scholarly journals Adaptation of Chimeric Retroviruses In Vitro and In Vivo: Isolation of Avian Retroviral Vectors with Extended Host Range

2001 ◽  
Vol 75 (11) ◽  
pp. 4973-4983 ◽  
Author(s):  
Eugene V. Barsov ◽  
William S. Payne ◽  
Stephen H. Hughes
Keyword(s):  
Host Range ◽  
Mammalian Cells ◽  
Leukemia Virus ◽  
Retroviral Vectors ◽  
Retroviral Vector ◽  
General Strategy ◽  
Coding Region ◽  
Chimeric Viruses

ABSTRACT We have designed and characterized two new replication-competent avian sarcoma/leukosis virus-based retroviral vectors with amphotropic and ecotropic host ranges. The amphotropic vector RCASBP-M2C(797-8), was obtained by passaging the chimeric retroviral vector RCASBP-M2C(4070A) (6) in chicken embryos. The ecotropic vector, RCASBP(Eco), was created by replacing theenv-coding region in the retroviral vector RCASBP(A) with the env region from an ecotropic murine leukemia virus. It replicates efficiently in avian DFJ8 cells that express murine ecotropic receptor. For both vectors, permanent cell lines that produce viral stocks with titers of about 5 × 106 CFU/ml on mammalian cells can be easily established by passaging transfected avian cells. Some chimeric viruses, for example, RCASBP(Eco), replicate efficiently without modifications. For those chimeric viruses that do require modification, adaptation by passage in vitro or in vivo is a general strategy. This strategy has been used to prepare vectors with altered host range and could potentially be used to develop vectors that would be useful for targeted gene delivery.

310 PRODUCTION OF TRANSGENIC CLONED PORCINE EMBRYOS EXPRESSING EGFP OR LacZ GENE THROUGH REPLICATION DEFECTIVE RETROVIRAL VECTOR

2008 ◽  
Vol 20 (1) ◽  
pp. 235
Author(s):  
S. J. Uhm ◽  
M. K. Gupta ◽  
T. Kim ◽  
H. T. Lee
Keyword(s):  
Fluorescent Protein ◽  
Leukemia Virus ◽  
Fluorescein Isothiocyanate ◽  
Retroviral Vectors ◽  
Retroviral Vector ◽  
Lacz Gene ◽  
Cell Stage ◽  
Uv Illumination ◽  
Green Fluorescent

We have demonstrated previously that retroviral-mediated gene transfer is a promising method to produce transgenic avian, porcine, and bovine embryos. This study was designed to evaluate the development potential of transgenic porcine embryos produced by somatic cell nuclear transfer (SCNT) of fetal fibroblast (pFF) cells transfected by a robust replication-defective retroviral vector harboring enhanced green fluorescent protein (EGFP) or β-galactosidase (LacZ) gene. Moloney murine leukemia virus (MoMLV)-based retroviral vectors encapsidated with VSV-G (vesicular stomatitis virus G) glycoprotein and harboring EGFP or LacZ under the control of β-actin promoter were produced and used to transfect primary pFF cells that were subsequently used for SCNT of enucleated porcine oocytes matured in vitro. Our results showed that all surviving cells after transfection and antibiotic selection expressed the genes without any evidence of replication-competent retrovirus. The fusion, cleavage, and blastocyst rates were 85.6 � 6.5, 53.6 � 6.4, and 12.0 � 5.7% for EGFP; 83.5 � 8.2, 57.5 � 6.3 and 10.1 � 4.1% for LacZ; and 80.5 � 4.2, 60.9 � 8.2 and 12.3 � 4.0% for controls, respectively. Mosaicism was not observed in any of the group as evidenced by the expression of LacZ or EGFP in individual blastomeres of all embryos upon staining with β-galactosidase (for LacZ) or when visualized under UV illumination of an epifluorescent microscope using the fluorescein isothiocyanate (FITC) filter set (for EGFP). Further recloning of EGFP-expressing blastomeres, obtained from 4-cell-stage cloned embryos produced by SCNT of pFF cells infected with EGFP harboring vector, into enucleated metaphase II (MII) oocytes resulted in consistent expression of EGFP in recloned blastocysts. Interspecies SCNT (iSCNT) of transfected pFF into enucleated bovine oocytes could also result in consistent gene expression without any adverse effect on blastocyst rate (5.5 v. 4.9%) compared with non-transfected pFF. These data indicate that the replication-defective retroviral vector used in the present study is robust and independent of the genes inserted. Furthermore, introduction of transgenes by this method does not influence the in vitro development rate of cloned embryos. This work was supported by a grant from Biogreen 21 Program, RDA, Republic of Korea.

