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Zinc-finger antiviral protein inhibits XMRV infection.

Wang X, Tu F, Zhu Y, Gao G - PLoS ONE (2012)

Bottom Line: ZAP inhibits XMRV replication by preventing the accumulation of viral mRNA in the cytoplasm.Documentation of ZAP inhibiting XMRV helps to broaden the spectrum of ZAP's antiviral activity.Comparison of the target sequences of ZAP in XMRV and MoMLV helps to better understand the features of ZAP-responsive elements.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.

ABSTRACT

Background: The zinc-finger antiviral protein (ZAP) is a host factor that specifically inhibits the replication of certain viruses, including Moloney murine leukemia virus (MoMLV), HIV-1, and certain alphaviruses and filoviruses. ZAP binds to specific viral mRNAs and recruits cellular mRNA degradation machinery to degrade the target RNA. The common features of ZAP-responsive RNA sequences remain elusive and thus whether a virus is susceptible to ZAP can only be determined experimentally. Xenotropic murine leukemia virus-related virus (XMRV) is a recently identified γ-retrovirus that was originally thought to be involved in prostate cancer and chronic fatigue syndrome but recently proved to be a laboratory artefact. Nonetheless, XMRV as a new retrovirus has been extensively studied. Since XMRV and MoMLV share only 67.9% sequence identity in the 3'UTRs, which is the target sequence of ZAP in MoMLV, whether XMRV is susceptible to ZAP remains to be determined.

Findings: We constructed an XMRV-luc vector, in which the coding sequences of Gag-Pol and part of Env were replaced with luciferase-coding sequence. Overexpression of ZAP potently inhibited the expression of XMRV-luc in a ZAP expression-level-dependent manner, while downregulation of endogenous ZAP rendered cells more sensitive to infection. Furthermore, ZAP inhibited the spreading of replication-competent XMRV. Consistent with the previously reported mechanisms by which ZAP inhibits viral infection, ZAP significantly inhibited the accumulation of XMRV-luc mRNA in the cytoplasm. The ZAP-responsive element in XMRV mRNA was mapped to the 3'UTR.

Conclusions: ZAP inhibits XMRV replication by preventing the accumulation of viral mRNA in the cytoplasm. Documentation of ZAP inhibiting XMRV helps to broaden the spectrum of ZAP's antiviral activity. Comparison of the target sequences of ZAP in XMRV and MoMLV helps to better understand the features of ZAP-responsive elements.

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Downregulation of endogenous hZAP enhances XMRV-luc expression.HOS cells were transfected with control siRNA (Ctrl) or siRNAs directed against hZAP (ZAPi-1 and ZAPi-2), followed by infection with XMRV-luc for 5 h. At 48 h postinfection, cells were lysed. (A) Endogenous hZAP mRNA levels were measured by real-time PCR. (B) Luciferase activity was measured and presented as relative light units (RLU). Data presented are means ± SD of three measurements.
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pone-0039159-g002: Downregulation of endogenous hZAP enhances XMRV-luc expression.HOS cells were transfected with control siRNA (Ctrl) or siRNAs directed against hZAP (ZAPi-1 and ZAPi-2), followed by infection with XMRV-luc for 5 h. At 48 h postinfection, cells were lysed. (A) Endogenous hZAP mRNA levels were measured by real-time PCR. (B) Luciferase activity was measured and presented as relative light units (RLU). Data presented are means ± SD of three measurements.

Mentions: To test whether endogenous hZAP inhibits XMRV-luc, HOS cells were transfected with siRNAs directed against hZAP (ZAPi-1 and ZAPi-2) to downregulate endogenous ZAP expression, and then challenged with XMRV-luc. The ZAP mRNA levels were downregulated by about 60% (Fig. 2A). As expected, the expression of XMRV-luc was significantly increased in cells transfected with the siRNAs directed against ZAP compared with control cells (Fig. 2B), indicating that endogenous hZAP was active against XMRV-luc infection.


