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Ming SL, Zhang S, Wang Q, Zeng L, Zhou LY, Wang MD, Ma YX, Han LQ, Zhong K, Zhu HS, Bai YL, Yang GY, Wang J, Chu BB. Inhibition of USP14 influences alphaherpesvirus proliferation by degrading viral VP16 protein via ER stress-triggered selective autophagy. Autophagy 2021; 18:1801-1821. [PMID: 34822318 DOI: 10.1080/15548627.2021.2002101] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Alphaherpesvirus infection results in severe health consequences in a wide range of hosts. USPs are the largest subfamily of deubiquitinating enzymes that play critical roles in immunity and other cellular functions. To investigate the role of USPs in alphaherpesvirus replication, we assessed 13 USP inhibitors for PRV replication. Our data showed that all the tested compounds inhibited PRV replication, with the USP14 inhibitor b-AP15 exhibiting the most dramatic effect. Ablation of USP14 also influenced PRV replication, whereas replenishment of USP14 in USP14 null cells restored viral replication. Although inhibition of USP14 induced the K63-linked ubiquitination of PRV VP16 protein, its degradation was not dependent on the proteasome. USP14 directly bound to ubiquitin chains on VP16 through its UBL domain during the early stage of viral infection. Moreover, USP14 inactivation stimulated EIF2AK3/PERK- and ERN1/IRE1-mediated signaling pathways, which were responsible for VP16 degradation through SQSTM1/p62-mediated selective macroautophagy/autophagy. Ectopic expression of non-ubiquitinated VP16 fully rescued PRV replication. Challenge of mice with b-AP15 activated ER stress and autophagy and inhibited PRV infection in vivo. Our results suggested that USP14 was a potential therapeutic target to treat alphaherpesvirus-induced infectious diseases.
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Affiliation(s)
- Sheng-Li Ming
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China.,Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, Henan Province, China.,Key Laboratory of Animal Growth and Development, Zhengzhou, Henan Province, People's Republic of China
| | - Shuang Zhang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China.,Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, Henan Province, China.,Key Laboratory of Animal Growth and Development, Zhengzhou, Henan Province, People's Republic of China
| | - Qi Wang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China.,Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, Henan Province, China.,Key Laboratory of Animal Growth and Development, Zhengzhou, Henan Province, People's Republic of China
| | - Lei Zeng
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China.,Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, Henan Province, China.,Key Laboratory of Animal Growth and Development, Zhengzhou, Henan Province, People's Republic of China
| | - Lu-Yu Zhou
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China.,Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, Henan Province, China.,Key Laboratory of Animal Growth and Development, Zhengzhou, Henan Province, People's Republic of China
| | - Meng-Di Wang
- The Education Department of Henan Province Henan University of Animal Husbandry and Economy, Zhengzhou, Henan Province, People's Republic of China
| | - Ying-Xian Ma
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China.,Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, Henan Province, China.,Key Laboratory of Animal Growth and Development, Zhengzhou, Henan Province, People's Republic of China
| | - Li-Qiang Han
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China.,Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, Henan Province, China.,Key Laboratory of Animal Growth and Development, Zhengzhou, Henan Province, People's Republic of China
| | - Kai Zhong
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China.,Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, Henan Province, China.,Key Laboratory of Animal Growth and Development, Zhengzhou, Henan Province, People's Republic of China
| | - He-Shui Zhu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China.,Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, Henan Province, China.,Key Laboratory of Animal Growth and Development, Zhengzhou, Henan Province, People's Republic of China
| | - Yi-Lin Bai
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi Province, People's Republic of China
| | - Guo-Yu Yang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China.,Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, Henan Province, China.,Key Laboratory of Animal Growth and Development, Zhengzhou, Henan Province, People's Republic of China.,International Joint Research Center of National Animal Immunology, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China
| | - Jiang Wang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China.,Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, Henan Province, China.,Key Laboratory of Animal Growth and Development, Zhengzhou, Henan Province, People's Republic of China
| | - Bei-Bei Chu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China.,Key Laboratory of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs of the People's Republic of China, Zhengzhou, Henan Province, China.,Key Laboratory of Animal Growth and Development, Zhengzhou, Henan Province, People's Republic of China.,International Joint Research Center of National Animal Immunology, Henan Agricultural University, Zhengzhou, Henan Province, People's Republic of China
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Fan D, Wang M, Cheng A, Jia R, Yang Q, Wu Y, Zhu D, Zhao X, Chen S, Liu M, Zhang S, Ou X, Mao S, Gao Q, Sun D, Wen X, Liu Y, Yu Y, Zhang L, Tian B, Pan L, Chen X. The Role of VP16 in the Life Cycle of Alphaherpesviruses. Front Microbiol 2020; 11:1910. [PMID: 33013729 PMCID: PMC7461839 DOI: 10.3389/fmicb.2020.01910] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 07/21/2020] [Indexed: 12/12/2022] Open
Abstract
The protein encoded by the UL48 gene of alphaherpesviruses is named VP16 or alpha-gene-transactivating factor (α-TIF). In the early stage of viral replication, VP16 is an important transactivator that can activate the transcription of viral immediate-early genes, and in the late stage of viral replication, VP16, as a tegument, is involved in viral assembly. This review will explain the mechanism of VP16 acting as α-TIF to activate the transcription of viral immediate-early genes, its role in the transition from viral latency to reactivation, and its effects on viral assembly and maturation. In addition, this review also provides new insights for further research on the life cycle of alphaherpesviruses and the role of VP16 in the viral life cycle.
