Herpes Simplex Virus Type 1 ICP27 Induces p38 Mitogen-Activated Protein Kinase Signaling and Apoptosis in HeLa Cells

Gillis, Peter A.; Okagaki, Laura H.; Rice, Stephen A.

doi:10.1128/jvi.01944-08

Cited by 59 publications

(43 citation statements)

References 57 publications

(75 reference statements)

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“…ICP27 affects pre-mRNA processing of >200 genes in ICP27-transfected cells involved in important cellular pathways, implying a broad program of ICP27-mediated cellular modification to favor the virus, and helping to explain the observation that ICP27 expression is toxic to the cell and is both required for efficient virus growth and for severe symptoms (43)(44)(45). Of the affected genes, >30, including PML, STING, TRAF6, PPP6C, MAP3K7, FBXW11, IFNAR2, NFKB1, RELA, and CREBP, are related to innate immunity pathways, which is consistent with ICP27's known role in regulating innate immunity (46)(47)(48)(49).…”

Section: Splicing Inhibition Mediated By Icp27 and Cytosine-rich Sequmentioning

confidence: 99%

Herpes simplex virus ICP27 regulates alternative pre-mRNA polyadenylation and splicing in a sequence-dependent manner

Tang

Patel

Krause

2016

Proc. Natl. Acad. Sci. U.S.A.

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The herpes simplex virus (HSV) infected cell culture polypeptide 27 (ICP27) protein is essential for virus infection of cells. Recent studies suggested that ICP27 inhibits splicing in a gene-specific manner via an unknown mechanism. Here, RNA-sequencing revealed that ICP27 not only inhibits splicing of certain introns in <1% of cellular genes, but also can promote use of alternative 5′ splice sites. In addition, ICP27 induced expression of pre-mRNAs prematurely cleaved and polyadenylated from cryptic polyadenylation signals (PAS) located in intron 1 or 2 of ∼1% of cellular genes. These previously undescribed prematurely cleaved and polyadenylated pre-mRNAs, some of which contain novel ORFs, were typically intronless, <2 Kb in length, expressed early during viral infection, and efficiently exported to cytoplasm. Sequence analysis revealed that ICP27-targeted genes are GC-rich (as are HSV genes), contain cytosine-rich sequences near the 5′ splice site, and have suboptimal splice sites in the impacted intron, suggesting that a common mechanism is shared between ICP27-mediated alternative polyadenylation and splicing. Optimization of splice site sequences or mutation of nearby cytosines eliminated ICP27-mediated splicing inhibition, and introduction of C-rich sequences to an ICP27-insensitive splicing reporter conferred this phenotype, supporting the inference that specific gene sequences confer susceptibility to ICP27. Although HSV is the first virus and ICP27 is the first viral protein shown to activate cryptic PASs in introns, we suspect that other viruses and cellular genes also encode this function. (ICP27), an immediate early (IE) gene (among those first expressed after virus enters the cells) that is required for expression of some early and late viral genes as well as for virus growth, is highly conserved between HSV-1 and -2, two closely related neurotropic herpesviruses (1). ICP27 has a role in transcriptional regulation through association with the C-terminal domain of RNA polymerase II (2, 3), forms homodimers (4, 5), interacts with U1 small nuclear ribonucleoprotein (snRNP) through its C-terminal domain, and colocalizes with U1 and U2 snRNPs (6, 7). It also interacts with splicing factors such as SRSF3, SRSF1, SRSF7, and SRSF2 (8-11), and is involved in nuclear export of some viral transcripts (12, 13). The role of ICP27 in regulating pre-mRNA splicing remains controversial. Early studies indicated that, in an in vitro pre-mRNA splicing system, ICP27 may nonspecifically inhibit host pre-mRNA splicing, impairing spliceosome assembly as a result of interaction with SR protein kinase 1 (SRPK1) through ICP27's N-terminal RGG RNA-binding motif and/or interaction with spliceosome-association protein 145 (SAP145 or SF3B2) through ICP27's C-terminal domain (8, 11). A recent communication reported that HSV-1 does not inhibit cotranscriptional splicing and proposed that previous reports of ICP27-induced splicing inhibition were artifacts, due to misinterpretation of run-on transcription (14). Indeed, splicing of ...

