scholarly journals A host gene regulates the structure of the transmembrane envelope protein of murine leukemia viruses.

1990 ◽  
Vol 171 (5) ◽  
pp. 1739-1752 ◽  
Author(s):  
M A Coppola ◽  
C Y Thomas
Keyword(s):  
Gene Structure ◽  
Envelope Protein ◽  
Leukemia Virus ◽  
Biological Significance ◽  
Endogenous Retroviruses ◽  
Host Gene ◽  
Class I ◽  
Chromosome 17 ◽  
Envelope Gene ◽  
Murine Leukemia

Heterogeneity in the structure of the envelope proteins has been observed in many human and animal retroviruses and may influence pathogenicity. However, the biological significance of this heterogeneity and the mechanisms by which it is generated are poorly understood. We have studied a mouse model in which the envelope gene structure of lymphoma-associated viruses appears to be controlled by a single host gene. The inoculation of HRS and CWD mice with a leukemogenic murine leukemia virus (MuLV) results in recombination between the injected virus and envelope gene sequences of endogenous retroviruses. The genomes of HRS (class I) env recombinants and CWD (class II) env recombinants differ in the sequences encoding the NH2-terminal portion of the transmembrane envelope protein (TM). We have shown that an HRS gene linked to the MHC on chromosome 17 mediates a dominant selection for recombinant retroviruses with the class I envelope gene structure. CBA mice, which share the H-2k haplotype with HRS, also carry the dominant allele at this locus. This system provides a useful model for studies of host factors involved in the selection of specific variants of pathogenic retroviruses.

scholarly journals The Mouse H-2A Region Influences the Envelope Gene Structure of Tumor-Associated Murine Leukemia Viruses

1998 ◽  
Vol 72 (5) ◽  
pp. 3973-3979 ◽  
Author(s):  
J. Dean Nuckols ◽  
Christopher Y. Thomas
Keyword(s):  
Gene Structure ◽  
Leukemia Virus ◽  
Dominant Gene ◽  
Envelope Gene ◽  
Type I ◽  
Major Histocompatibility ◽  
Gene Sequences ◽  
Major Histocompatibility Locus ◽  
Murine Leukemia

ABSTRACT C57BL/10 (B10) strains congenic at the mouse major histocompatibility locus (H-2) were injected with a modified ecotropic SL3-3 murine leukemia virus (MuLV) to determine the effect of the H-2 genes on the envelope gene structure of recombinant MuLVs. All tested strains rapidly developed T-cell lymphomas, and recombinant proviruses were detected in the tumor DNAs by Southern blot. The B10.D2 (H-2d ), B10.Br (H-2k ), B10.Q (H-2q ), and B10.RIII (H-2r ) strains exhibited a TI phenotype in which almost all tumors contained type I recombinants. These recombinants characteristically acquire envelope gene sequences from the endogenous polytropic viruses but retain the 5′ p15E (TM) gene sequences from the ecotropic virus. The parental B10 (H-2b ) strain, however, had a novel phenotype that was designated NS for nonselective. Only 30% of the B10 tumors had detectable type I recombinants, whereas a proportion of the others appeared to contain type II recombinants that lacked the type I-specific ecotropic p15E gene sequences. Studies of other B10 congenic strains with hybrid H-2 loci and selected F1animals revealed that the NS phenotype was regulated by a dominant gene(s) that mapped to the A region of H-2b . These results demonstrate that a host gene within the major histocompatibility complex can influence the genetic evolution of pathogenic retroviruses in vivo.

scholarly journals X-gp70: a third molecular species of the envelope protein gp70 of murine leukemia virus, expressed on mouse lymphoid cells.

1976 ◽  
Vol 143 (4) ◽  
pp. 969-974 ◽  
Author(s):  
J S Tung ◽  
F W Shen ◽  
E Fleissner ◽  
E A Boyse
Keyword(s):  
Molecular Species ◽  
Envelope Protein ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Virus Production ◽  
Lymphoid Cells ◽  
Mouse Strains ◽  
Type Virus ◽  
Murine Leukemia

Three variants of the gp70 envelope component of MuLV are now recognizable serologically: GIX-gp70, 0-gp70, and X-gp70. The last of these, X-gp70, has so far been found only in mice or cells producing abundant C-type virus. This distinguishes X-gp70, provisionally, from the GIX-gp70 and 0-gp70 variants, each of which can be expressed on normal thymocytes without accompanying virus production, as exemplified by mouse strains 129 and B6, respectively. The X-gp70 genotype, however, is not limited to strains of mice-producing abundant virus, because X-gp70+ leukemias occur in strains of mice which do not produce a great deal of virus and whose thymocytes and other tissues are X-gp70-; this is analogous to the appearance of GIX+ leukemias in GIX- mouse strains.

