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Wang J, Xiao M, Hu Z, Lin Y, Li K, Chen P, Lu C, Dong Z, Pan M. Bombyx mori nucleopolyhedrovirus LEF-2 disrupts the cell cycle in the G2/M phase by triggering a host cell DNA damage response. INSECT MOLECULAR BIOLOGY 2024. [PMID: 39150688 DOI: 10.1111/imb.12951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 07/25/2024] [Indexed: 08/17/2024]
Abstract
It is a common strategy for viruses to block the host cell cycle to favour their DNA replication. Baculovirus, being a double-stranded DNA virus, can arrest the cell cycle in the G2/M phase to facilitate its replication. However, the key viral genes and mechanisms crucial for inducing cell cycle arrest remain poorly understood. Here, we initially examined the impacts of several Bombyx mori nucleopolyhedrovirus (BmNPV) DNA replication-associated genes: ie1, lef-1, lef-2, lef-3, lef-4, odv-ec27 and dbp. We assessed their effects on both the host cells' DNA replication and cell cycle. Our findings reveal that when the lef-2 gene was overexpressed, it led to a significant increase in the number of cells in the G2/M phase and a reduction in the number of cells in the S phase. Furthermore, we discovered that the LEF-2 protein is located in the virogenic stroma and confirmed its involvement in viral DNA replication. Additionally, by employing interference and overexpression experiments, we found that LEF-2 influences host cell DNA replication and blocks the cell cycle in the G2/M phase by regulating the expression of CyclinB and CDK1. Finally, we found that BmNPV lef-2 triggered a DNA damage response in the host cell, and inhibiting this response removed the cell cycle block caused by BmNPV LEF-2. Thus, our findings indicate that the BmNPV lef-2 gene plays a crucial role in viral DNA replication and can regulate host cell cycle processes. This study furthers our understanding of baculovirus-host cell interactions and provides new insight into the molecular mechanisms of antiviral research.
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Affiliation(s)
- Jie Wang
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Miao Xiao
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Zhigang Hu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Yu Lin
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Kejie Li
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
| | - Peng Chen
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing, China
| | - Cheng Lu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing, China
| | - Zhanqi Dong
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing, China
| | - Minhui Pan
- State Key Laboratory of Resource Insects, Southwest University, Chongqing, China
- Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing, China
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Hu ZG, Cao MY, Zhu Y, Wang J, Lin Y, Chen P, Lu C, Dong ZQ, Pan MH. BmNPV Bm60 is a key target gene used by a resistant strain of Bombyx mori to inhibit BmNPV proliferation. Int J Biol Macromol 2024; 264:130842. [PMID: 38484820 DOI: 10.1016/j.ijbiomac.2024.130842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/22/2024] [Accepted: 03/11/2024] [Indexed: 03/18/2024]
Abstract
Bombyx mori nucleopolyhedrovirus (BmNPV) is a pathogen that causes significant losses to the silkworm industry. Numerous antiviral genes and proteins have been identified by studying silkworm resistance to BmNPV. However, the molecular mechanism of silkworm resistance to BmNPV is unclear. We analyzed the differences between the susceptible strain 871 and a near-isogenic resistant strain 871C. The survival of strain 871C was significantly greater than that of 871 after oral and subcutaneous exposure to BmNPV. Strain 871C exhibited a nearly 10,000-fold higher LD50 for BmNPV compared to 871. BmNPV proliferation was significantly inhibited in all tested tissues of strain 871C using HE strain and fluorescence analysis. Strain 871C exhibited cellular resistance to BmNPV rather than peritrophic membrane or serum resistance. Strain 871C suppressed the expression of the viral early gene Bm60. This led to the inhibition of BmNPV DNA replication and late structural gene transcription based on the cascade regulation of baculovirus gene expression. Bm60 could also interact with the viral DNA binding protein and alkaline nuclease, as well as host proteins Methylcrotonoyl-CoA carboxylase subunit alpha, mucin-2-like protein, and 30 K-8. Overexpression of 30 K-8 significantly inhibited BmNPV proliferation. These results increase understanding of the molecular mechanism behind silkworm resistance to BmNPV and suggest targets for the breeding of resistant silkworm strains and the controlling pest of Lepidoptera.
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Affiliation(s)
- Zhi-Gang Hu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China
| | - Ming-Ya Cao
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China; Joint National Laboratory for Antibody Drug Engineering, The First Affiliated Hospital, School of Medicine, Henan University, Kaifeng 475004, China
| | - Yan Zhu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China
| | - Jie Wang
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China
| | - Yu Lin
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China
| | - Peng Chen
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400716, China
| | - Cheng Lu
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400716, China
| | - Zhan-Qi Dong
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400716, China.
| | - Min-Hui Pan
- State Key Laboratory of Resource Insects, Southwest University, Chongqing 400716, China; Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Southwest University, Chongqing 400716, China.
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Yin J, Fu Y, Rao G, Li Z, Tian K, Chong T, Kuang K, Wang M, Hu Z, Cao S. Structural transitions during the cooperative assembly of baculovirus single-stranded DNA-binding protein on ssDNA. Nucleic Acids Res 2022; 50:13100-13113. [PMID: 36477586 PMCID: PMC9825184 DOI: 10.1093/nar/gkac1142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/28/2022] [Accepted: 11/16/2022] [Indexed: 12/12/2022] Open
Abstract
Single-stranded DNA-binding proteins (SSBs) interact with single-stranded DNA (ssDNA) to form filamentous structures with various degrees of cooperativity, as a result of intermolecular interactions between neighboring SSB subunits on ssDNA. However, it is still challenging to perform structural studies on SSB-ssDNA filaments at high resolution using the most studied SSB models, largely due to the intrinsic flexibility of these nucleoprotein complexes. In this study, HaLEF-3, an SSB protein from Helicoverpa armigera nucleopolyhedrovirus, was used for in vitro assembly of SSB-ssDNA filaments, which were structurally studied at atomic resolution using cryo-electron microscopy. Combined with the crystal structure of ssDNA-free HaLEF-3 octamers, our results revealed that the three-dimensional rearrangement of HaLEF-3 induced by an internal hinge-bending movement is essential for the formation of helical SSB-ssDNA complexes, while the contacting interface between adjacent HaLEF-3 subunits remains basically intact. We proposed a local cooperative SSB-ssDNA binding model, in which, triggered by exposure to oligonucleotides, HaLEF-3 molecules undergo ring-to-helix transition to initiate continuous SSB-SSB interactions along ssDNA. Unique structural features revealed by the assembly of HaLEF-3 on ssDNA suggest that HaLEF-3 may represent a new class of SSB.
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Affiliation(s)
| | | | | | - Zhiqiang Li
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, PR China,University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Kexing Tian
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, PR China,University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Tingting Chong
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, PR China,University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Kai Kuang
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, PR China,University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Manli Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety, Mega-Science, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Zhihong Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety, Mega-Science, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Sheng Cao
- To whom correspondence should be addressed. Tel: +86 27 87198286; Fax: +86 27 87198286;
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Wright LR, Wright DL, Weller SK. Viral Nucleases from Herpesviruses and Coronavirus in Recombination and Proofreading: Potential Targets for Antiviral Drug Discovery. Viruses 2022; 14:v14071557. [PMID: 35891537 PMCID: PMC9324378 DOI: 10.3390/v14071557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 02/05/2023] Open
Abstract
In this review, we explore recombination in two very different virus families that have become major threats to human health. The Herpesviridae are a large family of pathogenic double-stranded DNA viruses involved in a range of diseases affecting both people and animals. Coronaviridae are positive-strand RNA viruses (CoVs) that have also become major threats to global health and economic stability, especially in the last two decades. Despite many differences, such as the make-up of their genetic material (DNA vs. RNA) and overall mechanisms of genome replication, both human herpes viruses (HHVs) and CoVs have evolved to rely heavily on recombination for viral genome replication, adaptation to new hosts and evasion of host immune regulation. In this review, we will focus on the roles of three viral exonucleases: two HHV exonucleases (alkaline nuclease and PolExo) and one CoV exonuclease (ExoN). We will review the roles of these three nucleases in their respective life cycles and discuss the state of drug discovery efforts against these targets.
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Affiliation(s)
- Lee R. Wright
- Department of Pharmaceutical Sciences, University of Connecticut School of Pharmacy, Storrs, CT 06269, USA; (L.R.W.); (D.L.W.)
| | - Dennis L. Wright
- Department of Pharmaceutical Sciences, University of Connecticut School of Pharmacy, Storrs, CT 06269, USA; (L.R.W.); (D.L.W.)
| | - Sandra K. Weller
- Department of Molecular Biology and Biophysics, University of Connecticut School of Medicine, 263 Farmington Ave., Farmington, CT 06030, USA
- Correspondence: ; Tel.: +1-(860)-679-2310; Fax: +1-(860)-679-1239
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Gao X, Lei J, Zhu Y, Chen X, Mao F, Miao M, Quan Y, Yu W. Role of the Bombyx mori nucleopolyhedrovirus LEF3 acetylation on viral replication. Microb Pathog 2021; 158:105109. [PMID: 34314811 DOI: 10.1016/j.micpath.2021.105109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/15/2021] [Accepted: 07/20/2021] [Indexed: 11/25/2022]
Abstract
Late expression factor 3 (LEF3) is a single-stranded DNA binding protein of Bombyx mori nucleopolyhedrovirus (BmNPV) with multiple functions. It is an essential factor for viral DNA replication and plays an important regulatory role during BmNPV infection. Our recent quantitative analysis of protein acetylome revealed for the first time that LEF3 can be acetylated at four lysine residues during the viral infection, but the underlying mechanism is unknown. Among the modification sites, two of them (K18 and K27) are located in the conserved nuclear localization sequence region. The acetylation level for K18 especially was up-regulated approximately 7.4 times after 36 h of post-infection. To understand the regulatory function of this modification, site-direct mutagenesis for acetylated mimic (K18Q) or deacetylated mimic (K18R) mutants was performed on LEF3. The fluorescence analysis results showed that the replication capacity of the virus was significantly reduced after K18 acetylation. Meanwhile, co-localization analysis revealed that acetylation at K18 caused LEF3 to lose its nuclear targeting ability and affected the interaction between LEF3 and P143, retaining P143 in the cytoplasm. And further Yeast two-hybrid analysis results also confirmed that the acetylation at K18 did affect the interaction between LEF3 and P143. In conclusion, the acetylation of LEF3 at K18 might act as one of the antiviral strategies for silkworm host by affecting nuclear localization of LEF3, interaction with P143, and then blocking viral replication.
