title: Synthesis of Superhelical Simian Virus 40 Deoxyribonucleic Acid in Cell Lysates*.
abstract: In vivo-labeled SV40 replicating DNA molecules can be converted into covalently closed superhelical SV40 DNA (SV40(I) using a lysate of sv40-infected monkey cells containing intact nuclei. Replication in vitro occurred at one-third the in vivo rate for 30 min at 30 degrees. After 1 hour of incubation, about 54% of the replicating molecules had been converted to SV40(I), 5%  to nicked, circular molecules (SV40(II), 5% to covalently closed dimers; the remainder failed to complete replication although 75% of the prelabeled daughter strands had been elongated to one-genome length. Density labeling in vitro showed that all replicating molecules had participated during DNA synthesis in vitro. Velocity and equilibrium sedimentation analysis of pulse-chased and labeled DNA using radioactive and density labels suggested that SV40 DNA synthesis in vitro was a continuation of normal ongoing DNA synthesis. Initiation of new rounds of SV40 DNA replication was not detectable.
mesh_terms: D000645:Ammonium Sulfate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002460:Cell Line; D002474:Cell-Free System; D002499:Centrifugation, Density Gradient; D002729:Chloromercuribenzoates / Q000494:pharmacology; D004261:DNA Replication; D004270:DNA, Circular / