Murine sarcoma virus related nucleic acid sequences in a non‐transforming virus derived from an interspecies pseudotype sarcoma virus

Abstract

A number of sarcomagenic viruses recovered from hamster tumors induced originally by Moloney sarcoma virus or several of its mouse pseudotypes appear to be interspecies pseudotypes with structural proteins of hamster type-C viruses and nucleic acid sequences of both mouse and hamster specificity. A non-transforming virus (GLOH-minus) recovered from a sarcomagenic virus preparation obtained from a tumor induced by the Gross pseudotype of Moloney sarcoma virus was previously shown to retain mouse sequences. The ability to discriminate readily between Gross and Moloney viruses by molecular hybridization, especially with regard to thermal stability of inter-strain hybrid molecules, and the stability of Moloney virus sequences in a rat-mouse interspecies pseudotype, made it possible to specify that the mouse virus-specific sequences in GLOH-minus are derived from Moloney virus and not Gross. Thus, even though GLOH-minus is non-transforming in vitro or in vivo, it still retains sequences highly related to Moloney sarcoma virus. The lack of transforming ability is thus probably based on loss or change of specific sequences necessary for transformation at some point in the history of this virus.

A portion of the feline leukaemia virus genome is not endogenous in cat cells

“…[3H]cDNA was hybridized with cellular DNA in 0.6 M NaCl at 67" C to a given Coat value as described above and then the thermal stability of the hybrids was determined as described previously (Okabe et al, 1975). The radioactivity eluted after initial 60" C washes was considered to be released from hybrid molecules.…”

“…Qualitative differences of the hybrid molecules between heterologous reactants can be characterized by examining their thermal stability, and the technique has been successfully applied to analyze the genomic composition of pseudotype viruses (Okabe et al, 1975). To further characterize the FeLVspecific sequences and their distribution among cat cell DNA, thermal stability of hybrids of unfractionated and recycled R-FeLV [3H]cDNA with DNA from various cells were compared and are summarized in Table I.…”