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Affiliation(s)
- Xu Gao
- Institute of Biochemistry, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang Province, Hangzhou, 310018, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Zhejiang Province, Hangzhou, 310018, PR China
| | - Jihai Lei
- Institute of Biochemistry, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang Province, Hangzhou, 310018, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Zhejiang Province, Hangzhou, 310018, PR China
| | - Yajie Zhu
- Institute of Biochemistry, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang Province, Hangzhou, 310018, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Zhejiang Province, Hangzhou, 310018, PR China
| | - Xi Chen
- Institute of Biochemistry, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang Province, Hangzhou, 310018, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Zhejiang Province, Hangzhou, 310018, PR China
| | - Fuxiang Mao
- Institute of Biochemistry, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang Province, Hangzhou, 310018, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Zhejiang Province, Hangzhou, 310018, PR China
| | - Meng Miao
- Institute of Biochemistry, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang Province, Hangzhou, 310018, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Zhejiang Province, Hangzhou, 310018, PR China
| | - Yanping Quan
- Institute of Biochemistry, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang Province, Hangzhou, 310018, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Zhejiang Province, Hangzhou, 310018, PR China
| | - Wei Yu
- Institute of Biochemistry, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Zhejiang Province, Hangzhou, 310018, PR China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Zhejiang Province, Hangzhou, 310018, PR China.
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Nucleocapsid Assembly of Baculoviruses. Viruses 2019; 11:v11070595. [PMID: 31266177 PMCID: PMC6669607 DOI: 10.3390/v11070595] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 06/27/2019] [Accepted: 06/30/2019] [Indexed: 01/27/2023] Open
Abstract
The baculovirus nucleocapsid is formed through a rod-like capsid encapsulating a genomic DNA molecule of 80~180 kbp. The viral capsid is a large oligomer composed of many copies of various protein subunits. The assembly of viral capsids is a complex oligomerization process. The timing of expression of nucleocapsid-related proteins, transport pathways, and their interactions can affect the assembly process of preformed capsids. In addition, the selection of viral DNA and the injection of the viral genome into empty capsids are the critical steps in nucleocapsid assembly. This paper reviews the replication and recombination of baculovirus DNA, expression and transport of capsid proteins, formation of preformed capsids, DNA encapsulation, and nucleocapsid formation. This review will provide a basis for further study of the nucleocapsid assembly mechanism of baculovirus.
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Global Analysis of Baculovirus Autographa californica Multiple Nucleopolyhedrovirus Gene Expression in the Midgut of the Lepidopteran Host Trichoplusia ni. J Virol 2018; 92:JVI.01277-18. [PMID: 30209166 DOI: 10.1128/jvi.01277-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 08/16/2018] [Indexed: 01/01/2023] Open
Abstract
The baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a large double-stranded DNA (dsDNA) virus that encodes approximately 156 genes and is highly pathogenic to a variety of larval lepidopteran insects in nature. Oral infection of larval midgut cells is initiated by the occlusion-derived virus (ODV), while secondary infection of other tissues is mediated by the budded virus (BV). Global viral gene expression has been studied in detail in BV-infected cell cultures, but studies of ODV infection in the larval midgut are limited. In this study, we examined expression of the ∼156 AcMNPV genes in Trichoplusia ni midgut tissue using a transcriptomic approach. We analyzed expression profiles of viral genes in the midgut and compared them with profiles from a T. ni cell line (Tnms42). Several viral genes (p6.9, orf76, orf75, pp31, Ac-bro, odv-e25, and odv-ec27) had high expression levels in the midgut throughout the infection. Also, the expression of genes associated with occlusion bodies (polh and p10) appeared to be delayed in the midgut in comparison with the cell line. Comparisons of viral gene expression profiles revealed remarkable similarities between the midgut and cell line for most genes, although substantial differences were observed for some viral genes. These included genes associated with high level BV production (fp-25k), acceleration of systemic infection (v-fgf), and enhancement of viral movement (arif-1/orf20). These differential expression patterns appear to represent specific adaptations for virus infection and transmission through the polarized cells of the lepidopteran midgut.IMPORTANCE Baculoviruses such as AcMNPV are pathogens that are natural regulators of certain insect populations. Baculovirus infections are biphasic, with a primary phase initiated by oral infection of midgut epithelial cells by occlusion-derived virus (ODV) virions and a secondary phase in which other tissues are infected by budded-virus (BV) virions. While AcMNPV infections in cultured cells have been studied extensively, comparatively little is known regarding primary infection in the midgut. In these studies, we identified gene expression patterns associated with ODV-mediated infection of the midgut in Trichoplusia ni and compared those results with prior results from BV-infected cultured cells, which simulate secondary infection. These studies provide a detailed analysis of viral gene expression patterns in the midgut, which likely represent specific viral strategies to (i) overcome or avoid host defenses in the gut and (ii) rapidly move infection from the midgut, into the hemocoel to facilitate systemic infection.
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Dizman YA, Muratoglu H, Sandalli C, Nalcacioglu R, Demirbag Z. Chilo iridescent virus (CIV) ORF 012L encodes a protein with both exonuclease and endonuclease functions. Arch Virol 2016; 161:3029-37. [PMID: 27496102 DOI: 10.1007/s00705-016-3007-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 08/01/2016] [Indexed: 10/21/2022]
Abstract
Chilo iridescent virus (CIV) is the type member of the genus Iridovirus within the family Iridoviridae. The virions of CIV contain a single linear dsDNA molecule that is circularly permuted and terminally redundant. The genome of CIV contains an open reading frame (ORF 012L) encoding a protein homologous to exonuclease II of Schizosaccharomyces pombe. In this study, we focused on the characterization of CIV ORF 012L. The target ORF was cloned into the pET28a vector, expressed in E. coli strain BL21 (DE3) pLysS with an N-terminal His tag and purified to homogeneity by using Ni-NTA affinity chromatography. Biochemical characterization of the purified CIV 012L confirmed that this viral protein is a functional 5'-3' exonuclease that digests 3'-biotin-labelled oligonucleotides and linear double-stranded DNA (dsDNA) molecules from their 5' termini in a highly processive manner. CIV 012L also has a potent endonuclease activity on dsDNA in vitro. In addition, CIV 012L converted supercoiled plasmid DNA (replicative form I, RFI) into the open circular form (RFII) and then open circular form into linear form (RFIII). Endonuclease activity of CIV 012L was optimal in the presence of 10 mM Mg(2+) or 30 mM Mn(2+) ions and at 150 mM NaCl or KCl salt concentrations. The highest endonuclease activity was obtained at pH 8, and it reached a maximum at 55 °C. The CIV 012L protein showed deficiencies for both double- and single-stranded RNAs.
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Affiliation(s)
- Yesim Akturk Dizman
- Department of Biology, Faculty of Sciences, Karadeniz Technical University, 61080, Trabzon, Turkey.,Department of Biology, Faculty of Arts and Sciences, Recep Tayyip Erdoğan University, 53100, Rize, Turkey
| | - Hacer Muratoglu
- Department of Molecular Biology and Genetic, Faculty of Sciences, Karadeniz Technical University, 61080, Trabzon, Turkey
| | - Cemal Sandalli
- Department of Biology, Faculty of Arts and Sciences, Recep Tayyip Erdoğan University, 53100, Rize, Turkey
| | - Remziye Nalcacioglu
- Department of Biology, Faculty of Sciences, Karadeniz Technical University, 61080, Trabzon, Turkey.
| | - Zihni Demirbag
- Department of Biology, Faculty of Sciences, Karadeniz Technical University, 61080, Trabzon, Turkey
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Craveiro SR, Inglis PW, Togawa RC, Grynberg P, Melo FL, Ribeiro ZMA, Ribeiro BM, Báo SN, Castro MEB. The genome sequence of Pseudoplusia includens single nucleopolyhedrovirus and an analysis of p26 gene evolution in the baculoviruses. BMC Genomics 2015; 16:127. [PMID: 25765042 PMCID: PMC4346127 DOI: 10.1186/s12864-015-1323-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 02/04/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pseudoplusia includens single nucleopolyhedrovirus (PsinSNPV-IE) is a baculovirus recently identified in our laboratory, with high pathogenicity to the soybean looper, Chrysodeixis includens (Lepidoptera: Noctuidae) (Walker, 1858). In Brazil, the C. includens caterpillar is an emerging pest and has caused significant losses in soybean and cotton crops. The PsinSNPV genome was determined and the phylogeny of the p26 gene within the family Baculoviridae was investigated. RESULTS The complete genome of PsinSNPV was sequenced (Roche 454 GS FLX - Titanium platform), annotated and compared with other Alphabaculoviruses, displaying a genome apparently different from other baculoviruses so far sequenced. The circular double-stranded DNA genome is 139,132 bp in length, with a GC content of 39.3 % and contains 141 open reading frames (ORFs). PsinSNPV possesses the 37 conserved baculovirus core genes, 102 genes found in other baculoviruses and 2 unique ORFs. Two baculovirus repeat ORFs (bro) homologs, bro-a (Psin33) and bro-b (Psin69), were identified and compared with Chrysodeixis chalcites nucleopolyhedrovirus (ChchNPV) and Trichoplusia ni single nucleopolyhedrovirus (TnSNPV) bro genes and showed high similarity, suggesting that these genes may be derived from an ancestor common to these viruses. The homologous repeats (hrs) are absent from the PsinSNPV genome, which is also the case in ChchNPV and TnSNPV. Two p26 gene homologs (p26a and p26b) were found in the PsinSNPV genome. P26 is thought to be required for optimal virion occlusion in the occlusion bodies (OBs), but its function is not well characterized. The P26 phylogenetic tree suggests that this gene was obtained from three independent acquisition events within the Baculoviridae family. The presence of a signal peptide only in the PsinSNPV p26a/ORF-20 homolog indicates distinct function between the two P26 proteins. CONCLUSIONS PsinSNPV has a genomic sequence apparently different from other baculoviruses sequenced so far. The complete genome sequence of PsinSNPV will provide a valuable resource, contributing to studies on its molecular biology and functional genomics, and will promote the development of this virus as an effective bioinsecticide.
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Affiliation(s)
- Saluana R Craveiro
- Embrapa Recursos Genéticos e Biotecnologia, Parque Estação Biológica, W5 Norte Final, 70770-917, Brasília, DF, Brazil.
