1
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Manigat F, Connell LB, Stewart BN, LePabic AR, Tessier CJG, Emlaw JR, Calvert ND, Rössl A, Shuhendler AJ, daCosta CJB, Campbell-Valois FX. pUdOs: Concise Plasmids for Bacterial and Mammalian Cells. ACS Synth Biol 2024; 13:485-497. [PMID: 38235654 PMCID: PMC10878396 DOI: 10.1021/acssynbio.3c00408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 11/22/2023] [Accepted: 11/28/2023] [Indexed: 01/19/2024]
Abstract
The plasmids from the Université d'Ottawa (pUdOs) are 28 small plasmids each comprising one of four origins of replication and one of seven selection markers, which together afford flexible use in Escherichia coli and several related gram-negative bacteria. The promoterless multicloning site is insulated from upstream spurious promoters by strong transcription terminators and contains type IIP or IIS restriction sites for conventional or Golden Gate cloning. pUdOs can be converted into efficient expression vectors through the insertion of a promoter at the user's discretion. For example, we demonstrate the utility of pUdOs as the backbone for an improved version of a Type III Secretion System reporter in Shigella. In addition, we derive a series of pUdO-based mammalian expression vectors, affording distinct levels of expression and transfection efficiency comparable to commonly used mammalian expression plasmids. Thus, pUdOs could advantageously replace traditional plasmids in a wide variety of cell types and applications.
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Affiliation(s)
- France
O. Manigat
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Louise B. Connell
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Brittany N. Stewart
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Abdel-Rahman LePabic
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Christian J. G. Tessier
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Johnathon R. Emlaw
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Nicholas D. Calvert
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Anthony Rössl
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Adam J. Shuhendler
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- University
of Ottawa Heart Institute, Ottawa, Ontario K1Y 4W7, Canada
| | - Corrie J. B. daCosta
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - François-Xavier Campbell-Valois
- Center
for Chemical and Synthetic Biology, Department of Chemistry and Biomolecular
Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- bioGARAGE,
Faculty of Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- Centre
for Infection, Immunity and Inflammation, Department of Biochemistry,
Microbiology and Immunology, University
of Ottawa, Ottawa, Ontario K1N 6N5, Canada
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2
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Abstract
Human cytomegalovirus (HCMV) is a betaherpesvirus that establishes lifelong infection in its host and can cause severe comorbidities in individuals with suppressed or compromised immune systems. The lifecycle of HCMV consists of lytic and latent phases, largely dependent upon the cell type infected and whether transcription from the major immediate early locus can ensue. Control of this locus, which acts as a critical "switch" region from where the lytic gene expression cascade originates, as well as regulation of the additional ~235 kilobases of virus genome, occurs through chromatinization with cellular histone proteins after infection. Upon infection of a host cell, an initial intrinsic antiviral response represses gene expression from the incoming genome, which is relieved in permissive cells by viral and host factors in concert. Latency is established in a subset of hematopoietic cells, during which viral transcription is largely repressed while the genome is maintained. As these latently infected cells differentiate, the cellular milieu and epigenetic modifications change, giving rise to the initial stages of virus reactivation from latency. Thus, throughout the cycle of infection, chromatinization, chromatin modifiers, and the recruitment of specific transcription factors influence the expression of genes from the HCMV genome. In this review, we discuss epigenetic regulation of the HCMV genome during the different phases of infection, with an emphasis on recent reports that add to our current perspective.
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Affiliation(s)
- Stephen M. Matthews
- Infection Biology, Global Center for Pathogen and Human Health Research, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Ian J. Groves
- Infection Biology, Global Center for Pathogen and Human Health Research, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
- Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, Ohio, USA
| | - Christine M. O'Connor
- Infection Biology, Global Center for Pathogen and Human Health Research, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
- Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, Ohio, USA
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3
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Regulation of the MIE Locus During HCMV Latency and Reactivation. Pathogens 2020; 9:pathogens9110869. [PMID: 33113934 PMCID: PMC7690695 DOI: 10.3390/pathogens9110869] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/19/2020] [Accepted: 10/20/2020] [Indexed: 12/20/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a ubiquitous herpesviral pathogen that results in life-long infection. HCMV maintains a latent or quiescent infection in hematopoietic cells, which is broadly defined by transcriptional silencing and the absence of de novo virion production. However, upon cell differentiation coupled with immune dysfunction, the virus can reactivate, which leads to lytic replication in a variety of cell and tissue types. One of the mechanisms controlling the balance between latency and reactivation/lytic replication is the regulation of the major immediate-early (MIE) locus. This enhancer/promoter region is complex, and it is regulated by chromatinization and associated factors, as well as a variety of transcription factors. Herein, we discuss these factors and how they influence the MIE locus, which ultimately impacts the phase of HCMV infection.
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4
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Mlera L, Moy M, Maness K, Tran LN, Goodrum FD. The Role of the Human Cytomegalovirus UL133-UL138 Gene Locus in Latency and Reactivation. Viruses 2020; 12:E714. [PMID: 32630219 PMCID: PMC7411667 DOI: 10.3390/v12070714] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 06/29/2020] [Accepted: 06/29/2020] [Indexed: 12/13/2022] Open
Abstract
Human cytomegalovirus (HCMV) latency, the means by which the virus persists indefinitely in an infected individual, is a major frontier of current research efforts in the field. Towards developing a comprehensive understanding of HCMV latency and its reactivation from latency, viral determinants of latency and reactivation and their host interactions that govern the latent state and reactivation from latency have been identified. The polycistronic UL133-UL138 locus encodes determinants of both latency and reactivation. In this review, we survey the model systems used to investigate latency and new findings from these systems. Particular focus is given to the roles of the UL133, UL135, UL136 and UL138 proteins in regulating viral latency and how their known host interactions contribute to regulating host signaling pathways towards the establishment of or exit from latency. Understanding the mechanisms underlying viral latency and reactivation is important in developing strategies to block reactivation and prevent CMV disease in immunocompromised individuals, such as transplant patients.
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Affiliation(s)
- Luwanika Mlera
- BIO5 Institute, University of Arizona, Tucson, AZ 85719, USA;
| | - Melissa Moy
- Graduate Interdisciplinary Program in Cancer Biology, Tucson, AZ 85719, USA;
| | - Kristen Maness
- Immunobiology Department, University of Arizona, Tucson, AZ 85719, USA; (K.M.); (L.N.T.)
| | - Linh N. Tran
- Immunobiology Department, University of Arizona, Tucson, AZ 85719, USA; (K.M.); (L.N.T.)
| | - Felicia D. Goodrum
- BIO5 Institute, University of Arizona, Tucson, AZ 85719, USA;
- Graduate Interdisciplinary Program in Cancer Biology, Tucson, AZ 85719, USA;
- Immunobiology Department, University of Arizona, Tucson, AZ 85719, USA; (K.M.); (L.N.T.)
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5
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Collins-McMillen D, Rak M, Buehler JC, Igarashi-Hayes S, Kamil JP, Moorman NJ, Goodrum F. Alternative promoters drive human cytomegalovirus reactivation from latency. Proc Natl Acad Sci U S A 2019; 116:17492-17497. [PMID: 31409717 PMCID: PMC6717278 DOI: 10.1073/pnas.1900783116] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Reactivation from latency requires reinitiation of viral gene expression and culminates in the production of infectious progeny. The major immediate early promoter (MIEP) of human cytomegalovirus (HCMV) drives the expression of crucial lytic cycle transactivators but is silenced during latency in hematopoietic progenitor cells (HPCs). Because the MIEP has poor activity in HPCs, it is unclear how viral transactivators are expressed during reactivation. It has been presumed that viral gene expression is reinitiated via de-repression of the MIEP. We demonstrate that immediate early transcripts arising from reactivation originate predominantly from alternative promoters within the canonical major immediate early locus. Disruption of these intronic promoters results in striking defects in re-expression of viral genes and viral genome replication in the THP-1 latency model. Furthermore, we show that these promoters are necessary for efficient reactivation in primary CD34+ HPCs. Our findings shift the paradigm for HCMV reactivation by demonstrating that promoter switching governs reactivation from viral latency in a context-specific manner.
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Affiliation(s)
| | - Mike Rak
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721
| | | | | | - Jeremy P Kamil
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center, Shreveport, LA 71103
| | - Nathaniel J Moorman
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Felicia Goodrum
- BIO5 Institute, University of Arizona, Tucson, AZ 85721;
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721
- Department of Immunobiology, University of Arizona, Tucson, AZ 85721
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6
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Collins-McMillen D, Buehler J, Peppenelli M, Goodrum F. Molecular Determinants and the Regulation of Human Cytomegalovirus Latency and Reactivation. Viruses 2018; 10:E444. [PMID: 30127257 PMCID: PMC6116278 DOI: 10.3390/v10080444] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 08/16/2018] [Accepted: 08/17/2018] [Indexed: 02/06/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a beta herpesvirus that establishes a life-long persistence in the host, like all herpesviruses, by way of a latent infection. During latency, viral genomes are maintained in a quieted state. Virus replication can be reactivated from latency in response to changes in cellular signaling caused by stress or differentiation. The past decade has brought great insights into the molecular basis of HCMV latency. Here, we review the complex persistence of HCMV with consideration of latent reservoirs, viral determinants and their host interactions, and host signaling and the control of cellular and viral gene expression that contributes to the establishment of and reactivation from latency.
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Affiliation(s)
| | - Jason Buehler
- BIO5 Institute, University of Arizona, Tucson, AZ 85721, USA.
| | | | - Felicia Goodrum
- BIO5 Institute, University of Arizona, Tucson, AZ 85721, USA.
- Department of Immunobiology, University of Arizona, Tucson, AZ 85721, USA.
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7
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Iwasaki K, Temin HM. Multiple sequence elements are involved in RNA 3' end formation in spleen necrosis virus. Gene Expr 2018; 2:7-18. [PMID: 1319783 PMCID: PMC6057358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The function of the poly(A) signal in spleen necrosis virus (SNV) is dependent upon the distance between the cap site and the poly(A) site, while the function of the SV40 late poly(A) signal is independent of the distance. Deletions in the SNV poly(A) sequence do not alter the distance-dependent function. SNV/SV40 chimeric poly(A) signals show intermediate behavior between the SNV and SV40 poly(A) signals. These results indicate that multiple sequence elements are involved in the functions of either the SNV or SV40 poly(A) signals. This intermediate behavior is also observed with poly(A) signals from the mouse alpha-globin and herpes simplex virus thymidine kinase genes.