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Affiliation(s)
- Dengjian Fan
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Renyong Jia
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Qiao Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Ying Wu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Dekang Zhu
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xinxin Zhao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Mafeng Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Shaqiu Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xumin Ou
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Sai Mao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Qun Gao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Di Sun
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xingjian Wen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yunya Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yanling Yu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Ling Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Bin Tian
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Leichang Pan
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xiaoyue Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
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Tyagi S, Mazumdar PA, Mayee P, Shivaraj SM, Anand S, Singh A, Madhurantakam C, Sharma P, Das S, Kumar A, Singh A. Natural variation in Brassica FT homeologs influences multiple agronomic traits including flowering time, silique shape, oil profile, stomatal morphology and plant height in B. juncea. Plant Sci 2018; 277:251-266. [PMID: 30466591 DOI: 10.1016/j.plantsci.2018.09.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 09/17/2018] [Accepted: 09/21/2018] [Indexed: 06/09/2023]
Abstract
Natural structural variants of regulatory proteins causing quantitative phenotypic consequences have not been reported in plants. Herein, we show that 28 natural structural variants of FT homeologs, isolated from 6 species of Brassica, differ with respect to amino-acid substitutions in regions critical for interactions with FD and represent two evolutionarily distinct categories. Analysis of structural models of selected candidates from Brassica juncea (BjuFT_AAMF1) and Brassica napus (BnaFT_CCLF) predicted stronger binding between BjuFT and Arabidopsis thaliana FD. Over-expression of BjuFT and BnaFT in wild type and ft-10 mutant backgrounds of Arabidopsis validated higher potency of BjuFT in triggering floral transition. Analysis of gain-of-function and artificial miRNA mediated silenced lines of B. juncea implicated Brassica FT in multiple agronomic traits beyond flowering, consistent with a pleiotropic effect. Several dependent and independent traits such as lateral branching, silique shape, seed size, oil-profile, stomatal morphology and plant height were found altered in mutant lines. Enhanced FT levels caused early flowering, which in turn was positively correlated to a higher proportion of desirable fatty acids (PUFA). However, higher FT levels also resulted in altered silique shape and reduced seed size, suggesting trait trade-offs. Modulation of FT levels for achieving optimal balance of trait values and parsing pair-wise interactions among a reportoire of regulatory protein homeologs in polyploid genomes are indeed future areas of crop research.
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Affiliation(s)
- Shikha Tyagi
- Department of Biotechnology, TERI School of Advanced Studies, 10, Institutional Area, Vasant Kunj, New Delhi, 110070, India
| | | | - Pratiksha Mayee
- Department of Biotechnology, TERI School of Advanced Studies, 10, Institutional Area, Vasant Kunj, New Delhi, 110070, India; Department of Research, Ankur Seeds Pvt. Ltd., 27, Nagpur, Maharashtra, 440018, India
| | - S M Shivaraj
- Department of Biotechnology, TERI School of Advanced Studies, 10, Institutional Area, Vasant Kunj, New Delhi, 110070, India; Departement de Phytologie, Université Laval, Quebec City, Quebec, G1V 0A6, Canada
| | - Saurabh Anand
- Department of Botany, University of Delhi, New Delhi, 110007, India
| | - Anupama Singh
- Department of Biotechnology, TERI School of Advanced Studies, 10, Institutional Area, Vasant Kunj, New Delhi, 110070, India
| | - Chaithanya Madhurantakam
- Department of Biotechnology, TERI School of Advanced Studies, 10, Institutional Area, Vasant Kunj, New Delhi, 110070, India
| | - Prateek Sharma
- Department of Energy and Environment, TERI School of Advanced Studies, 10, Institutional Area, Vasant Kunj, New Delhi, 110070, India
| | - Sandip Das
- Department of Botany, University of Delhi, New Delhi, 110007, India
| | - Arun Kumar
- National Phytotron Facility, IARI, New Delhi, 110012, India
| | - Anandita Singh
- Department of Biotechnology, TERI School of Advanced Studies, 10, Institutional Area, Vasant Kunj, New Delhi, 110070, India.
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Teo CSH, O’Hare P. A bimodal switch in global protein translation coupled to eIF4H relocalisation during advancing cell-cell transmission of herpes simplex virus. PLoS Pathog 2018; 14:e1007196. [PMID: 30028874 PMCID: PMC6070287 DOI: 10.1371/journal.ppat.1007196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/01/2018] [Accepted: 07/02/2018] [Indexed: 12/28/2022] Open
Abstract
We used the bioorthogonal protein precursor, homopropargylglycine (HPG) and chemical ligation to fluorescent capture agents, to define spatiotemporal regulation of global translation during herpes simplex virus (HSV) cell-to-cell spread at single cell resolution. Translational activity was spatially stratified during advancing infection, with distal uninfected cells showing normal levels of translation, surrounding zones at the earliest stages of infection with profound global shutoff. These cells further surround previously infected cells with restored translation close to levels in uninfected cells, reflecting a very early biphasic switch in translational control. While this process was dependent on the virion host shutoff (vhs) function, in certain cell types we also observed temporally altered efficiency of shutoff whereby during early transmission, naïve cells initially exhibited resistance to shutoff but as infection advanced, naïve target cells succumbed to more extensive translational suppression. This may reflect spatiotemporal variation in the balance of oscillating suppression-recovery phases. Our results also strongly indicate that a single particle of HSV-2, can promote pronounced global shutoff. We also demonstrate that the vhs interacting factor, eIF4H, an RNA helicase accessory factor, switches from cytoplasmic to nuclear localisation precisely correlating with the initial shutdown of translation. However translational recovery occurs despite sustained eIF4H nuclear accumulation, indicating a qualitative change in the translational apparatus before and after suppression. Modelling simulations of high multiplicity infection reveal limitations in assessing translational activity due to sampling frequency in population studies and how analysis at the single cell level overcomes such limitations. The work reveals new insight and a revised model of translational manipulation during advancing infection which has important implications both mechanistically and with regards to the physiological role of translational control during virus propagation. The work also demonstrates the potential of bioorthogonal chemistry for single cell analysis of cellular metabolic processes during advancing infections in other virus systems.
