A cypovirus VP5 displays the RNA chaperone-like activity that destabilizes RNA helices and accelerates strand annealing

Jie Yang, Zhenyun Cheng, Songliu Zhang, Wei Xiong, Hongjie Xia, Yang Qiu, Zhaowei Wang, Feige Wu, Cheng Feng Qin, Lei Yin, Yuanyang Hu, Xi Zhou

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Abstract

For double-stranded RNA (dsRNA) viruses in the family Reoviridae, their inner capsids function as the machinery for viral RNA (vRNA) replication. Unlike other multishelled reoviruses, cypovirus has a single-layered capsid, thereby representing a simplified model for studying vRNA replication of reoviruses. VP5 is one of the three major cypovirus capsid proteins and functions as a clamp protein to stabilize cypovirus capsid. Here, we expressed VP5 from type 5 Helicoverpa armigera cypovirus (HaCPV-5) in a eukaryotic system and determined that this VP5 possesses RNA chaperone-like activity, which destabilizes RNA helices and accelerates strand annealing independent of ATP. Our further characterization of VP5 revealed that its helix-destabilizing activity is RNA specific, lacks directionality and could be inhibited by divalent ions, such as Mg2+, Mn2+, Ca2+ or Zn2+, to varying degrees. Furthermore, we found that HaCPV-5 VP5 facilitates the replication initiation of an alternative polymerase (i.e. reverse transcriptase) through a panhandle-structured RNA template, which mimics the 5′-3′ cyclization of cypoviral positive-stranded RNA. Given that the replication of negative-stranded vRNA on the positive-stranded vRNA template necessitates the dissociation of the 5′-3′ panhandle, the RNA chaperone activity of VP5 may play a direct role in the initiation of reoviral dsRNA synthesis.

Original languageEnglish (US)
Pages (from-to)2538-2554
Number of pages17
JournalNucleic acids research
Volume42
Issue number4
DOIs
StatePublished - Feb 1 2014
Externally publishedYes

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ASJC Scopus subject areas

  • Genetics

Cite this

Yang, J., Cheng, Z., Zhang, S., Xiong, W., Xia, H., Qiu, Y., Wang, Z., Wu, F., Qin, C. F., Yin, L., Hu, Y., & Zhou, X. (2014). A cypovirus VP5 displays the RNA chaperone-like activity that destabilizes RNA helices and accelerates strand annealing. Nucleic acids research, 42(4), 2538-2554. https://doi.org/10.1093/nar/gkt1256