- Departamento de Biologia Celular, Universidade de Brasília-UnB, Brasília, DF, Brazil.
| | - Peter W Inglis
- Embrapa Recursos Genéticos e Biotecnologia, Parque Estação Biológica, W5 Norte Final, 70770-917, Brasília, DF, Brazil.
| | - Roberto C Togawa
- Embrapa Recursos Genéticos e Biotecnologia, Parque Estação Biológica, W5 Norte Final, 70770-917, Brasília, DF, Brazil.
| | - Priscila Grynberg
- Embrapa Recursos Genéticos e Biotecnologia, Parque Estação Biológica, W5 Norte Final, 70770-917, Brasília, DF, Brazil.
| | - Fernando L Melo
- Departamento de Biologia Celular, Universidade de Brasília-UnB, Brasília, DF, Brazil.
| | - Zilda Maria A Ribeiro
- Embrapa Recursos Genéticos e Biotecnologia, Parque Estação Biológica, W5 Norte Final, 70770-917, Brasília, DF, Brazil.
| | - Bergmann M Ribeiro
- Departamento de Biologia Celular, Universidade de Brasília-UnB, Brasília, DF, Brazil.
| | - Sônia N Báo
- Departamento de Biologia Celular, Universidade de Brasília-UnB, Brasília, DF, Brazil.
| | - Maria Elita B Castro
- Embrapa Recursos Genéticos e Biotecnologia, Parque Estação Biológica, W5 Norte Final, 70770-917, Brasília, DF, Brazil.
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Liu X, Yin F, Zhu Z, Hou D, Wang J, Zhang L, Wang M, Wang H, Hu Z, Deng F. Genomic sequencing and analysis of Sucra jujuba nucleopolyhedrovirus. PLoS One 2014; 9:e110023. [PMID: 25329074 PMCID: PMC4201490 DOI: 10.1371/journal.pone.0110023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 09/08/2014] [Indexed: 11/19/2022] Open
Abstract
The complete nucleotide sequence of Sucra jujuba nucleopolyhedrovirus (SujuNPV) was determined by 454 pyrosequencing. The SujuNPV genome was 135,952 bp in length with an A+T content of 61.34%. It contained 131 putative open reading frames (ORFs) covering 87.9% of the genome. Among these ORFs, 37 were conserved in all baculovirus genomes that have been completely sequenced, 24 were conserved in lepidopteran baculoviruses, 65 were found in other baculoviruses, and 5 were unique to the SujuNPV genome. Seven homologous regions (hrs) were identified in the SujuNPV genome. SujuNPV contained several genes that were duplicated or copied multiple times: two copies of helicase, DNA binding protein gene (dbp), p26 and cg30, three copies of the inhibitor of the apoptosis gene (iap), and four copies of the baculovirus repeated ORF (bro). Phylogenetic analysis suggested that SujuNPV belongs to a subclade of group II alphabaculovirus, which differs from other baculoviruses in that all nine members of this subclade contain a second copy of dbp.
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Affiliation(s)
- Xiaoping Liu
- State Key Laboratory of Virology, Virus Resource and Bioinformatics Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Feifei Yin
- State Key Laboratory of Virology, Virus Resource and Bioinformatics Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Zheng Zhu
- State Key Laboratory of Virology, Virus Resource and Bioinformatics Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Dianhai Hou
- State Key Laboratory of Virology, Virus Resource and Bioinformatics Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Jun Wang
- State Key Laboratory of Virology, Virus Resource and Bioinformatics Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Lei Zhang
- State Key Laboratory of Virology, Virus Resource and Bioinformatics Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Manli Wang
- State Key Laboratory of Virology, Virus Resource and Bioinformatics Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Hualin Wang
- State Key Laboratory of Virology, Virus Resource and Bioinformatics Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Zhihong Hu
- State Key Laboratory of Virology, Virus Resource and Bioinformatics Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Fei Deng
- State Key Laboratory of Virology, Virus Resource and Bioinformatics Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
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Braconi CT, Ardisson-Araújo DMP, Leme AFP, Oliveira JVDC, Pauletti BA, Garcia-Maruniak A, Ribeiro BM, Maruniak JE, Zanotto PMDA. Proteomic analyses of baculovirus Anticarsia gemmatalis multiple nucleopolyhedrovirus budded and occluded virus. J Gen Virol 2014; 95:980-989. [PMID: 24443474 DOI: 10.1099/vir.0.061127-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Baculoviruses infect insects, producing two distinct phenotypes during the viral life cycle: the budded virus (BV) and the occlusion-derived virus (ODV) for intra- and inter-host spread, respectively. Since the 1980s, several countries have been using Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) as a biological control agent against the velvet bean caterpillar, A. gemmatalis. The genome of AgMNPV isolate 2D (AgMNPV-2D) carries at least 152 potential genes, with 24 that possibly code for structural proteins. Proteomic studies have been carried out on a few baculoviruses, with six ODV and two BV proteomes completed so far. Moreover, there are limited data on virion proteins carried by AgMNPV-2D. Therefore, structural proteins of AgMNPV-2D were analysed by MALDI- quadrupole-TOF and liquid chromatography MS/MS. A total of 44 proteins were associated with the ODV and 33 with the BV of AgMNPV-2D. Although 38 structural proteins were already known, we found six new proteins in the ODV and seven new proteins carried by the AgMNPV-2D BV. Eleven cellular proteins that were found on several other enveloped viruses were also identified, which are possibly carried with the virion. These findings may provide novel insights into baculovirus biology and their host interaction. Moreover, our data may be helpful in subsequent applied studies aiming to improve AgMNPV use as a biopesticide and a biotechnology tool for gene expression or delivery.
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Affiliation(s)
- Carla Torres Braconi
- Laboratory of Molecular Evolution and Bioinformatics, Department of Microbiology, Biomedical Sciences Institute - ICB II, University of São Paulo - USP, Brazil
| | | | - Adriana Franco Paes Leme
- Laboratory of Mass Spectrometry, Brazilian Biosciences National Laboratory - LNBio - CNPEM, Campinas - SP, Brazil
| | - Juliana Velasco de Castro Oliveira
- Laboratory of Molecular Evolution and Bioinformatics, Department of Microbiology, Biomedical Sciences Institute - ICB II, University of São Paulo - USP, Brazil
| | - Bianca Alves Pauletti
- Laboratory of Mass Spectrometry, Brazilian Biosciences National Laboratory - LNBio - CNPEM, Campinas - SP, Brazil
| | - Alejandra Garcia-Maruniak
- Insect Virology Laboratory, Entomology and Nematology Department, 970 Natural Area Dr., University of Florida, Gainesville, FL 32611, USA
| | | | - James E Maruniak
- Insect Virology Laboratory, Entomology and Nematology Department, 970 Natural Area Dr., University of Florida, Gainesville, FL 32611, USA
| | - Paolo Marinho de Andrade Zanotto
- Laboratory of Molecular Evolution and Bioinformatics, Department of Microbiology, Biomedical Sciences Institute - ICB II, University of São Paulo - USP, Brazil
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Wu Y, Wu Y, Wu Y, Tang H, Wu H, Zhang G, Wang W. Screening of candidate proteins interacting with IE-2 of Bombyx mori nucleopolyhedrovirus. Mol Biol Rep 2013; 40:5797-804. [DOI: 10.1007/s11033-013-2683-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Accepted: 09/14/2013] [Indexed: 10/26/2022]
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Downie K, Adetola G, Carstens EB. Characterization of protein-protein interaction domains within the baculovirus Autographa californica multiple nucleopolyhedrovirus late expression factor LEF-3. J Gen Virol 2013; 94:2530-2535. [PMID: 23997180 DOI: 10.1099/vir.0.056267-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Autographa californica nucleopolyhedrovirus late expression factor 3 (LEF-3) is required for late viral gene expression probably through its numerous functions related to DNA replication, including nuclear localization of the virus helicase P143 and binding to ssDNA. LEF-3 appears to interact with itself as a homo-oligomer, although the details of this oligomeric structure are not yet known. To examine LEF-3-LEF-3 interactions, a bimolecular fluorescent protein complementation assay was used. Pairs of recombinant plasmids expressing full-length LEF-3 fused to one of two complementary fragments (V1 or V2) of a variant of yellow fluorescent protein named 'Venus' were constructed. Plasmids expressing fusions with complementary fragments of Venus were co-transfected into Sf21 cells and analysed by fluorescence microscopy. Co-transfected plasmids expressing full-length V1-LEF-3 and V2-LEF-3 showed positive fluorescence, confirming the formation of homo-oligomers. A series of truncated V1/V2-LEF-3 fusions was constructed and used to investigate interactions with one another as well as with full-length LEF-3.
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Affiliation(s)
- Kelsey Downie
- Department of Biomedical and Molecular Sciences Queen's University Kingston, ON K7L 3N6 Canada
| | - Gbolagade Adetola
- Department of Biomedical and Molecular Sciences Queen's University Kingston, ON K7L 3N6 Canada
| | - Eric B Carstens
- Department of Biomedical and Molecular Sciences Queen's University Kingston, ON K7L 3N6 Canada
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Cérutti M, Golay J. Lepidopteran cells, an alternative for the production of recombinant antibodies? MAbs 2012; 4:294-309. [PMID: 22531440 DOI: 10.4161/mabs.19942] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Monoclonal antibodies are used with great success in many different therapeutic domains. In order to satisfy the growing demand and to lower the production cost of these molecules, many alternative systems have been explored. Among them, the baculovirus/insect cells system is a good candidate. This system is very safe, given that the baculoviruses have a highly restricted host range and they are not pathogenic to vertebrates or plants. But the major asset is the speed with which it is possible to obtain very stable recombinant viruses capable of producing fully active proteins whose glycosylation pattern can be modulated to make it similar to the human one. These features could ultimately make the difference by enabling the production of antibodies with very low costs. However, efforts are still needed, in particular to increase production rates and thus make this system commercially viable for the production of these therapeutic agents.
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Affiliation(s)
- Martine Cérutti
- CNRS UPS3044 Baculovirus et Thérapie, CNRS GDR3260, ACCITH Anticorps et Ciblage Thérapeutique and LabEx MabImprove, Saint Christol Lèz Alès, France.
