In vitro and in vivo enhancement of ddI activity against rauscher murine leukemia virus (RMuLV) by ribavirin

1995 ◽  
Vol 26 (3) ◽  
pp. A274
Keyword(s):  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Murine Leukemia

Strong selection for cells containing new ecotropic recombinant murine leukemia virus provirus after propagation of C57BL/6 radiation-induced thymoma cells in vitro or in vivo

1983 ◽  
Vol 3 (9) ◽  
pp. 1675-1679
Author(s):  
P Jolicoeur ◽  
E Rassart ◽  
P Sankar-Mistry
Keyword(s):  
Cell Lines ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Primary Radiation ◽  
Secondary Tumors ◽  
Radiation Induced ◽  
Viral Sequences ◽  
Murine Leukemia

Using the Southern procedure, we have studied the presence of ecotropic-specific murine leukemia viral sequences in genomic DNA isolated from primary X-ray-induced thymomas, from lymphoid cell lines established from them, or from secondary tumors passaged in vivo. We found that primary radiation-induced thymomas and infiltrated spleens do not harbor newly acquired ecotropic provirus. However, additional ecotropic proviruses (which appear recombinant in the gagpol region) could be detected in most of the tumorigenic cell lines established in vitro from them and in tumors arising from subcutaneous transplantation of the primary thymomas. These results suggest that primary radiation-induced thymomas may not be clonal. They also indicate a strong correlation between the presence of ecotropic recombinant proviruses in the genome and the growth ability, both in vitro and in vivo, of specific cells within these thymomas, suggesting a possible mitogenic function for murine leukemia virus.

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.

scholarly journals R-Peptide Cleavage Potentiates Fusion-Controlling Isomerization of the Intersubunit Disulfide in Moloney Murine Leukemia Virus Env

2007 ◽  
Vol 82 (5) ◽  
pp. 2594-2597 ◽  
Author(s):  
Robin Löving ◽  
Kejun Li ◽  
Michael Wallin ◽  
Mathilda Sjöberg ◽  
Henrik Garoff
Keyword(s):  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Moloney Murine Leukemia Virus ◽  
Isomerization Reaction ◽  
Peptide Cleavage ◽  
In Vivo Assays ◽  
Env Protein ◽  
Murine Leukemia

ABSTRACT Fusion of the membrane of the Moloney murine leukemia virus (Mo-MLV) Env protein is facilitated by cleavage of the R peptide from the cytoplasmic tail of its TM subunit, but the mechanism for this effect has remained obscure. The fusion is also controlled by the isomerization of the intersubunit disulfide of the Env SU-TM complex. In the present study, we used several R-peptide-cleavage-inhibited virus mutants to show that the R peptide suppresses the isomerization reaction in both in vitro and in vivo assays. Thus, the R peptide affects early steps in the activation pathway of murine leukemia virus Env.

scholarly journals SERINC5 Potently Restricts Retrovirus Infection In Vivo

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Uddhav Timilsina ◽  
Supawadee Umthong ◽  
Brian Lynch ◽  
Aimee Stablewski ◽  
Spyridon Stavrou
Keyword(s):  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Viral Envelope ◽  
The Other ◽  
Immunodeficiency Virus ◽  
Retrovirus Infection ◽  
Hiv 1 ◽  
Murine Leukemia

ABSTRACT The serine incorporator (SERINC) proteins are multipass transmembrane proteins that affect sphingolipid and phosphatidylserine synthesis. Human SERINC5 and SERINC3 were recently shown to possess antiretroviral activity for a number of retroviruses, including human immunodeficiency virus (HIV), murine leukemia virus (MLV), and equine infectious anemia virus (EIAV). In the case of MLV, the glycosylated Gag (glyco-Gag) protein was shown to counteract SERINC5-mediated restriction in in vitro experiments and the viral envelope was found to determine virion sensitivity or resistance to SERINC5. However, nothing is known about the in vivo function of SERINC5. Antiretroviral function of a host factor in vitro is not always associated with antiretroviral function in vivo. Using SERINC5−/− mice that we had generated, we showed that mouse SERINC5 (mSERINC5) restriction of MLV infection in vivo is influenced not only by glyco-Gag but also by the retroviral envelope. Finally, we also examined the in vivo function of the other SERINC gene with known antiretroviral functions, SERINC3. By using SERINC3−/− mice, we found that the murine homologue, mSERINC3, had no antiretroviral role either in vivo or in vitro. To our knowledge, this report provides the first data showing that SERINC5 restricts retrovirus infection in vivo and that restriction of retrovirus infectivity in vivo is dependent on the presence of both glyco-Gag and the viral envelope. IMPORTANCE This study examined for the first time the in vivo function of the serine incorporator (SERINC) proteins during retrovirus infection. SERINC3 and SERINC5 (SERINC3/5) restrict a number of retroviruses, including human immunodeficiency virus 1 (HIV-1) and murine leukemia virus (MLV), by blocking their entry into cells. Nevertheless, HIV-1 and MLV encode factors, Nef and glycosylated Gag, respectively, that counteract SERINC3/5 in vitro. We recently developed SERINC3 and SERINC5 knockout mice to examine the in vivo function of these genes. We found that SERINC5 restriction is dependent on the absence of glycosylated Gag and the expression of a specific viral envelope glycoprotein. On the other hand, SERINC3 had no antiviral function. Our findings have implications for the development of therapeutics that target SERINC5 during retrovirus infection.

