Abstract
Complementary DNA (cDNA) synthesized by Moloney murine sarcoma virus (M-MSV) was separated into two parts, the first, termed MSV-specific cDNA, composed of nucleotide sequences found only in M-MSV viral RNA, and the second, termed MSV-MuLV common cDNA, composed of nucleotide sequences that were found in both M-MSV and murine leukemia virus (MuLV) VIRAL RNAs. RNA complementary to the MSV-specific cDNA was not found in several other MSV isolates, nor in ecotropic MuLV, mouse mammary tumor virus, or several murine xenotropic oncoviruses. Cellular DNA of several species was examined for the presence of nucleotide sequences complementary to MSV-specific cDNA. Cells transformed by M-MSV did contain MSV-specific cDNA in their DNA. Normal mouse cell DNA apparently contained the majority of MSV-specific nucleotide sequences. Cellular DNA of related species contained proportionally less MSV-specific cDNA. Hybrids of MSV-spedivic cDNA and cellular DNA of related species melted at lower temperatures than hybrids of MSV-specific cDNA and mouse cellular DNA. RNA from normal mouse adult or embryonic cells did not contain detectable nucleotide sequences complementary to MSV-specific cDNA. Transformation of cells with M-msv resulted in transcription of RNA hybridizing with MSV-specific cDNA. Methylcholanthrene-induced mouse sarcomas and cell lines derived from them did not contain RNA complementary to MSV-specific cDNA. Mouse cell lines transformed with avian sarcoma virus or Kirsten MSV-specific cDNA. RNA homologous to MSV-specific nucleotide sequences is measurably present only in cells transformed by M-MSV and not in cells transformed by other biological or chemical agents that also cause sarcomas.