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Analysis of the autographa californica multiple nucleopolyhedrovirus overlapping gene pair lef3 and ac68 reveals that AC68 is a per os infectivity factor and that LEF3 is critical, but not essential, for virus replication. J Virol 2012; 86:3985-94. [PMID: 22278232 DOI: 10.1128/jvi.06849-11] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Autographa californica multiple nucleopolyhedrovirus ac68 is a core gene that overlaps lef3 which encodes the single-stranded DNA binding protein. A knockout (KO) virus lacking both lef3 and ac68 was generated (lef3-ac68 2×KO) to enable the functional study of ac68. To produce an ac68KO virus that did not impact lef3 expression, the lef3-ac68 2×KO virus was repaired with a DNA fragment containing lef3 and ac68, in which ac68 contained point mutations so that only LEF3 was expressed. Repair of lef3-ac68 2×KO with just ac68 generated an lef3KO virus. Analysis of the ac68KO virus showed that viral DNA replication and budded virus (BV) levels were unaffected compared to levels in the double-repair or wild-type (WT) control virus. Bioassay analyses of Trichoplusia ni larvae injected with BV directly into the hemolymph, bypassing the gut, showed no difference in mortality rates between the ac68KO and the WT viruses. However, in oral bioassays the ac68KO occlusion bodies failed to kill larvae. These results show that the core gene ac68 encodes a per os infectivity factor (pif6). The lef3KO virus was also analyzed, and virus replication was drastically reduced compared to WT virus, but very low levels of lef3KO virus DNA replication and BV production could be detected. In addition, in transfected cells P143 was transported to the nucleus in the absence of LEF3. This study therefore shows for the first time that even though the loss of LEF3 severely impairs virus replication, it is not absolutely essential for P143 nuclear import or viral replication.
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Burand JP, Kim W, Afonso CL, Tulman ER, Kutish GF, Lu Z, Rock DL. Analysis of the genome of the sexually transmitted insect virus Helicoverpa zea nudivirus 2. Viruses 2012; 4:28-61. [PMID: 22355451 PMCID: PMC3280521 DOI: 10.3390/v4010028] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 12/30/2011] [Accepted: 12/31/2011] [Indexed: 01/10/2023] Open
Abstract
The sexually transmitted insect virus Helicoverpa zea nudivirus 2 (HzNV-2) was determined to have a circular double-stranded DNA genome of 231,621 bp coding for an estimated 113 open reading frames (ORFs). HzNV-2 is most closely related to the nudiviruses, a sister group of the insect baculoviruses. Several putative ORFs that share homology with the baculovirus core genes were identified in the viral genome. However, HzNV-2 lacks several key genetic features of baculoviruses including the late transcriptional regulation factor, LEF-1 and the palindromic hrs, which serve as origins of replication. The HzNV-2 genome was found to code for three ORFs that had significant sequence homology to cellular genes which are not generally found in viral genomes. These included a presumed juvenile hormone esterase gene, a gene coding for a putative zinc-dependent matrix metalloprotease, and a major facilitator superfamily protein gene; all of which are believed to play a role in the cellular proliferation and the tissue hypertrophy observed in the malformation of reproductive organs observed in HzNV-2 infected corn earworm moths, Helicoverpa zea.
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Affiliation(s)
- John P. Burand
- Department of Plant, Soil and Insect Sciences, University of Massachusetts Amherst, Amherst, MA 01003, USA;
| | - Woojin Kim
- Department of Plant, Soil and Insect Sciences, University of Massachusetts Amherst, Amherst, MA 01003, USA;
| | - Claudio L. Afonso
- Plum Island Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY 11944, USA; (C.L.A.); (E.R.T.); (G.F.K.); (Z.L.); (D.L.R.)
| | - Edan R. Tulman
- Plum Island Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY 11944, USA; (C.L.A.); (E.R.T.); (G.F.K.); (Z.L.); (D.L.R.)
| | - Gerald F. Kutish
- Plum Island Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY 11944, USA; (C.L.A.); (E.R.T.); (G.F.K.); (Z.L.); (D.L.R.)
| | - Zhiqiang Lu
- Plum Island Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY 11944, USA; (C.L.A.); (E.R.T.); (G.F.K.); (Z.L.); (D.L.R.)
| | - Daniel L. Rock
- Plum Island Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Greenport, NY 11944, USA; (C.L.A.); (E.R.T.); (G.F.K.); (Z.L.); (D.L.R.)
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Chen WY, Ho JW, Huang JD, Watt RM. Functional characterization of an alkaline exonuclease and single strand annealing protein from the SXT genetic element of Vibrio cholerae. BMC Mol Biol 2011; 12:16. [PMID: 21501469 PMCID: PMC3118119 DOI: 10.1186/1471-2199-12-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 04/18/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND SXT is an integrating conjugative element (ICE) originally isolated from Vibrio cholerae, the bacterial pathogen that causes cholera. It houses multiple antibiotic and heavy metal resistance genes on its ca. 100 kb circular double stranded DNA (dsDNA) genome, and functions as an effective vehicle for the horizontal transfer of resistance genes within susceptible bacterial populations. Here, we characterize the activities of an alkaline exonuclease (S066, SXT-Exo) and single strand annealing protein (S065, SXT-Bet) encoded on the SXT genetic element, which share significant sequence homology with Exo and Bet from bacteriophage lambda, respectively. RESULTS SXT-Exo has the ability to degrade both linear dsDNA and single stranded DNA (ssDNA) molecules, but has no detectable endonuclease or nicking activities. Adopting a stable trimeric arrangement in solution, the exonuclease activities of SXT-Exo are optimal at pH 8.2 and essentially require Mn2+ or Mg2+ ions. Similar to lambda-Exo, SXT-Exo hydrolyzes dsDNA with 5'- to 3'-polarity in a highly processive manner, and digests DNA substrates with 5'-phosphorylated termini significantly more effectively than those lacking 5'-phosphate groups. Notably, the dsDNA exonuclease activities of both SXT-Exo and lambda-Exo are stimulated by the addition of lambda-Bet, SXT-Bet or a single strand DNA binding protein encoded on the SXT genetic element (S064, SXT-Ssb). When co-expressed in E. coli cells, SXT-Bet and SXT-Exo mediate homologous recombination between a PCR-generated dsDNA fragment and the chromosome, analogous to RecET and lambda-Bet/Exo. CONCLUSIONS The activities of the SXT-Exo protein are consistent with it having the ability to resect the ends of linearized dsDNA molecules, forming partially ssDNA substrates for the partnering SXT-Bet single strand annealing protein. As such, SXT-Exo and SXT-Bet may function together to repair or process SXT genetic elements within infected V. cholerae cells, through facilitating homologous DNA recombination events. The results presented here significantly extend our general understanding of the properties and activities of alkaline exonuclease and single strand annealing proteins of viral/bacteriophage origin, and will assist the rational development of bacterial recombineering systems.
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Affiliation(s)
- Wen-yang Chen
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, Hong Kong
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Miele SAB, Garavaglia MJ, Belaich MN, Ghiringhelli PD. Baculovirus: molecular insights on their diversity and conservation. INTERNATIONAL JOURNAL OF EVOLUTIONARY BIOLOGY 2011; 2011:379424. [PMID: 21716740 PMCID: PMC3119482 DOI: 10.4061/2011/379424] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 01/04/2011] [Accepted: 02/14/2011] [Indexed: 12/11/2022]
Abstract
The Baculoviridae is a large group of insect viruses containing circular double-stranded DNA genomes of 80 to 180 kbp. In this study, genome sequences from 57 baculoviruses were analyzed to reevaluate the number and identity of core genes and to understand the distribution of the remaining coding sequences. Thirty one core genes with orthologs in all genomes were identified along with other 895 genes differing in their degrees of representation among reported genomes. Many of these latter genes are common to well-defined lineages, whereas others are unique to one or a few of the viruses. Phylogenetic analyses based on core gene sequences and the gene composition of the genomes supported the current division of the Baculoviridae into 4 genera: Alphabaculovirus, Betabaculovirus, Gammabaculovirus, and Deltabaculovirus.
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Affiliation(s)
- Solange Ana Belen Miele
- LIGBCM (Laboratorio de Ingeniería Genética y Biología Celular y Molecular), Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Roque Saenz Peña 352, Bernal, Argentina
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Identification of a domain of the baculovirus Autographa californica multiple nucleopolyhedrovirus single-strand DNA-binding protein LEF-3 essential for viral DNA replication. J Virol 2010; 84:6153-62. [PMID: 20357098 DOI: 10.1128/jvi.00115-10] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Autographa californica multiple nucleopolyhedrovirus (AcMNPV) lef-3 is one of nine genes required for viral DNA replication in transient assays. LEF-3 is predicted to contain several domains related to its functions, including nuclear localization, single-strand DNA binding, oligomerization, interaction with P143 helicase, and interaction with a viral alkaline nuclease. To investigate the essential nature of LEF-3 and the roles it may play during baculovirus DNA replication, a lef-3 null bacmid (bKO-lef3) was constructed in Escherichia coli and characterized in Sf21 cells. The results showed that AcMNPV lef-3 is essential for DNA replication, budded virus production, and late gene expression in vivo. Cells transfected with the lef-3 knockout bacmid produced low levels of early proteins (P143, DNA polymerase, and early GP64) and no late proteins (P47, VP39, or late GP64). To investigate the functional role of domains within the LEF-3 open reading frame in the presence of the whole viral genome, plasmids expressing various LEF-3 truncations were transfected into Sf21 cells together with bKO-lef3 DNA. The results showed that expression of AcMNPV LEF-3 amino acids 1 to 125 was sufficient to stimulate viral DNA replication and to support late gene expression. Expression of Choristoneura fumiferana MNPV lef-3 did not rescue any LEF-3 functions. The construction of a LEF-3 amino acid 1 to 125 rescue bacmid revealed that this region of LEF-3, when expressed in the presence of the rest of the viral genome, stimulated viral DNA replication and late and very late protein expression, as well as budded virus production.
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Peng K, Wu M, Deng F, Song J, Dong C, Wang H, Hu Z. Identification of protein-protein interactions of the occlusion-derived virus-associated proteins of Helicoverpa armigera nucleopolyhedrovirus. J Gen Virol 2009; 91:659-70. [PMID: 19906939 DOI: 10.1099/vir.0.017103-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The purpose of this study was to identify protein-protein interactions among the components of the occlusion-derived virus (ODV) of Helicoverpa armigera nucleopolyhedrovirus (HearNPV), a group II alphabaculovirus in the family Baculoviridae. To achieve this, 39 selected genes of potential ODV structural proteins were cloned and expressed in the Gal4 yeast two-hybrid (Y2H) system. The direct-cross Y2H assays identified 22 interactions comprising 13 binary interactions [HA9-ODV-EC43, ODV-E56-38K, ODV-E56-PIF3, LEF3-helicase, LEF3-alkaline nuclease (AN), GP41-38K, GP41-HA90, 38K-PIF3, 38K-PIF2, VP80-HA100, ODV-E66-PIF3, ODV-E66-PIF2 and PIF3-PIF2] and nine self-associations (IE1, HA44, LEF3, HA66, GP41, CG30, 38K, PIF3 and P24). Five of these interactions - LEF3-helicase and LEF3-AN, and the self-associations of IE1, LEF3 and 38K - have been reported previously in Autographa californica multiple nucleopolyhedrovirus. As HA44 and HA100 were two newly identified ODV proteins of group II viruses, their interactions were further confirmed. The self-association of HA44 was verified with a His pull-down assay and the interaction of VP80-HA100 was confirmed by a co-immunoprecipitation assay. A summary of the protein-protein interactions of baculoviruses reported so far, comprising 68 interactions with 45 viral proteins and five host proteins, is presented, which will facilitate our understanding of the molecular mechanisms of baculovirus infection.
