scholarly journals Mutation of the core or adjacent LVb elements of the Moloney murine leukemia virus enhancer alters disease specificity.

1990 ◽  
Vol 4 (2) ◽  
pp. 233-242 ◽  
Author(s):  
N A Speck ◽  
B Renjifo ◽  
E Golemis ◽  
T N Fredrickson ◽  
J W Hartley ◽  
...  
Keyword(s):  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Moloney Murine Leukemia Virus ◽  
The Core ◽  
Disease Specificity ◽  
Murine Leukemia

scholarly journals Core-Binding Factor Influences the Disease Specificity of Moloney Murine Leukemia Virus

1999 ◽  
Vol 73 (7) ◽  
pp. 5535-5547 ◽  
Author(s):  
Amy F. Lewis ◽  
Terryl Stacy ◽  
William R. Green ◽  
Lekidelu Taddesse-Heath ◽  
Janet W. Hartley ◽  
...  
Keyword(s):  
T Cell ◽  
Latent Period ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Moloney Murine Leukemia Virus ◽  
Cell Disease ◽  
The Core ◽  
Core Site ◽  
Disease Specificity ◽  
Murine Leukemia

ABSTRACT The core site in the Moloney murine leukemia virus (Moloney MLV) enhancer was previously shown to be an important determinant of the T-cell disease specificity of the virus. Mutation of the core site resulted in a significant shift in disease specificity of the Moloney virus from T-cell leukemia to erythroleukemia. We and others have since determined that a protein that binds the core site, one of the core-binding factors (CBF) is highly expressed in thymus and is essential for hematopoiesis. Here we test the hypothesis that CBF plays a critical role in mediating pathogenesis of Moloney MLV in vivo. We measured the affinity of CBF for most core sites found in MLV enhancers, introduced sites with different affinities for CBF into the Moloney MLV genome, and determined the effects of these sites on viral pathogenesis. We found a correlation between CBF affinity and the latent period of disease onset, in that Moloney MLVs with high-affinity CBF binding sites induced leukemia following a shorter latent period than viruses with lower-affinity sites. The T-cell disease specificity of Moloney MLV also appeared to correlate with the affinity of CBF for its binding site. The data support a role for CBF in determining the pathogenic properties of Moloney MLV.

Cloning and characterization of subunits of the T-cell receptor and murine leukemia virus enhancer core-binding factor

1993 ◽  
Vol 13 (6) ◽  
pp. 3324-3339
Author(s):  
S Wang ◽  
Q Wang ◽  
B E Crute ◽  
I N Melnikova ◽  
S R Keller ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Cell Receptor ◽  
Cdna Clones ◽  
The Core ◽  
Core Site ◽  
Disease Specificity ◽  
Murine Leukemia

Moloney murine leukemia virus causes thymic leukemias when injected into newborn mice. A major determinant of the thymic disease specificity of Moloney virus genetically maps to the conserved viral core motif in the Moloney virus enhancer. Point mutations introduced into the core site significantly shifted the disease specificity of the Moloney virus from thymic leukemia to erythroid leukemia (N.A. Speck, B. Renjifo, E. Golemis, T.N. Fredrickson, J.W. Hartley, and N. Hopkins, Genes Dev. 4:233-242, 1990). We previously reported the purification of core-binding factors (CBF) from calf thymus nuclei (S. Wang and N.A. Speck, Mol. Cell. Biol. 12:89-102, 1992). CBF binds to core sites in murine leukemia virus and T-cell receptor enhancers. Affinity-purified CBF contains multiple polypeptides. In this study, we sequenced five tryptic peptides from two of the bovine CBF proteins and isolated three cDNA clones from a mouse thymus cDNA library encoding three of the tryptic peptides from the bovine proteins. The cDNA clones, which we call CBF beta p22.0, CBF beta p21.5, and CBF beta p17.6, encode three highly related but distinct proteins with deduced molecular sizes of 22.0, 21.5, and 17.6 kDa that appear to be translated from multiply spliced mRNAs transcribed from the same gene. CBF beta p22.0, CBF beta p21.5, and CBF beta p17.6 do not by themselves bind the core site. However, CBF beta p22.0 and CBF beta p21.5 form a complex with DNA-binding CBF alpha subunits and as a result decrease the rate of dissociation of the CBF protein-DNA complex. Association of the CBF beta subunits does not extend the phosphate contacts in the binding site. We propose that CBF beta is a non-DNA-binding subunit of CBF and does not contact DNA directly.

scholarly journals Purification of core-binding factor, a protein that binds the conserved core site in murine leukemia virus enhancers.