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Affiliation(s)
- K Iwasaki
- McArdle Laboratory for Cancer Research, University of Wisconsin, Madison 53706
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8
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Shimizu N, Doyal MF, Goins WF, Kadekawa K, Wada N, Kanai AJ, de Groat WC, Hirayama A, Uemura H, Glorioso JC, Yoshimura N. Morphological changes in different populations of bladder afferent neurons detected by herpes simplex virus (HSV) vectors with cell-type-specific promoters in mice with spinal cord injury. Neuroscience 2017; 364:190-201. [PMID: 28942324 DOI: 10.1016/j.neuroscience.2017.09.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 09/08/2017] [Accepted: 09/12/2017] [Indexed: 01/06/2023]
Abstract
Functional and morphological changes in C-fiber bladder afferent pathways are reportedly involved in neurogenic detrusor overactivity (NDO) after spinal cord injury (SCI). This study examined the morphological changes in different populations of bladder afferent neurons after SCI using replication-defective herpes simplex virus (HSV) vectors encoding the mCherry reporter driven by neuronal cell-type-specific promoters. Spinal intact (SI) and SCI mice were injected into the bladder wall with HSV mCherry vectors driven by the cytomegalovirus (CMV) promoter, CGRP promoter, TRPV1 promoter or neurofilament 200 (NF200) promoter. Two weeks after vector inoculation into the bladder wall, L1 and L6 dorsal root ganglia (DRG) were removed bilaterally for immunofluorescent staining using anti-mCherry antibody. The number of CMV promoter vector-labeled neurons was not altered after SCI. The number of CGRP and TRPV1 promoter vector-labeled neurons was significantly increased whereas the number of NF200 vector-labeled neurons was decreased in L6 DRG after SCI. The median size of CGRP promoter-labeled C-fiber neurons was increased from 247.0 in SI mice to 271.3μm2 in SCI mice whereas the median cell size of TRPV1 promoter vector-labeled neurons was decreased from 245.2 in SI mice to 216.5μm2 in SCI mice. CGRP and TRPV1 mRNA levels of laser-captured bladder afferent neurons labeled with Fast Blue were significantly increased in SCI mice compared to SI mice. Thus, using a novel HSV vector-mediated neuronal labeling technique, we found that SCI induces expansion of the CGRP- and TRPV1-expressing C-fiber cell population, which could contribute to C-fiber afferent hyperexcitability and NDO after SCI.
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Affiliation(s)
- Nobutaka Shimizu
- Department of Urology, University of Pittsburgh, Pittsburgh, PA 15213, United States; Department of Urology, Faculty of Medicine, Kindai University, Osaka-Sayama, Japan
| | - Mark F Doyal
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, United States
| | - William F Goins
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, United States
| | - Katsumi Kadekawa
- Department of Urology, University of Pittsburgh, Pittsburgh, PA 15213, United States
| | - Naoki Wada
- Department of Urology, University of Pittsburgh, Pittsburgh, PA 15213, United States
| | - Anthony J Kanai
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, United States
| | - William C de Groat
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15213, United States
| | - Akihide Hirayama
- Department of Urology, Faculty of Medicine, Kindai University Nara Hospital, Nara, Japan
| | - Hirotsugu Uemura
- Department of Urology, Faculty of Medicine, Kindai University, Osaka-Sayama, Japan
| | - Joseph C Glorioso
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, United States
| | - Naoki Yoshimura
- Department of Urology, University of Pittsburgh, Pittsburgh, PA 15213, United States; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15213, United States.
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9
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Bae S, Kang SC, Song YJ. Inhibition of human cytomegalovirus immediate-early gene expression and replication by the ethyl acetate (EtOAc) fraction of Elaeocarpus sylvestris in vitro. Altern Ther Health Med 2017; 17:428. [PMID: 28851336 PMCID: PMC5576240 DOI: 10.1186/s12906-017-1941-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 08/21/2017] [Indexed: 11/10/2022]
Abstract
Background In immunocompromised patients, human cytomegalovirus (HCMV) infection can lead to severe, life-threatening diseases, such as pneumonitis, hepatitis, gastrointestinal tract disease, and retinitis. We previously reported that a 70% ethanol extract of Elaeocarpus sylvestris leaves (ESE) inhibits human cytomegalovirus (HCMV) replication in vitro. In the present study, we determined the solvent fraction of ESE that inhibits HCMV replication using activity-guided fractionation. Methods Activity-guided fractionation of ESE was performed to determine the solvent fraction that inhibits HCMV replication. Effects of solvent fractions on HCMV lytic gene expression and major immediate-early (MIE) enhancer/promoter activity were further investigated. Results Among the solvent fractions tested, the EtOAc fraction of ESE markedly reduced HCMV lytic gene expression and viral replication in vitro without exerting significant cytotoxic effects against human foreskin fibroblasts (HFF). Furthermore, the EtOAc fraction negatively affected HCMV MIE enhancer/promoter activity. Conclusion Our data collectively indicate that the EtOAc fraction of ESE contains active constituents that inhibit HCMV MIE enhancer/promoter activity and viral replication. The EtOAc fraction of ESE is a good source of novel drug candidates for treatment of HCMV-associated diseases.
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10
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Hancock MH, Nelson JA. Modulation of the NFκb Signalling Pathway by Human Cytomegalovirus. VIROLOGY (HYDERABAD) 2017; 1:104. [PMID: 29082387 PMCID: PMC5659363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Many viruses trigger innate and adaptive immune responses and must circumvent the negative consequences to successfully establish infection in their hosts. Human Cytomegalovirus (HCMV) is no exception, and devotes a significant portion of its coding capacity to genes involved in immune evasion. Activation of the NFκB signalling pathway by viral binding and entry results in induction of antiviral and pro-inflammatory genes that have significant negative effects on HCMV infection. However, NFκB signalling stimulates transcription from the Major Immediate Early Promoter (MIEP) and pro-inflammatory signalling is crucial for cellular differentiation and viral reactivation from latency. Accordingly, HCMV encodes proteins that act to both stimulate and inhibit the NFκB signalling pathway. In this Review we will highlight the complex interactions between HCMV and NFκB, discussing the known agonists and antagonists encoded by the virus and suggest why manipulation of the pathway may be critical for both lytic and latent infections.
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Affiliation(s)
- Meaghan H Hancock
- Corresponding author: Meaghan H. Hancock, Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, USA, Tel: 503-418-2784;
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11
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Pellissier LP, Hoek RM, Vos RM, Aartsen WM, Klimczak RR, Hoyng SA, Flannery JG, Wijnholds J. Specific tools for targeting and expression in Müller glial cells. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2014; 1:14009. [PMID: 26015954 PMCID: PMC4362388 DOI: 10.1038/mtm.2014.9] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 02/12/2014] [Indexed: 12/17/2022]
Abstract
Despite their physiological roles, Müller glial cells are involved directly or indirectly in retinal disease pathogenesis and are an interesting target for therapeutic approaches for retinal diseases and regeneration such as CRB1 inherited retinal dystrophies. In this study, we characterized the efficiency of adeno-associated virus (AAV) capsid variants and different promoters to drive protein expression in Müller glial cells. ShH10Y and AAV9 were the most powerful capsids to infect mouse Müller glial cells. Retinaldehyde-binding protein 1 (RLBP1) promoter was the most powerful promoter to transduce Müller glial cells. ShH10Y capsids and RLBP1 promoter targeted human Müller glial cells in vitro. We also developed and tested smaller promoters to express the large CRB1 gene via AAV vectors. Minimal cytomegalovirus (CMV) promoter allowed expression of full-length CRB1 protein in Müller glial cells. In summary, ShH10Y and AAV9 capsids, and RLBP1 or minimal CMV promoters are of interest as specific tools to target and express in mouse or human Müller glial cells.
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Affiliation(s)
- Lucie P Pellissier
- Department of Neuromedical Genetics, Netherlands Institute for Neuroscience, an institute of the Royal Netherlands Academy of Arts and Sciences , Amsterdam, The Netherlands
| | - Robert M Hoek
- Department of Neuromedical Genetics, Netherlands Institute for Neuroscience, an institute of the Royal Netherlands Academy of Arts and Sciences , Amsterdam, The Netherlands
| | - Rogier M Vos
- Department of Neuromedical Genetics, Netherlands Institute for Neuroscience, an institute of the Royal Netherlands Academy of Arts and Sciences , Amsterdam, The Netherlands
| | - Wendy M Aartsen
- Department of Neuromedical Genetics, Netherlands Institute for Neuroscience, an institute of the Royal Netherlands Academy of Arts and Sciences , Amsterdam, The Netherlands
| | - Ryan R Klimczak
- Department of Molecular and Cellular Biology and The Helen Wills Neuroscience Institute, University of California , Berkeley, California, USA
| | - Stefan A Hoyng
- Department of Neuroregeneration, Netherlands Institute for Neuroscience, an institute of the Royal Netherlands Academy of Arts and Sciences , Amsterdam, The Netherlands
| | - John G Flannery
- Department of Molecular and Cellular Biology and The Helen Wills Neuroscience Institute, University of California , Berkeley, California, USA
| | - Jan Wijnholds
- Department of Neuromedical Genetics, Netherlands Institute for Neuroscience, an institute of the Royal Netherlands Academy of Arts and Sciences , Amsterdam, The Netherlands
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12
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Abstract
The history of the molecular biology of cytomegaloviruses from the purification of the virus and the viral DNA to the cloning and expression of the viral genes is reviewed. A key genetic element of cytomegalovirus (the CMV promoter) contributed to our understanding of eukaryotic cell molecular biology and to the development of lifesaving therapeutic proteins. The study of the molecular biology of cytomegaloviruses also contributed to the development of antivirals to control the viral infection.
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Affiliation(s)
- Mark F Stinski
- Department of Microbiology, Carver College of Medicine, University of Iowa, 3-701 BSB, 51 Newton Rd., Iowa City, IA, 52242, USA,
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13
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Penkert RR, Kalejta RF. Tale of a tegument transactivator: the past, present and future of human CMV pp71. Future Virol 2012; 7:855-869. [PMID: 23378857 DOI: 10.2217/fvl.12.86] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Herpesviruses assemble large virions capable of delivering to a newly infected cell not only the viral genome, but also viral proteins packaged within the tegument layer between the DNA-containing capsid and the lipid envelope. In this review, we describe the tegument transactivator of the β-herpesvirus human CMV, the pp71 protein. We present the known mechanistic features through which it activates viral gene expression during a lytic infection but fails to do so when the virus establishes latency, and describe how pp71 stimulates the cell cycle and may help infected cells avoid detection by the adaptive immune system. A historical overview of pp71 is extended with current perceptions of its roles during human CMV infections and suggestions for future avenues of experimentation.