scholarly journals Effect of Host Modification and Age on Airway Epithelial Gene Transfer Mediated by a Murine Leukemia Virus-Derived Vector

1998 ◽  
Vol 72 (11) ◽  
pp. 8861-8872 ◽  
Author(s):  
Larry G. Johnson ◽  
Jennifer P. Mewshaw ◽  
Hong Ni ◽  
Theodore Friedmann ◽  
Richard C. Boucher ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Brdu Incorporation ◽  
Transduction Efficiency ◽  
Airway Epithelial ◽  
Murine Leukemia ◽  
Airway Cells

ABSTRACT To study retroviral gene transfer to airway epithelia, we used a transient transfection technique to generate high titers (∼109 infectious units/ml after concentration) of murine leukemia virus (MuLV)-derived vectors pseudotyped with the vesicular stomatitis virus envelope glycoprotein (VSV-G). Transformed (CFT1) and primary airway epithelial cells were efficiently transduced by a VSV-G-pseudotyped lacZ vector (HIT-LZ) in vitro. CFT1 cells and primary cystic fibrosis (CF) airway cell monolayers infected with a vector (HIT-LCFSN) containing human CF transmembrane conductance regulator (CFTR) in the absence of selection expressed CFTR, as assessed by Western blot analysis, and exhibited functional correction of CFTR-mediated Cl− secretion. In vitro studies of persistence suggested that pseudotransduction was not a significant problem with our vector preparations. In a sulfur dioxide (SO2) inhalational injury model, bromodeoxyuridine (BrdU) incorporation rates were measured and found to exceed 50% in SO2-injured murine tracheal epithelium. HIT-LZ vector (multiplicity of infection of ∼10) instilled into the SO2-injured tracheas of anesthetized mice transduced 6.1% ± 1.3% of superficial airway cells in tracheas of weanling mice (3 to 4 weeks old; n = 10), compared to 1.4 ± 0.9% in mice 5 weeks of age (n = 4) and 0.2% in mice older than 6 weeks (n = 15). No evidence for gene transfer following delivery of HIT-LZ to tracheas of either weanling or older mice not injured with SO2 was detected. Because only a small fraction of BrdU-labeled airway cells were transduced, we examined the stability of the vector. No significant loss of vector infectivity over intervals (2 h) paralleling those of in vivo protocols was detected in in vitro assays using CFT1 cells. In summary, high-titer vectors permitted complementation of defective CFTR-mediated Cl− transport in CF airway cells in vitro without selection and demonstrated that the age of the animal appeared to be a major factor affecting in vivo retroviral transduction efficiency.

Monoclonal proliferation of Friend murine leukemia virus-transformed myeloblastic cells occurs early in the leukemogenic process

1985 ◽  
Vol 5 (5) ◽  
pp. 1009-1014
Author(s):  
B Sola ◽  
J M Heard ◽  
S Fichelson ◽  
M A Martial ◽  
F Pozo ◽  
...  
Keyword(s):  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Latency Period ◽  
Transformation Process ◽  
Distinct Pattern ◽  
Mouse Bone Marrow ◽  
Line Characteristic ◽  
Murine Leukemia

Integrated Friend murine leukemia virus copies were analyzed by the Southern blotting procedure in myeloblastic cell lines obtained after in vitro infection of long-term mouse bone marrow cultures. Several steps leading to the generation of malignant myeloblastic cells after a long latency period were observed in the evolution of infected cultures. Shortly after infection, a random distribution of integrated provirus copies was observed in the DNA of normally differentiating myeloid cells. In contrast, a distinct pattern of integrated Friend murine leukemia virus copies was evident in the first non-differentiating immature myeloblastic cells appearing in cultures, suggesting a monoclonal origin of these cells. For each cell line, characteristic hybridizing fragments were conserved during the 1-year culture period necessary for the acquisition of tumorigenic properties and were also observed in tumors grafted in vivo. We can conclude that monoclonality is effective very early in the myeloid transformation process, as soon as the precursor cells are blocked in their differentiation.