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Affiliation(s)
- Ke Peng
- State Key Laboratory of Virology and Joint Laboratory of Invertebrate Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, PR China
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Cohen DPA, Marek M, Davies BG, Vlak JM, van Oers MM. Encyclopedia of Autographa californica nucleopolyhedrovirus genes. Virol Sin 2009. [DOI: 10.1007/s12250-009-3059-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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Noad RJ, Stewart M, Boyce M, Celma CC, Willison KR, Roy P. Multigene expression of protein complexes by iterative modification of genomic Bacmid DNA. BMC Mol Biol 2009; 10:87. [PMID: 19725957 PMCID: PMC2749033 DOI: 10.1186/1471-2199-10-87] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Accepted: 09/02/2009] [Indexed: 02/26/2023] Open
Abstract
Background Many cellular multi-protein complexes are naturally present in cells at low abundance. Baculovirus expression offers one approach to produce milligram quantities of correctly folded and processed eukaryotic protein complexes. However, current strategies suffer from the need to produce large transfer vectors, and the use of repeated promoter sequences in baculovirus, which itself produces proteins that promote homologous recombination. One possible solution to these problems is to construct baculovirus genomes that express each protein in a complex from a separate locus within the viral DNA. However current methods for selecting such recombinant genomes are too inefficient to routinely modify the virus in this way. Results This paper reports a method which combines the lambda red and bacteriophage P1 Cre-recombinase systems to efficiently generate baculoviruses in which protein complexes are expressed from multiple, single-locus insertions of foreign genes. This method is based on an 88 fold improvement in the selection of recombinant viruses generated by red recombination techniques through use of a bipartite selection cassette. Using this system, seven new genetic loci were identified in the AcMNPV genome suitable for the high level expression of recombinant proteins. These loci were used to allow the recovery two recombinant virus-like particles with potential biotechnological applications (influenza A virus HA/M1 particles and bluetongue virus VP2/VP3/VP5/VP7 particles) and the mammalian chaperone and cancer drug target CCT (16 subunits formed from 8 proteins). Conclusion 1. Use of bipartite selections can significantly improve selection of modified bacterial artificial chromosomes carrying baculovirus DNA. Furthermore this approach is sufficiently robust to allow routine modification of the virus genome. 2. In addition to the commonly used p10 and polyhedrin loci, the ctx, egt, 39k, orf51, gp37, iap2 and odv-e56 loci in AcMNPV are all suitable for the high level expression of heterologous genes. 3. Two protein, four protein and eight protein complexes including virus-like particles and cellular chaperone complexes can be produced using the new approach.
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Affiliation(s)
- Rob J Noad
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
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Au V, Yu M, Carstens EB. Characterization of a baculovirus nuclear localization signal domain in the late expression factor 3 protein. Virology 2009; 385:209-17. [DOI: 10.1016/j.virol.2008.10.051] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Revised: 10/12/2008] [Accepted: 10/30/2008] [Indexed: 10/21/2022]
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Chen YR, Wu CY, Lee ST, Wu YJ, Lo CF, Tsai MF, Wang CH. Genomic and host range studies of Maruca vitrata nucleopolyhedrovirus. J Gen Virol 2008; 89:2315-2330. [PMID: 18753242 DOI: 10.1099/vir.0.2008/001412-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The complete genome of the Maruca vitrata nucleopolyhedrovirus (MaviNPV) isolated from the legume pod borer, Maruca vitrata (Lepidoptera: Pyralidae), was sequenced. It was found to be 111 953 bp in length, with an overall 39 % G+C content, and contained 126 open reading frames (ORFs) encoding predicted proteins of over 50 aa. The gene content and gene order of MaviNPV have the highest similarity to those of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and their shared homologous genes are 100 % collinear. In fact, MaviNPV seems to be a mini-AcMNPV that is native to Taiwan and possesses a smaller genome with fewer auxiliary genes than the AcMNPV type species. Except for one ORF (Mv74), all of the MaviNPV ORFs have homologues in the AcMNPV genome. MaviNPV is the first lepidopteran-specific baculovirus to lack homologues of vfgf and odv-e66. In addition, MaviNPV lacks the baculovirus repeat ORF (bro) gene that corresponds to AcMNPV ORF2. Five homologous regions (hrs) were located within the MaviNPV genome, and these contained a total of 44 imperfect palindromes. Phylogenetic analysis of the whole genome revealed that MaviNPV was separated from the common ancestor of AcMNPV and Bombyx mori nucleopolyhedrovirus before these two viral species diverged from each other. Moreover, replication of MaviNPV in several cell lines and an egfp-MaviNPV infection assay revealed that IPLB-LD-652Y cells are only partially permissive to MaviNPV, which supports our conclusion that MaviNPV is a distinct species of the group I lepidopteran NPVs.
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Affiliation(s)
- Yun-Ru Chen
- Department of Entomology, National Taiwan University, Taipei, Taiwan, ROC
| | - Chih-Yu Wu
- Department of Entomology, National Taiwan University, Taipei, Taiwan, ROC
| | - Song-Tay Lee
- Department of Biotechnology, Southern Taiwan University of Technology, No. 1 Nantai Street, Yung-Kang City, Tainan 710, Taiwan, ROC
| | - Yan-Jheng Wu
- Department of Biotechnology, Southern Taiwan University of Technology, No. 1 Nantai Street, Yung-Kang City, Tainan 710, Taiwan, ROC
| | - Chu-Fang Lo
- Department of Zoology, National Taiwan University, Taipei, Taiwan, ROC
| | - Meng-Feng Tsai
- Department of Molecular Biotechnology, Dayeh University, No. 112 Shanjiao Road, Dacun, Changhua, Taiwan, ROC
| | - Chung-Hsiung Wang
- Department of Entomology, National Taiwan University, Taipei, Taiwan, ROC
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27
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Harwood S. Small-scale protein production with the baculovirus expression vector system. Methods Mol Biol 2007; 388:211-24. [PMID: 17951772 DOI: 10.1007/978-1-59745-457-5_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Improved methods of baculovirus cloning and insect cell culture and their commercialization have made the use of the baculovirus expression vector system (BEVS) a routine tool for the production of preparative quantities of recombinant protein. This chapter outlines basic techniques for small-scale protein production using the BEVS, including protocols for expression from adherent and suspension insect cell cultures, titer estimation, and expression optimization.
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Affiliation(s)
- Steve Harwood
- Molecular Probes Invitrogen Detection Technologies, Eugene, OR, USA
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28
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Mikhailov VS, Vanarsdall AL, Rohrmann GF. Isolation and characterization of the DNA-binding protein (DBP) of the Autographa californica multiple nucleopolyhedrovirus. Virology 2007; 370:415-29. [PMID: 17935748 DOI: 10.1016/j.virol.2007.09.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Revised: 08/29/2007] [Accepted: 09/05/2007] [Indexed: 11/24/2022]
Abstract
DNA-binding protein (DBP) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) was expressed as an N-terminal His(6)-tag fusion using a recombinant baculovirus and purified to near homogeneity. Purified DBP formed oligomers that were crosslinked by redox reagents resulting in predominantly protein dimers and tetramers. In gel retardation assays, DBP showed a high affinity for single-stranded oligonucleotides and was able to compete with another baculovirus SSB protein, LEF-3, for binding sites. DBP binding protected ssDNA against hydrolysis by a baculovirus alkaline nuclease AN/LEF-3 complex. Partial proteolysis by trypsin revealed a domain structure of DBP that is required for interaction with DNA and that can be disrupted by thermal treatment. Binding to ssDNA, but not to dsDNA, changed the pattern of proteolytic fragments of DBP indicating adjustments in protein structure upon interaction with ssDNA. DBP was capable of unwinding short DNA duplexes and also promoted the renaturation of long complementary strands of ssDNA into duplexes. The unwinding and renaturation activities of DBP, as well as the DNA binding activity, were sensitive to sulfhydryl reagents and were inhibited by oxidation of thiol groups with diamide or by alkylation with N-ethylmaleimide. A high affinity of DBP for ssDNA and its unwinding and renaturation activities confirmed identification of DBP as a member of the SSB/recombinase family. These activities and a tight association with subnuclear structures suggests that DBP is a component of the virogenic stroma that is involved in the processing of replicative intermediates.
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Affiliation(s)
- Victor S Mikhailov
- Department of Microbiology, Oregon State University, Corvallis, OR 97331-3804, USA.
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29
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Abstract
Baculoviruses play an important ecological role regulating the size of insect populations. For many years, baculoviruses have been applied as targeted biocontrol agents against forestry and agriculture pests. Baculovirus insecticides are effective against insect pests such as velvetbean caterpillar (Anticarsia gemmatalis ), cotton bollworm (Helicoverpa zea ), and gypsy moth (Lymantria dispar ). Baculoviruses are transmitted to insects by the oral route mediated by the occlusion-derived virus (ODV). The ODV is also specialized to exploit the insect midgut that is one of the most extreme biological environments where the viruses are subject to caustic pH and digestive proteases. The molecular biology of the ODV reveals new frontiers in protein chemistry. Finally, ODVs establishes infection in insect gut tissues that are virtually nonsupportive to virus replication and which are continuously sloughed away. ODVs carry with them a battery of proteins that enable them to rapidly exploit and harness these unstable cells for virus replication.