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Section: Splicing Inhibition Mediated By Icp27 and Cytosine-rich Sequmentioning

confidence: 99%

Herpes simplex virus ICP27 regulates alternative pre-mRNA polyadenylation and splicing in a sequence-dependent manner

Tang

Patel

Krause

2016

Proc. Natl. Acad. Sci. U.S.A.

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“…If LMB-resistant mutations weaken or abrogate an ICP27 activity, what might that activity be? A possibility that is consistent with many of the existing data is that the mutations weaken ICP27's ability to induce cellular signaling pathways, including the mitogen-activated protein kinases p38 and Jun N-terminal protein kinase (JNK) (56,58), and the NF-B system (57). There are several reasons why this idea is appealing.…”

Section: Genetic Basis Of Lmb Resistance In Hsvmentioning

confidence: 49%

“…It would also be worthwhile to see if other N-terminal additions to ICP27 (e.g., a green fluorescent protein moiety) lead to LMB resistance. Third, the N-terminal portion of ICP27 has been implicated in the ability of HSV-1 to stimulate several cellular signal transduction pathways (56)(57)(58). This activity and its possible relevance to LMB resistance are discussed further below.…”

Section: Genetic Basis Of Lmb Resistance In Hsvmentioning

confidence: 99%

Role of Immediate Early Protein ICP27 in the Differential Sensitivity of Herpes Simplex Viruses 1 and 2 to Leptomycin B

Park

Lengyel

Rice

2013

J Virol

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Leptomycin B (LMB) is a highly specific inhibitor of CRM1, a cellular karyopherin-␤ that transports nuclear export signal-containing proteins from the nucleus to the cytoplasm. Previous work has shown that LMB blocks herpes simplex virus 1 (HSV-1) replication in Vero cells and that certain mutations in viral immediate early protein ICP27 can confer LMB resistance. However, little is known of the molecular mechanisms involved. Here we report that HSV-2, a close relative of HSV-1, is naturally resistant to LMB. To see whether the ICP27 gene determines this phenotypic difference, we generated an HSV-1 mutant that expresses the HSV-2 ICP27 instead of the HSV-1 protein. This recombinant was fully sensitive to LMB, indicating that one or more other viral genes must be important in determining HSV-2's LMB-resistant phenotype. In additional work, we report several findings that shed light on how HSV-1 ICP27 mutations can confer LMB resistance. First, we show that LMB treatment of HSV-1-infected cells leads to suppression of late viral protein synthesis and a block to progeny virion release. Second, we identify a novel type of ICP27 mutation that can confer LMB resistance, that being the addition of a 100-residue amino-terminal affinity purification tag. Third, by studying infections where both LMB-sensitive and LMB-resistant forms of ICP27 are present, we show that HSV-1's sensitivity to LMB is dominant to its resistance. Together, our results suggest a model in which the N-terminal portion of ICP27 mediates a nonessential activity that interferes with HSV-1 replication when CRM1 is inactive. We suggest that LMB resistance mutations weaken or abrogate this activity. Herpes simplex virus 1 (HSV-1) is a widely distributed human alphaherpesvirus that is capable of causing serious and in some cases life-threatening infections. The HSV-1 infectious cycle involves both nuclear and cytoplasmic processes, and thus, productive viral replication requires that viral and cellular protein and RNA components travel efficiently between the nucleus and cytoplasm. Such movement is largely mediated by dedicated cellular transporters, one important class of which consists of the karyopherin-␤ family of proteins (1). Among this family, CRM1 is perhaps the most well studied member. It is an essential protein that exports ribosomal subunits and various protein cargos from the nucleus to the cytoplasm (2-4). Transport by CRM1 is dependent on the presence of a specific nuclear export signal (NES) on the cargo protein. This signal consists of an ϳ15-residue consensus sequence that is rich in leucine and other hydrophobic residues. The NES binds to a hydrophobic cleft on the surface of nucleus-localized CRM1 (5, 6). Following binding, CRM1 escorts the cargo through the nuclear pore to the cytoplasm, whereupon it is released. One of the first leucine-rich NESs described was that of the human immunodeficiency virus type 1 (HIV-1) Rev protein (7). Rev uses CRM1 to facilitate the nuclear export of unspliced and partially spliced HIV-1 transcripts. S...

