scholarly journals The Left Half of the XMRV Retrovirus Is Present in an Endogenous Retrovirus of NIH/3T3 Swiss Mouse Cells

2011 ◽  
Vol 85 (17) ◽  
pp. 9247-9248 ◽  
Author(s):  
R. Mendoza ◽  
A. E. Vaughan ◽  
A. D. Miller
Keyword(s):  
Endogenous Retrovirus ◽  
Swiss Mouse ◽  
Left Half ◽  
Mouse Cells ◽  
Nih 3T3

scholarly journals Modulation of the transport of a lysosomal enzyme by PDGF.

1990 ◽  
Vol 110 (2) ◽  
pp. 319-326 ◽  
Author(s):  
E M Prence ◽  
J M Dong ◽  
G G Sahagian
Keyword(s):  
Secretory Pathway ◽  
Cathepsin L ◽  
Control Level ◽  
3T3 Cells ◽  
Lysosomal Protease ◽  
Affinity Ligand ◽  
The Media ◽  
Mouse Cells ◽  
Nih 3T3 ◽  
The Relationship

The major excreted protein (MEP) of transformed mouse fibroblasts is the lysosomal protease, cathepsin L. MEP is also secreted by untransformed mouse cells in response to growth factors and tumor promoters, and is thought to play a role in cell growth and transformation. To determine the relationship between MEP synthesis and MEP secretion, we have examined these events in PDGF-treated NIH 3T3 cells. PDGF enhanced MEP synthesis and caused the diversion of MEP from the lysosomal delivery pathway to a secretory pathway. These two effects were found to be regulated independently at various times after growth factor addition. Short PDGF treatments (0.5 or 1 h) resulted in quantitative secretion of MEP although synthesis was near the control level. High levels of both synthesis and secretion occurred between 2 and 14 h of PDGF treatment. Between 18 and 30 h, the amount of secreted MEP returned to the low control level even though synthesis remained elevated. The secretion was specific for MEP; other lysosomal enzymes were not found in the media from PDGF-treated cells. PDGF-induced secretion of MEP was inhibited 84% by cycloheximide, suggesting that protein synthesis is required to elicit this effect. PDGF also caused a time-dependent increase in mannose 6-phosphate (Man-6-P) receptor-mediated endocytosis. These data support a model in which PDGF alters the distribution of Man-6-P receptors such that the Golgi concentration of receptors becomes limiting, thereby causing the selective secretion of the low affinity ligand, MEP.

scholarly journals Membrane cofactor protein (CD46) protects cells from complement-mediated attack by an intrinsic mechanism.

1992 ◽  
Vol 175 (6) ◽  
pp. 1547-1551 ◽  
Author(s):  
T J Oglesby ◽  
C J Allen ◽  
M K Liszewski ◽  
D J White ◽  
J P Atkinson
Keyword(s):  
Protective Role ◽  
Cellular Level ◽  
Host Cells ◽  
Membrane Cofactor Protein ◽  
Alternative Pathways ◽  
Intrinsic Mechanism ◽  
Dose Dependent Fashion ◽  
Mouse Cells ◽  
Nih 3T3 ◽  
Relationship Of

The cleavage of C3 is a critical step for complement (C) activation in the classical and alternative pathways. This reaction is controlled by the regulators of C activation protein family. Membrane cofactor protein (MCP) is a cofactor for the factor I-mediated inactivation of C3b and C4b. As a widely distributed membrane protein, MCP may protect host cells from inadvertent C activation. Human MCP has recently been shown to protect transfected rodent cells from human C-mediated lysis. In this report the relationship of MCP expression to C3b deposition and cytoprotection was examined using NIH/3T3 cells transfected with human MCP and exposed to human serum as a source of C and naturally occurring anti-mouse antibody. MCP inhibited C3b deposition in a dose-dependent fashion and inhibited lysis of the mouse cells expressing it. MCP did not inhibit lysis on bystander cells. These results demonstrate the protective role of MCP, at the cellular level, by an intrinsic mechanism.

Transformation of NIH/3T3 mouse cells by DNA of Rous sarcoma virus

Cell ◽  
1979 ◽  
Vol 17 (4) ◽  
pp. 993-1002 ◽  
Author(s):  
Neal G. Copeland ◽  
Andrew D. Zelenetz ◽  
Geoffrey M. Cooper
Keyword(s):  
Rous Sarcoma Virus ◽  
Rous Sarcoma ◽  
Sarcoma Virus ◽  
Mouse Cells ◽  
Nih 3T3

scholarly journals Regulation of telomerase activity in immortal cell lines.