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Affiliation(s)
- Catherine Su Hui Teo
- Section of Virology, Faculty of Medicine, Imperial College London, St Mary’s Medical School, London, United Kingdom
| | - Peter O’Hare
- Section of Virology, Faculty of Medicine, Imperial College London, St Mary’s Medical School, London, United Kingdom
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Finnen RL, Zhu M, Li J, Romo D, Banfield BW. Herpes Simplex Virus 2 Virion Host Shutoff Endoribonuclease Activity Is Required To Disrupt Stress Granule Formation. J Virol 2016; 90:7943-55. [PMID: 27334584 DOI: 10.1128/JVI.00947-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 06/20/2016] [Indexed: 12/15/2022] Open
Abstract
UNLABELLED We previously established that cells infected with herpes simplex virus 2 (HSV-2) are disrupted in their ability to form stress granules (SGs) in response to oxidative stress and that this disruption is mediated by virion host shutoff protein (vhs), a virion-associated endoribonuclease. Here, we test the requirement for vhs endoribonuclease activity in disruption of SG formation. We analyzed the ability of HSV-2 vhs carrying the point mutation D215N, which ablates its endoribonuclease activity, to disrupt SG formation in both transfected and infected cells. We present evidence that ablation of vhs endoribonuclease activity results in defects in vhs-mediated disruption of SG formation. Furthermore, we demonstrate that preformed SGs can be disassembled by HSV-2 infection in a manner that requires vhs endoribonuclease activity and that, befitting this ability to promote SG disassembly, vhs is able to localize to SGs. Together these data indicate that endoribonuclease activity must be maintained in order for vhs to disrupt SG formation. We propose a model whereby vhs-mediated destruction of SG mRNA promotes SG disassembly and may also prevent SG assembly. IMPORTANCE Stress granules (SGs) are transient cytoplasmic structures that form when a cell is exposed to stress. SGs are emerging as potential barriers to viral infection, necessitating a more thorough understanding of their basic biology. We identified virion host shutoff protein (vhs) as a herpes simplex virus 2 (HSV-2) protein capable of disrupting SG formation. As mRNA is a central component of SGs and the best-characterized activity of vhs is as an endoribonuclease specific for mRNA in vivo, we investigated the requirement for vhs endoribonuclease activity in disruption of SG formation. Our studies demonstrate that endoribonuclease activity is required for vhs to disrupt SG formation and, more specifically, that SG disassembly can be driven by vhs endoribonuclease activity. Notably, during the course of these studies we discovered that there is an ordered departure of SG components during their disassembly and, furthermore, that vhs itself has the capacity to localize to SGs.
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Rivas HG, Schmaling SK, Gaglia MM. Shutoff of Host Gene Expression in Influenza A Virus and Herpesviruses: Similar Mechanisms and Common Themes. Viruses 2016; 8:102. [PMID: 27092522 DOI: 10.3390/v8040102] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 04/04/2016] [Accepted: 04/09/2016] [Indexed: 12/14/2022] Open
Abstract
The ability to shut off host gene expression is a shared feature of many viral infections, and it is thought to promote viral replication by freeing host cell machinery and blocking immune responses. Despite the molecular differences between viruses, an emerging theme in the study of host shutoff is that divergent viruses use similar mechanisms to enact host shutoff. Moreover, even viruses that encode few proteins often have multiple mechanisms to affect host gene expression, and we are only starting to understand how these mechanisms are integrated. In this review we discuss the multiplicity of host shutoff mechanisms used by the orthomyxovirus influenza A virus and members of the alpha- and gamma-herpesvirus subfamilies. We highlight the surprising similarities in their mechanisms of host shutoff and discuss how the different mechanisms they use may play a coordinated role in gene regulation.
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Abstract
Alphaherpesviruses like herpes simplex virus are large DNA viruses characterized by their ability to establish lifelong latent infection in neurons. As for all herpesviruses, alphaherpesvirus virions contain a protein-rich layer called “tegument” that links the DNA-containing capsid to the glycoprotein-studded membrane envelope. Tegument proteins mediate a diverse range of functions during the virus lifecycle, including modulation of the host-cell environment immediately after entry, transport of virus capsids to the nucleus during infection, and wrapping of cytoplasmic capsids with membranes (secondary envelopment) during virion assembly. Eleven tegument proteins that are conserved across alphaherpesviruses have been implicated in the formation of the tegument layer or in secondary envelopment. Tegument is assembled via a dense network of interactions between tegument proteins, with the redundancy of these interactions making it challenging to determine the precise function of any specific tegument protein. However, recent studies have made great headway in defining the interactions between tegument proteins, conserved across alphaherpesviruses, which facilitate tegument assembly and secondary envelopment. We summarize these recent advances and review what remains to be learned about the molecular interactions required to assemble mature alphaherpesvirus virions following the release of capsids from infected cell nuclei.
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Affiliation(s)
- Danielle J Owen
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Colin M Crump
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
| | - Stephen C Graham
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.