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Affiliation(s)
- Rhiannon R Penkert
- Institute for Molecular Virology & McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, 1525 Linden Drive, Madison, WI 53706, USA
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14
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Simian virus 40 strains with novel properties generated by replacing the viral enhancer with synthetic oligonucleotides. J Virol 2012; 86:3135-42. [PMID: 22238322 DOI: 10.1128/jvi.06293-11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Typical enhancers of viral or cellular genes are approximately 100 to 400 bp long and contain several transcription factor binding sites. Previously, we have shown that simian virus 40 (SV40) genomic DNA that lacks its own enhancer can be used as an "enhancer trap" since it reacquires infectivity upon incorporation of heterologous enhancers. Here, we show that SV40 infectivity can be restored with synthetic enhancers that are assembled by the host cell. We found that several oligonucleotides, cotransfected with enhancerless SV40 DNA into host cells, were incorporated into the viral genome via cellular DNA end joining. The oligonucleotides tested included metal response elements (MREs), the binding sites for the transcription factor MTF-1, which induces gene activity in response to heavy metals. These recombinant SV40 strains showed preferential growth on cells overloaded with zinc or cadmium. We also cotransfected enhancerless SV40 DNA with oligonucleotides corresponding to enhancer motifs of human and mouse cytomegalovirus (HCMV and MCMV, respectively). In contrast to SV40 wild type, the viruses with cytomegalovirus-derived patchwork enhancers strongly expressed T-antigen in human HEK293 cells, accompanied by viral DNA replication. Occasionally, we also observed the assembly of functional viral genomes by incorporation of fragments of bovine DNA, an ingredient of the fetal calf serum in the medium. These fragments contained, among other sites, binding sites for AP-1 and CREB transcription factors. Taken together, our studies show that viruses with novel properties can be generated by intracellular incorporation of synthetic enhancer DNA motifs.
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15
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Aihara Y, Fujiwara N, Yamazaki T, Kambe T, Nagao M, Hirose Y, Masuda S. Enhancing recombinant protein production in human cell lines with a constitutive transport element and mRNA export proteins. J Biotechnol 2011; 153:86-91. [PMID: 21473891 DOI: 10.1016/j.jbiotec.2011.03.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 03/05/2011] [Accepted: 03/29/2011] [Indexed: 11/16/2022]
Abstract
Recent research into mRNA maturation processes in the nucleus has identified a number of proteins involved in mRNA transcription, capping, splicing, end processing and export. Among them, the Tap-p15 heterodimer acts as an mRNA export receptor. Tap-p15 is recruited onto fully processed mRNA in the nucleus, which is ready for export to the cytoplasm, through associating with Aly or SR proteins on mRNA, or by directly associating with a constitutive transport element (CTE), an RNA element derived from type D retroviruses. mRNA containing a CTE is exported to the cytoplasm by directly associating with Tap-p15, even in the absence of Tap-recruiting proteins such as Aly or SR proteins on the mRNA. Here, we showed that the use of a CTE enhanced the expression of recombinant protein in human cell lines. The co-expression of reporter proteins and Tap-p15 also enhanced recombinant protein expression. Moreover, the use of a CTE and Tap-p15 synergistically further enhanced the recombinant protein expression. In addition to Tap-p15, several Tap-p15-recruiting proteins, including Aly and SR proteins, enhanced recombinant protein expression, albeit independently of the CTE. The incorporation of a CTE and Tap-p15-recruiting proteins into protein expression system is useful to increase recombinant protein yield in human cells.
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Affiliation(s)
- Yuki Aihara
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
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Development of a glycoprotein D-expressing dominant-negative and replication-defective herpes simplex virus 2 (HSV-2) recombinant viral vaccine against HSV-2 infection in mice. J Virol 2011; 85:5036-47. [PMID: 21389121 DOI: 10.1128/jvi.02548-10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Using the T-REx (Invitrogen, California) gene switch technology and a dominant-negative mutant polypeptide of herpes simplex virus 1 (HSV-1)-origin binding protein UL9, we previously constructed a glycoprotein D-expressing replication-defective and dominant-negative HSV-1 recombinant viral vaccine, CJ9-gD, for protection against HSV infection and disease. It was demonstrated that CJ9-gD is avirulent following intracerebral inoculation in mice, cannot establish detectable latent infection following different routes of infection, and offers highly effective protective immunity against primary HSV-1 and HSV-2 infection and disease in mouse and guinea pig models of HSV infections. Given these favorable safety and immunological profiles of CJ9-gD, aiming to maximize levels of HSV-2 glycoprotein D (gD2) expression, we have constructed an ICP0 null mutant-based dominant-negative and replication-defective HSV-2 recombinant, CJ2-gD2, that contains 2 copies of the gD2 gene driven by the tetracycline operator (tetO)-bearing HSV-1 major immediate-early ICP4 promoter. CJ2-gD2 expresses gD2 as efficiently as wild-type HSV-2 infection and can lead to a 150-fold reduction in wild-type HSV-2 viral replication in cells coinfected with CJ2-gD2 and wild-type HSV-2 at the same multiplicity of infection. CJ2-gD2 is avirulent following intracerebral injection and cannot establish a detectable latent infection following subcutaneous (s.c.) immunization. CJ2-gD2 is a more effective vaccine than HSV-1 CJ9-gD and a non-gD2-expressing dominant-negative and replication-defective HSV-2 recombinant in protection against wild-type HSV-2 genital disease. Using recall response, we showed that immunization with CJ2-gD2 elicited strong HSV-2-specific memory CD4(+) and CD8(+) T-cell responses. Collectively, given the demonstrated preclinical immunogenicity and its unique safety profiles, CJ2-gD2 represents a new class of HSV-2 replication-defective recombinant viral vaccines in protection against HSV-2 genital infection and disease.
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Functional properties of the human cytomegalovirus IE86 protein required for transcriptional regulation and virus replication. J Virol 2010; 84:8839-48. [PMID: 20554773 DOI: 10.1128/jvi.00327-10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human cytomegalovirus (HCMV) IE86 protein is essential for HCMV replication due to its ability to transactivate critical viral early promoters. In the current study, we performed a comprehensive mutational analysis between amino acids (aa) 535 and 545 of IE86 and assessed the impact of these mutations on IE86-mediated transcriptional activation. Using transient assays and complementing analysis with recombinant HCMV clones, we show that single amino acid mutations differentially impair the ability of IE86 to mediate transactivation of essential early gene promoters. The conserved tyrosine at amino acid 544 is critical for activation of the UL54 promoter in vitro and in the context of the viral genome. In contrast, mutation of the proline at position 535 disrupted activation of the UL54 promoter in transient assays but displayed activity similar to that of wild-type (WT) IE86 when assessed in the genomic context. To examine the underlying mechanism of this differential effect, glutathione S-transferase (GST) pulldown assays were performed, revealing that Y544 is critical for binding to the TATA binding protein (TBP), suggesting that this interaction is likely necessary for the ability of IE86 to activate the UL54 promoter. In contrast, mutation of either P535 or Y544 disrupted activation of the UL112-113 promoter both in vitro and in vivo, suggesting that interaction with TBP is not sufficient for IE86-mediated activation of this early promoter. Together, these studies demonstrate that IE86 activates early promoters by distinct mechanisms.
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Mariati, Ng YK, Chao SH, Yap MGS, Yang Y. Evaluating regulatory elements of human cytomegalovirus major immediate early gene for enhancing transgene expression levels in CHO K1 and HEK293 cells. J Biotechnol 2010; 147:160-3. [PMID: 20416345 DOI: 10.1016/j.jbiotec.2010.02.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 01/13/2010] [Accepted: 02/23/2010] [Indexed: 11/17/2022]
Abstract
The upstream regulatory sequence (URS), NF1 region, enhancer, promoter, 1st exon, and intron A of human cytomegalovirus major immediate early gene (hCMV MIE) are evaluated for enhancing transient and stable gene expression levels in two industrial cell lines, CHO K1 and HEK293 using firefly luciferase (Fluc) and erythropoietin (EPO). As compared to the control vector which only contains the enhancer and promoter (EP), vectors containing the 1st exon (EPE) and intron A (EPEI) enhance transient expression levels of the two proteins by approximately 2.5- to 4.3-fold in the two cell lines. Addition of NF1 and URS to EP (NEP and UNEP) or EPEI (NEPEI and UNEPEI) results in a lesser effect on the expression. In stable transfections, UNEPEI provides the highest expression level in CHO K1 cells, yielding approximately 4.0-fold increase in Fluc expression and 2.5-fold increase in EPO expression. In HEK293 cells, EPE is the best and enhances Fluc and EPO expression by more than 2.0-fold. Such information is valuable for the development of optimal vectors to enhance transient and stable production of recombinant proteins in CHO K1 and HEK293 cells.
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Affiliation(s)
- Mariati
- Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
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Senkel S, Waldner C, Ryffel GU, Thomas H. Improved conditional expression systems resulting in physiological level of HNF4alpha expression confirm HNF4alpha induced apoptosis in the pancreatic beta-cell line INS-1. BMC Res Notes 2009; 2:210. [PMID: 19835622 PMCID: PMC2768738 DOI: 10.1186/1756-0500-2-210] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Accepted: 10/17/2009] [Indexed: 11/10/2022] Open
Abstract
Background To analyze gene function in mammalian cells tetracycline inducible expression of a gene-of-interest at a specific genomic location (Flp-In T-REx™) is most attractive. However, leakiness of basal transgene expression and artificially high expression level upon tetracycline addition may be disadvantageous. Findings To solve these problems, we developed two different approaches to improve our pancreatic β-cell line INS-1 Flp-In T-REx™ expressing the tissue restricted transcription factor HNF4α under control of tetracycline. On the one hand we replaced the strong full length CMV promoter (CMV-Wt) with a weaker 5'-deleted CMV promoter fragment of 138 nucleotides in length (CMV-138). On the other hand we extended our INS-1 Flp-In T-REx™ cell lines with a Shield-1 dependent conditional control system of protein stability. Therefore, we fused HNF4α to the destabilization domain (DD) deduced from human FKBP12 protein. As a result in both approaches basal transgene expression level was markedly reduced, but HNF4α induction could still be maintained. Additionally, we could show that a low increase in HNF4α induces caspase activity indicating an apoptotic effect of HNF4α in these cells. Conclusion In the present study we considerably improved our INS-1 Flp-In T-REx™ cell lines conditionally expressing HNF4α to reduce leakiness and to optimize exogenous HNF4α protein expression to a physiological level. As an important result we could extend our previous results that HNF4α induces apoptosis in the pancreatic β-cell line INS-1 with the new aspect that an expression level of the HNF4α transgene marginally exceeding the endogenous level is sufficient to trigger apoptosis.
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Affiliation(s)
- Sabine Senkel
- Institut für Zellbiologie (Tumorforschung), Universitätsklinikum Essen, Universität, Duisburg-Essen, D-45122 Essen, Germany.
