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Novel Role for Protein Inhibitor of Activated STAT 4 (PIAS4) in the Restriction of Herpes Simplex Virus 1 by the Cellular Intrinsic Antiviral Immune Response.

Conn KL, Wasson P, McFarlane S, Tong L, Brown JR, Grant KG, Domingues P, Boutell C - J. Virol. (2016)

Bottom Line: Despite characterization of the host factors that rely on SUMOylation to exert their antiviral effects, the enzymes that mediate these SUMOylation events remain to be defined.Moreover, in the absence of ICP0, high-molecular-weight SUMO-conjugated proteins do not accumulate if HSV-1 DNA does not replicate.The protein inhibitor of activated STAT (PIAS) family of SUMO ligases is predominantly associated with the suppression of innate immune signaling.

View Article: PubMed Central - PubMed

Affiliation: MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow, Scotland, United Kingdom.

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PIAS4 can associate with PML in ICP0- mutant HSV-1 replication compartments in a SIM-dependent manner. (A to I) Confocal images show the nuclear localization of eYFP or eYFP.PIAS4 wild-type or mutant proteins (as indicated) with respect to ICP0- mutant (ΔICP0) HSV-1 replication compartments, identified by ICP4 accumulation, or PML. Transgenic HFt cells were infected with 1 PFU of ICP0- mutant HSV-1 per cell for 16 h prior to DOX induction of eYFP or eYFP.PIAS4 wild-type or mutant protein expression for 6 to 8 h. Localization of PML (cyan) and ICP4 (red) was visualized by indirect immunofluorescence. The inset (dashed box in panel B) highlights a region within a replication compartment where eYFP.P4 wt and PML colocalize in string-like structures (69). (J) Validation of PIAS4 polyclonal antibody (pAb; cyan) detection of eYFP.P4 wt within ICP0- mutant HSV-1 replication compartments (ICP4; red). (K) Confocal images show the association of endogenous PIAS4 (red) with PML (cyan) in ICP0- mutant HSV-1 replication compartments. (L) Emission spectra depict the pixel intensity and colocalization between eYFP.ICP4, endogenous PIAS4, and PML within a focus or region of an ICP0- mutant HSV-1 replication compartment indicated by the corresponding numbered lines in panel K. Nuclei were visualized by DAPI (blue).
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Figure 6: PIAS4 can associate with PML in ICP0- mutant HSV-1 replication compartments in a SIM-dependent manner. (A to I) Confocal images show the nuclear localization of eYFP or eYFP.PIAS4 wild-type or mutant proteins (as indicated) with respect to ICP0- mutant (ΔICP0) HSV-1 replication compartments, identified by ICP4 accumulation, or PML. Transgenic HFt cells were infected with 1 PFU of ICP0- mutant HSV-1 per cell for 16 h prior to DOX induction of eYFP or eYFP.PIAS4 wild-type or mutant protein expression for 6 to 8 h. Localization of PML (cyan) and ICP4 (red) was visualized by indirect immunofluorescence. The inset (dashed box in panel B) highlights a region within a replication compartment where eYFP.P4 wt and PML colocalize in string-like structures (69). (J) Validation of PIAS4 polyclonal antibody (pAb; cyan) detection of eYFP.P4 wt within ICP0- mutant HSV-1 replication compartments (ICP4; red). (K) Confocal images show the association of endogenous PIAS4 (red) with PML (cyan) in ICP0- mutant HSV-1 replication compartments. (L) Emission spectra depict the pixel intensity and colocalization between eYFP.ICP4, endogenous PIAS4, and PML within a focus or region of an ICP0- mutant HSV-1 replication compartment indicated by the corresponding numbered lines in panel K. Nuclei were visualized by DAPI (blue).

Mentions: The subnuclear localization of mutant eYFP.PIAS4 proteins was initially evaluated during ICP0- mutant HSV-1 infection to avoid potential ICP0-mediated disruption of relevant interactions. EYFP alone did not accumulate in replication compartments, while eYFP.PIAS4 did (Fig. 6A and B), demonstrating that fusion to eYFP did not adversely affect PIAS4 localization. However, endogenous PIAS4 tended to localize throughout individual replication compartments, whereas eYFP.PIAS4 tended to occupy subdomains within them (Fig. 6B and J). Notably, endogenous or exogenous PIAS4 could colocalize with PML, a known intrinsic antiviral factor (Fig. 6B, K, and L). The regions where eYFP.PIAS4 and PML colocalized were largely restrained to subdomains within individual replication compartments and often resembled string-like structures (Fig. 6B, inset) (69).