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8
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Finnen RL, Hay TJ, Dauber B, Smiley JR, Banfield BW. The herpes simplex virus 2 virion-associated ribonuclease vhs interferes with stress granule formation. J Virol 2014; 88:12727-39. [PMID: 25142597 DOI: 10.1128/JVI.01554-14] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED In a previous study, it was observed that cells infected with herpes simplex virus 2 (HSV-2) failed to accumulate stress granules (SGs) in response to oxidative stress induced by arsenite treatment. As a follow-up to this observation, we demonstrate here that disruption of arsenite-induced SG formation by HSV-2 is mediated by a virion component. Through studies on SG formation in cells infected with HSV-2 strains carrying defective forms of UL41, the gene that encodes vhs, we identify vhs as a virion component required for this disruption. Cells infected with HSV-2 strains producing defective forms of vhs form SGs spontaneously late in infection. In addition to core SG components, these spontaneous SGs contain the viral immediate early protein ICP27 as well as the viral serine/threonine kinase Us3. As part of these studies, we reexamined the frameshift mutation known to reside within the UL41 gene of HSV-2 strain HG52. We demonstrate that this mutation is unstable and can rapidly revert to restore wild-type UL41 following low-multiplicity passaging. Identification of the involvement of virion-associated vhs in the disruption of SG formation will enable mechanistic studies on how HSV-2 is able to counteract antiviral stress responses early in infection. In addition, the ability of Us3 to localize to stress granules may indicate novel roles for this viral kinase in the regulation of translation. IMPORTANCE Eukaryotic cells respond to stress by rapidly shutting down protein synthesis and storing mRNAs in cytoplasmic stress granules (SGs). Stoppages in protein synthesis are problematic for all viruses as they rely on host cell machinery to synthesize viral proteins. Thus, many viruses target SGs for disruption or modification. Infection by herpes simplex virus 2 (HSV-2) was previously observed to disrupt SG formation induced by oxidative stress. In this follow-up study, we identify virion host shutoff protein (vhs) as a viral protein involved in this disruption. The identification of a specific viral protein involved in disrupting SG formation is a key step toward understanding how HSV-2 interacts with these antiviral structures. Additionally, this understanding may provide insights into the biology of SGs that may find application in studies on human motor neuron degenerative diseases, like amyotrophic lateral sclerosis (ALS), which may arise as a result of dysregulation of SG formation.
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Danaher RJ, Cook RK, Wang C, Triezenberg SJ, Jacob RJ, Miller CS. C-terminal trans-activation sub-region of VP16 is uniquely required for forskolin-induced herpes simplex virus type 1 reactivation from quiescently infected-PC12 cells but not for replication in neuronally differentiated-PC12 cells. J Neurovirol 2012. [PMID: 23192733 DOI: 10.1007/s13365-012-0137-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The HSV-1 tegument protein VP16 contains a trans-activation domain (TAD) that is required for induction of immediate early (IE) genes during lytic infection and induced reactivation from latency. Here we report the differential contributions of the two sub-regions of the TAD in neuronal and non-neuronal cells during activation of IE gene expression, virus replication, and reactivation from quiescently infected (QIF)-PC12 cells. Our studies show that VP16- and chemical (hexamethylenebisacetamide)-induced IE gene activation is attenuated in neuronal cells. Irrespective of neuronal or non-neuronal cell backgrounds, IE gene activation demonstrated a greater requirement for the N-terminal sub-region of VP16 TAD (VP16N) than the C-terminal sub-region (VP16C). In surprising contrast to these findings, a recombinant virus (RP4) containing the VP16N deletion was capable of modest forskolin-induced reactivation whereas a recombinant (RP3) containing a deletion of VP16C was incapable of stress-induced reactivation from QIF-PC12 cells. These unique process-dependent functions of the VP16 TAD sub-regions may be important during particular stages of the virus life cycle (lytic, entrance, and maintenance of a quiescent state and reactivation) when viral DNA would be expected to be differentially modified.
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Affiliation(s)
- Robert J Danaher
- Department of Oral Health Practice, Division of Oral Medicine, Center for Oral Health Research, College of Dentistry, University of Kentucky, Lexington, KY 40536-0297, USA
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10
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Svobodova S, Bell S, Crump CM. Analysis of the interaction between the essential herpes simplex virus 1 tegument proteins VP16 and VP1/2. J Virol 2012; 86:473-83. [PMID: 22013045 DOI: 10.1128/JVI.05981-11] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The incorporation of tegument proteins into the herpes simplex virus 1 (HSV-1) virion during virion assembly is thought to be a complex, multistage process occurring via numerous interactions between the tegument and the capsid, within the tegument, and between the tegument and the envelope. Here, we set out to examine if the direct interaction between two essential tegument proteins VP1/2 and VP16 is required for connecting the inner tegument with the outer tegument. By using glutathione S-transferase (GST) pulldowns, we identified an essential role of lysine 343 in VP16, mutation of which to a neutral amino acid abrogated the interaction between VP1/2 and VP16. When the K343A substitution was inserted into the gene encoding VP16 (UL48) of the viral genome, HSV-1 replicated successfully although its growth was delayed, and final titers were reduced compared to titers of wild-type virus. Surprisingly, the mutated VP16 was incorporated into virions at levels similar to those of wild-type VP16. However, the analysis of VP16 on cytoplasmic capsids by fluorescence microscopy showed that VP16 associated with cytoplasmic capsids less efficiently when the VP16-VP1/2 interaction was inhibited. This implies that the direct interaction between VP1/2 and VP16 is important for the efficiency/timing of viral assembly but is not essential for HSV-1 replication in cell culture. These data also support the notion that the incorporation of tegument proteins into the herpesviruses is a very complex process with significant redundancy.
