A distinct class of inducible murine type-C viruses that replicates in the rabbit SIRC cell line

Proc Natl Acad Sci U S A. 1974 Mar;71(3):602-6. doi: 10.1073/pnas.71.3.602.


The existence of the selectively permissive rabbit cell line SIRC allows definition of a new class of endogenous murine type-C virus. Continuous clonal lines of transformed cells derived from the BALB/c mouse-embryo cell line BALB/3T3 contain at least two distinct classes of endogenous type-C viral genomes. Spontaneously released endogenous viruses grow well on the mouse cell line NIH/3T3 (N-tropic viruses) but not on the rabbit cell line SIRC. Type-C viruses induced by treatment with BrdU grow well on SIRC (S-tropic viruses) but not in NIH/3T3 or BALB/3T3. BrdU-treated AKR mouse-embryo cells also release an S-tropic virus. N-tropic and S-tropic viruses both have the mouse intraspecies gs-1 and viral RNA-directed DNA polymerase antigenic determinants. DNA.RNA hybridization techniques reveal that the two host-range classes of endogenous viruses are only partially related to each other. Cell transformation facilitates the spontaneous release of the N-tropic viruses; treatment with thymidine analogues induces the production of the S-tropic viruses. Thus, the two classes of viral genomes appear to be subject to different cellular controls.

MeSH terms

  • Animals
  • Antigens, Viral / analysis
  • Cats
  • Cell Line*
  • Clone Cells
  • Cornea
  • Fibroblasts
  • Haplorhini
  • Humans
  • Mice
  • Mice, Inbred BALB C
  • Nucleic Acid Hybridization
  • RNA, Viral / analysis
  • RNA-Directed DNA Polymerase / analysis
  • RNA-Directed DNA Polymerase / metabolism
  • Rabbits
  • Rats
  • Retroviridae / classification
  • Retroviridae / enzymology
  • Retroviridae / growth & development
  • Retroviridae / isolation & purification*
  • Species Specificity
  • Thymidine / metabolism
  • Tritium
  • Virus Cultivation*
  • Virus Replication*


  • Antigens, Viral
  • RNA, Viral
  • Tritium
  • RNA-Directed DNA Polymerase
  • Thymidine