Novel Role for Protein Inhibitor of Activated STAT 4 (PIAS4) in the Restriction of Herpes Simplex Virus 1 by the Cellular Intrinsic Antiviral Immune Response.

Conn KL, Wasson P, McFarlane S, Tong L, Brown JR, Grant KG, Domingues P, Boutell C - J. Virol. (2016)

PIAS4 can associate with PML in ICP0- mutant HSV-1 replication compartments in a SIM-dependent manner. (A to I) Confocal images show the nuclear localization of eYFP or eYFP.PIAS4 wild-type or mutant proteins (as indicated) with respect to ICP0- mutant (ΔICP0) HSV-1 replication compartments, identified by ICP4 accumulation, or PML. Transgenic HFt cells were infected with 1 PFU of ICP0- mutant HSV-1 per cell for 16 h prior to DOX induction of eYFP or eYFP.PIAS4 wild-type or mutant protein expression for 6 to 8 h. Localization of PML (cyan) and ICP4 (red) was visualized by indirect immunofluorescence. The inset (dashed box in panel B) highlights a region within a replication compartment where eYFP.P4 wt and PML colocalize in string-like structures (69). (J) Validation of PIAS4 polyclonal antibody (pAb; cyan) detection of eYFP.P4 wt within ICP0- mutant HSV-1 replication compartments (ICP4; red). (K) Confocal images show the association of endogenous PIAS4 (red) with PML (cyan) in ICP0- mutant HSV-1 replication compartments. (L) Emission spectra depict the pixel intensity and colocalization between eYFP.ICP4, endogenous PIAS4, and PML within a focus or region of an ICP0- mutant HSV-1 replication compartment indicated by the corresponding numbered lines in panel K. Nuclei were visualized by DAPI (blue).
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Figure 6: PIAS4 can associate with PML in ICP0- mutant HSV-1 replication compartments in a SIM-dependent manner. (A to I) Confocal images show the nuclear localization of eYFP or eYFP.PIAS4 wild-type or mutant proteins (as indicated) with respect to ICP0- mutant (ΔICP0) HSV-1 replication compartments, identified by ICP4 accumulation, or PML. Transgenic HFt cells were infected with 1 PFU of ICP0- mutant HSV-1 per cell for 16 h prior to DOX induction of eYFP or eYFP.PIAS4 wild-type or mutant protein expression for 6 to 8 h. Localization of PML (cyan) and ICP4 (red) was visualized by indirect immunofluorescence. The inset (dashed box in panel B) highlights a region within a replication compartment where eYFP.P4 wt and PML colocalize in string-like structures (69). (J) Validation of PIAS4 polyclonal antibody (pAb; cyan) detection of eYFP.P4 wt within ICP0- mutant HSV-1 replication compartments (ICP4; red). (K) Confocal images show the association of endogenous PIAS4 (red) with PML (cyan) in ICP0- mutant HSV-1 replication compartments. (L) Emission spectra depict the pixel intensity and colocalization between eYFP.ICP4, endogenous PIAS4, and PML within a focus or region of an ICP0- mutant HSV-1 replication compartment indicated by the corresponding numbered lines in panel K. Nuclei were visualized by DAPI (blue).
Mentions: The subnuclear localization of mutant eYFP.PIAS4 proteins was initially evaluated during ICP0- mutant HSV-1 infection to avoid potential ICP0-mediated disruption of relevant interactions. EYFP alone did not accumulate in replication compartments, while eYFP.PIAS4 did (Fig. 6A and B), demonstrating that fusion to eYFP did not adversely affect PIAS4 localization. However, endogenous PIAS4 tended to localize throughout individual replication compartments, whereas eYFP.PIAS4 tended to occupy subdomains within them (Fig. 6B and J). Notably, endogenous or exogenous PIAS4 could colocalize with PML, a known intrinsic antiviral factor (Fig. 6B, K, and L). The regions where eYFP.PIAS4 and PML colocalized were largely restrained to subdomains within individual replication compartments and often resembled string-like structures (Fig. 6B, inset) (69).

Bottom Line: Despite characterization of the host factors that rely on SUMOylation to exert their antiviral effects, the enzymes that mediate these SUMOylation events remain to be defined.Moreover, in the absence of ICP0, high-molecular-weight SUMO-conjugated proteins do not accumulate if HSV-1 DNA does not replicate.The protein inhibitor of activated STAT (PIAS) family of SUMO ligases is predominantly associated with the suppression of innate immune signaling.

View Article: PubMed Central - PubMed

Affiliation: MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow, Scotland, United Kingdom.

Show MeSH
Related in: MedlinePlus