1996 ◽  
Vol 16 (6) ◽  
pp. 2932-2939 ◽  
Author(s):  
S E Holt ◽  
W E Wright ◽  
J W Shay
Keyword(s):  
Stem Cells ◽  
Germ Line ◽  
Telomerase Activity ◽  
Cancer Therapies ◽  
Quiescent Cells ◽  
Amplification Protocol ◽  
Mouse Cells ◽  
Immortal Cells ◽  
Quiescent Stem Cells ◽  
Nih 3T3

Telomerase is a ribonucleoprotein whose activity has been detected in germ line cells, immortal cells, and most cancer cells. Except in stem cells, which have a low level of telomerase activity, its activity is absent from normal somatic tissues. Understanding the regulation of telomerase activity is critical for the development of potential tools for the diagnosis and treatment of cancer. Using the telomeric repeat amplification protocol, we found that immortal, telomerase-positive, pseudodiploid human cells (HT1080 and HL60 cells) sorted by flow repressed in quiescent cells. This was true whether quiescence was induced by contact inhibition (NIH 3T3 mouse cells), growth factor removal (bromodeoxyuridine-blocked mouse myoblasts), reexpression of cellular senescence (the reversibly immortalized IDH4 cells), or irreversible cell differentiation (HL60 promyelocytic leukemia cells and C2C12 mouse myoblasts). Taken together, these results indicate that telomerase is active throughout the cell in dividing, immortal cells but that its activity is repressed in cells that exit the cell cycle. This suggests that quiescent stem cells that have the potential to express telomerase may remain unaffected by potential antitelomerase cancer therapies.

scholarly journals Transfected DNA is mutated in monkey, mouse, and human cells.

1984 ◽  
Vol 4 (10) ◽  
pp. 1951-1960 ◽  
Author(s):  
J S Lebkowski ◽  
R B DuBridge ◽  
E A Antell ◽  
K S Greisen ◽  
M P Calos
Keyword(s):  
Mammalian Cells ◽  
Time Course ◽  
Mutation Frequency ◽  
Spontaneous Mutation ◽  
Bacterial Cells ◽  
Shuttle Vectors ◽  
High Mutation Frequency ◽  
Mouse Cells ◽  
Nih 3T3 ◽  
Viral Sequences

Papovavirus-based shuttle vectors containing the bacterial lacI gene were used to show that a mutation frequency in the range of 1% occurs in lacI when such vectors are transfected into COS7 and CV-1 simian cells, NIH 3T3, 3T6, L, and C127 mouse cells, and human 293 and HeLa cells. This frequency is approximately four orders of magnitude higher than the spontaneous mutation frequency in either mammalian or bacterial cells. The mutations are predominantly base substitutions and deletions and also include insertions from the mammalian genome. Time course experiments argue that mutagenesis occurs soon after arrival of the DNA into the nucleus. However, replication of the vector is not required since mutations occur even when the vector lacks all viral sequences. The high mutation frequency appears to be the characteristic outcome of transfection of DNA into mammalian cells.

scholarly journals Sodium-Dependent Neutral Amino Acid Transporter Type 1 Is an Auxiliary Receptor for Baboon Endogenous Retrovirus

2000 ◽  
Vol 74 (17) ◽  
pp. 8085-8093 ◽  
Author(s):  
Mariana Marin ◽  
Chetankumar S. Tailor ◽  
Ali Nouri ◽  
David Kabat
Keyword(s):  
Amino Acid ◽  
Amino Acid Transporter ◽  
Endogenous Retrovirus ◽  
Neutral Amino Acid ◽  
Type D ◽  
Neutral Amino Acid Transporter ◽  
Sodium Dependent ◽  
Mouse Cells ◽  
Acid Transporter ◽  
Type D Retroviruses

ABSTRACT The baboon endogenous retrovirus (BaEV) belongs to a large, widely dispersed interference group that includes the RD114 feline endogenous virus and primate type D retroviruses. Recently, we and another laboratory independently cloned a human receptor for these viruses and identified it as the human sodium-dependent neutral amino acid transporter type 2 (hASCT2). Interestingly, mouse and rat cells are efficiently infected by BaEV but only become susceptible to RD114 and type D retroviruses if the cells are pretreated with tunicamycin, an inhibitor of protein N-linked glycosylation. To investigate this host range difference, we cloned and analyzed NIH Swiss mouse ASCT2 (mASCT2). Surprisingly, mASCT2 did not mediate BaEV infection, which implied that mouse cells might have an alternative receptor for this virus. In addition, elimination of the two N-linked oligosaccharides from mASCT2 by mutagenesis, as substantiated by proteinN-glycosidase F digestions and Western immunoblotting, did not enable it to function as a receptor for RD114 or type D retroviruses. Based on these results, we found that the related ASCT1 transporters of humans and mice are efficient receptors for BaEV but are relatively inactive for RD114 and type D retroviruses. Furthermore, elimination of the two N-linked oligosaccharides from extracellular loop 2 of mASCT1 by mutagenesis enabled it to function as an efficient receptor for RD114 and type D retroviruses. Thus, we infer that the tunicamycin-dependent infection of mouse cells by RD114 and type D retroviruses is caused by deglycosylation of mASCT1, which unmasks previously buried sites for viral interactions. In contrast, BaEV efficiently employs the glycosylated forms of mASCT1 that occur normally in untreated mouse cells.