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Epigenetic modulation of gene expression from quiescent herpes simplex virus genomes. J Virol 2009; 83:8514-24. [PMID: 19535445 DOI: 10.1128/jvi.00785-09] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The ability of herpes simplex virus to persist in cells depends on the extent of viral-gene expression, which may be controlled by epigenetic mechanisms. We used quiescent infection with the viral mutants d109 and d106 to explore the effects of cell type and the presence of the viral protein ICP0 on the expression and chromatin structure of the human cytomegalovirus (HCMV) tk and gC promoters on the viral genome. Expression from the HCMV promoter on the d109 genome decreased with time and was considerably less in HEL cells than in Vero cells. Expression from the HCMV promoter in d106 was considerably more abundant than in d109, and this increased with time in both cell types. The same pattern of expression was seen on the tk and gC genes on the viral genomes, although the levels of tk and gC RNA were approximately 10(2)- and 10(5)-fold lower than those of wild-type virus in d106 and d109, respectively. In micrococcal-nuclease digestion experiments, nucleosomes were evident on the d109 genome, and the amount of total H3 as determined by chromatin immunoprecipitation was considerably greater on d109 than d106 genomes. The acetylation of histone H3 on the d106 genomes was evident at early and late times postinfection in Vero cells, but only at late times in HEL cells. The same pattern was observed for H3 acetylated on lysine 9. Trimethylation of H3K9 on d109 genomes was evident only at late times postinfection in Vero cells, while it was observed both early and late in HEL cells. Heterochromatin protein 1gamma (HP1gamma) was generally present only on d109 genomes at late times postinfection of HEL cells. The observations of chromatin structure correlate with the expression patterns of the three analyzed genes on the quiescent genomes. Therefore, several mechanisms generally affect the expression and contribute to the silencing of persisting genomes. These are the abundance of nucleosomes, the acetylation state of the histones, and heterochromatin. The extents to which these different mechanisms contribute to repression vary in different cell types and are counteracted by the presence of ICP0.
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High-level expression of glycoprotein D by a dominant-negative HSV-1 virus augments its efficacy as a vaccine against HSV-1 infection. J Invest Dermatol 2008; 129:1174-84. [PMID: 19005489 DOI: 10.1038/jid.2008.349] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Using the T-REx (Invitrogen, Carlsbad, CA) gene switch technology, we previously generated a dominant-negative herpes simplex virus (HSV)-1 recombinant, CJ83193, capable of inhibiting its own replication as well as that of wild-type HSV-1 and HSV-2. It has been further demonstrated that CJ83193 is an effective vaccine against HSV-1 infection in a mouse ocular model. To ensure its safety and augment its efficacy, we generated an improved CJ83193-like HSV-1 recombinant, CJ9-gD, which contains a deletion in an HSV-1 essential gene and encodes an extra copy of gene-encoding glycoprotein D (gD) driven by the tetO-bearing human cytomegalovirus major immediate-early promoter. Unlike CJ83193, which exhibits limited plaque-forming capability in Vero cells and expresses little gD in infected cells, CJ9-gD is completely replication defective, yields high-level expression of gD following infection, and cannot establish detectable infection in mouse trigeminal ganglia following intranasal and ocular inoculation. Mice immunized with CJ9-gD produced 3.5-fold higher HSV-1 neutralizing antibody titer than CJ83193-immunized mice, and were completely protected from herpetic ocular disease following corneal challenge with wild-type HSV-1. Moreover, immunization of mice with CJ9-gD elicited a strong HSV-1-specific T-cell response and led to an 80% reduction in latent infection by challenge wild-type HSV-1 compared with the mock-immunized control.
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Moon JS, Lee MY, Park SW, Han WK, Hong SW, Ahn JH, Kim KS. Androgen-dependent activation of human cytomegalovirus major immediate-early promoter in prostate cancer cells. Prostate 2008; 68:1450-60. [PMID: 18615458 DOI: 10.1002/pros.20817] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Human cytomegalovirus (HCMV) major immediate early (MIE) promoter, which is involved in viral reactivation, is specifically activated by androgen in LNCaP prostate cancer cells. METHODS Androgen-dependent transcriptional activities of the HCMV MIE promoter were measured by transient transfection assay. Expression levels of genes related to protein kinase A (PKA)-signaling pathway was measured by RT-PCR. RESULTS Activation of the HCMV MIE promoter by androgen results from an increase in PKA activities. The expression level of PKA catalytic (C) subunit beta transcript variant 2 (PKA-C beta 2) was decreased by serum deprivation and was increased by R1881 treatment, in a pattern similar to changes of the HCMV MIE promoter activities. Furthermore the exogenous expression of PKA-C beta 2 strongly activated the HCMV MIE promoter, indicating that regulation of the PKA-C beta 2 expression might be a direct upstream factor in the HCMV MIE promoter regulation by androgen in LNCaP cells. CONCLUSIONS The data elucidated the mechanisms by which androgen activates PKA in androgen-dependent prostate cancer cells, resulting in activation of the HCMV MIE promoter. These results support the possibility that activation of the HCMV MIE promoter by androgen in the prostate could cause the productive infection, which might contribute to oncomodulation in prostate cancers.
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Affiliation(s)
- Jong-Seok Moon
- Department of Biochemistry and Molecular Biology, Institute of Genetic Science, Center for Chronic Metabolic Disease Research, Brain Korea 21 Project for Medical Science, Yonsei University, College of Medicine, Seodaemungu, Seoul, Korea
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Abstract
SUMMARY Human cytomegalovirus (HCMV) is a common, medically relevant human herpesvirus. The tegument layer of herpesvirus virions lies between the genome-containing capsids and the viral envelope. Proteins within the tegument layer of herpesviruses are released into the cell upon entry when the viral envelope fuses with the cell membrane. These proteins are fully formed and active and control viral entry, gene expression, and immune evasion. Most tegument proteins accumulate to high levels during later stages of infection, when they direct the assembly and egress of progeny virions. Thus, viral tegument proteins play critical roles at the very earliest and very last steps of the HCMV lytic replication cycle. This review summarizes HCMV tegument composition and structure as well as the known and speculated functions of viral tegument proteins. Important directions for future investigation and the challenges that lie ahead are identified and discussed.
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TNF Receptor Independent Activation of the Cytomegalovirus Major Immediate Early Enhancer in Response to Transplantation. Transplantation 2008; 85:1039-45. [DOI: 10.1097/tp.0b013e318168449c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Kuroda T, Martuza RL, Todo T, Rabkin SD. Flip-Flop HSV-BAC: bacterial artificial chromosome based system for rapid generation of recombinant herpes simplex virus vectors using two independent site-specific recombinases. BMC Biotechnol 2006; 6:40. [PMID: 16995942 PMCID: PMC1609115 DOI: 10.1186/1472-6750-6-40] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Accepted: 09/22/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Oncolytic herpes simplex virus (HSV) vectors that specifically replicate in and kill tumor cells sparing normal cells are a promising cancer therapy. Traditionally, recombinant HSV vectors have been generated through homologous recombination between the HSV genome and a recombination plasmid, which usually requires laborious screening or selection and can take several months. Recent advances in bacterial artificial chromosome (BAC) technology have enabled cloning of the whole HSV genome as a BAC plasmid and subsequent manipulation in E. coli. Thus, we sought a method to generate recombinant oncolytic HSV vectors more easily and quickly using BAC technology. RESULTS We have developed an HSV-BAC system, termed the Flip-Flop HSV-BAC system, for the rapid generation of oncolytic HSV vectors. This system has the following features: (i) two site-specific recombinases, Cre and FLPe, are used sequentially to integrate desired sequences and to excise the BAC sequences, respectively; and (ii) the size of the HSV-BAC-insert genome exceeds the packaging limit of HSV so only correctly recombined virus grows efficiently. We applied this to the construction of an HSV-BAC plasmid that can be used for the generation of transcriptionally-targeted HSV vectors. BAC sequences were recombined into the UL39 gene of HSV ICP4-deletion mutant d120 to generate M24-BAC virus, from which HSV-BAC plasmid pM24-BAC was isolated. An ICP4 expression cassette driven by an exogenous promoter was re-introduced to pM24-BAC by Cre-mediated recombination and nearly pure preparations of recombinant virus were obtained typically in two weeks. Insertion of the ICP4 coding sequence alone did not restore viral replication and was only minimally better than an ICP4-null construct, whereas insertion of a CMVIE promoter-ICP4 transgene (bM24-CMV) efficiently drove viral replication. The levels of bM24-CMV replication in tumor cells varied considerably compared to hrR3 (UL39 mutant). CONCLUSION Our Flip-Flop HSV-BAC system enables rapid generation of HSV vectors carrying transgene inserts. By introducing a tumor-specific-promoter-driven ICP4 cassette into pM24-BAC using this system, one should be able to generate transcriptionally-targeted oncolytic HSV vectors. We believe this system will greatly facilitate the screening of a plethora of clinically useful tumor-specific promoters in the context of oncolytic HSV vectors.
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Affiliation(s)
- Toshihiko Kuroda
- Molecular Neurosurgery Laboratory, Department of Neurosurgery, Massachusetts General Hospital/Harvard Medical School, 185 Cambridge St., CPZN-3800, Boston, MA 02114, USA
| | - Robert L Martuza
- Molecular Neurosurgery Laboratory, Department of Neurosurgery, Massachusetts General Hospital/Harvard Medical School, 185 Cambridge St., CPZN-3800, Boston, MA 02114, USA
| | - Tomoki Todo
- Molecular Neurosurgery Laboratory, Department of Neurosurgery, Massachusetts General Hospital/Harvard Medical School, 185 Cambridge St., CPZN-3800, Boston, MA 02114, USA
- Present address: Department of Neurosurgery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113–8655, Japan
| | - Samuel D Rabkin
- Molecular Neurosurgery Laboratory, Department of Neurosurgery, Massachusetts General Hospital/Harvard Medical School, 185 Cambridge St., CPZN-3800, Boston, MA 02114, USA
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Yao F, Theopold C, Hoeller D, Bleiziffer O, Lu Z. Highly efficient regulation of gene expression by tetracycline in a replication-defective herpes simplex viral vector. Mol Ther 2006; 13:1133-41. [PMID: 16574491 DOI: 10.1016/j.ymthe.2006.01.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2004] [Revised: 01/09/2006] [Accepted: 01/12/2006] [Indexed: 11/19/2022] Open
Abstract
Employing the tetracycline repressor tetR and the wild-type hCMV major immediate-early promoter, we have developed a highly sensitive tetracycline-inducible transcription switch in mammalian cells (T-REx; Invitrogen, Carlsbad, CA, USA). In view of the previous difficulty in achieving regulatable gene expression in recombinant HSV vector systems, we constructed a T-REx-encoding replication-defective HSV-1 recombinant, QR9TO-lacZ, that encodes two copies of the tetR gene controlled by the HSV-1 immediate-early ICP0 promoter and a reporter, the LacZ gene, under the control of the tetO-bearing hCMV major immediate-early promoter. Infection of cells, such as Vero, PC12, and NGF-differentiated PC12 cells, with QR9TO-lacZ led to 300- to 1000-fold tetracycline-regulated gene expression. Moreover, the expression of the LacZ gene by QR9TO-lacZ can be finely controlled by tetracycline in a dose-dependent fashion. Efficiently regulated gene expression can also be achieved in vivo following intracerebral and footpad inoculations in mice. The demonstrated capability of T-REx for achieving high levels of sensitively regulated gene expression in the context of the HSV-1 genome will significantly expand the utility of HSV-based vector systems for studying gene function in the nervous system and delivering regulated gene expression in therapeutic applications, particularly in the treatment of CNS diseases.