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11
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Benítez-Páez A, Cárdenas-Brito S, Gutiérrez AJ. A practical guide for the computational selection of residues to be experimentally characterized in protein families. Brief Bioinform 2011; 13:329-36. [PMID: 21930656 DOI: 10.1093/bib/bbr052] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In recent years, numerous biocomputational tools have been designed to extract functional and evolutionary information from multiple sequence alignments (MSAs) of proteins and genes. Most biologists working actively on the characterization of proteins from a single or family perspective use the MSA analysis to retrieve valuable information about amino acid conservation and the functional role of residues in query protein(s). In MSAs, adjustment of alignment parameters is a key point to improve the quality of MSA output. However, this issue is frequently underestimated and/or misunderstood by scientists and there is no in-depth knowledge available in this field. This brief review focuses on biocomputational approaches complementary to MSA to help distinguish functional residues in protein families. These additional analyses involve issues ranging from phylogenetic to statistical, which address the detection of amino acids pivotal for protein function at any level. In recent years, a large number of tools has been designed for this very purpose. Using some of these relevant, useful tools, we have designed a practical pipeline to perform in silico studies with a view to improving the characterization of family proteins and their functional residues. This review-guide aims to present biologists a set of specially designed tools to study proteins. These tools are user-friendly as they use web servers or easy-to-handle applications. Such criteria are essential for this review as most of the biologists (experimentalists) working in this field are unfamiliar with these biocomputational analysis approaches.
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Affiliation(s)
- Alfonso Benítez-Páez
- Bioinformatic Analysis Group - GABi, Centro de Investigación y Desarrollo en Biotecnología, Bogotá DC, Colombia.
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12
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Tombácz D, Tóth JS, Boldogkoi Z. Deletion of the virion host shut: off gene of pseudorabies virus results in selective upregulation of the expression of early viral genes in the late stage of infection. Genomics 2011; 98:15-25. [PMID: 21466845 DOI: 10.1016/j.ygeno.2011.03.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 03/25/2011] [Accepted: 03/28/2011] [Indexed: 02/03/2023]
Abstract
A real-time RT-PCR technique was applied to evaluate the impact of deletion of the virion host shut-off (VHS) gene on the kinetics of pseudorabies virus gene expression. Selective suppression of early gene transcripts by the viral ribonuclease occurs after 4h of infection; while VHS protein appears to act non-selectively on the transcripts belonging in different kinetic classes in the first 2h of infection. VHS protein disrupts the close correlation between the transcription kinetics of the immediate-early 180 protein and the other pseudorabies virus transcripts. The typical pattern of early gene expression was found to be altered in the VHS gene-deleted virus in that the production rates of their transcripts did not decline from 4h post-infection. This observation led us to put forward the hypothesis that the VHS protein may play a pivotal role in the switch from the early to the late stage of infection.
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13
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Dauber B, Pelletier J, Smiley JR. The herpes simplex virus 1 vhs protein enhances translation of viral true late mRNAs and virus production in a cell type-dependent manner. J Virol 2011; 85:5363-73. [PMID: 21430045 DOI: 10.1128/JVI.00115-11] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The herpes simplex virus 1 (HSV-1) virion host shutoff protein (vhs) degrades viral and cellular mRNAs. Here, we demonstrate for the first time that vhs also boosts translation of viral true late mRNAs in a cell type-dependent manner and that this effect determines the viral growth phenotype in the respective cell type. Our study was prompted by the detection of stress granules, indicators of stalled translation initiation, in cells infected with vhs mutants but not in wild-type-virus-infected cells. Accumulation of true late-gene products gC and US11 was strongly reduced in the absence of vhs in HeLa cells and several other restrictive cell lines but not in Vero and other permissive cells and was independent of phosphorylation of the α subunit of eukaryotic initiation factor 2 (eIF2α). Polysome analysis showed that gC and US11 transcripts were poorly translated in vhs-null-virus-infected HeLa cells, while translation of a cellular mRNA was not affected. Interestingly, hippuristanol, an eIF4A inhibitor, produced a similar phenotype in HeLa cells infected with wild-type HSV-1, while Vero cells were much more resistant to the inhibitor. These results suggest that translation of true late-gene transcripts is particularly sensitive to conditions of limited access to translation factors and that vhs is able either to prevent the limiting conditions or to facilitate translation initiation under these conditions. The varied permissivity of cell lines to vhs-null infection may stem from differences in the resilience of the translation machinery or the ability to control the accumulation of mRNAs.
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14
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Abstract
All herpesviruses have a layer of protein called the tegument that lies between the virion membrane and the capsid. The tegument consists of multiple, virus-encoded protein species that together can account for nearly half the total virus protein. To clarify the structure of the tegument and its attachment to the capsid, we used electron microscopy and protein analysis to examine the tegument of herpes simplex virus type 1 (HSV-1). Electron microscopic examination of intact virions revealed that whereas the tegument was asymmetrically distributed around the capsid in extracellular virions, it was symmetrically arranged in cell-associated virus. Examination of virions after treatment with nonionic detergent demonstrated that: (i) in extracellular virus the tegument was resistant to removal with Triton X-100 (TX-100), whereas it was lost nearly completely when cell-associated virus was treated in the same way; (ii) the tegument in TX-100-treated extracellular virions was asymmetrically distributed around the capsid as it is in unextracted virus; and (iii) in some images, tegument was seen to be linked to the capsid by short, regularly spaced connectors. Further analysis was carried out with extracellular virus harvested from cells at different times after infection. It was observed that while the amount of tegument present in virions was not affected by time of harvest, the amount remaining after TX-100 treatment increased markedly as the time of harvest was increased from 24 h to 64 h postinfection. The results support the view that HSV-1 virions undergo a time-dependent change in which the tegument is transformed from a state in which it is symmetrically organized around the capsid and extractable with TX-100 to a state where it is asymmetrically arranged and resistant to extraction.
