title: Characterization of defective simian virus 40 DNA: comparison between large-plaque and small-plaque types.
abstract: We characterized defective DNA molecules of large-plaque and small-plaque SV40 produced and accumulated during serial undiluted passages. The electron microscope heteroduplex method revealed that defective SV40 DNA contains deletions, insertions and substitutions. The majority of the large-plaque defective molecules had a simple deletion. The deletions were heterogeneous in size, and the sites of deletion appeared to be mostly overlapping. The majority of the small-plaque defective molecules had a deletion, and more than half of the deletion molecules also had an insertion at a separate site. The small-plaque SV40 genome appeared to have more sites for deletion to occur than large-plaque SV40, and the deletions have occurred at more than two sites. The change of a local nucleo tide sequence resulting from mutation may be related to the difference between the two plaque types.
mesh_terms: D002471:Cell Transformation, Neoplastic; D004270:DNA, Circular / Q000032:analysis*; D004277:DNA, Single-Stranded / Q000032:analysis; D004279:DNA, Viral / Q000032:analysis*; D003673:Defective Viruses / Q000032:analysis*; D004720:Endonucleases; D006822:Hybrid Cells; D010641:Phenotype; D013539:Simian virus 40 / Q000032:analysis*; D010948:Viral Plaque Assay; D014776:Virus Cultivation
chemical_list: D004270:DNA, Circular; D004277:DNA, Single-Stranded; D004279:DNA, Viral; D004720:Endonucleases