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“…Our results are consistent with a role for telomerase activation early in infection. Interestingly, HSV-1 has been shown to activate p38 mitogen-activated protein kinase (MAPK) in an ICP27-dependent manner (39,40). This kinase can downregulate telomerase activity by inhibiting hTERT transcription (41).…”

Section: Discussionmentioning

confidence: 99%

The Telomerase Inhibitor MST-312 Interferes with Multiple Steps in the Herpes Simplex Virus Life Cycle

Haberichter

Abbasi

Dedthanou

et al. 2015

J Virol

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The life cycle of herpes simplex virus (HSV) has the potential to be further manipulated to yield novel, more effective therapeutic treatments. Recent research has demonstrated that HSV-1 can increase telomerase activity and that expression of the catalytic component of telomerase, telomerase reverse transcriptase (TERT), alters sensitivity to HSV-dependent apoptosis. Telomerase is a cellular enzyme that synthesizes nucleotide repeats at the ends of chromosomes (telomeres), which prevents shortening of the 3= ends of DNA with each cell division. Once telomeres reach a critical length, cells undergo senescence and apoptosis. Here, we used a cell-permeable, reversible inhibitor of the telomerase enzyme, MST-312, to investigate telomerase activity during HSV infection. Herpes simplex virus (HSV) is well known as the causative agent of cold sores and genital herpes (reviewed in reference 1). When the virus infects tissues other than the oral or genital mucosa, such as ocular and brain tissues, much more serious diseases occur. Initial HSV-1 infections generally occur in toddlers and young children, and over two-thirds of the U.S. population is infected by adulthood (2). Primary infections may be asymptomatic or lead to the formation of characteristic blistering lesions (e.g., on or around the oral mucosa). The host immune system is usually able to clear the virus from infected epithelial tissues. However, HSV-1 establishes a latent infection in neuronal ganglia servicing the site of initial infection and persists there for the lifetime of the infected individual. HSV-1 may then reactivate from its latent state, which leads to recurrent viral replication in the epithelium and the formation of new lesions. Although currently available antiviral agents that act against HSV polymerase (Pol) can limit lytic replication in epithelial tissues, they are unable to eliminate latent HSV infections. Improvement of treatment for HSV disease relies heavily on a better understanding of cellular factors controlling HSV-1 replication in general.One such cellular factor is telomerase. Increased telomerase activity has been detected in cells infected with a variety of herpesviruses (3-11). There is evidence that HSV can mediate elevated telomerase activity during infection. Telomerase activity was found to be between 4 and 8 times greater in cells infected with a replication-defective mutant of HSV than in uninfected counterparts (3). This increase in activity was accompanied by enhanced telomerase reverse transcriptase (TERT) promoter activity.Previously, we determined that the levels of TERT could determine the sensitivity to HSV-dependent apoptosis (HDAP). Specifically, when tumor suppressor pathways were restored in HeLa cells, expression of TERT sensitized the cells to HDAP (12). This finding suggested that telomerase activation was sufficient to confer sensitivity to HDAP in HeLa cells. The initial goal of this study was to determine whether telomerase was necessary for HDAP. To do this, we utilized a small-molecule in...

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Herpes Simplex Virus Type 1 ICP27 Induces p38 Mitogen-Activated Protein Kinase Signaling and Apoptosis in HeLa Cells

Cited by 59 publications

References 57 publications

Herpes simplex virus ICP27 regulates alternative pre-mRNA polyadenylation and splicing in a sequence-dependent manner

Herpes simplex virus ICP27 regulates alternative pre-mRNA polyadenylation and splicing in a sequence-dependent manner

Role of Immediate Early Protein ICP27 in the Differential Sensitivity of Herpes Simplex Viruses 1 and 2 to Leptomycin B

The Telomerase Inhibitor MST-312 Interferes with Multiple Steps in the Herpes Simplex Virus Life Cycle

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