. Moreover, yeast two-hybrid and GST pull-down assays demonstrated the existence of an interaction between NbHsp90 and the BaMV RNA-dependent RNA polymerase. These results reveal a novel role for NbHsp90 in the selective enhancement of BaMV replication, most likely through direct interaction with the 3' UTR of BaMV RNA during the initiation of BaMV RNA replication.
Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan.
Ying Wen
YW
Huang
Chung Chi
CC
Hu
Ming Ru
MR
Liou
Ban Yang
BY
Chang
Ching Hsiu
CH
Tsai
Menghsiao
M
Meng
Na Sheng
NS
Lin
Yau Heiu
YH
Hsu
D020413:3' Untranslated Regions; D016227:Benzoquinones / Q000494:pharmacology; D055786:Gene Knockout Techniques; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D047029:Lactams, Macrocyclic / Q000494:pharmacology; D009690:Nucleic Acid Conformation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D017863:Potexvirus / Q000235:genetics* / Q000502:physiology*; D019244:RNA, Satellite / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism*; D014026:Nicotiana / Q000378:metabolism / Q000821:virology*; D014779:Virus Replication
D020413:3' Untranslated Regions; D016227:Benzoquinones; D018841:HSP90 Heat-Shock Proteins; D047029:Lactams, Macrocyclic; D010940:Plant Proteins; D019244:RNA, Satellite; D012367:RNA, Viral; C112765:tanespimycin