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15
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Abstract
Herpes Simplex Virus Type 1 (HSV-1) is a nuclear replicating enveloped virus, usually acquired through direct contact with infected lesions or body fluids (typically saliva). The prevalence of HSV-1 infection increases progressively from childhood, the seroprevalence being inversely related to socioeconomic background. Primary HSV-1 infections in children are either asymptomatic or following an incubation period of about 1 week gives rise to mucocutaneous vesicular eruptions. Herpetic gingivostomatitis typically affects the tongue, lips, gingival, buccal mucosa and the hard and soft palate. Most primary oro-facial HSV infection is caused by HSV-1, infection by HSV-2 is increasingly common. Recurrent infections, which occur at variable intervals, typically give rise to vesiculo-ulcerative lesions at mucocutaneous junctions particularly the lips (herpes labialis). Recurrent HSV-1 infection within the mouth is uncommon in otherwise healthy patients, although in immunocompromised patients, recurrent infection can be more extensive and/or aggressive. The diagnosis of common herpetic infection can usually be based upon the clinical history and presenting features. Confirmatory laboratory diagnosis is, however, required when patients are, or may be, immunocompromised.
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Affiliation(s)
- Paolo G Arduino
- Department of Biomedical Sciences and Human Oncology, Oral Medicine Section, University of Turin, Turin, Italy.
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16
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Kalamvoki M, Qu J, Roizman B. Translocation and colocalization of ICP4 and ICP0 in cells infected with herpes simplex virus 1 mutants lacking glycoprotein E, glycoprotein I, or the virion host shutoff product of the UL41 gene. J Virol 2008; 82:1701-13. [PMID: 18057247 DOI: 10.1128/JVI.02157-07] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In wild-type herpes simplex virus 1-infected cells, the major regulatory protein ICP4 resides in the nucleus whereas ICP0 becomes dynamically associated with proteasomes and late in infection is translocated and dispersed in the cytoplasm. Inhibition of proteasomal function results in retention or transport of ICP0 to the nucleus. We report that in cells infected with mutants lacking glycoprotein E (gE), glycoprotein I (gI), or the product of the U(L)41 gene, both ICP4 and ICP0 are translocated to the cytoplasm and coaggregate in small dense structures that, in the presence of proteasomal inhibitor MG132, also contain proteasomal components. Gold particle-conjugated antibody to ICP0 reacted in thin sections with dense protein aggregates in the cytoplasm of mutant virus-infected cells. Similar aggregates were present in the nuclei but not in the cytoplasm of wild-type virus-infected cells. Exposure of cells early in infection to MG132 does not result in retention of ICP0 as in wild-type virus-infected cells. The results suggest that the retention of ICP4 and ICP0 in the nucleus is a dynamic process that involves the function of other viral proteins that may include the Fc receptor formed by the gE/gI complex and is not merely the consequence of expression of a nuclear localization signal. It is noteworthy that in DeltaU(L)41-infected cells gE is retained in the trans-Golgi network and is not widely dispersed in cellular membranes.
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17
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Taddeo B, Sciortino MT, Zhang W, Roizman B. Interaction of herpes simplex virus RNase with VP16 and VP22 is required for the accumulation of the protein but not for accumulation of mRNA. Proc Natl Acad Sci U S A 2007; 104:12163-8. [PMID: 17620619 PMCID: PMC1924560 DOI: 10.1073/pnas.0705245104] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The virion host shutoff (vhs) protein encoded by the U(L)41 gene of herpes simplex virus 1 is an endoribonuclease. The enzyme is introduced into the cell during unpackaging of the virion upon entry and selectively degrades mRNA for several hours. The RNase activity ceases after the onset of synthesis of late (gamma) viral proteins. Here we report that vhs protein does not accumulate in cells transiently transfected with only a plasmid encoding the U(L)41 gene. However, vhs does accumulate in cells cotransfected with plasmids expressing two other tegument proteins, VP16 and VP22. vhs does not directly interact with VP22 but, instead, binds VP22 only in the presence of VP16. In contrast to these findings, the amounts of vhs mRNA accumulating in the cells transfected solely with vhs are not significantly different from those detected in cells coexpressing vhs, VP16, and VP22. We conclude from these studies that the steady state of vhs mRNA, reflecting synthesis and turnover of mRNA, is not affected by the interaction of vhs protein with VP16 with VP22. A model is proposed in which the vhs protein may function to sequester mRNAs in compartments inaccessible to the cellular translational machinery and that VP16 and VP22 rescue the mRNAs by interacting with the vhs protein.