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Affiliation(s)
- Feng Yao
- Laboratory of Tissue Repair and Gene Transfer, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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Lu F, Day L, Lieberman PM. Kaposi's sarcoma-associated herpesvirus virion-induced transcription activation of the ORF50 immediate-early promoter. J Virol 2005; 79:13180-5. [PMID: 16189019 PMCID: PMC1235868 DOI: 10.1128/jvi.79.20.13180-13185.2005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lytic cycle reactivation of Kaposi's sarcoma-associated herpesvirus (KSHV) can be initiated by transcription activation of the ORF50 immediate-early (IE) gene promoter (ORF50p). We provide evidence that KSHV virions stimulate transcription of ORF50p. Virion activation was resistant to UV inactivation and cycloheximide treatment. The virion-responsive element was mapped to core promoter region -150 to + 1 relative to the ORF50 initiation codon. Electrophoretic mobility shift assays and chromatin immunoprecipitation suggest that KSHV virions indirectly alter the protein composition and chromatin modifications at ORF50p. These data suggest that KSHV virions possess an IE trans-inducing function similar to that observed in alpha- and betaherpesviruses.
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Affiliation(s)
- Fang Lu
- The Wistar Institute, Philadelphia, PA 19104, USA
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Kim SJ, Varghese TK, Zhang Z, Zhao LC, Thomas G, Hummel M, Abecassis M. Renal ischemia/reperfusion injury activates the enhancer domain of the human cytomegalovirus major immediate early promoter. Am J Transplant 2005; 5:1606-13. [PMID: 15943618 DOI: 10.1111/j.1600-6143.2005.00912.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Reactivation of latent human cytomegalovirus is of significant concern in immunocompromised transplant patients and is likely to occur through transcriptional activation of immediate early (ie) gene expression through mechanisms that are not well understood. TNF-mediated activation of NF-kappaB has been proposed to be one pathway leading to transcriptional activation of CMV ie gene expression. Using transgenic mice carrying a lacZ reporter gene under the control of the HCMV major ie promoter/enhancer (MIEP-lacZ mice) and MIEP-lacZ mice deficient in TNF receptor 1 and TNF receptor 2 (MIEP-lac Z TNFR DKO mice), we demonstrate that renal ischemia/reperfusion (I/R) injury activates the HCMV enhancer independently of TNF. Induction of MIEP-lacZ expression was preceded by TNFR-independent formation of reactive oxygen species (ROS), weak and transient activation of NF-kappaB and strong and sustained activation of AP-1. Our studies show that, in addition to TNF-mediated signaling, TNF-independent signaling induced by I/R injury can contribute to the activation of the HCMV enhancer. This likely occurs through ROS-mediated activation of AP-1. Targeting MAP kinase signaling pathways as well as NF-kappaB may be of therapeutic value in patients with CMV infection.
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Affiliation(s)
- Soo Jung Kim
- Department of Surgery, Transplant Lab, Northwestern University, Chicago, IL 60611, USA
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Ostedgaard LS, Rokhlina T, Karp PH, Lashmit P, Afione S, Schmidt M, Zabner J, Stinski MF, Chiorini JA, Welsh MJ. A shortened adeno-associated virus expression cassette for CFTR gene transfer to cystic fibrosis airway epithelia. Proc Natl Acad Sci U S A 2005; 102:2952-7. [PMID: 15703296 PMCID: PMC549485 DOI: 10.1073/pnas.0409845102] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Adeno-associated viruses (AAVs) such as AAV5 that transduce airway epithelia from the apical surface are attractive vectors for gene transfer in cystic fibrosis (CF). However, their utility in CF has been limited because packaging of the insert becomes inefficient when its length exceeds approximately 4,900-5,000 bp. To partially circumvent this size constraint, we previously developed a CF transmembrane conductance regulator (CFTR) transgene that deleted a portion of the R domain (CFTRDeltaR). In this study, we focused on shortening the other elements in the AAV expression cassette. We found that portions of the CMV immediate/early (CMVie) enhancer/promoter could be deleted without abolishing activity. We also tested various intervening sequences, poly(A) signals, and an intron to develop an expression cassette that meets the size restrictions imposed by AAV. We then packaged these shortened elements with the CFTRDeltaR transgene into AAV5 and applied them to the apical surface of differentiated CF airway epithelia. Two to 4 weeks later, the AAV5 vectors partially corrected the CF Cl(-) transport defect. These results demonstrate that a single AAV vector can complement the CF defect in differentiated airway epithelia and thereby further the development of effective CF gene transfer.
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Affiliation(s)
- Lynda S Ostedgaard
- Howard Hughes Medical Institute and Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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Schierling K, Stamminger T, Mertens T, Winkler M. Human cytomegalovirus tegument proteins ppUL82 (pp71) and ppUL35 interact and cooperatively activate the major immediate-early enhancer. J Virol 2004; 78:9512-23. [PMID: 15308743 PMCID: PMC506970 DOI: 10.1128/jvi.78.17.9512-9523.2004] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The tegument protein ppUL82 (pp71) of human cytomegalovirus (HCMV) has previously been shown to activate the immediate-early transcription of HCMV and to enhance the infectivity of viral DNA. This is concordant with its localization adjacent to promyelocytic leukemia oncogenic domains (PODs) immediately after infection. In a yeast two-hybrid screen, we identified the tegument protein ppUL35 as an interacting partner of ppUL82. The interaction could be confirmed in transfected and infected cells. The domain responsible for interaction was narrowed down to amino acids 447 to 516 within ppUL35, thus allowing both forms of ppUL35 to interact with ppUL82. Immunofluorescence experiments showed a relocalization of ppUL35 from a diffuse nuclear pattern when expressed alone to PODs when expressed together with ppUL82. In accordance with this observation and the role of ppUL82 as a transactivator, we observed a cooperative activation of the HCMV major immediate-early enhancer but not of heterologous viral enhancer elements. These results suggest an important role for this interaction in the stimulation of viral immediate-early gene expression and viral infection.
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Michelson S. Consequences of human cytomegalovirus mimicry. Hum Immunol 2004; 65:465-75. [PMID: 15172446 DOI: 10.1016/j.humimm.2004.02.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2003] [Revised: 01/15/2004] [Accepted: 02/03/2004] [Indexed: 12/19/2022]
Abstract
The HCMV genome has evolved with its host by incorporating a series of genes that are homologous to, or functionally mimic, cellular genes. Some are designed to counteract the stress of infection on the host cell, notably the viral antiapoptotic proteins (vICA, vMIA). Others potentially help the infected cell maintain a low immunologic profile. These include virus-encoded chemokine receptors (UL33, UL78, US27, US28), FcRs (gp TRL11/IRL11, gp UL119-118), and proteins that directly or indirectly thwart natural killer cell activity (UL16, gpUL40). In addition, some viral proteins may play a role in immunopathology because of fortuitous cross-reactivity with host cell proteins. This overview discusses how these proteins affect the life of the host cell and its immediate neighbors.
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Affiliation(s)
- Susan Michelson
- Unité d'Immunologie Virale, Institut Pasteur, Paris, France.
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Blancou P, Chenciner N, Ho Tsong Fang R, Monceaux V, Cumont MC, Guétard D, Hurtrel B, Wain-Hobson S. Simian immunodeficiency virus promoter exchange results in a highly attenuated strain that protects against uncloned challenge virus. J Virol 2004; 78:1080-92. [PMID: 14722263 PMCID: PMC321388 DOI: 10.1128/jvi.78.3.1080-1092.2004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Among the many simian immunodeficiency virus (SIV) immunogens, only live attenuated viral vaccines have afforded strong protection to a natural pathogenic isolate. Since the promoter is crucial to the tempo of viral replication in general, it was reasoned that promoter exchange might confer a novel means of attenuating SIV. The core enhancer and promoter sequences of the SIV macaque 239nefstop strain (NF-kappaB/Sp1 region from -114 bp to mRNA start) have been exchanged for those of the human cytomegalovirus immediate-early promoter (CMV-IE; from -525 bp to mRNA start). During culture of the resulting virus, referred to as SIVmegalo, on CEMx174 or rhesus macaque peripheral blood mononuclear cells, deletions arose in distal regions of the CMV-IE sequences that stabilized after 1 or 2 months of culture. However, when the undeleted form of SIVmegalo was inoculated into rhesus macaques, animals showed highly controlled viremia during primary and persistent infection. Compared to parental virus infection in macaques, primary viremia was reduced by >1,000-fold to undetectable levels, with little sign of an increase of cycling cells in lymph nodes, CD4(+) depletion, or altered T-cell activation markers in peripheral blood. Moreover, in contrast to wild-type infection in most infected animals, the nef stop mutation did not revert to the wild-type codon, indicating yet again that replication was dramatically curtailed. Despite such drastic attenuation, antibody titers and enzyme-linked immunospot reactivity to SIV peptides, although slower to appear, were comparable to those seen in a parental virus infection. When animals were challenged intravenously at 4 or 6 months with the uncloned pathogenic SIVmac251 strain, viremia was curtailed by approximately 1,000-fold at peak height without any sign of hyperactivation in CD4(+)- or CD8(+)-T-cell compartment or increase in lymph node cell cycling. To date, there has been a general inverse correlation between attenuation and protection; however, these findings show that promoter exchange constitutes a novel means to highly attenuate SIV while retaining the capacity to protect against challenge virus.
