Disease relevance of Mink Cell Focus-Inducing Viruses

• Recent studies have indicated that both the replication-defective spleen focus-forming virus (SFFV) in the Friend virus complex and the helper-independent mink cell focus-inducing (MCF) viruses derived from AKR-murine leukemia virus (MuLV) are env gene recombinants between ecotropic virus and xenotropic virus [1].
• The ability to isolate replicating MCF viruses derived from F-MuLV FURTHER strengthens the parallels between the Friend erythroleukemia system and the AKR thymic leukemia system [1].
• To determine whether infection by MCF viruses altered the growth phenotype of retrovirus-induced T-cell lymphomas, a Moloney murine leukemia virus-induced interleukin-2 (IL-2)-dependent rat T-cell lymphoma line (4437A) was infected with MCF-247, modified MCF-V33 (mMCF-V33), or NZB-xenotropic (NZB-X) virus [2].
• The Friend or Moloney mink cell focus-forming (MCF) virus encodes a recombinant-type envelope glycoprotein, gp70, that is closely related to the membrane glycoprotein, gp55, of Friend spleen focus-forming virus (SFFV) [3].
• LP-BM5 murine leukemia virus, a derivative of Duplan-Laterjet virus, contains a mixture of replication-competent B-tropic ecotropic and mink cell focus-inducing (MCF) viruses and a defective genome that is the proximal cause of a syndrome, murine AIDS (MAIDS), characterized by lymphoproliferation and immunodeficiency [4].

High impact information on Mink Cell Focus-Inducing Viruses

• Previously we reported that in cell cultures from first backcross progeny, this Rmcf-linked restriction segregates with the expression of an endogenous retroviral gp70 serologically related to that of MCF viruses [5].
• The expression of the Rmcfr gene is correlated with the constitutive expression of an MCF virus-related envelope glycoprotein that apparently blocks the receptor for MCF viruses, preventing their spread [6].
• Friend murine leukemia virus-induced leukemia is associated with the formation of mink cell focus-inducing viruses and is blocked in mice expressing endogenous mink cell focus-inducing xenotropic viral envelope genes [7].
• The serological profile of MCF viruses thus supports the contention that they are env gene recombinants between ecotropic and xenotropic murine leukemia viruses [8].
• The majority of Akv oligonucleotides missing from T1 fingerprints of MCFs and the majority of oligonucleotides unique to MCF viruses are clustered and lie at corresponding positions in the 3' half of the oligonucleotide maps of Akv and MCF viruses [9].

Chemical compound and disease context of Mink Cell Focus-Inducing Viruses

• The gp52 shared immunological reactivity and methionine-containing tryptic peptides with the gp70 of a Friend MCF virus and was expressed on the surface of SFFV-infected cells as well as in the cytoplasm [10].

Biological context of Mink Cell Focus-Inducing Viruses

• Nucleotide sequence comparisons suggest that the nonecotropic region may be more closely related to the 5' substitution in dualtropic mink cell focus-inducing viruses that it is to the 5' end of xenotropic virus env genes [11].
• In a molecular clone (MCF 247-W) of the murine leukemia virus MCF 247, a leukemogenic mink cell focus-inducing (MCF) virus, the U3 enhancer sequences are tandemly repeated in the LTR [12].
• The Bxv-1 provirus and its flanking sequences also contain the same restriction sites as the provirus thought to contribute U3 long terminal repeat sequences to leukemogenic (class I) AKR MCF viruses [13].
• Despite their different pathogenicity, the nucleotide sequences of the env gene of Friend MCF virus and Moloney MCF virus were quite homologous, suggesting that the putative parent sequence for the generation of both MCF viruses and the recombinational mechanism for their generation might be the same [14].
• Pim-1 is an oncogene activated in mouse T-cell lymphomas induced by Moloney and AKR mink cell focus (MCF) viruses [15].

Anatomical context of Mink Cell Focus-Inducing Viruses

• Furthermore, when the cDNA for the human IL-2 receptor beta chain, which is related by sequence to the erythropoietin receptor, was introduced into this cell line, it became growth factor independent after infection either with SFFV or with one of the two MCF viruses but not with an ecotropic virus [3].
• Newborn IRW mice inoculated with Moloney-MuLV produced MCF viruses in both spleen and thymus [16].

Gene context of Mink Cell Focus-Inducing Viruses

• The Rmcf gene may be of much use as a means of determining the role of MCF viruses in various forms of leukemogenesis [17].
• Some alteration in c-myc and Pim-1 genes were also found in MNU-induced tumors, but, mainly, these involved integration of ecotropic-like rather than recombinant MCF viruses [18].
• In backcross progeny, inheritance of Rmcf resistance correlated with inheritance of a specific endogenous MCF virus env-containing 4.6-kb EcoRI fragment [19].
• The rate of MCF virus spread through a population of permissive human cells was increased by establishment of trans activation, indicating that Syg1 receptor-dependent and -independent pathways function in parallel [20].
• To determine whether the Ikaros-binding sites are functional in vivo, we inoculated newborn mice with a variant MCF virus containing a mutant Ikaros-binding site [21].

References