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Affiliation(s)
- Brunella Taddeo
- *The Marjorie Kovler Viral Oncology Laboratories, University of Chicago, 910 East 58th Street, Chicago, IL 60637; and
| | - Maria Teresa Sciortino
- Department of Microbiological, Genetic, and Molecular Sciences, University of Messina, Salita Sperone, 31, 98166 Messina, Italy
| | - Weiran Zhang
- *The Marjorie Kovler Viral Oncology Laboratories, University of Chicago, 910 East 58th Street, Chicago, IL 60637; and
| | - Bernard Roizman
- *The Marjorie Kovler Viral Oncology Laboratories, University of Chicago, 910 East 58th Street, Chicago, IL 60637; and
- To whom correspondence should be addressed. E-mail:
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18
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Abstract
The ability to regulate cellular gene expression is a key aspect of the lifecycles of a diverse array of viruses. In fact, viral infection often results in a global shutoff of host cellular gene expression; such inhibition serves not only to ensure maximal viral gene expression without competition from the host for essential machinery and substrates but also aids in evasion of immune responses detrimental to successful viral replication and dissemination. Within the herpesvirus family, host shutoff is a prominent feature of both the alpha- and gamma-herpesviruses. Intriguingly, while both classes of herpesviruses block cellular gene expression by inducing decay of messenger RNAs, the viral factors responsible for this phenotype as well as the mechanisms by which it is achieved are quite distinct. However, data suggest that the host shutoff functions of alpha- and gamma-herpesviruses are likely achieved both through the activity of virally encoded nucleases as well as via modulation of cellular RNA degradation pathways. This review highlights the processes governing normal cellular messenger RNA decay and then details the mechanisms by which herpesviruses promote accelerated RNA turnover. Parallels between the viral and cellular degradation systems as well as the known interactions between viral host shutoff factors and the cellular RNA turnover machinery are highlighted.
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Affiliation(s)
- Britt A Glaunsinger
- Howard Hughes Medical Institute, Department of Microbiology, University of California, San Francisco, 94143, USA
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19
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Knez J, Piluso D, Bilan P, Capone JP. Host Cell Factor-1 and E2F4 Interact Via Multiple Determinants in Each Protein. Mol Cell Biochem 2006; 288:79-90. [PMID: 16633736 DOI: 10.1007/s11010-006-9122-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Accepted: 01/09/2006] [Indexed: 12/17/2022]
Abstract
Host Cell Factor (HCF-1) is a conserved, essential protein initially identified as a co-regulator for the Herpes Simplex Virus transactivator VP16. HCF-1 is variously involved in regulating transcription, splicing, cell proliferation and cytokinesis; however, its mechanisms of action remain unknown. HCF-1 function is manifested through an increasing assortment of cellular factors that target different regions of the protein. Several HCF-1 partners target the amino-terminal kelch domain of HCF-1 (residues 1-380) via a consensus HCF-binding motif (HBM) comprising the tetrapeptide (D/E)HXY. Searches of sequence databases indicated that this motif is present in E2F1 and E2F4, two members of the E2F family of cell cycle regulators. We show here that E2F4 specifically and directly interacts with HCF-1. Mutational analysis showed E2F4 independently targets the kelch domain and the basic domain (residues 450-902) of HCF-1, both of which are required for normal cell-cycle progression via separate determinants. The HBM-containing domain of E2F4 was necessary for interaction with the kelch domain of HCF-1 but not for interaction with the basic domain. Mutations in the HCF-1 kelch domain known to block cell growth abrogated E2F4 binding to the kelch domain in the absence but not in the presence of the juxtaposed basic region. Functionally, HCF-1 co-activated E2F4/DP-1 in transient transfection assays, while E2F4 blocked HCF-1-dependent rescue of a cell line that harbors a temperature sensitive mutant of HCF-1 that causes growth arrest. Our findings show that HCF-1 and E2F4 interact via multiple determinants and suggest a linkage between E2F4 and HCF-1 cell growth pathways.
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Affiliation(s)
- Jozo Knez
- Department of Biochemistry and Biomedical Sciences, McMaster University Medical Center, McMaster University, 1200 Main St. W., Hamilton, Ontario, L8N 3Z5, Canada
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20
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Ottosen S, Herrera FJ, Doroghazi JR, Hull A, Mittal S, Lane WS, Triezenberg SJ. Phosphorylation of the VP16 transcriptional activator protein during herpes simplex virus infection and mutational analysis of putative phosphorylation sites. Virology 2005; 345:468-81. [PMID: 16297954 PMCID: PMC1717022 DOI: 10.1016/j.virol.2005.10.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2005] [Revised: 05/02/2005] [Accepted: 10/12/2005] [Indexed: 11/21/2022]
Abstract
VP16 is a virion phosphoprotein of herpes simplex virus and a transcriptional activator of the viral immediate-early (IE) genes. We identified four novel VP16 phosphorylation sites (Ser18, Ser353, Ser411, and Ser452) at late times in infection but found no evidence of phosphorylation of Ser375, a residue reportedly phosphorylated when VP16 is expressed from a transfected plasmid. A virus carrying a Ser375Ala mutation of VP16 was viable in cell culture but with a slow growth rate. The association of the mutant VP16 protein with IE gene promoters and subsequent IE gene expression was markedly reduced during infection, consistent with prior transfection and in vitro results. Surprisingly, the association of Oct-1 with IE promoters was also diminished during infection by the mutant strain. We propose that Ser375 is important for the interaction of VP16 with Oct-1, and that the interaction is required to enable both proteins to bind to IE promoters.
