Cellular Transcriptional Coactivator RanBP10 and Herpes Simplex Virus 1 ICP0 Interact and Synergistically Promote Viral Gene Expression and Replication

Abstract

To investigate the molecular mechanism(s) by which herpes simplex virus 1 (HSV-1) regulatory protein ICP0 promotes viral gene expression and replication, we screened cells overexpressing ICP0 for ICP0-binding host cell proteins. Tandem affinity purification of transiently expressed ICP0 coupled with mass spectrometry-based proteomics technology and subsequent analyses showed that ICP0 interacted with cell protein RanBP10, a known transcriptional coactivator, in HSV-1-infected cells. Knockdown of RanBP10 in infected HEp-2 cells resulted in a phenotype similar to that observed with the ICP0-null mutation, including reduction in viral replication and in the accumulation of viral immediate early (ICP27), early (ICP8), and late (VP16) mRNAs and proteins. In addition, RanBP10 knockdown or the ICP0-null mutation increased the level of histone H3 association with the promoters of these viral genes, which is known to repress transcription. These effects observed in wild-type HSV-1-infected HEp-2 RanBP10 knockdown cells or those observed in ICP0-null mutant virus-infected control HEp-2 cells were remarkably increased in ICP0-null mutant virus-infected HEp-2 RanBP10 knockdown cells. Our results suggested that ICP0 and RanBP10 redundantly and synergistically promoted viral gene expression by regulating chromatin remodeling of the HSV-1 genome for efficient viral replication. IMPORTANCEUpon entry of herpesviruses into a cell, viral gene expression is restricted by heterochromatinization of the viral genome. Therefore, HSV-1 has evolved multiple mechanisms to counteract this epigenetic silencing for efficient viral gene expression and replication. HSV-1 ICP0 is one of the viral proteins involved in counteracting epigenetic silencing. Here, we identified RanBP10 as a novel cellular ICP0-binding protein and showed that RanBP10 and ICP0 appeared to act synergistically to promote viral gene expression and replication by modulating viral chromatin remodeling. Our results provide insight into the mechanisms by which HSV-1 regulates viral chromatin remodeling for efficient viral gene expression and replication. H erpes simplex virus 1 (HSV-1) has more than 80 different genes that fall into three major classes, designated immediate early (IE) or ␣, early (E) or ␤, and late (L) or ␥, which are expressed in a regulated cascade during the HSV-1 lytic infection cycle (1). ICP0, the subject of this study, is an IE protein with a RING finger domain that confers E3 ubiquitin ligase activity, thereby mediating the ubiquitination and proteasome-dependent degradation of target proteins in HSV-1-infected cells (1-4). Based on studies using ICP0-null mutant viruses, ICP0 has been shown to be required for efficient HSV-1 gene expression and replication in cell cultures (3-7). Numerous studies of ICP0 have gradually identified the mechanisms by which ICP0 acts in HSV-1-infected cells as follows. (i) ICP0 induces the disruption of nuclear structures, designated ND10, by degrading promyelocytic leukemia protein (PML) and Sp100, major cellula...

Regulation of Herpes Simplex Virus 2 Protein Kinase UL13 by Phosphorylation and Its Role in Viral Pathogenesis

“…Cells and viruses. Vero, U2OS, HEK293T, SP2/O, and rabbit skin cells were described previously (39,(43)(44)(45), as was HSV-2 wild-type strain 186 (46). Recombinant virus YK356, which was reconstituted from pYEbac356 containing a full-length HSV-2 186 genome with a BAC sequence inserted into the intergenic region between UL50 and UL51, was described previously (23).…”

Genetic variation and gene expression across multiple tissues and developmental stages in a non-human primate

“…Recent evidence points to immune functions for the products of several of these genes. For example, RANBP10, a transcriptional coactivator, promotes viral gene expression and replication in HSV-1 infected cells 43 . SUGT1, a cell cycle regulator, is the homolog of SGT1, which plays an essential role in innate immunity in plants as well as mammals 44,45 , while TMEM57 has shown association in a human population, at a genome-wide significance threshold, to blood markers of inflammation 46 .…”

Herpesviruses and Their Host Cells: A Successful Liaison

“…Global phosphorylation patterns in signaling pathways modulated by the EBV protein kinase BGLF4 [62] Mass-Spec-based proteomics Identification of an interaction between HSV-1 ICP0 and the cellular protein RanBP10 by tandem affinity purification (TAP) and mass spectrometry [63] Quantitative temporal viromics Systematic quantitative analysis of temporal changes in host and viral proteins during HCMV infection by multiplexed tandem-mass-tag-based mass spectrometry [64] Subcellular fractionation combined with quantitative proteomics Identification of Hsp70 isoforms as constituents of the KSHV replication and transcription compartments (RTCs) [65] Single-cell mass cytometry (CyTOF) Analysis of concurrent changes in multiple host cell factors at the single cell level to follow phenotypic remodeling of T cells infected with VZV [9] High-resolution chromatin immunoprecipitation and deep sequencing (ChIP-Seq) immune responses or cell death. Viruses can establish productive infection only when they find ways to counteract these lines of defense.…”

“…HCMV codes for a gH/gL/gO complex which drives infection of cells expressing platelet-derived growth factor receptor alpha (PDGFR-/) [16], and for a gH/gL/pUL(128,130,131A) complex which drives infection of most PDGFR-/-negative cells through a still unknown receptor. In cell culture, fibroblasts infected with HCMV release virions with high or low amounts of gH/gL/pUL Noncoding RNAs (including miRNAs) [44,45,47] Origins of lytic replication (oriLyts) [51] Antiapoptotic genes [70] Genes counteracting host cell defense mechanisms (immune evasion genes) [71][72][73][74][75][76][77][78] Genes influencing cell cycle or proliferation [79,80] Genes interfering with epigenetic silencing [63,81] Cellular (host) factors Refs…”

“…, and signaling coreceptors [67,82] Noncoding RNAs (including miRNAs) [41,42,48] Proteins interacting with oriLyts [51] Interferons and other cytokines [30,[32][33][34] Sensors of viral infection [23,83,84] Cell cycle proteins [62,85,86] Proteins regulating apoptosis [87][88][89][90] Transcription factors [91] DNA damage response proteins [5] Proteins involved in epigenetic gene regulation including chromatin assembly, histone modifications[ 3 _ T D $ D I F F ] , and DNA methylation [21][22][23][24][25][26][27][28]63,[92][93][94][95][96][97][98] Autophagy and xenophagy [99][100][101] Ubiquitination and NEDDylation [102][103][104][105] Chaperones [65] Post-translational modification proteins …”