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Affiliation(s)
- Philippe Blancou
- Unité de Rétrovirologie Moléculaire. Unité de Physiopathologie des Infections Lentivirales, Institut Pasteur, 75724 Paris Cedex 15, France
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33
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Keller MJ, Wheeler DG, Cooper E, Meier JL. Role of the human cytomegalovirus major immediate-early promoter's 19-base-pair-repeat cyclic AMP-response element in acutely infected cells. J Virol 2003; 77:6666-75. [PMID: 12767986 PMCID: PMC156166 DOI: 10.1128/jvi.77.12.6666-6675.2003] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2003] [Accepted: 03/18/2003] [Indexed: 01/08/2023] Open
Abstract
Prior studies have suggested a role of the five copies of the 19-bp-repeat cyclic AMP (cAMP)-response element (CRE) in major immediate-early (MIE) promoter activation, the rate-limiting step in human cytomegalovirus (HCMV) replication. We used two different HCMV genome modification strategies to test this hypothesis in acutely infected cells. We report the following: (i) the CREs do not govern basal levels of MIE promoter activity at a high or low multiplicity of infection (MOI) in human foreskin fibroblast (HFF)- or NTera2-derived neuronal cells; (ii) serum and virion components markedly increase MIE promoter-dependent transcription at a low multiplicity of infection (MOI), but this increase is not mediated by the CREs; (iii) forskolin stimulation of the cAMP signaling pathway induces a two- to threefold increase in MIE RNA levels in a CRE-specific manner at a low MOI in both HFF- and NTera2-derived neuronal cells; and (iv) the CREs do not regulate basal levels of HCMV DNA replication at a high or low MOI in HFF. Their presence does impart a forskolin-induced increase in viral DNA replication at a low MOI but only when basal levels of MIE promoter activity are experimentally diminished. In conclusion, the 19-bp-repeat CREs add to the robust MIE promoter activity that occurs in the acutely infected stimulated cells, although the CREs' greater role may be in other settings.
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Affiliation(s)
- M J Keller
- Department of Internal Medicine and the Helen C. Levitt Center for Viral Pathogenesis and Disease, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242, USA
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34
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Oertel M, Rosencrantz R, Chen YQ, Thota PN, Sandhu JS, Dabeva MD, Pacchia AL, Adelson ME, Dougherty JP, Shafritz DA. Repopulation of rat liver by fetal hepatoblasts and adult hepatocytes transduced ex vivo with lentiviral vectors. Hepatology 2003; 37:994-1005. [PMID: 12717380 DOI: 10.1053/jhep.2003.50183] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Recent studies have shown that nondividing primary cells, such as hepatocytes, can be efficiently transduced in vitro by human immunodeficiency virus-based lentivirus vectors. Other studies have reported that, under certain conditions, the liver can be repopulated with transplanted hepatocytes. In the present study, we combined these procedures to develop a model system for ex vivo gene therapy by repopulating rat livers with hepatocytes and hepatoblasts transduced with a lentivirus vector expressing a reporter gene, green fluorescent protein (GFP). Long-term GFP expression in vivo (up to 4 months) was achieved when the transgene was driven by the liver-specific albumin enhancer/promoter but was silenced when the cytomegalovirus (CMV) enhancer/promoter was used. Transplanted cells were massively amplified ( approximately 10 cell doublings) under the influence of retrorsine/partial hepatectomy, and both repopulation and continued transgene expression in individual cells were documented by dual expression of a cell transplantation marker, dipeptidyl peptidase IV (DPPIV), and GFP. In this system, maintenance or expansion of the transplanted cells did not depend on expression of the transgene, establishing that positive selection is not required to maintain transgene expression following multiple divisions of transplanted, lentivirus-transduced hepatic cells. In conclusion, fetal hepatoblasts (liver stem/progenitor cells) can serve as efficient vehicles for ex vivo gene therapy and suggest that liver-based genetic disorders that do not shorten hepatocyte longevity or cause liver damage, such as phenylketonuria, hyperbilirubinemias, familial hypercholesterolemia, primary oxalosis, and factor IX deficiency, among others, might be amenable to treatment by this approach.
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Affiliation(s)
- Michael Oertel
- Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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35
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Nyquist AC, Zhang L, Weinberg A. Human fibroblasts transfected with cytomegalovirus immediate-early genes show increased MHC class I expression and are targets for natural killer cell-mediated cytotoxicity. Viral Immunol 2002; 15:147-54. [PMID: 11952136 DOI: 10.1089/088282402317340297] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Natural killer (NK) cells are an important line of defense against viral infections, such as those caused by cytomegalovirus (CMV), but in the context of solid organ transplantation NK responses to CMV-infected graft cells might be deleterious to the graft survival. To gain a better understanding of NK responses to CMV-infected human lung fibroblasts (HLF), we transfected HLF with a plasmid expressing CMV immediate-early (IE) genes under the control of the CMV major IE promoter and compared major histocompatibility complex (MHC) class I expression and NK-mediated lysis of transfected cells, CMV-infected cells, and appropriate controls. HLF transfected with CMV IE genes showed increased MHC Class I expression and triggered NK-mediated cytotoxicity at the same level as CMV-infected HLF and at significantly higher levels than mock-infected or mock-transfected controls. Transfection of CMV genes provides an experimental model for molecular studies of CMV- and allograft-specific cell-mediated immunity and modulation.
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Affiliation(s)
- Ann-Christine Nyquist
- Department of Pediatrics, University of Colorado Health Sciences Center, Denver, USA.
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36
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Abstract
BACKGROUND Reactivation of CMV from latency results in serious morbidity and mortality in immunocompromised transplant recipients. The mechanism by which CMV reactivates from latency has not been well understood. OBJECTIVE In this review we discuss three models for reactivation from latency and present evidence in favor of the model that reactivation is a multi-step process which is initiated by the allogeneic response to the transplanted organ. Study design (J. Virol. 75 (2001) 4814). Mice latently infected with murine cytomegalovirus (MCMV) were used as donors for allogeneic or syngeneic kidney transplants into immunocompetent recipients. The contralateral donor kidneys were used as controls. Transplanted kidneys were removed at various times after transplant and analyzed for expression of viral genes associated with productive infection and for expression of inflammatory cytokines. Electrophoretic mobility shift assay was performed on nuclear extracts of control and transplanted kidneys to examine activation of AP-1 and NFkappaB. Latently infected mice were also injected with tumor necrosis factor (TNF) to examine the effect of TNF alone on induction of MCMV immediate-early (IE) gene expression. Transgenic major immediate early promoter-lacZ mice carrying a beta-galactosidase reporter gene under the control of the human cytomegalovirus (HCMV) IE promoter/enhancer were used as donors for allogeneic kidney transplants to study the effect of allogeneic transplantation on induction of HCMV IE gene expression. RESULTS Allogeneic, but not syngeneic transplantation induces MCMV IE-1 expression and expression of inflammatory cytokines, including TNF. Allogeneic transplantation activates transcription factors, including NFkappaB and AP-1. TNF alone can induce MCMV IE-1 gene expression and activation of NFkappaB and AP-1 in some tissues. CONCLUSIONS We propose that induction of IE-1 gene expression is the first step in reactivation of the virus in an immunocompromised transplant recipient, and that it occurs as a result of the allogeneic response, which induces expression of TNF and subsequent activation of NFkappaB, and ischemia/reperfusion injury, which induces activation of AP-1. We speculate that the natural stimulus for reactivation in an immunocompetent host is an inflammatory immune response to infection and that allogeneic transplantation mimics this process.
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Affiliation(s)
- Mary Hummel
- Department of Surgery, Division of Organ Transplantation, Northwestern University Medical School, Chicago, IL 60611, USA.
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37
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Hofmann H, Sindre H, Stamminger T. Functional interaction between the pp71 protein of human cytomegalovirus and the PML-interacting protein human Daxx. J Virol 2002; 76:5769-83. [PMID: 11992005 PMCID: PMC137040 DOI: 10.1128/jvi.76.11.5769-5783.2002] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The tegument protein pp71 (UL82) of human cytomegalovirus (HCMV) has previously been shown to transactivate the major immediate-early enhancer-promoter of HCMV. Furthermore, this protein is able to enhance the infectivity of viral DNA and to accelerate the infection cycle, suggesting an important regulatory function during viral replication. To gain insight into the underlying mechanisms that are used by pp71 to exert these pleiotropic effects, we sought for cellular factors interacting with pp71 in a yeast two-hybrid screen. Here, we report the isolation of the human Daxx (hDaxx) protein as a specific interaction partner of HCMV pp71. hDaxx, which was initially described as an adapter protein involved in apoptosis regulation, has recently been identified as a nuclear protein that interacts and colocalizes with PML in the nuclear domain ND10. In order to assess whether pp71 can also be detected in ND10 structures, a vector expressing pp71 in fusion with the green fluorescent protein was used for transfection of human fibroblasts. This revealed a colocalization of pp71 with the ND10 proteins PML and Sp100. In addition, cotransfection of a hDaxx expression vector resulted in an enhanced recruitment of pp71 to ND10. Targeting of pp71 to nuclear dots could also be observed in infected human fibroblasts in the absence of de novo viral protein synthesis. Moreover, cotransfection experiments revealed that pp71-mediated transactivation of the major immediate-early enhancer-promoter was synergistically enhanced in the presence of hDaxx. These results suggest an important role of hDaxx for pp71 protein function.
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Affiliation(s)
- Heike Hofmann
- Institut für Klinische und Molekulare Virologie der Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
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38
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Meier JL, Keller MJ, McCoy JJ. Requirement of multiple cis-acting elements in the human cytomegalovirus major immediate-early distal enhancer for viral gene expression and replication. J Virol 2002; 76:313-26. [PMID: 11739696 PMCID: PMC135711 DOI: 10.1128/jvi.76.1.313-326.2002] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We have shown previously that the human cytomegalovirus (HCMV) major immediate-early (MIE) distal enhancer is needed for MIE promoter-dependent transcription and viral replication at low multiplicities of infection (MOI). To understand how this region works, we constructed and analyzed a series of HCMVs with various distal enhancer mutations. We show that the distal enhancer is composed of at least two parts that function independently to coordinately activate MIE promoter-dependent transcription and viral replication. One such part is contained in a 47-bp segment that has consensus binding sites for CREB/ATF, SP1, and YY1. At low MOI, these working parts likely function in cis to directly activate MIE gene expression, thus allowing viral replication to ensue. Three findings support the view that these working parts are likely cis-acting elements. (i) Deletion of either part of a bisegmented distal enhancer only slightly alters MIE gene transcription and viral replication. (ii) Reversing the distal enhancer's orientation largely preserves MIE gene transcription and viral replication. (iii) Placement of stop codons at -300 or -345 in all reading frames does not impair MIE gene transcription and viral replication. Lastly, we show that these working parts are dispensable at high MOI, partly because of compensatory stimulation of MIE promoter activity and viral replication that is induced by a virion-associated component(s) present at a high viral particle/cell ratio. We conclude that the distal enhancer is a complex multicomponent cis-acting region that is required to augment both MIE promoter-dependent transcription and HCMV replication.
