Intracellular Viral RNA Species in Mouse Cells Nonproductively Transformed by the Murine Sarcoma Virus

Abstract

The size and quantity of virus-specific RNA in five non-virus-producing mouse cells transformed by the Moloney isolate of murine sarcoma virus (MSV) was determined. Hybridization of RNA from transformed cells with the [3H]DNA product of the RNA-directed DNA polymerase of the murine sarcoma-leukemia virus was used to detect and quantitate virus-specific RNA. The amount of virus-specific RNA in non-virus-producing cells was less than one-sixth of that found in virus-producing cells. A striking correlation was found between the amount of intracellular virus-specific RNA and the degree of agglutination by conconavalin A previously reported for the four non-virus-producing NIH/3T3 cell lines (Salzberg and Green, 1974). A major RNA subunit sedimenting at 26 to 28S was detected in all five MSV-transformed non-virus-producing cells. This could represent the RNA genome of defective MSV.

“sarc” Sequence Transcription in Moloney Sarcoma Virus-Transformed Nonproducer Cell Lines

“…Nucleotide sequences complementary to M-MSV-specific cDNA were quantitated in the cytoplasmic RNA and nuclear DNA of several MSV-transformed nonproducer clones derived from NIH 3T3. Specific clones tested exhibit a wide range of transformation properties (23,28). The present study demonstrates that the degree of transformation correlates well with the amount of M-MSV-specific RNA in the cytoplasm of each of three clones tested, implying that the steady-state level of MSV sequences (and possible translation of a specific polypeptide) is directly related to transfornation.…”

Size of virus-specific RNA in B-34, a hamster tumor cell producing nucleic acids of type C viruses from three species

“…This result is in agreement with our conclusions that the 30S KiSV-specific sequences of rat origin do not direct synthesis of type C virus structural proteins even when incorporated into virions. In the case of M-MSV where a 30S RNA subunit is also detected in denatured viral RNA and NP transformed cells (25), hybridization experiments indicate (in contrast to the rat system) considerable homology to helper virus sequences (23)(24)(25). As with the rat 30S RNA subunit, MSV 30S RNA apparently does not direct the synthesis of structural proteins common to the helper virus.…”

“…In previous studies we have found that the Moloney strain of MSV (M-MSV) genome in nonproducer (NP) tumor cells or cells transformed by M-MSV was expressed in the form of RNA molecules sedimenting at 30S (24,25) as opposed to helper virus subunits which sediment at 35S (23)(24)(25). The KiSV-specific sequences found in KiSV-transformed NP cells also sedimented at 30S and could be found in normal rat cells as well (21,26,27).…”

“…Size of virus-specific RNA. The whole cell RNA was treated with dimethylsulfoxide (Me2SO) as described (21, 23,24) and layered on a 15 to 30% sucrose gradient in NTE buffer (0.01 M Tris-hydrochloride [pH 7.0], 0.1 M NaCl, 0.001 M EDTA) containing 0.5% NaDodSO4. The RNA was centrifuged for 5 to 6 h at 36,000 rpm at 20 C in the SW41 rotor in a Spinco model L2-65 ultracentrifuge.…”

Sequence homology between Moloney murine sarcoma virus and Moloney leukemia virus RNA

“…However, they do indicate that, if the small RNA species represent the M-MSV genome, these species contain no more than one or possibly two small genes not present in the M-MuLV genome. It is of great importance to make comparisons of RNA from M-MuLV with other potential sarcoma-specific RNA species such as those obtained from MSV(MuLV) populations in which there is great excess of MSV (17) or with virus-specific intracellular RNA from nonproducer cell lines (transformed lines that are presumably not infected with M-MuLV) (14,16). The purpose of such experiments would be to establish more clearly the number of genes responsible for morphological transformation of cells by the sarcoma agent.…”