1992 ◽  
Vol 12 (1) ◽  
pp. 89-102 ◽  
Author(s):  
S W Wang ◽  
N A Speck
Keyword(s):  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Polyacrylamide Gel ◽  
Newborn Mice ◽  
The Core ◽  
Core Site ◽  
Disease Specificity ◽  
Murine Leukemia

The Moloney murine leukemia virus causes thymic leukemias when injected into newborn mice. A major genetic determinant of the thymic disease specificity of the Moloney virus genetically maps to two protein binding sites in the Moloney virus enhancer, the leukemia virus factor b site and the adjacent core site. Point mutations introduced into either of these sites significantly shifts the disease specificity of the Moloney virus from thymic leukemia to erythroleukemia (N. A. Speck, B. Renjifo, E. Golemis, T. Frederickson, J. Hartley, and N. Hopkins, Genes Dev. 4:233-242, 1990). We have purified several polypeptides that bind to the core site in the Moloney virus enhancer. These proteins were purified from calf thymus nuclear extracts by selective pH denaturation, followed by chromatography on heparin-Sepharose, nonspecific double-stranded DNA-cellulose, and core oligonucleotide-coupled affinity columns. We have achieved greater than 13,000-fold purification of the core-binding factors (CBFs), with an overall yield of approximately 19%. Analysis of purified protein fractions by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis reveals more than 10 polypeptides. Each of the polypeptides was recovered from an SDS-polyacrylamide gel, and those in the molecular size range of 19 to 35 kDa were demonstrated to have core-binding activity. The purified CBFs were shown by DNase I footprint analyses to bind the core site in the Moloney virus enhancer specifically, and also to core motifs in the enhancers from a simian immunodeficiency virus, the immunoglobulin mu chain, and T-cell receptor gamma-chain genes.

scholarly journals Cloning and characterization of subunits of the T-cell receptor and murine leukemia virus enhancer core-binding factor.

1993 ◽  
Vol 13 (6) ◽  
pp. 3324-3339 ◽  
Author(s):  
S Wang ◽  
Q Wang ◽  
B E Crute ◽  
I N Melnikova ◽  
S R Keller ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Cell Receptor ◽  
Cdna Clones ◽  
The Core ◽  
Core Site ◽  
Disease Specificity ◽  
Murine Leukemia

Moloney murine leukemia virus causes thymic leukemias when injected into newborn mice. A major determinant of the thymic disease specificity of Moloney virus genetically maps to the conserved viral core motif in the Moloney virus enhancer. Point mutations introduced into the core site significantly shifted the disease specificity of the Moloney virus from thymic leukemia to erythroid leukemia (N.A. Speck, B. Renjifo, E. Golemis, T.N. Fredrickson, J.W. Hartley, and N. Hopkins, Genes Dev. 4:233-242, 1990). We previously reported the purification of core-binding factors (CBF) from calf thymus nuclei (S. Wang and N.A. Speck, Mol. Cell. Biol. 12:89-102, 1992). CBF binds to core sites in murine leukemia virus and T-cell receptor enhancers. Affinity-purified CBF contains multiple polypeptides. In this study, we sequenced five tryptic peptides from two of the bovine CBF proteins and isolated three cDNA clones from a mouse thymus cDNA library encoding three of the tryptic peptides from the bovine proteins. The cDNA clones, which we call CBF beta p22.0, CBF beta p21.5, and CBF beta p17.6, encode three highly related but distinct proteins with deduced molecular sizes of 22.0, 21.5, and 17.6 kDa that appear to be translated from multiply spliced mRNAs transcribed from the same gene. CBF beta p22.0, CBF beta p21.5, and CBF beta p17.6 do not by themselves bind the core site. However, CBF beta p22.0 and CBF beta p21.5 form a complex with DNA-binding CBF alpha subunits and as a result decrease the rate of dissociation of the CBF protein-DNA complex. Association of the CBF beta subunits does not extend the phosphate contacts in the binding site. We propose that CBF beta is a non-DNA-binding subunit of CBF and does not contact DNA directly.

Purification of core-binding factor, a protein that binds the conserved core site in murine leukemia virus enhancers

1992 ◽  
Vol 12 (1) ◽  
pp. 89-102
Author(s):  
S W Wang ◽  
N A Speck
Keyword(s):  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Polyacrylamide Gel ◽  
Newborn Mice ◽  
The Core ◽  
Core Site ◽  
Disease Specificity ◽  
Murine Leukemia

The Moloney murine leukemia virus causes thymic leukemias when injected into newborn mice. A major genetic determinant of the thymic disease specificity of the Moloney virus genetically maps to two protein binding sites in the Moloney virus enhancer, the leukemia virus factor b site and the adjacent core site. Point mutations introduced into either of these sites significantly shifts the disease specificity of the Moloney virus from thymic leukemia to erythroleukemia (N. A. Speck, B. Renjifo, E. Golemis, T. Frederickson, J. Hartley, and N. Hopkins, Genes Dev. 4:233-242, 1990). We have purified several polypeptides that bind to the core site in the Moloney virus enhancer. These proteins were purified from calf thymus nuclear extracts by selective pH denaturation, followed by chromatography on heparin-Sepharose, nonspecific double-stranded DNA-cellulose, and core oligonucleotide-coupled affinity columns. We have achieved greater than 13,000-fold purification of the core-binding factors (CBFs), with an overall yield of approximately 19%. Analysis of purified protein fractions by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis reveals more than 10 polypeptides. Each of the polypeptides was recovered from an SDS-polyacrylamide gel, and those in the molecular size range of 19 to 35 kDa were demonstrated to have core-binding activity. The purified CBFs were shown by DNase I footprint analyses to bind the core site in the Moloney virus enhancer specifically, and also to core motifs in the enhancers from a simian immunodeficiency virus, the immunoglobulin mu chain, and T-cell receptor gamma-chain genes.

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