scholarly journals Regulated expression of a mammalian nonsense suppressor tRNA gene in vivo and in vitro using the lac operator/repressor system.

1992 ◽  
Vol 12 (10) ◽  
pp. 4271-4278 ◽  
Author(s):  
D E Syroid ◽  
R I Tapping ◽  
J P Capone
Keyword(s):  
Mammalian Cells ◽  
Trna Gene ◽  
Rna Polymerase Iii ◽  
Lac Repressor ◽  
Trna Genes ◽  
Coding Region ◽  
Lac Operator ◽  
Cell Extracts

We have exploited the Escherichia coli lac operator/repressor system as a means to regulate the expression of a mammalian tRNA gene in vivo and in vitro. An oligonucleotide containing a lac operator (lacO) site was cloned immediately upstream of a human serine amber suppressor (Su+) tRNA gene. Insertion of a single lac repressor binding site at position -1 or -32 relative to the coding region had no effect on the amount of functional tRNA made in vivo, as measured by suppression of a nonsense mutation in the E. coli chloramphenicol acetyltransferase gene following cotransfection of mammalian cells. Inclusion of a plasmid expressing the lac repressor in the transfections resulted in 75 to 98% inhibition of suppression activity of lac operator-linked tRNA genes but had no effect on expression of the wild-type gene. Inhibition could be quantitatively relieved with the allosteric inducer isopropylthio-beta-D-galactoside (IPTG). Similarly, transcription in vitro of lac operator-linked tRNA genes in HeLa cell extracts was repressed in the presence of lac repressor, and this inhibition was reversible with IPTG. These results demonstrate that the bacterial lac operator/repressor system can be used to reversibly control the expression of mammalian genes that are transcribed by RNA polymerase III.

scholarly journals Bromo- and Extraterminal Domain Chromatin Regulators Serve as Cofactors for Murine Leukemia Virus Integration

2013 ◽  
Vol 87 (23) ◽  
pp. 12721-12736 ◽  
Author(s):  
Saumya Shree Gupta ◽  
Tobias Maetzig ◽  
Goedele N. Maertens ◽  
Azar Sharif ◽  
Michael Rothe ◽  
...  
Keyword(s):  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Retroviral Vectors ◽  
Transcription Start ◽  
Preintegration Complex ◽  
Transcription Start Sites ◽  
Bet Inhibitors ◽  
Murine Leukemia

Retroviral integrase (IN) proteins catalyze the permanent integration of proviral genomes into host DNA with the help of cellular cofactors. Lens epithelium-derived growth factor (LEDGF) is a cofactor for lentiviruses, including human immunodeficiency virus type 1 (HIV-1), and targets lentiviral integration toward active transcription units in the host genome. In contrast to lentiviruses, murine leukemia virus (MLV), a gammaretrovirus, tends to integrate near transcription start sites. Here, we show that the bromodomain and extraterminal domain (BET) proteins BRD2, BRD3, and BRD4 interact with gammaretroviral INs and stimulate the catalytic activity of MLV INin vitro. We mapped the interaction site to a characteristic structural feature within the BET protein extraterminal (ET) domain and to three amino acids in MLV IN. The ET domains of different BET proteins stimulate MLV integrationin vitroand, in the case of BRD2, alsoin vivo. Furthermore, two small-molecule BET inhibitors, JQ1 and I-BET, decrease MLV integration and shift it away from transcription start sites. Our data suggest that BET proteins might act as chromatin-bound acceptors for the MLV preintegration complex. These results could pave a way to redirecting MLV DNA integration as a basis for creating safer retroviral vectors.

