Separation of sarcoma virus-specific and leukemia virus-specific genetic sequences of Moloney sarcoma virus.

114

Cell clones nonproductively transformed by the replication-defective Abelson strain of murine leukemia virus (AbLV) were analyzed for type C viral antigen expression by competition immunoassay. AbLV-transformed mink non-producer lines were found to express a 110,000- to 130,000-molecular weight polyprotein containing murine leukemia virus gag proteins p15 and p12 covalently linked to nonstructural AbLV-coded component(s) of around 80,000-100,000 molecular weight. This polyprotein lacked detectable antigenic cross-reactivity with other virion-coded gag gene proteins such as p30, p10, the viral reverse transcriptase (RNA-dependent DNA polymerase), or the major viral envelope glycoprotein, gp70. By analogy to earlier data on feline and avian sarcoma viruses, these results suggest that a portion of this polyprotein might represent the AbLV src gene product and that in translation it is initially linked in precursor form to gag structural proteins. Superinfection of mink cells nonproductively transformed by AbLV--with either a wild mouse amphotropic type C virus isolate, 4070-A, or with the endogenous cat virus, RD114--led to production of pseudotype virus containing high concentrations of the AbLV-coded precursor polyprotein.

Section: Discussionmentioning

confidence: 99%

Cells nonproductively transformed by Abelson murine leukemia virus express a high molecular weight polyprotein containing structural and nonstructural components.

Reynolds¹,

Sacks²,

Deobagkar³

et al. 1978

114

“…The following cell lines were used in these studies and have been described (4,5): SC-1, BALB/c 3T3, and NIH 3T3 mouse embryo fibroblast cell lines, permissive for ecotropic MuLV; mink lung fibroblasts, permissive for the growth of xenotropic type C viruses; nonproducer cells containing the Friend strain of SFFV, BALB clone 4, and SFFV-NRK clone 1; normal rat kidney (NRK) cells; a subclone of NRK (V-NRK) that produces rat type C viruses; and NRK cells nonproductively infected with the p30+ strain of Moloney sarcoma virus (S+L-NRK) and Abelson virus (Ab-NRK) (8).…”

Section: Methodsmentioning

confidence: 99%

“…Replicating type C virus (ecotropic, xenotropic, and amphotropic) was detected by assay of a 24-hr collection of supernatant medium from infected cells for reverse transcriptase activity by procedures that have been described (4). MuLV were also assayed by (i) the XC plaque assay (13) and (ii) assay for cytopathic effects on mink lung fibroblasts by procedures recently described (11 (8,14). The cDNAgag used in these studies was identical to fraction 5 (14).…”

Section: Methodsmentioning

confidence: 99%

Friend strain of spleen focus-forming virus is a recombinant between ecotropic murine type C virus and the env gene region of xenotropic type C virus.

Troxler¹,

Lowy²,

Howk³

et al. 1977

Self Cite

106

The spleen focus-forming virus (SFFV), a replication-defective murine leukemia virus that causes the rapid transformation of certain hematopoietic target cells, has acquired specific xenotropic viral genetic information not contained in Friend helper virus. In the current studies, it is shown that a cDNA that represents a xenotropic virus portion of SFFV detects genetic sequences derived from the env gene region of murine xenotropic virus. The significance of the acquisition of these xenotropic viral sequences by SFFV is discussed with regard to their possible role in the rapid leukemogenicity of SFFV, and an analogy is drawn between the formation of SFFV and the formation of the Kirsten and Harvey sarcoma viruses.

“…In most cases, these transforming viruses have been shown to be recombinants between portions of the genomes of helperindependent type C viruses and other genetic information derived from the host species from which the transforming virus was originally isolated. In studies on isolates derived from a given species, one of the interesting facts that has emerged is the diversity in the newly acquired host genetic information among the isolates (4,5).…”

mentioning

confidence: 99%

Different rat-derived transforming retroviruses code for an immunologically related intracellular phosphoprotein.

Young¹,

Shih²,

Scolnick³

et al. 1979

Self Cite

Kirsten sarcoma virus (Ki-MSV) and Harvey sarcoma virus (Ha-MSV) are mouse-rat recombinant viruses that were originally isolated by experimental inoculation of rats with helper-independent mouse type C viruses. We 75,[2972][2973][2974][2975][2976]. We report here that this new, purely rat sarcoma virus apparently codes for a p29, which shares immunological determinants and common V-8 protease-generated peptides with the p21 of Ha-MSV. The data suggest that the RaSV has acquired genetic information with similar coding capacity to some rat genetic information in the mouse-rat recombinant viruses, Ki-MSV and Ha-MSV. Based on data obtained on the p21 of a mutant of Ki-MSV temperature-sensitive for the maintenance of transformation, we suggest that the gene in RaSV that codes for the p29 is also required for the maintenance of RaSV-induced fibroblast transformation.