scholarly journals Wild Mouse Variants of Envelope Genes of Xenotropic/Polytropic Mouse Gammaretroviruses and Their XPR1 Receptors Elucidate Receptor Determinants of Virus Entry

2007 ◽  
Vol 81 (19) ◽  
pp. 10550-10557 ◽  
Author(s):  
Yuhe Yan ◽  
Ryan C. Knoper ◽  
Christine A. Kozak
Keyword(s):  
Virus Entry ◽  
Wild Mouse ◽  
Receptor Site ◽  
Viral Envelope ◽  
Amino Acid Residues ◽  
Identify Amino Acid ◽  
Mouse Species ◽  
Mouse Cells ◽  
Leukemia Viruses ◽  
Nih 3T3

ABSTRACT Mouse xenotropic and polytropic leukemia viruses (XMVs and PMVs) are closely related gammaretroviruses that use the XPR1 receptor for entry. To identify amino acid residues in XPR1 important for virus entry, we tested mouse cells derived from evolutionarily divergent species for susceptibility to prototypical PMVs, XMVs, and the wild mouse isolate CasE#1. CasE#1 has a variant XMV/PMV host range, and sequence analysis of the CasE#1 env gene identifies segments related to PMVs and XMVs. Cells from the Asian mouse species Mus pahari show a unique pattern of susceptibility to these three viruses; these cells are susceptible to XMVs and CasE#1 but are resistant to PMVs, whereas NIH 3T3 cells show the reciprocal pattern, susceptibility to only PMVs. The M. pahari XPR1 gene differs from that of NIH 3T3 in the two extracellular loops (ECLs) previously shown to mediate virus entry (M. Marin, C. S. Tailor, A. Nouri, S. L. Kozak, and D. Kabat, J. Virol. 73:9362-9368, 1999, and N. S. Van Hoeven and A. D. Miller, Retrovirology 2:76, 2005). Using transfected hamster cells expressing chimeric and mutated XPR1s, we demonstrated that the susceptibility differences between NIH 3T3 and M. pahari cells are receptor mediated, that PMV entry requires residues in ECL3, that the CasE#1 entry determinant is in ECL4, and that determinants for XMV entry are in both ECL3 and ECL4. Additional substitutions in ECL3 and ECL4 modulate virus susceptibility and suggest that ECL3 and ECL4 may contribute to the formation of a single virus receptor site. The position of M. pahari at the base of the Mus phylogenetic tree indicates that XPR1-mediated susceptibility to XMVs is the ancestral type in this genus and that the phenotypic variants of mouse XPR1 likely arose in conjunction with exposure to gammaretrovirus infections and coevolutionary adaptations in the viral envelope.

Transfected DNA is mutated in monkey, mouse, and human cells

1984 ◽  
Vol 4 (10) ◽  
pp. 1951-1960
Author(s):  
J S Lebkowski ◽  
R B DuBridge ◽  
E A Antell ◽  
K S Greisen ◽  
M P Calos
Keyword(s):  
Mammalian Cells ◽  
Time Course ◽  
Mutation Frequency ◽  
Spontaneous Mutation ◽  
Bacterial Cells ◽  
Shuttle Vectors ◽  
High Mutation Frequency ◽  
Mouse Cells ◽  
Nih 3T3 ◽  
Viral Sequences

Papovavirus-based shuttle vectors containing the bacterial lacI gene were used to show that a mutation frequency in the range of 1% occurs in lacI when such vectors are transfected into COS7 and CV-1 simian cells, NIH 3T3, 3T6, L, and C127 mouse cells, and human 293 and HeLa cells. This frequency is approximately four orders of magnitude higher than the spontaneous mutation frequency in either mammalian or bacterial cells. The mutations are predominantly base substitutions and deletions and also include insertions from the mammalian genome. Time course experiments argue that mutagenesis occurs soon after arrival of the DNA into the nucleus. However, replication of the vector is not required since mutations occur even when the vector lacks all viral sequences. The high mutation frequency appears to be the characteristic outcome of transfection of DNA into mammalian cells.

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