Infection of mammalian cells with Theileria species

Parasitology ◽  
1983 ◽  
Vol 86 (2) ◽  
pp. 243-254 ◽  
Author(s):  
D. A. Stagg ◽  
A. S. Young ◽  
B. L. Leitch ◽  
J. G. Grootenhuis ◽  
T. T. Dolan
Keyword(s):  
Host Range ◽  
Mammalian Cells ◽  
Mammalian Species ◽  
Rhipicephalus Appendiculatus ◽  
Host Cells ◽  
Transformed Cells ◽  
Theileria Parva ◽  
African Buffalo

SUMMARYExperiments were carried out to determine the susceptibility of mammalian cells to infection with different species of Theileria in vitro. Sporozoites of Theileria parva (parva), Theileria parva (lawrencei) and Theileria taurotragi were isolated from Rhipicephalus appendiculatus ticks by grinding infected ticks in medium, filtering the suspension and concentrating by centrifugation. The sporozoites were used in attempts to infect in vitro peripheral blood leucocytes harvested from 16 different mammalian species which included 12 species of Bovidae from 6 different sub-families. The technique was shown to be both sensitive and reproducible. The sporozoites of T. parva (parva) infected and transformed cells from 2 species of the sub-family Bovinae, the two cattle types and African buffalo. Theileria parva (lawrencei) infected and transformed cells from the two cattle types, African buffalo and Defassa waterbuck. Theileria taurotragi sporozoites infected in vitro cells from 11 different species of Bovidae which were members of 6 sub-families; Bovinae, Tragelaphinae, Reduncinae, Alcelaphinae, Antilopinae and Caprinae. Transformed lymphoblastoid cell lines were established from 7 of the species infected. Sporozoite attachment and infection was not observed with non-susceptible bovid host cells, nor were any of the non-bovid leucocytes infected by the parasites. The host range observed in this study corresponded to the known host range in vivo.

scholarly journals Deoxyribonucleoside Triphosphate Pool Imbalances In Vivo Are Associated with an Increased Retroviral Mutation Rate

1998 ◽  
Vol 72 (10) ◽  
pp. 7941-7949 ◽  
Author(s):  
John G. Julias ◽  
Vinay K. Pathak
Keyword(s):  
Reverse Transcription ◽  
Leukemia Virus ◽  
Retroviral Vectors ◽  
Mutation Rates ◽  
Target Cells ◽  
Dntp Pool ◽  
Deoxyribonucleoside Triphosphate ◽  
Spleen Necrosis

ABSTRACT Deoxyribonucleoside triphosphate (dNTP) pool imbalances are associated with an increase in the rate of misincorporation and hypermutation during in vitro reverse transcription reactions. However, the effects of in vivo dNTP pool imbalances on the accuracy of reverse transcription are unknown. We sought to determine the effects of in vivo dNTP pool imbalances on retroviral mutation rates and to test our hypothesis that 3′-azido-3′-deoxythymidine (AZT) increases the retroviral mutation rates through induction of dNTP pool imbalances. D17 cells were treated with thymidine, hydroxyurea (HU), or AZT, and the effects on in vivo dNTP pools were measured. Thymidine and HU treatments induced significant dNTP pool imbalances. In contrast, AZT treatment had very little effect on the dNTP pools. The effects of in vivo dNTP pool imbalances induced by thymidine and HU treatments on the retroviral mutation rates were also determined. Spleen necrosis virus (SNV)-based and murine leukemia virus (MLV)-based retroviral vectors that expressed the lacZ mutant reporter gene were used. The frequencies of inactivating mutations introduced in thelacZ gene in a single replication cycle provided a measure of the retroviral mutation rates. Treatment of D17 target cells with 500 μM thymidine increased the SNV and MLV mutant frequencies 4.7- and 4-fold, respectively. Treatment of D17 target cells with 2 mM HU increased the SNV and MLV mutant frequencies 2.1- and 2.7-fold, respectively. These results demonstrate that dNTP pool imbalances are associated with an increase in the in vivo retroviral mutation rates, but AZT treatment results in an increase in the retroviral mutation rates by a mechanism not involving alterations in dNTP pools.

scholarly journals STUDIES OF GENETIC TRANSMISSION OF MURINE LEUKEMIA VIRUS BY AKR MICE