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Affiliation(s)
- Jeffery L Meier
- Department of Internal Medicine and the Helen C. Levitt Center for Viral Pathogenesis and Disease, University of Iowa College of Medicine, Iowa City, Iowa, 52242, USA.
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39
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Hummel M, Zhang Z, Yan S, DePlaen I, Golia P, Varghese T, Thomas G, Abecassis MI. Allogeneic transplantation induces expression of cytomegalovirus immediate-early genes in vivo: a model for reactivation from latency. J Virol 2001; 75:4814-22. [PMID: 11312353 PMCID: PMC114236 DOI: 10.1128/jvi.75.10.4814-4822.2001] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Reactivation of cytomegalovirus (CMV) from latency is a frequent complication of organ transplantation, and the molecular mechanism by which this occurs is unknown. Previous studies have shown that allogeneic stimulation induces reactivation of human CMV (HCMV) in vitro (64). We find that transplantation of vascularized allogeneic kidneys induces murine CMV (MCMV) and HCMV immediate-early (ie) gene expression. This induction is accompanied by increased expression of transcripts encoding inflammatory cytokines, including tumor necrosis factor (TNF), interleukin-2, and gamma interferon, and by activation of NF-kappaB. TNF alone can substitute for allogeneic transplantation in inducing HCMV and MCMV ie gene expression in some tissues. Our studies suggest that reactivation is a multistep process which is initiated by factors that induce ie gene expression, including TNF and NF-kappaB. Allogeneic transplantation combined with immunosuppression may be required to achieve complete reactivation in vivo.
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Affiliation(s)
- M Hummel
- Department of Surgery, Division of Organ Transplantation, Northwestern University Medical School, Chicago, Illinois 60611, USA
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40
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Sanchez TA, Habib I, Leland Booth J, Evetts SM, Metcalf JP. Zinc finger and carboxyl regions of adenovirus E1A 13S CR3 are important for transactivation of the cytomegalovirus major immediate early promoter by adenovirus. Am J Respir Cell Mol Biol 2000; 23:670-7. [PMID: 11062146 DOI: 10.1165/ajrcmb.23.5.3675] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Reactivation of latent cytomegalovirus (CMV) is an important cause of disease in susceptible patients. We previously demonstrated that an adenovirus early gene product can transactivate the CMV major immediate early (IE) promoter in inflammatory cells. This effect was due to the conserved region 3 (CR3) of the adenovirus E1A 13S gene product. There are two domains in the CR3 region, a zinc finger (aa 147-177) and a carboxyl (aa 180-188) domain. Both are crucial for transactivation of downstream promoter elements of adenovirus in E1A 13S. We sought to determine if either or both of these specific domains is also necessary for transactivation of the CMV IE promoter by the adenovirus E1A 13S gene product. We cotransfected T-lymphocyte Jurkat cells and monocyte/macrophage-like THP-1 cells with plasmids expressing wild-type (WT) or CR3 mutant E1A 13S and a CMV IE chloramphenicol acetyltransferase (CAT) reporter construct. With extracts of cells coinfected with E1A WT set to 100%, mutation in the zinc finger domain, the carboxyl domain, or both domains decreased CMV IE CAT activity by >/= 96%. In contrast, a mutation in the region between the zinc finger and carboxyl domains reduced CMV IE CAT activity by only 24 to 26%. Mixing studies in Jurkat cells confirmed the importance of these domains. We also evaluated the active site of the CMV IE promoter involved in transactivation in THP-1 cells using CMV IE promoter deletions and single promoter element constructs. These studies showed that progressive deletion of the 19-bp CMV IE repeats containing cyclic AMP response element binding protein/activating transcription factor (CREB/ATF) sites resulted in progressive loss of activity. The importance of this element was confirmed using single promoter elements containing CMV IE 16-, 18-, 19-, and 21-bp repeats. Finally, using a 19-bp single promoter element construct and the CR3 mutants we demonstrated that mutations in the zinc finger (C171S) carboxyl region (S185N) or both regions (C171S/ S185N) resulted in significant (83, 94, and 85%) loss of activity. We conclude that the zinc finger and carboxyl domains of the CR3 region of E1A 13S are necessary for transactivation of the CMV promoter and that this occurs mainly through activation of the 19-bp CREB/ATF site of the promoter.
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Affiliation(s)
- T A Sanchez
- Pulmonary and Critical Care Division, Department of Internal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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41
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Meier JL, Pruessner JA. The human cytomegalovirus major immediate-early distal enhancer region is required for efficient viral replication and immediate-early gene expression. J Virol 2000; 74:1602-13. [PMID: 10644329 PMCID: PMC111634 DOI: 10.1128/jvi.74.4.1602-1613.2000] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human cytomegalovirus (HCMV) major immediate-early (MIE) genes, encoding IE1 p72 and IE2 p86, are activated by a complex enhancer region (base positions -65 to -550) that operates in a cell type- and differentiation-dependent manner. The expression of MIE genes is required for HCMV replication. Previous studies analyzing functions of MIE promoter-enhancer segments suggest that the distal enhancer region variably modifies MIE promoter activity, depending on cell type, stimuli, or state of differentiation. To further understand the mechanism by which the MIE promoter is regulated, we constructed and analyzed several different recombinant HCMVs that lack the distal enhancer region (-300 to -582, -640, or -1108). In human fibroblasts, the HCMVs without the distal enhancer replicate normally at high multiplicity of infection (MOI) but replicate poorly at low MOI in comparison to wild-type virus (WT) or HCMVs that lack the neighboring upstream unique region and modulator (-582 or -640 to -1108). The growth aberrancy was normalized after restoring the distal enhancer in a virus lacking this region. For HCMVs without a distal enhancer, the impairment in replication at low MOI corresponds to a deficiency in production of MIE RNAs compared to WT or virus lacking the unique region and modulator. An underproduction of viral US3 RNA was also evident at low MOI. Whether lower production of IE1 p72 and IE2 p86 causes a reduction in expression of the immediate-early (IE) class US3 gene remains to be determined. We conclude that the MIE distal enhancer region possesses a mechanism for augmenting viral IE gene expression and genome replication at low MOI, but this regulatory function is unnecessary at high MOI.
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Affiliation(s)
- J L Meier
- Department of Internal Medicine and the Helen C. Levitt Center for Viral Pathogenesis and Disease, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
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42
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Christenson SD, Lund D, Ooboshi H, Faraci FM, Davidson L, Heistad DD. Approaches to enhance expression after adenovirus-mediated gene transfer to the carotid artery. ENDOTHELIUM : JOURNAL OF ENDOTHELIAL CELL RESEARCH 1999; 7:75-82. [PMID: 10599561 DOI: 10.3109/10623329909165313] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The goal of this study was to enhance transgene expression after adenoviral-mediated gene transfer to the carotid artery. We used an adenoviral vector with a transgene that expresses beta-galactosidase, driven by the human cytomegalovirus (CMV) promoter/enhancer. The CMV promoter drives constitutive expression, and response elements within the enhancer allow inducible expression through binding of active transcription factors, such as cAMP response element binding protein (CREB) and nuclear factor kappa B (NFkappaB). Rings of rabbit carotid artery were incubated ex vivo with a replication-deficient adenovirus that expresses beta-galactosidase (AdCMV-betagal). Virus was removed from the medium, and forskolin or phorbol-12-myristate-13-acetate (PMA), which can induce activation of CREB or NFkappaB, respectively, were added to the medium. Pyrrolidine dithiocarbamate (PDTC) was used to inhibit activation of NFkappaB. Following incubation for 24 hours, beta-galactosidase activity was assessed by chemiluminescent reporter assay. Forskolin and PMA enhanced transgene expression in the carotid artery. Activity increased from 56+/-13 mU/mg protein (mean+/-SE) in rings of carotid treated with virus alone (10(9) pfu) to 159+/-23 mU/mg protein (P<0.05) in rings treated with forskolin, and to 189+/-40 mU/mg protein (P<0.05) in rings treated with PMA. Phorbol didecanoate, an inactive phorbol, did not affect expression of beta-galactosidase. After pre-incubation with PDTC prior to PMA, expression of beta-galactosidase was less than in rings incubated with PMA alone (29+/-11, P<0.05). Histochemical staining of carotid artery for beta-galactosidase demonstrated enhanced endothelial expression following administration of PMA. These findings suggest that expression after gene transfer to the carotid artery using an adenoviral vector with the CMV promoter/enhancer may be enhanced by PMA and forskolin, perhaps by activation of transcription factors.
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Affiliation(s)
- S D Christenson
- Department of Internal Medicine and Center on Aging University of Iowa College of Medicine and Veterans Administration Medical Center Iowa City, 52242, USA
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43
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Homer EG, Rinaldi A, Nicholl MJ, Preston CM. Activation of herpesvirus gene expression by the human cytomegalovirus protein pp71. J Virol 1999; 73:8512-8. [PMID: 10482604 PMCID: PMC112871 DOI: 10.1128/jvi.73.10.8512-8518.1999] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The activation of gene expression by the human cytomegalovirus (HCMV) particle was investigated. The HCMV major immediate-early (IE) promoter was cloned upstream of the Escherichia coli lacZ coding sequences, and the resulting cassette was introduced into the genome of a herpes simplex virus type 1 (HSV-1) mutant lacking functional VP16. Upon infection with the HSV-1 recombinant in the presence of cycloheximide, to block de novo protein synthesis, expression of lacZ-specific transcripts was increased by fivefold when HCMV was included in the inoculum. Accumulation of HSV-1 IE RNAs was also stimulated by coinfection with HCMV, as was expression of the adenovirus 5 VAI transcript when the VAI gene was cloned into the HSV-1 genome. Coinfection with HCMV did not alter mRNA stability or uncoating of the HSV-1 genome. The coding sequences for the HCMV phosphoprotein pp71, controlled by the HCMV IE promoter, were cloned into an HSV-1 recombinant impaired for the production of the three major transactivators (VP16, ICP0, and ICP4) to yield a recombinant (in1324) which expressed pp71 but did not cause significant cytotoxicity. Infection with in1324 resulted in stimulation of HCMV IE, HSV-1 IE, and VAI expression, demonstrating that pp71 is responsible for the effects we observed when using the entire HCMV particle. Therefore, HCMV pp71 exhibits novel properties in its ability to stimulate gene expression from a range of promoters present in a herpesvirus genome.