scholarly journals Inhibition of Murine Leukemia Virus Envelope Protein (Env) Processing by Intracellular Expression of the Env N-Terminal Heptad Repeat Region

2005 ◽  
Vol 79 (8) ◽  
pp. 4782-4792 ◽  
Author(s):  
Wu Ou ◽  
Jonathan Silver
Keyword(s):  
Influenza Virus ◽  
Envelope Protein ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Proteolytic Processing ◽  
Structural Motif ◽  
Type I ◽  
Alpha Helices ◽  
Intracellular Expression ◽  
Murine Leukemia

ABSTRACT A conserved structural motif in the envelope proteins of several viruses consists of an N-terminal, alpha-helical, trimerization domain and a C-terminal region that refolds during fusion to bind the N-helix trimer. Interaction between the N and C regions is believed to pull viral and target membranes together in a crucial step during membrane fusion. For several viruses with type I fusion proteins, C regions pack as alpha-helices in the grooves between N-helix monomers, and exogenously added N- and C-region peptides block fusion by inhibiting the formation of the six-helix bundle. For other viruses, including influenza virus and murine leukemia virus (MLV), there is no evidence for comparably extended C-region alpha-helices, although a short, non-alpha-helical interaction structure has been reported for influenza virus. We tested candidate N-helix and C-region peptides from MLV for their ability to inhibit cell fusion but found no inhibitory activity. In contrast, intracellular expression of the MLV N-helix inhibited fusion by efficiently blocking proteolytic processing and intracellular transport of the envelope protein. The results highlight another mechanism by which the N-helix peptides can inhibit fusion.

scholarly journals Host Cell Cathepsins Potentiate Moloney Murine Leukemia Virus Infection

2007 ◽  
Vol 81 (19) ◽  
pp. 10506-10514 ◽  
Author(s):  
Pankaj Kumar ◽  
Deepa Nachagari ◽  
Carolyn Fields ◽  
John Franks ◽  
Lorraine M. Albritton
Keyword(s):  
Envelope Protein ◽  
Murine Leukemia Virus ◽  
Cathepsin B ◽  
Leukemia Virus ◽  
Moloney Murine Leukemia Virus ◽  
Dependent Manner ◽  
Virus Binding ◽  
Dose Dependent ◽  
Murine Leukemia

ABSTRACT The roles of cellular proteases in Moloney murine leukemia virus (MLV) infection were investigated using MLV particles pseudotyped with vesicular stomatitis virus (VSV) G glycoprotein as a control for effects on core MLV particles versus effects specific to Moloney MLV envelope protein (Env). The broad-spectrum inhibitors cathepsin inhibitor III and E-64d gave comparable dose-dependent inhibition of Moloney MLV Env and VSV G pseudotypes, suggesting that the decrease did not involve the envelope protein. Whereas, CA-074 Me gave a biphasic response that differentiated between Moloney MLV Env and VSV G at low concentrations, at which the drug is highly selective for cathepsin B, but was similar for both glycoproteins at higher concentrations, at which CA-074 Me inhibits other cathepsins. Moloney MLV infection was lower on cathepsin B knockout fibroblasts than wild-type cells, whereas VSV G infection was not reduced on the B−/− cells. Taken together, these results support the notion that cathepsin B acts at an envelope-dependent step while another cathepsin acts at an envelope-independent step, such as uncoating or viral-DNA synthesis. Virus binding was not affected by CA-074 Me, whereas syncytium induction was inhibited in a dose-dependent manner, consistent with cathepsin B involvement in membrane fusion. Western blot analysis revealed specific cathepsin B cleavage of SU in vitro, while TM and CA remained intact. Infection could be enhanced by preincubation of Moloney MLV with cathepsin B, consistent with SU cleavage potentiating infection. These data suggested that during infection of NIH 3T3 cells, endocytosis brings Moloney MLV to early lysosomes, where the virus encounters cellular proteases, including cathepsin B, that cleave SU.

In vivo distribution of receptor for ecotropic murine leukemia virus and binding of envelope protein of Friend Murine leukemia virus

2003 ◽  
Vol 148 (6) ◽  
pp. 1175-1184 ◽  
Author(s):  
S. Yamaguchi ◽  
M. Hasegawa ◽  
T. Suzuki ◽  
H. Ikeda ◽  
S. Aizawa ◽  
...  
Keyword(s):  
Envelope Protein ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
In Vivo Distribution ◽  
Murine Leukemia
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