1972 ◽  
Vol 136 (5) ◽  
pp. 1286-1301 ◽  
Author(s):  
Wallace P. Rowe ◽  
Janet W. Hartley
Keyword(s):  
Host Range ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Conclusive Evidence ◽  
Genetic Determinants ◽  
Genetic Transmission ◽  
Range Type ◽  
Murine Leukemia

The transmission of murine leukemia virus (MLV) to hybrids between AKR and Fv-1b mice was studied in order to evaluate the effect of the Fv-1 gene on endogenous MLV infection and to attempt to determine if the genetic loci contributed by AKR carry viral genetic determinants. Fv-1 was shown to have a marked suppressive effect on time of appearance of detectable infectious virus and on the titers attained in vivo, but did not affect the ability of the cells to produce virus in vitro after induction with 5-iododeoxyuridine. The host range type of the virus detected in the hybrid mice was almost always of the type carried by AKR, although the low-virus Fv-1b parents carry the genome of a different host range type. This finding provides strong, but not conclusive, evidence that the virus-inducing loci of AKR contain MLV genetic determinants.

scholarly journals Detection and Induction of Equine Infectious Anemia Virus-Specific Cytotoxic T-Lymphocyte Responses by Use of Recombinant Retroviral Vectors

1999 ◽  
Vol 73 (4) ◽  
pp. 2762-2769 ◽  
Author(s):  
S. M. Lonning ◽  
W. Zhang ◽  
S. R. Leib ◽  
T. C. McGuire
Keyword(s):  
Equine Infectious Anemia Virus ◽  
Leukemia Virus ◽  
Retroviral Vectors ◽  
Retroviral Vector ◽  
Simian Virus ◽  
Target Cells ◽  
Equine Infectious Anemia ◽  
Anemia Virus ◽  
Ctl Responses

ABSTRACT Cytotoxic T lymphocytes (CTL) appear to be critical in resolving or reducing the severity of lentivirus infections. Retroviral vectors expressing the Gag/Pr or SU protein of the lentivirus equine infectious anemia virus (EIAV) were constructed and used to evaluate EIAV-specific CTL responses in horses. Three promoters, cytomegalovirus, simian virus SV40, and Moloney murine sarcoma virus (MoMSV) long terminal repeat (LTR), were used, and there was considerable variation in their ability to direct expression of Gag/Pr and SU. Vectors expressing EIAV proteins under the direction of MoMSV LTR and using the gibbon ape leukemia virus (GALV) Env for internalization were efficient at transducing equine kidney (EK) target cells and were effective targets for EIAV-specific CTL lysis. CTL from EIAV-infected horses caused lysis of retroviral vector-transduced EK cells expressing either Gag/Pr or SU in an ELA-A-restricted manner. In contrast, lysis of recombinant vaccinia virus-infected EK cells expressing Gag/Pr and SU/TM was often non-LA-A restricted. Five horses were immunized by direct intramuscular injection with a mixture of retroviral vectors expressing Gag/Pr or SU, and one responded with EIAV-specific CTL. This result indicates that retroviral vector stimulation of CTL in horses needs to be optimized, perhaps by inclusion of appropriate cytokine genes in the constructs. However, the studies demonstrated that retroviral vector-transduced target cells were very effective for in vitro dissection of EIAV-specific CTL responses.

scholarly journals Binding of Murine Leukemia Virus Gag Polyproteins to KIF4, a Microtubule-Based Motor Protein

1998 ◽  
Vol 72 (8) ◽  
pp. 6898-6901 ◽  
Author(s):  
Wankee Kim ◽  
Yao Tang ◽  
Yasushi Okada ◽  
Ted A. Torrey ◽  
Sisir K. Chattopadhyay ◽  
...  
Keyword(s):  
Murine Leukemia Virus ◽  
Mammalian Cells ◽  
Leukemia Virus ◽  
Motor Protein ◽  
Cellular Protein ◽  
Gag Proteins ◽  
C Terminus ◽  
Murine Leukemia