Zinc-finger antiviral protein inhibits XMRV infection.

Wang X, Tu F, Zhu Y, Gao G - PLoS ONE (2012)

Downregulation of endogenous hZAP enhances XMRV-luc expression.HOS cells were transfected with control siRNA (Ctrl) or siRNAs directed against hZAP (ZAPi-1 and ZAPi-2), followed by infection with XMRV-luc for 5 h. At 48 h postinfection, cells were lysed. (A) Endogenous hZAP mRNA levels were measured by real-time PCR. (B) Luciferase activity was measured and presented as relative light units (RLU). Data presented are means ± SD of three measurements.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3376128&req=5

pone-0039159-g002: Downregulation of endogenous hZAP enhances XMRV-luc expression.HOS cells were transfected with control siRNA (Ctrl) or siRNAs directed against hZAP (ZAPi-1 and ZAPi-2), followed by infection with XMRV-luc for 5 h. At 48 h postinfection, cells were lysed. (A) Endogenous hZAP mRNA levels were measured by real-time PCR. (B) Luciferase activity was measured and presented as relative light units (RLU). Data presented are means ± SD of three measurements.
Mentions: To test whether endogenous hZAP inhibits XMRV-luc, HOS cells were transfected with siRNAs directed against hZAP (ZAPi-1 and ZAPi-2) to downregulate endogenous ZAP expression, and then challenged with XMRV-luc. The ZAP mRNA levels were downregulated by about 60% (Fig. 2A). As expected, the expression of XMRV-luc was significantly increased in cells transfected with the siRNAs directed against ZAP compared with control cells (Fig. 2B), indicating that endogenous hZAP was active against XMRV-luc infection.

Bottom Line: ZAP inhibits XMRV replication by preventing the accumulation of viral mRNA in the cytoplasm.Documentation of ZAP inhibiting XMRV helps to broaden the spectrum of ZAP's antiviral activity.Comparison of the target sequences of ZAP in XMRV and MoMLV helps to better understand the features of ZAP-responsive elements.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.

ABSTRACT

Background: The zinc-finger antiviral protein (ZAP) is a host factor that specifically inhibits the replication of certain viruses, including Moloney murine leukemia virus (MoMLV), HIV-1, and certain alphaviruses and filoviruses. ZAP binds to specific viral mRNAs and recruits cellular mRNA degradation machinery to degrade the target RNA. The common features of ZAP-responsive RNA sequences remain elusive and thus whether a virus is susceptible to ZAP can only be determined experimentally. Xenotropic murine leukemia virus-related virus (XMRV) is a recently identified γ-retrovirus that was originally thought to be involved in prostate cancer and chronic fatigue syndrome but recently proved to be a laboratory artefact. Nonetheless, XMRV as a new retrovirus has been extensively studied. Since XMRV and MoMLV share only 67.9% sequence identity in the 3'UTRs, which is the target sequence of ZAP in MoMLV, whether XMRV is susceptible to ZAP remains to be determined.

Findings: We constructed an XMRV-luc vector, in which the coding sequences of Gag-Pol and part of Env were replaced with luciferase-coding sequence. Overexpression of ZAP potently inhibited the expression of XMRV-luc in a ZAP expression-level-dependent manner, while downregulation of endogenous ZAP rendered cells more sensitive to infection. Furthermore, ZAP inhibited the spreading of replication-competent XMRV. Consistent with the previously reported mechanisms by which ZAP inhibits viral infection, ZAP significantly inhibited the accumulation of XMRV-luc mRNA in the cytoplasm. The ZAP-responsive element in XMRV mRNA was mapped to the 3'UTR.

Conclusions: ZAP inhibits XMRV replication by preventing the accumulation of viral mRNA in the cytoplasm. Documentation of ZAP inhibiting XMRV helps to broaden the spectrum of ZAP's antiviral activity. Comparison of the target sequences of ZAP in XMRV and MoMLV helps to better understand the features of ZAP-responsive elements.

Show MeSH
Related in: MedlinePlus