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Affiliation(s)
- E G Homer
- Medical Research Council Virology Unit, Glasgow G11 5JR, Scotland
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44
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Thorsell A, Fox E, Heilig M. Lipid mediated gene delivery in the adult rat brain: quantitative analysis of expression. Neurochem Int 1999; 35:65-71. [PMID: 10403431 DOI: 10.1016/s0197-0186(99)00034-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Gene transfer into the adult brain is potentially an attractive alternative to commonly employed transgenic approaches. DNA-lipid complexes have been used to obtain brain gene transfer, but data are sparse to indicate to what extent this results in significant expression of functional protein. Here, an expression construct encoding the functional reporter, chloramphenicol-acetyl-transferase (CAT), was complexed to a novel biodegradable lipid, and delivered into the rat brain. CAT-activity was assayed in tissue extracts to allow a precise quantitation of functional enzyme protein. Following bilateral intraventricular (i.c.v.) injection, robust enzyme activity was found in all brain regions studied, peaking at 4 weeks. Other routes of administration, e.g. intra-parenchymal injection or chronic infusion of complexes, resulted in marginal or no activity. Presence of CAT mRNA and plasmid DNA in tissue extracts was confirmed at 4 weeks post i.c.v. administration. In agreement with previous studies, labelled lipid-DNA complexes were mainly found in the ventricular ependyma. Present data support the feasibility of lipid mediated brain gene transfer, and outline some of its anatomical and temporal limitations.
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Affiliation(s)
- A Thorsell
- Addiction Centre South, Clinical Research Centre Novum, Huddinge University Hospital, Sweden
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45
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McClarrinon M, Gilkey L, Watral V, Fox B, Bullock C, Fradkin L, Liggitt D, Roche L, Bussey LB, Fox E, Gorman C. In vivo studies of gene expression via transient transgenesis using lipid-DNA delivery. DNA Cell Biol 1999; 18:533-47. [PMID: 10433552 DOI: 10.1089/104454999315088] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
As the sequencing of the human genome proceeds, the need for a new screen for in vivo function is becoming apparent. Many investigators are turning to various transgenic models as a means of studying function. However, these approaches are very time consuming, with a transgene-expressing mouse model often taking months to establish. We have developed an efficient system for delivering genes in vivo, which allows the gene product to be studied as early as 24 h after introduction into the mouse model. The delivery system employs a novel cationic lipid, 1-[2-(9-(Z)-octadecenoyloxy)ethyl]-2-(8-(Z)-heptadecenyl)-3- (hydroxyethyl)imidazolinium chloride (DOTIM), and a neutral lipid, cholesterol, complexed with an expression vector containing the reporter gene chloramphenicol acetyl transferase (CAT). After a single intravenous injection of these complexes, several tissues were seen to express the transgene. High, persistent expression in the vascular endothelial cells in the mouse lung was obtained. Delivery of DNA in vivo has been evaluated by quantitative polymerase chain reaction and protein expression by CAT activity assays. In vivo studies showed reproducible expression in more than 500 mice injected via the tail vein. An early peak of expression was followed by lower, but sustained, expression for > 50 days. Transgene expression of CAT could also be identified by immunohistochemistry staining in mouse lung and appeared to be located within the capillaries. The pattern of in vivo expression could be modulated and targeted to specific organs by altering the lipid-DNA formulation. New expression vectors with altered introns and polyadenylation sites further improved expression. The expression reported here may be sufficient in magnitude, duration, and flexibility to be an attractive alternative, in some cases, to establishing transgenic animals by stable gene transfer.
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Goins WF, Lee KA, Cavalcoli JD, O'Malley ME, DeKosky ST, Fink DJ, Glorioso JC. Herpes simplex virus type 1 vector-mediated expression of nerve growth factor protects dorsal root ganglion neurons from peroxide toxicity. J Virol 1999; 73:519-32. [PMID: 9847358 PMCID: PMC103859 DOI: 10.1128/jvi.73.1.519-532.1999] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/1998] [Accepted: 09/02/1998] [Indexed: 11/20/2022] Open
Abstract
Nerve growth factor beta subunit (beta-NGF) transgene delivery and expression by herpes simplex virus type 1 (HSV-1) vectors was examined in a cell culture model of neuroprotection from hydrogen peroxide toxicity. Replication-competent (tk- K mutant background) and replication-defective (ICP4(-);tk- S mutant background) vectors were engineered to contain the murine beta-NGF cDNA under transcriptional control of either the human cytomegalovirus immediate-early gene promoter (HCMV IEp) (e.g., KHN and SHN) or the latency-active promoter 2 (LAP2) (e.g., KLN and SLN) within the viral thymidine kinase (tk) locus. Infection of rat B103 and mouse N2A neuronal cell lines, 9L rat glioma cells, and Vero cells with the KHN or SHN vectors resulted in the production of beta-NGF-specific transcripts and beta-NGF protein reaching a maximum at 3 days postinfection (p.i.). NGF protein was released into the culture media in amounts ranging from 10.83 to 352.86 ng/ml, with the highest levels being achieved in B103 cells, and was capable of inducing neurite sprouting of PC-12 cells. The same vectors produced high levels of NGF in primary dorsal root ganglion (DRG) cultures at 3 days. In contrast to HCMV IEp-mediated expression, the LAP2-NGF vectors showed robust expression in primary DRG neurons at 14 days. The neuroprotective effect of vector produced NGF was assessed by its ability to inhibit hydrogen peroxide-induced neuron toxicity in primary DRG cultures. Consistent with the kinetics of vector-mediated NGF expression, HCMV-NGF vectors were effective in abrogating the toxic effects of peroxide at 3 but not 14 days p.i. whereas LAP2-NGF vector transduction inhibited apoptosis in DRG neurons at 14 days p.i. but was ineffective at 3 days p.i. Similar kinetics of NGF expression were observed with the KHN and KLN vectors in latently infected mouse trigeminal ganglia, where high levels of beta-NGF protein expression were detected at 4 wks p.i. only from the LAP2; HCMV-NGF-driven expression peaked at 3 days but could not be detected during HSV latency at 4 weeks. Together, these results indicate that (i) NGF vector-infected cells produce and secrete mature, biologically active beta-NGF; (ii) vector-synthesized NGF was capable of blocking peroxide-induced apoptosis in primary DRG cultures; and (iii) the HCMV-IEp functioned to produce high levels of NGF for several days; but (iv) only the native LAP2 was capable of long-term expression of a therapeutic gene product in latently infected neurons in vivo.
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Affiliation(s)
- W F Goins
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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Angulo A, Messerle M, Koszinowski UH, Ghazal P. Enhancer requirement for murine cytomegalovirus growth and genetic complementation by the human cytomegalovirus enhancer. J Virol 1998; 72:8502-9. [PMID: 9765387 PMCID: PMC110259 DOI: 10.1128/jvi.72.11.8502-8509.1998] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cytomegalovirus (CMV) enhancer is a highly complex regulatory region containing multiple elements that interact with a variety of host-encoded transcription factors. Many of these sequence elements are conserved among the different species strains of CMV, although the arrangement of the various elements and overall sequence composition of the CMV enhancers differ remarkably. To delineate the importance of this region to a productive infection and to explore the possibility of generating a murine CMV (MCMV) under the control of human CMV (HCMV) genetic elements, the MCMV enhancer was resected and replaced either with nonregulatory sequences or with paralogous sequences from HCMV. The effects of these various deletions and substitutions on viral growth in transfected or infected tissue-culture cells were evaluated. We found that mutations in MCMV that eliminate or substitute for the enhancer with nonregulatory sequences showed a severe deficiency in virus synthesis. This growth defect is effectively complemented by the homologous MCMV enhancer as well as the HCMV enhancer. In the latter case, the chimeric viruses (hybrid MCMV strains) containing the molecularly shuffled human enhancer exhibit infectious kinetics similar to that of parental wild-type and wild-type revertant MCMV. These results also show that open reading frames m124, m124.1, and m125 located within the enhancer region are nonessential for growth of MCMV in cells. Most importantly, we conclude that the enhancer of MCMV is required for optimal infection and that its diverged human counterpart can advantageously replace its role in promoting viral infectivity.
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Affiliation(s)
- A Angulo
- Departments of Immunology and Molecular Biology, Division of Virology, The Scripps Research Institute, La Jolla, California 92037, USA
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48
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Abstract
The goal of physiologically responsive gene therapy is to allow a host's endogenous regulatory mechanisms to control the production of therapeutic proteins (effectors). Ideally, effector production would be switched on in response to specific signals, stay within therapeutic limits and be switched off when no longer needed. In this way, the unwanted consequences of constitutive, high-level effector expression could be avoided. While recent studies have shown that transgenes can be regulated within animal hosts, they have also highlighted significant problems that require much further research.
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Affiliation(s)
- A W Varley
- Department of Internal Medicine, UT-Southwestern Medical Center, Dallas, TX 75235-9113, USA
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Roskrow MA, Gänsbacher B. Recent developments in gene therapy for oncology and hematology. Crit Rev Oncol Hematol 1998; 28:139-51. [PMID: 9793743 DOI: 10.1016/s1040-8428(98)00017-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- M A Roskrow
- Institut für Experimentelle Chirurgie, Klinikum rechts der Isar, München, Germany
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Yao F, Svensjö T, Winkler T, Lu M, Eriksson C, Eriksson E. Tetracycline repressor, tetR, rather than the tetR-mammalian cell transcription factor fusion derivatives, regulates inducible gene expression in mammalian cells. Hum Gene Ther 1998; 9:1939-50. [PMID: 9741432 DOI: 10.1089/hum.1998.9.13-1939] [Citation(s) in RCA: 203] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This article describes the first (to our knowledge) tetracycline-inducible regulatory system that demonstrates that the tetracycline repressor (tetR) alone, rather than tetR-mammalian cell transcription factor fusion derivatives, can function as a potent trans-modulator to regulate gene expression in mammalian cells. With proper positioning of tetracycline operators downstream of the TATA element and of human epidermal growth factor (hEGF) as a reporter, we show that gene expression from the tetracycline operator-bearing hCMV major immediate-early enhancer-promoter (pcmvtetO) can be regulated by tetR over three orders of magnitude in response to tetracycline when (1) the reporter was cotransfected with tetR-expressing plasmid in transient expression assays, and (2) the reporter unit was stably integrated into the chromosome of a tetR-expressing cell line. This level of tetR-mediated inducible gene regulation is significantly higher than that of other repression-based mammalian cell transcription switch systems. In an in vivo porcine wound model, close to 60-fold tetR-mediated regulatory effects were detected and it was reversed when tetracycline was administered. Collectively, this study provides a direct implementation of this tetracycline-inducible regulatory switch for controlling gene expression in vitro, in vivo, and in gene therapy.
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Affiliation(s)
- F Yao
- Division of Plastic Surgery, Brigham and Women's Hospital, Boston, MA 02115, USA
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