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Affiliation(s)
- Søren Ottosen
- Department of Biochemistry and Molecular Biology, Michigan State University, 510 Biochemistry Building, East Lansing, 48824-1319, USA
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21
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Yedowitz JC, Kotsakis A, Schlegel EFM, Blaho JA. Nuclear localizations of the herpes simplex virus type 1 tegument proteins VP13/14, vhs, and VP16 precede VP22-dependent microtubule reorganization and VP22 nuclear import. J Virol 2005; 79:4730-43. [PMID: 15795259 PMCID: PMC1069571 DOI: 10.1128/jvi.79.8.4730-4743.2005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Herpes simplex virus type 1 (HSV-1) induces microtubule reorganization beginning at approximately 9 h postinfection (hpi), and this correlates with the nuclear localization of the tegument protein VP22. Thus, the active retention of this major virion component by cytoskeletal structures may function to regulate its subcellular localization (A. Kotsakis, L. E. Pomeranz, A. Blouin, and J. A. Blaho, J. Virol. 75:8697-8711, 2001). The goal of this study was to determine whether the subcellular localization patterns of other HSV-1 tegument proteins are similar to that observed with VP22. To address this, we performed a series of indirect immunofluorescence analyses using synchronously infected cells. We observed that tegument proteins VP13/14, vhs, and VP16 localized to the nucleus as early as 5 hpi and were concentrated in nuclei by 9 hpi, which differed from that seen with VP22. Microtubule reorganization was delayed during infection with HSV-1(RF177), a recombinant virus that does not produce full-length VP22. These infected cells did not begin to lose microtubule-organizing centers until 13 hpi. Repair of the unique long 49 (UL49) locus in HSV-1(RF177) yielded HSV-1(RF177R). Microtubule reorganization in HSV-1(RF177R)-infected cells occurred with the same kinetics as HSV-1(F). Acetylated tubulin remained unchanged during infection with either HSV-1(F) or HSV-1(RF177). Thus, while alpha-tubulin reorganized during infection, acetylated tubulin was stable, and the absence of full-length VP22 did not affect this stability. Our findings indicate that the nuclear localizations of tegument proteins VP13/14, VP16, and vhs do not appear to require HSV-1-induced microtubule reorganization. We conclude that full-length VP22 is needed for optimal microtubule reorganization during infection. This implies that VP22 mainly functions to reorganize microtubules later, rather than earlier, in infection. That acetylated tubulin does not undergo restructuring during VP22-dependent, virus-induced microtubule reorganization suggests that it plays a role in stabilizing the infected cells. Our results emphasize that VP22 likely plays a key role in cellular cytopathology during HSV-1 infection.
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Affiliation(s)
- Jamie C Yedowitz
- Department of Microbiology, Mount Sinai School of Medicine, One Gustave L. Levy Pl., New York, NY 10029-6574, USA
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22
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Affiliation(s)
- Angelika Oehmig
- Department of Neurology, Massachusetts General Hospital, and Program in Neuroscience, Harvard Medical School, Boston, MA 02114, USA
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23
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Abstract
The virion host shutoff (vhs) protein of herpes simplex virus type 1 causes the degradation of host and viral mRNA immediately upon infection of permissive cells. vhs can interact with VP16 through a 20-amino-acid binding domain, and viruses containing a deletion of this VP16-binding domain of vhs (Delta20) and a corresponding marker rescue (Delta20R) were constructed and characterized. Transient-transfection assays showed that this domain was dispensable for vhs activity. The Delta20 recombinant virus, however, was unable to induce mRNA degradation in the presence of actinomycin D, while degradation induced by Delta20R was equivalent to that for wild-type virus. Delta20, Delta20R, and KOS caused comparable RNA degradation in the absence of actinomycin D. Western blot analysis of infected cells indicated that comparable levels of vhs were expressed by Delta20, Delta20R, and KOS, and there was only a modest reduction of vhs packaging in Delta20. Immunoprecipitation of protein from cells infected with Delta20 and Delta20R showed equivalent coprecipitation of vhs and VP16. Pathogenesis studies with Delta20 showed a significant decrease in replication in the corneas, trigeminal ganglia, and brains, as well as a significant reduction in clinical disease and lethality, but no significant difference in the establishment of, or reactivation from, latency compared to results with KOS and Delta20R. These results suggest that the previously described VP16-binding domain is not required for vhs packaging or for binding to VP16. It is required, however, for RNA degradation activity of tegument-derived vhs and wild-type replication and virulence in mice.
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Affiliation(s)
- Stephanie S Strand
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Box 8096, 660 S. Euclid Ave., St. Louis, MO 63110, USA
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Doepker RC, Hsu WL, Saffran HA, Smiley JR. Herpes simplex virus virion host shutoff protein is stimulated by translation initiation factors eIF4B and eIF4H. J Virol 2004; 78:4684-99. [PMID: 15078951 PMCID: PMC387725 DOI: 10.1128/jvi.78.9.4684-4699.2004] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The virion host shutoff protein (vhs) of herpes simplex virus triggers accelerated degradation of cellular and viral mRNAs while sparing other cytoplasmic RNA species. Previous work has shown that vhs forms a complex with translation initiation factor eIF4H, which displays detectable RNase activity in the absence of other viral or host proteins. However, the contributions of eIF4H and other host factors to the activity and mRNA targeting properties of vhs have not yet been directly examined. An earlier report from our laboratory demonstrated that rabbit reticulocyte lysate (RRL) contains one or more factors that strongly stimulate the RNase activity of vhs produced in Saccharomyces cerevisiae. We report here that such yeast extracts display significant vhs-dependent RNase activity in the absence of mammalian factors. This activity differs from that displayed by vhs generated in RRL in that it is not targeted to the encephalomyocarditis virus (EMCV) internal ribosome entry site (IRES). Activity was strongly enhanced by the addition of RRL, eIF4H, or the related translation factor eIF4B. RRL also reconstituted strong targeting to the EMCV IRES, resulting in a major change in the RNA cleavage pattern. In contrast, eIF4H and eIF4B did not reconstitute IRES-directed targeting. These data indicate that eIF4B and 4H stimulate the nuclease activity of vhs, and they provide evidence that additional mammalian factors are required for targeting to the EMCV IRES.
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Affiliation(s)
- Rosalyn C Doepker
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
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