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Affiliation(s)
- Jeffery Slack
- Laboratory for Molecular Virology, Great Lakes Forestry Centre, Sault Ste. Marie, Ontario, Canada
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30
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Okano K, Vanarsdall AL, Rohrmann GF. A baculovirus alkaline nuclease knockout construct produces fragmented DNA and aberrant capsids. Virology 2006; 359:46-54. [PMID: 17046043 PMCID: PMC1852455 DOI: 10.1016/j.virol.2006.09.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Revised: 05/19/2006] [Accepted: 09/05/2006] [Indexed: 11/19/2022]
Abstract
DNA replication of bacmid-derived constructs of the Autographa californica multiple nucleocapsid nucleopolyhedrovirus (AcMNPV) was analyzed by field inversion gel electrophoresis (FIGE) in combination with digestion at a unique Eco81I restriction enzyme site. Three constructs were characterized: a parental bacmid, a bacmid deleted for the alkaline nuclease gene, and a bacmid from which the gp64 gene had been deleted. The latter was employed as a control for comparison with the alkaline nuclease knockout because neither yields infectious virus and their replication is limited to the initially transfected cells. The major difference between DNA replicated by the different constructs was the presence in the alkaline nuclease knockout of high concentrations of relatively small, subgenome length DNA in preparations not treated with Eco81I. Furthermore, upon Eco81I digestion, the alkaline nuclease knockout bacmid also yielded substantially more subgenome size DNA than the other constructs. Electron microscopic examination of cells transfected with the alkaline nuclease knockout indicated that, in addition to a limited number of normal-appearing electron-dense nucleocapsids, numerous aberrant capsid-like structures were observed indicating a defect in nucleocapsid maturation or in a DNA processing step that is necessary for encapsidation. Because of the documented role of the baculovirus alkaline nuclease and its homologs from other viruses in homologous recombination, these data suggest that DNA recombination may play a major role in the production of baculovirus genomes.
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Affiliation(s)
| | | | - George F. Rohrmann
- Correspondence author: George F. Rohrmann, Department of Microbiology, Nash Hall Room 220, Oregon State University, Corvallis, Oregon 97331-3804, Phone: 541 737 1793, FAX 541 737 0496,
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31
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Okano K, Vanarsdall AL, Mikhailov VS, Rohrmann GF. Conserved molecular systems of the Baculoviridae. Virology 2006; 344:77-87. [PMID: 16364739 DOI: 10.1016/j.virol.2005.09.019] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Accepted: 09/10/2005] [Indexed: 10/25/2022]
Abstract
Although the Baculoviridae are a large and diverse family of viruses, they are united by a number of shared features that form the basis for their unique life cycle. These include the mechanism of cell entry, genome replication and processing, and late and very late gene transcription. In this review, the molecular systems that are conserved within the Baculoviridae and that are responsible these processes are described.
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Affiliation(s)
- Kazuhiro Okano
- Department of Microbiology, Nash Hall Room 220, Oregon State University, Corvallis, OR 97331-3804, USA
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32
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Mikhailov VS, Okano K, Rohrmann GF. Structural and functional analysis of the baculovirus single-stranded DNA-binding protein LEF-3. Virology 2006; 346:469-78. [PMID: 16375940 DOI: 10.1016/j.virol.2005.11.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Revised: 11/04/2005] [Accepted: 11/18/2005] [Indexed: 11/17/2022]
Abstract
The single-stranded DNA-binding protein LEF-3 of Autographa californica multinucleocapsid nucleopolyhedrovirus consists of 385 amino acid residues, forms oligomers, and promotes Mg2+-independent unwinding of DNA duplexes and annealing of complementary DNA strands. Partial proteolysis revealed that the DNA-binding domain of LEF-3 is located within a central region (residues 28 to 326) that is relatively resistant to proteolysis. In contrast, the N-terminus (27 residues) and C-terminal portion (59 residues) are not involved in interaction with DNA and are readily accessible to proteolytic digestion. Circular dichroism analyses showed that LEF-3 is a folded protein with an estimated alpha-helix content of more than 40%, but it is structurally unstable and undergoes unfolding in aqueous solutions at temperatures near 50 degrees C. Unfolding eliminated the LEF-3 domains that are resistant to proteolysis and randomized the digestion pattern by trypsin. The structural transition was irreversible and was accompanied by the generation of high molecular weight (MW) complexes. The thermal treatment inhibited DNA-binding and unwinding activity of LEF-3 but markedly stimulated its annealing activity. We propose that the shift in LEF-3 activities resulted from the generation of the high MW protein complexes, that specifically stimulate the annealing of complementary DNA strands by providing multiple DNA-binding sites and bringing into close proximity the interacting strands. The unfolded LEF-3 was active in a strand exchange reaction suggesting that it could be involved in the production of recombination intermediates.
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Affiliation(s)
- Victor S Mikhailov
- Department of Microbiology, Oregon State University, Nash Hall 220, Corvallis, OR 97331-3804, USA.
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33
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Li Y, Wang J, Deng R, Zhang Q, Yang K, Wang X. vlf-1 deletion brought AcMNPV to defect in nucleocapsid formation. Virus Genes 2005; 31:275-84. [PMID: 16175333 DOI: 10.1007/s11262-005-3242-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 04/07/2005] [Accepted: 04/07/2005] [Indexed: 10/25/2022]
Abstract
Recent studies have provided direct evidence that the baculovirus very late factor 1 (VLF-I) of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) was essential for BV production. To elucidate how vlf-1 deletion blocks BV production we generated a vlf-1 knockout bacmid by ET-recombination technology on AcMNPV bacmid propagated in Escherichia coli. Bacmid DNA transfection and supernatant passage assay revealed that the vlf-1 knockout bacmid was unable to replicate in cell culture, while vlf-1 repair bacmid, which was generated by transposition of the vlf-1 ORF under control of its native promoter into polyhedrin gene locus of vlf-1 knockout bacmid, resumed viral replication ability at wildtype levels. Results of these assays proved the correct construction of the vlf-1 knockout bacmid. Subsequent electron microscopy revealed that the vlf-1 knockout bacmid failed to form nueleocapsid in the nuclei of the transfected cells. Instead, intensely electron-dense virogenic stroma characteristic of viral DNA synthesis were observed. Thus, it is demonstrated for the first time that vlf-1 knockout blocked nucleocapsid formation and the defective nucleocapsid formation resulted in the abolishment of BV and ODV production. Possible roles of vlf-1 in genome processing are suggested and discussed.
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Affiliation(s)
- Yi Li
- State Key Laboratory for Biocontrol, School of Life Sciences, SunYat-Sen (Zhongshan) University, Guangzhou, People's Republic of China
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34
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Chen Z, Carstens EB. Identification of domains in Autographa californica multiple nucleopolyhedrovirus late expression factor 3 required for nuclear transport of P143. J Virol 2005; 79:10915-22. [PMID: 16103143 PMCID: PMC1193572 DOI: 10.1128/jvi.79.17.10915-10922.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Autographa californica multiple nucleopolyhedrovirus (AcMNPV) late expression factor 3 (LEF-3) is an essential protein for DNA replication in transient assays. P143, a large DNA-binding protein with DNA-unwinding activity, is also essential for viral DNA replication in vivo. Both LEF-3 and P143 are found in the nucleus of AcMNPV-infected cells, but only LEF-3 localizes to the nucleus when expressed in transfected cells on its own from a plasmid expression vector. P143 requires LEF-3 as a transporter to enter the nucleus. To investigate the possibility that LEF-3 carries a nuclear localization signal domain, we constructed a series of LEF-3 deletion mutants and examined the intracellular localization of the products in plasmid-transfected cells. We discovered that the N-terminal 56 amino acid residues of LEF-3 were sufficient for nuclear localization and that this domain, when fused with either the green fluorescent protein reporter gene or P143, was able to direct these proteins to the nucleus. Transient DNA replication assays demonstrated that fusing the LEF-3 nuclear localization signal domain to P143 did not alter the function of P143 in supporting DNA replication but was not sufficient to substitute for whole LEF-3. These data show that although one role for LEF-3 during virus infection is to transport P143 to the nucleus, LEF-3 performs other essential replication functions once inside the nucleus.
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Affiliation(s)
- Zhilin Chen
- Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada
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35
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Martínez-Jiménez MI, Alonso JC, Ayora S. Bacillus subtilis bacteriophage SPP1-encoded gene 34.1 product is a recombination-dependent DNA replication protein. J Mol Biol 2005; 351:1007-19. [PMID: 16055153 DOI: 10.1016/j.jmb.2005.06.064] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 06/22/2005] [Accepted: 06/29/2005] [Indexed: 11/16/2022]
Abstract
SPP1-encoded replication and recombination proteins, involved in the early steps of the initiation of concatemeric DNA synthesis, have been analyzed. Dimeric G34.1P exonuclease degrades, with a 5' to 3' polarity and in a Mg2+-dependent reaction, preferentially linear double-stranded (ds) DNA rather than single-stranded (ss) DNA. Binding of the replisome organizer, G38P, to its cognate sites (oriDNA) halts the 5' to 3' exonucleolytic activity of G34.1P on dsDNA. The G35P recombinase increases the affinity of G34.1P for dsDNA, and stimulates G34.1P activity on dsDNA, but not on ssDNA. Then, filamented G35P promotes limited strand exchange with a homologous sequence. The ssDNA binding protein, G36P, protects ssDNA from the G34.1P exonuclease activity and stimulates G35P-catalyzed strand exchange. The data presented suggest a model for the role of G34.1P during initiation of sigma replication: G38P bound to oriDNA might halt replication fork progression, and G35P, G34.1P and G36P in concert might lead to the re-establishment of a unidirectional recombination-dependent replication that accounts for the direction of DNA packaging.
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Affiliation(s)
- María I Martínez-Jiménez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Darwin 3, Campus de la Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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36
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Mikhailov VS, Okano K, Rohrmann GF. The redox state of the baculovirus single-stranded DNA-binding protein LEF-3 regulates its DNA binding, unwinding, and annealing activities. J Biol Chem 2005; 280:29444-53. [PMID: 15944160 DOI: 10.1074/jbc.m503235200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The single-stranded (ss) DNA-binding protein LEF-3 of Autographa californica multinucleocapsid nucleopolyhedrovirus promoted Mg(2+)-independent unwinding of DNA duplexes and annealing of complementary DNA strands. The unwinding and annealing activities of LEF-3 appeared to act in a competitive manner and were determined by the ratio of protein to DNA. At subsaturating and saturating concentrations, LEF-3 promoted annealing, whereas it promoted unwinding at oversaturation of DNA substrates. The LEF-3 binding to ssDNA and unwinding activity were sensitive to redox agents and were inhibited by oxidation of thiol groups in LEF-3 with 1,1'-azobis(N,N-dimethylformamide) (diamide) or by modification with the thiol-conjugating agent N-ethylmaleimide. Both oxidation and alkylation increased the dissociation constant of the interaction with model oligonucleotides indicating a decrease in an intrinsic affinity of LEF-3 for ssDNA. These results proved that free thiol groups are essential both for LEF-3 interaction with ssDNA and for DNA unwinding. In contrast, oxidation or modification of thiol groups stimulated the annealing activity of LEF-3 partially due to suppression of its unwinding activity. Treatment of LEF-3 with the reducing agent dithiothreitol inhibited annealing, indicating association of this activity with the oxidized protein. Thus, the balance between annealing and unwinding activities of LEF-3 was determined by the redox state of protein with the oxidized state favoring annealing and the reduced state favoring unwinding. An LEF-3 mutant in which the conservative cysteine Cys(214) was replaced with serine showed both a decreased binding to DNA and a reduced unwinding activity, thus indicating that this residue might participate in the regulation of LEF-3 activities.