scholarly journals Expression of Moloney Murine Leukemia Virus RNase H Rescues the Growth Defect of an Escherichia coliMutant

2001 ◽  
Vol 75 (13) ◽  
pp. 6212-6217 ◽  
Author(s):  
Andrew G. Campbell
Keyword(s):  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Rnase H ◽  
Moloney Murine Leukemia Virus ◽  
In Vitro Assays ◽  
Growth Defect ◽  
Protein Variant ◽  
Murine Leukemia

ABSTRACT A 157-amino-acid fragment of Moloney murine leukemia virus reverse transcriptase encoding RNase H is shown to rescue the growth-defective phenotype of an Escherichia coli mutant. In vitro assays of the recombinant wild-type protein purified from the conditionally defective mutant confirm that it is catalytically active. Mutagenesis of one of the presumptive RNase H-catalytic residues results in production of a protein variant incapable of rescue and which lacks activity in vitro. Analyses of additional active site mutants demonstrate that their encoded variant proteins lack robust activity yet are able to rescue the bacterial mutant. These results suggest that genetic complementation may be useful for in vivo screening of mutant viral RNase H gene fragments and in evaluating their function under conditions that more closely mimic physiological conditions. The rescue system may also be useful in verifying the functional outcomes of mutations based on protein structural predictions and modeling.

scholarly journals Allelism and linkage studies of murine leukemia virus activation genes in low leukemic strains of mice.

1982 ◽  
Vol 155 (4) ◽  
pp. 1233-1238 ◽  
Author(s):  
J McCubrey ◽  
R Risser
Keyword(s):  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Virus Production ◽  
Chromosome 8 ◽  
Linkage Studies ◽  
Ecotropic Virus ◽  
Virus Strains ◽  
Murine Leukemia

Previously, we identified two genes, termed Inc-1 and Inb-1, that interact to enhance ecotropic murine leukemia virus induction in low virus strains of mice. Mice related to BALB/c in origin carry a locus termed Inc-1, whereas mice related to B6 carry an Inb-1 locus. Mice that carry both Inc-1 and Inb-1 yield 10- to 50-fold more virus-producing cells than parental strains on induction with halogenated pyrimidines in vitro and demonstrate enhanced murine leukemia virus production in vivo. Here, we show that mice related to BALB/c in origin, i.e., A, C3H/He, and SEC, have an Inc-1 locus that is allelic with that of BALB/c. The C57BR mouse strain has an Inb-1 locus that is allelic with that of B6, located on chromosome 8, 30 cM from Es-1. We also show that the Inc-1 locus of BALB/c mice is located on chromosome 5, 24 cM from Pgm-1 and 43 cM from Gus. Kozak and Rowe (6,8) and Ihle and co-workers (3) have shown that the ecotropic virus-inducing genes in BALB/c and B10 mice are located on chromosomes 5 and 8, respectively, with similar distances from the previously mentioned biochemical markers. Our data are consistent with two possibilities: Inc-1 and Inb-1 are part of the virus-inducing genes Cv-1 and Bv-1, respectively , or Inc-1 and Inb2-1 are tightly linked regulatory genes.

scholarly journals Monoclonal proliferation of Friend murine leukemia virus-transformed myeloblastic cells occurs early in the leukemogenic process.

1985 ◽  
Vol 5 (5) ◽  
pp. 1009-1014 ◽  
Author(s):  
B Sola ◽  
J M Heard ◽  
S Fichelson ◽  
M A Martial ◽  
F Pozo ◽  
...  
Keyword(s):  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Latency Period ◽  
Transformation Process ◽  
Distinct Pattern ◽  
Mouse Bone Marrow ◽  
Line Characteristic ◽  
Murine Leukemia

Integrated Friend murine leukemia virus copies were analyzed by the Southern blotting procedure in myeloblastic cell lines obtained after in vitro infection of long-term mouse bone marrow cultures. Several steps leading to the generation of malignant myeloblastic cells after a long latency period were observed in the evolution of infected cultures. Shortly after infection, a random distribution of integrated provirus copies was observed in the DNA of normally differentiating myeloid cells. In contrast, a distinct pattern of integrated Friend murine leukemia virus copies was evident in the first non-differentiating immature myeloblastic cells appearing in cultures, suggesting a monoclonal origin of these cells. For each cell line, characteristic hybridizing fragments were conserved during the 1-year culture period necessary for the acquisition of tumorigenic properties and were also observed in tumors grafted in vivo. We can conclude that monoclonality is effective very early in the myeloid transformation process, as soon as the precursor cells are blocked in their differentiation.

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