ABSTRACT A cDNA clone encoding a cellular protein that interacts with murine leukemia virus (MuLV) Gag proteins was isolated from a T-cell lymphoma library. The sequence of the clone is identical to the C terminus of a cellular protein, KIF4, a microtubule-associated motor protein that belongs to the kinesin superfamily. KIF4-MuLV Gag associations have been detected in vitro and in vivo in mammalian cells. We suggest that KIF4 could be involved in Gag polyprotein translocation from the cytoplasm to the cell membrane.

scholarly journals The Resistance of Retroviral Vectors Produced from Human Cells to Serum Inactivation In Vivo and In Vitro Is Primate Species Dependent

1999 ◽  
Vol 73 (8) ◽  
pp. 6708-6714 ◽  
Author(s):  
Nicholas J. DePolo ◽  
Cataline E. Harkleroad ◽  
Mordechai Bodner ◽  
Andrew T. Watt ◽  
Carol G. Anderson ◽  
...  
Keyword(s):  
Cell Lines ◽  
Half Life ◽  
Retroviral Vectors ◽  
Retroviral Vector ◽  
Biologically Active ◽  
Primate Species ◽  
Phylogenetic Distance ◽  
Packaging Cell

ABSTRACT The ability to deliver genes as therapeutics requires an understanding of the vector pharmacokinetics similar to that required for conventional drugs. A first question is the half-life of the vector in the bloodstream. Retroviral vectors produced in certain human cell lines differ from vectors produced in nonhuman cell lines in being substantially resistant to inactivation in vitro by human serum complement (F. L. Cosset, Y. Takeuchi, J. L. Battini, R. A. Weiss, and M. K. Collins, J. Virol. 69:7430–7436, 1995). Thus, use of human packaging cell lines (PCL) may produce vectors with longer half-lives, resulting in more-efficacious in vivo gene therapy. However, survival of human PCL-produced vectors in vivo following systemic administration has not been explored. In this investigation, the half-lives of retroviral vectors packaged by either canine D17 or human HT1080 PCL were measured in the bloodstreams of macaques and chimpanzees. Human PCL-produced vectors exhibited significantly higher concentrations of circulating biologically active vector at the earliest time points measured (>1,000-fold in chimpanzees), as well as substantially extended half-lives, compared to canine PCL-produced vectors. In addition, the circulation half-life of human PCL-produced vector was longer in chimpanzees than in macaques. This was consistent with in vitro findings which demonstrated that primate serum inactivation of vector produced from human PCL increased with increasing phylogenetic distance from humans. These results establish that in vivo retroviral vector half-life correlates with in vitro resistance to complement. Furthermore, these findings should influence the choice of animal models used to evaluate retroviral-vector-based therapies.

scholarly journals Retroviral Vector Biosafety: Lessons from Sheep

2003 ◽  
Vol 2003 (1) ◽  
pp. 9-12 ◽  
Author(s):  
Anne Van den Broeke ◽  
Arsène Burny
Keyword(s):  
Gene Therapy ◽  
Future Development ◽  
Retroviral Vectors ◽  
Retroviral Vector ◽  
Pathogenic Potential ◽  
Production Methods ◽  
Endogenous Viruses ◽  
In Vivo Gene Delivery

The safety of retroviral-based systems and the possible transmission of replication-competent virus to patients is a major concern associated with using retroviral vectors for gene therapy. While much effort has been put into the design of safe retroviral production methods and effective in vitro monitoring assays, there is little data evaluating the risks resulting from retroviral vector instability at post-transduction stages especially following in vivo gene delivery. Here, we briefly describe and discuss our observations in an in vivo experimental model based on the inoculation of retroviral vector-transduced tumor cells in sheep. Our data indicates that the in vivo generation of mosaic viruses is a dynamic process and that virus variants, generated by retroviral vector-mediated recombination, may be stored and persist in infected individuals prior to selection at the level of replication. Recombination may not only restore essential viral functions or provide selective advantages in a changing environment but also reestablish or enhance the pathogenic potential of the particular virus undergoing recombination. These observations in sheep break new ground in our understanding of how retroviral vectors may have an impact on the course of a preestablished disease or reactivate dormant or endogenous viruses. The in vivo aspects of vector stability raise important biosafety issues for the future development of safe retroviral vector-based gene therapy.

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