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Affiliation(s)
- Victor S Mikhailov
- Department of Microbiology, Oregon State University, Corvallis, Oregon 97331-3804
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37
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de Jong JG, Lauzon HAM, Dominy C, Poloumienko A, Carstens EB, Arif BM, Krell PJ. Analysis of the Choristoneura fumiferana nucleopolyhedrovirus genome. J Gen Virol 2005; 86:929-943. [PMID: 15784887 DOI: 10.1099/vir.0.80490-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The double-stranded DNA genome of Choristoneura fumiferana nucleopolyhedrovirus (CfMNPV) was sequenced and analysed in the context of other group I nucleopolyhedroviruses (NPVs). The genome consists of 129 593 bp with a G+C content of 50·1 mol%. A total of 146 open reading frames (ORFs) of greater than 150 bp, and with no or minimal overlap were identified. In addition, five homologous regions were identified containing 7–10 repeats of a 36 bp imperfect palindromic core. Comparison with other completely sequenced baculovirus genomes revealed that 139 of the CfMNPV ORFs have homologues in at least one other baculovirus and seven ORFs are unique to CfMNPV. Of the 117 CfMNPV ORFs common to all group I NPVs, 12 are exclusive to group I NPVs. Overall, CfMNPV is most similar to Orgyia pseudotsugata MNPV based on gene content, arrangement and overall amino acid identity. Unlike other group I baculoviruses, however, CfMNPV encodes a viral enhancing factor (vef) and has two copies of p26.
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Affiliation(s)
- Jondavid G de Jong
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Hilary A M Lauzon
- Great Lakes Forestry Centre, Sault Ste Marie, Ontario, Canada, P6A 2E5
| | - Cliff Dominy
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Arkadi Poloumienko
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Eric B Carstens
- Department of Microbiology and Immunology, Queens University, Kingston, Ontario, Canada, K7L 3N6
| | - Basil M Arif
- Great Lakes Forestry Centre, Sault Ste Marie, Ontario, Canada, P6A 2E5
| | - Peter J Krell
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
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38
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Porter IM, Stow ND. Replication, recombination and packaging of amplicon DNA in cells infected with the herpes simplex virus type 1 alkaline nuclease null mutant ambUL12. J Gen Virol 2004; 85:3501-3510. [PMID: 15557223 DOI: 10.1099/vir.0.80403-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The alkaline nuclease (AN) encoded by gene UL12 of herpes simplex virus type 1 (HSV-1) is essential for efficient virus replication but its role during the lytic cycle remains incompletely understood. Inactivation of the UL12 gene results in reductions in viral DNA synthesis, DNA packaging, egress of DNA-containing capsids from the nucleus and ability of progeny virions to initiate new cycles of infection. Mechanistically, AN has been implicated in resolving branched structures in HSV-1 replicative intermediates prior to encapsidation, and promoting DNA strand-exchange. In this study, amplicons (bacterial plasmids containing functional copies of a virus replication origin and packaging signal) were used to analyse further the defects of the UL12 null mutant ambUL12. When ambUL12 was used as a helper virus both replication and packaging of the transfected amplicon were reduced in comparison with cells infected with wild-type (wt) HSV-1, and to extents similar to those previously observed for genomic ambUL12 DNA. By using amplicons differing at a specific restriction endonuclease site it was demonstrated that replicating molecules exhibit high frequency intermolecular recombination in both wt- and mutant-infected cells. Surprisingly, in the absence of the UL12 product, amplicons lacking a functional encapsidation signal were packaged. Moreover, these packaged molecules could be serially propagated indicating that they had been incorporated into functional virions. This difference in packaging specificity between wt HSV-1 and ambUL12 might indicate that replicative intermediates accumulating in the absence of AN contain an increased incidence of structures that can serve for the initiation of DNA packaging.
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Affiliation(s)
- Iain M Porter
- MRC Virology Unit, Institute of Virology, Church Street, Glasgow G11 5JR, UK
| | - Nigel D Stow
- MRC Virology Unit, Institute of Virology, Church Street, Glasgow G11 5JR, UK
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39
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Yang DH, de Jong JG, Makhmoudova A, Arif BM, Krell PJ. Choristoneura fumiferana nucleopolyhedrovirus encodes a functional 3′–5′ exonuclease. J Gen Virol 2004; 85:3569-3573. [PMID: 15557229 DOI: 10.1099/vir.0.80592-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Choristoneura fumiferana nucleopolyhedrovirus (CfMNPV) encodes an ORF homologous to type III 3'-5' exonucleases. The CfMNPV v-trex ORF was cloned into the Bac-to-Bac baculovirus expression-vector system, expressed in insect Sf21 cells with an N-terminal His tag and purified to homogeneity by using Ni-NTA affinity chromatography. Biochemical characterization of the purified V-TREX confirmed that this viral protein is a functional 3'-5' exonuclease that cleaves oligonucleotides from the 3' end in a stepwise, distributive manner, suggesting a role in proofreading during viral DNA replication and DNA repair. Enhanced degradation of a 5'-digoxigenin- or 5'-(32)P-labelled oligo(dT)(30) substrate was observed at increasing incubation times or increased amounts of V-TREX. The 3'-excision activity of V-TREX was maximal at alkaline pH (9.5) in the presence of 5 mM MgCl(2), 2 mM dithiothreitol and 0.1 mg BSA ml(-1).
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Affiliation(s)
- Dan-Hui Yang
- Department of Microbiology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Jondavid G de Jong
- Department of Microbiology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Amina Makhmoudova
- Department of Microbiology, University of Guelph, Guelph, ON, Canada, N1G 2W1
| | - Basil M Arif
- Great Lakes Forestry Centre, Sault Ste Marie, ON, Canada, P6A 2E5
| | - Peter J Krell
- Department of Microbiology, University of Guelph, Guelph, ON, Canada, N1G 2W1
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40
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Ito E, Sahri D, Knippers R, Carstens EB. Baculovirus proteins IE-1, LEF-3, and P143 interact with DNA in vivo: a formaldehyde cross-linking study. Virology 2004; 329:337-47. [PMID: 15518813 DOI: 10.1016/j.virol.2004.08.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Revised: 08/18/2004] [Accepted: 08/27/2004] [Indexed: 10/26/2022]
Abstract
IE-1, LEF-3, and P143 are three of six proteins encoded by Autographa californica nucleopolyhedrovirus (AcMNPV) essential for baculovirus DNA replication in transient replication assays. IE-1 is the major baculovirus immediate early transcription regulator. LEF-3 is a single-stranded DNA binding protein (SSB) and P143 is a DNA helicase protein. To investigate their interactions in vivo, we treated AcMNPV-infected Spodoptera frugiperda cells with formaldehyde and separated soluble proteins from chromatin by cell fractionation and cesium chloride equilibrium centrifugation. Up to 70% of the total LEF-3 appeared in the fraction of soluble, probably nucleoplasmic proteins, while almost all P143 and IE-1 were associated with viral chromatin in the nucleus. This suggests that LEF-3 is produced in quantities that are higher than needed for the coverage of single stranded regions that arise during viral DNA replication and is consistent with the hypothesis that LEF-3 has other functions such as the localization of P143 to the nucleus. Using a chromatin immunoprecipitation procedure, we present the first direct evidence of LEF-3, P143, and IE-1 proteins binding to closely linked sites on viral chromatin in vivo, suggesting that they may form replication complexes on viral DNA in infected cells.
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Affiliation(s)
- Emma Ito
- Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada K7L 3N6
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41
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Abstract
The Autographa californica multiple nucleocapsid nucleopolyhedrovirus (AcMNPV) alkaline nuclease (AN) associates with the baculovirus single-stranded DNA binding protein LEF-3 and possesses both a 5'-->3' exonuclease and an endonuclease activity. These activities are thought to be involved in DNA recombination and replication. To investigate the role of AN in AcMNPV replication, the lambda Red system was used to replace the an open reading frame with a chloramphenicol acetyltransferase gene (cat) and a bacmid containing the AcMNPV genome in Escherichia coli. The AcMNPV an knockout bacmid (vAcAN-KO/GUS) was unable to propagate in Sf9 cells, although an an-rescued bacmid (vAcAN-KO/GUS-Res) propagated normally. In addition, the mutant did not appear to produce budded virions. These data indicated that an is an essential baculovirus gene. Slot blot and DpnI assays of DNA replication in Sf9 cells transfected with vAcAN-KO/GUS, vAcAN-KO/GUS-Res, and a wild-type bacmid showed that the vAcAN-KO/GUS bacmid was able to replicate to levels similar to those seen with the vAcAN-KO/GUS-Res and wild-type bacmids at early stages posttransfection. However, at later time points DNA did not accumulate to the levels seen with the repaired or wild-type bacmids. Northern analysis of Sf9 cells transfected with bacmid vAcAN-KO/GUS showed that transcription of late and very late genes was lower at later times posttransfection relative to the results seen with wild-type and vAcAN-KO/GUS-Res bacmids. These data suggest that the an gene might be involved in the maturation of viral DNA or packaging of the DNA into virions.
