A single mutation in one of the CORE elements of Moloney murine leukemia virus reduced binding of a 42-kDa T lymphoma cell nuclear factor but did not affect lymphomagenesis.
The genetic determinant responsible for virulence in Moloney murine leukemia virus (MoMuLV) induced T-cell lymphomagenesis has recently been mapped [J Virol 63:471-480, 1989] by homologous genomic fragment exchange between MoMuLV and MoMuLV-TB to the Clal/Xbal at the 3' end of the genome. This region of MoMuLV and MoMuLV-TB differs in 11 nucleotides. Of these 11 nucleotide differences, 9 are distributed within the two CORE, the two distal NF1, and the two GRE/LVa elements of the enhancer. Since both the CORE binding sites of MoMuLV-TB are mutated with respect to those of MoMuLV, we compared nuclear proteins of a thymus-bone marrow cell line and a T-lymphoma cell line (EMT), which bind to the wild-type and mutant CORE binding sites. Using both the bandshift assay and southwestern analysis with labeled synthetic deoxyoligonucleotides, we showed that a 42-kDa protein from TB and EMT cells bound specifically to the MoMuLV CORE element. The T----C transversion of nucleotide 6 of the CORE consensus, TGTGGT/CTAA, significantly reduced binding of the 42-kDa TB and EMT cell factors. However, the transversion of nucleotide 3 from T----C had little effect on the binding of the 42-kDa protein to the CORE element. In addition, the 42-kDa protein bound weakly to the CCAAT element of MoMuLV. A recombinant virus, NwtTB-6, was generated by introducing the two CORE mutations of MoMuLV-TB into the MoMuLV genome. Although the latency period of NwtTB-6 in the induction of lymphoma was not significantly different from that of MoMuLV, preliminary findings suggest that the lymphoma induced by NwtTB-6 may be more widely distributed.
Case
R S
RS
Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville 78957.
Khang
Y H
YH
Kumar
A
A
Yuen
P H
PH
D000818:Animals; D001483:Base Sequence; D002472:Cell Transformation, Viral; D003001:Cloning, Molecular; D015342:DNA Probes; D004279:DNA, Viral / Q000032:analysis; D004742:Enhancer Elements, Genetic; D008223:Lymphoma / Q000235:genetics* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D008979:Moloney murine leukemia virus / Q000235:genetics*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics*; D013601:T-Lymphocytes / Q000378:metabolism; D014407:Tumor Cells, Cultured
D015342:DNA Probes; D004279:DNA, Viral; D009687:Nuclear Proteins