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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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ZAP targets the 3′LTR of XMRV.(A) Schematic structures of HR'-CMV-luc vectors. (B) 293TRex-hZAP-v2 cells were infected with the vectors indicated. At 3 h postinfection, cells were mock treated or treated with 1 μg/ml tetracycline to induce ZAP expression. At 48 h postinfection the cells were lysed and luciferase activity was measured. Fold inhibition was calculated as luciferase activity in mock treated cells divided by luciferase activity in tetracycline treated cells (up panel). Data presented are means ± SD of three independent experiments. The expression of hZAP-v2 was confirmed by Western blotting (lower panel).
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pone-0039159-g005: ZAP targets the 3′LTR of XMRV.(A) Schematic structures of HR'-CMV-luc vectors. (B) 293TRex-hZAP-v2 cells were infected with the vectors indicated. At 3 h postinfection, cells were mock treated or treated with 1 μg/ml tetracycline to induce ZAP expression. At 48 h postinfection the cells were lysed and luciferase activity was measured. Fold inhibition was calculated as luciferase activity in mock treated cells divided by luciferase activity in tetracycline treated cells (up panel). Data presented are means ± SD of three independent experiments. The expression of hZAP-v2 was confirmed by Western blotting (lower panel).

Mentions: Previous studies demonstrate that ZAP targets specific viral mRNA sequences [5]. To identify the ZAP-responsive element (ZRE) in XMRV, the sequence corresponding to the 5′ or 3′ UTR of XMRV-luc was cloned into pHR'-CMV-luc (Fig. 5A), a lentivector that is not responsive to ZAP [4]. The vectors were packaged to infect 293TRex-hZAP-v2 cells and assayed for their sensitivities to ZAP. The vector containing the 3′UTR sequence displayed sensitivity comparable to that of XMRV-luc. In contrast, the vector containing the 5′UTR failed to do so (Fig. 5B). These results established that the 3′UTR of XMRV-luc is the target sequence of ZAP.


Zinc-finger antiviral protein inhibits XMRV infection.

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

ZAP targets the 3′LTR of XMRV.(A) Schematic structures of HR'-CMV-luc vectors. (B) 293TRex-hZAP-v2 cells were infected with the vectors indicated. At 3 h postinfection, cells were mock treated or treated with 1 μg/ml tetracycline to induce ZAP expression. At 48 h postinfection the cells were lysed and luciferase activity was measured. Fold inhibition was calculated as luciferase activity in mock treated cells divided by luciferase activity in tetracycline treated cells (up panel). Data presented are means ± SD of three independent experiments. The expression of hZAP-v2 was confirmed by Western blotting (lower panel).
© Copyright Policy
Related In: Results  -  Collection

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

pone-0039159-g005: ZAP targets the 3′LTR of XMRV.(A) Schematic structures of HR'-CMV-luc vectors. (B) 293TRex-hZAP-v2 cells were infected with the vectors indicated. At 3 h postinfection, cells were mock treated or treated with 1 μg/ml tetracycline to induce ZAP expression. At 48 h postinfection the cells were lysed and luciferase activity was measured. Fold inhibition was calculated as luciferase activity in mock treated cells divided by luciferase activity in tetracycline treated cells (up panel). Data presented are means ± SD of three independent experiments. The expression of hZAP-v2 was confirmed by Western blotting (lower panel).
Mentions: Previous studies demonstrate that ZAP targets specific viral mRNA sequences [5]. To identify the ZAP-responsive element (ZRE) in XMRV, the sequence corresponding to the 5′ or 3′ UTR of XMRV-luc was cloned into pHR'-CMV-luc (Fig. 5A), a lentivector that is not responsive to ZAP [4]. The vectors were packaged to infect 293TRex-hZAP-v2 cells and assayed for their sensitivities to ZAP. The vector containing the 3′UTR sequence displayed sensitivity comparable to that of XMRV-luc. In contrast, the vector containing the 5′UTR failed to do so (Fig. 5B). These results established that the 3′UTR of XMRV-luc is the target sequence of ZAP.

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