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Affiliation(s)
- Kazuhiro Okano
- Department of Microbiology, Nash Hall Room 220, Oregon State University, Corvallis, OR 97331-3804, USA
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Reuven NB, Willcox S, Griffith JD, Weller SK. Catalysis of strand exchange by the HSV-1 UL12 and ICP8 proteins: potent ICP8 recombinase activity is revealed upon resection of dsDNA substrate by nuclease. J Mol Biol 2004; 342:57-71. [PMID: 15313607 PMCID: PMC4412345 DOI: 10.1016/j.jmb.2004.07.012] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2004] [Revised: 07/09/2004] [Accepted: 07/12/2004] [Indexed: 11/29/2022]
Abstract
The replication of herpes simplex virus type 1 (HSV-1) is associated with a high degree of homologous recombination, which is likely to be mediated, in part, by HSV-1-encoded proteins. We have previously shown that the HSV-1 encoded ICP8 protein and alkaline nuclease UL12 are capable of catalyzing an in vitro strand-exchange reaction. Here, we show, by electron microscopy, that the products of the strand exchange reaction between linear double-stranded DNA and circular single-stranded DNA consist of the expected joint molecule forms: sigma, alpha, and gapped circles. Other exonucleases, such as lambda Red alpha, which, like UL12, digests 5'-3', as well as Escherichia coli exonuclease III (ExoIII), which digests 3'-5', could substitute for UL12 in the strand exchange reaction by providing a resected DNA end. ICP8 generated the same intermediates and strand exchange products when the double-stranded DNA substrate was preresected by any of the nucleases. Using substrates with large regions of non-homology we found that pairing by ICP8 could be initiated from the middle of a DNA molecule and did not require a homologous end. In this reaction, the resection of a DNA end by the nuclease is required to reveal homologous sequences capable of being paired by ICP8. This study further illustrates the complexity of the multi-functional ICP8 protein.
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Affiliation(s)
- Nina B. Reuven
- Department of Molecular Microbial, and Structural Biology, University of Connecticut Health Center Farmington, CT 06030-3205 USA
| | - Smaranda Willcox
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill NC 27599, USA
| | - Jack D. Griffith
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill NC 27599, USA
| | - Sandra K. Weller
- Department of Molecular Microbial, and Structural Biology, University of Connecticut Health Center Farmington, CT 06030-3205 USA
- Corresponding author:
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43
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Vanarsdall AL, Okano K, Rohrmann GF. Characterization of a baculovirus with a deletion of vlf-1. Virology 2004; 326:191-201. [PMID: 15262507 DOI: 10.1016/j.virol.2004.06.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Accepted: 06/02/2004] [Indexed: 12/22/2022]
Abstract
Very late expression factor (VLF-1) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is essential for high levels of expression of the very late genes p10 and polh, and evidence suggests VLF-1 may also be involved in viral DNA replication. In this study, investigations determined whether VLF-1 is essential for viral DNA replication by generating a vlf-1 knockout bacmid containing the AcMNPV genome through homologous recombination in Escherichia coli. Additionally, a vlf-1 repair bacmid was constructed by transposing the vlf-1 ORF and native promoter region into the polh locus of the vlf-1 knockout bacmid. After transfecting these virus constructs into Spodoptera frugiperda (Sf-9) cells, the vlf-1 knockout bacmid was unable to produce a viral infection while the repair bacmid propagated at wild-type levels. Experiments were performed to conclude whether the vlf-1 knockout phenotype was due to a defect in viral DNA synthesis or late gene transcription. Southern blot analyses determined that the vlf-1 knockout bacmid was able to replicate viral DNA but only to about one-third the level of wild-type or rescued controls. In addition, virion DNA was not detected in the supernatant of transfected cells, indicating that the DNA synthesized by the mutant virus was unable to assemble into virions that bud out of the cells. Analysis of viral gene transcription confirmed that late gene transcription was not affected by the vlf-1 knockout but transcription of the very late gene p10 was substantially reduced.
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Affiliation(s)
- Adam L Vanarsdall
- Department of Microbiology, Oregon State University, Corvallis, OR 97331-3804, USA
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44
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Slack JM, Shapiro M. Anticarsia gemmatalis multicapsid nucleopolyhedrovirus v-trex gene encodes a functional 3' to 5' exonuclease. J Gen Virol 2004; 85:2863-2871. [PMID: 15448348 DOI: 10.1099/vir.0.80109-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The viral three-prime repair exonuclease (v-trex) gene of the Anticarsia gemmatalis multicapsid nucleopolyhedrovirus (AgMNPV) is the first baculovirus gene to be described with significant homology to a 3' exonuclease. v-trex is an early gene that is expressed by AgMNPV from 3 h post-infection. In the present study, the AgMNPV v-trex ORF was cloned into the baculovirus Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) under the control of a polyhedrin promoter. The resulting virus produced an abundant, soluble protein that migrated with an apparent size of 23.7 kDa. The 3' to 5' exonuclease activity associated with this v-trex-expressing recombinant AcMNPV was 2000-fold above that of wild-type AcMNPV. This exonuclease activity was inhibited by EDTA and was activated in the presence of Mg2+ and, to a lesser extent, Mn2+. From these results, the AgMNPV v-trex gene is concluded to encode an independently active 3' to 5' exonuclease.
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Affiliation(s)
- Jeffrey M Slack
- USDA/ARS, Insect Biocontrol Laboratory, BARC-West, Building 011A, Room 214, Beltsville, MD 20852-2350, USA
| | - Martin Shapiro
- USDA/ARS, Insect Biocontrol Laboratory, BARC-West, Building 011A, Room 214, Beltsville, MD 20852-2350, USA
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45
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Porter IM, Stow ND. Virus particles produced by the herpes simplex virus type 1 alkaline nuclease null mutant ambUL12 contain abnormal genomes. J Gen Virol 2004; 85:583-591. [PMID: 14993641 DOI: 10.1099/vir.0.19657-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Open reading frame UL12 of herpes simplex virus type 1 (HSV-1) encodes an alkaline nuclease that has previously been implicated in processing the complex, branched, viral DNA replication intermediates and allowing egress of DNA-containing capsids from the nucleus. This report describes experiments using the HSV-1 UL12 null mutant ambUL12, which aim to explain the approximately 200- to 1000-fold decrease in the yield of infectious virus, compared with wild-type (wt) HSV-1, from non-complementing cells. A detailed examination revealed that both DNA replication and encapsidation were affected in ambUL12-infected cells, resulting in an approximately 15- to 20-fold reduction in the amount of packaged DNA. In contrast to previous reports, the absence of UL12 function did not greatly impair capsid release into the cytoplasm, and virus particles were readily detected in the supernatant medium from ambUL12-infected cells. The released virus, however, exhibited much higher particle/p.f.u. ratios than wt HSV-1, and this made a further important contribution to the overall reduction in yield. Gel analyses of packaged ambUL12 and wt DNAs revealed the presence of structural abnormalities. The DNA obtained from extracellular ambUL12 virions was non-infectious in transfection assays, and both ambUL12 DNA and virus particles exerted a dominant inhibitory effect on the growth of wt virus. These results suggest that ambUL12 virions produced in non-complementing cells have a greatly reduced ability to initiate new cycles of infection, and that this defect results from the encapsidation of abnormal genomes.
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Affiliation(s)
- Iain M Porter
- MRC Virology Unit, Institute of Virology, Church Street, Glasgow G11 5JR, UK
| | - Nigel D Stow
- MRC Virology Unit, Institute of Virology, Church Street, Glasgow G11 5JR, UK
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Mikhailov VS, Okano K, Rohrmann GF. Specificity of the Endonuclease Activity of the Baculovirus Alkaline Nuclease for Single-stranded DNA. J Biol Chem 2004; 279:14734-45. [PMID: 14736888 DOI: 10.1074/jbc.m311658200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Autographa californica multiple nucleocapsid nucleopolyhedrovirus (AcMNPV) alkaline nuclease (AN) likely participates in the maturation of virus genomes and in DNA recombination. AcMNPV AN was expressed in a recombinant baculovirus as a His -tagged fusion and obtained in pure form (*AN) or as a (6)complex with the baculoviral single-stranded DNA-binding protein LEF-3 (*AN/L3). Both AN preparations possessed potent 5' --> 3'-exonuclease and weak endonuclease activities. Mutant *AN(S146A)/L3 with a change from serine to alanine at position 146 in a conservative motif was impaired in both activities. This proved that the endonuclease is an intrinsic activity of baculovirus AN. The AN endonuclease showed specificity for single-stranded DNA and converted supercoiled plasmid DNA (replicative form I, RFI) into the open circular form (RFII) by a single strand break. Plasmid DNA relaxed with topoisomerase I was resistant to *AN/L3 indicating that the partially single-stranded regions in negatively supercoiled molecules served as targets for the endonuclease. Unwinding the supercoiled DNA with ethidium bromide also made DNA resistant to AN/L3. In reactions with nicked circular DNA (RFII), AN and AN/L3 hydrolyzed exonucleolytically the broken strand or cut endonucleolytically the intact strand at the position opposite the nick (gap). When LEF-3 was added to the assay, the balance between the exonucleolytic and endonucleolytic modes of hydrolysis shifted in favor of the exonuclease. The data suggest that the AN endonuclease may digest the intermediates in replication and recombination at positions of structural irregularities in DNA duplexes, whereas LEF-3 may further regulate processing of the intermediates by AN via the endonuclease and exonuclease pathways.
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Affiliation(s)
- Victor S Mikhailov
- Department of Microbiology, Oregon State University, Corvallis, Oregon 97331-3804, USA
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Reuven NB, Staire AE, Myers RS, Weller SK. The herpes simplex virus type 1 alkaline nuclease and single-stranded DNA binding protein mediate strand exchange in vitro. J Virol 2003; 77:7425-33. [PMID: 12805441 PMCID: PMC164775 DOI: 10.1128/jvi.77.13.7425-7433.2003] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The replication of herpes simplex virus type 1 (HSV-1) DNA is associated with a high degree of homologous recombination. While cellular enzymes may take part in mediating this recombination, we present evidence for an HSV-1-encoded recombinase activity. HSV-1 alkaline nuclease, encoded by the UL12 gene, is a 5'-->3' exonuclease that shares homology with Redalpha, commonly known as lambda exonuclease, an exonuclease required for homologous recombination by bacteriophage lambda. The HSV-1 single-stranded DNA binding protein ICP8 is an essential protein for HSV DNA replication and possesses single-stranded DNA annealing activities like the Redbeta synaptase component of the phage lambda recombinase. Here we show that UL12 and ICP8 work together to effect strand exchange much like the Red system of lambda. Purified UL12 protein and ICP8 mediated the complete exchange between a 7.25-kb M13mp18 linear double-stranded DNA molecule and circular single-stranded M13 DNA, forming a gapped circle and a displaced strand as final products. The optimal conditions for strand exchange were 1 mM MgCl(2), 40 mM NaCl, and pH 7.5. Stoichiometric amounts of ICP8 were required, and strand exchange did not depend on the nature of the double-stranded end. Nuclease-defective UL12 could not support this reaction. These data suggest that diverse DNA viruses appear to utilize an evolutionarily conserved recombination mechanism.
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Affiliation(s)
- Nina Bacher Reuven
- Department of Microbiology, University of Connecticut Health Center, Farmington, Connecticut 06030-3205, USA
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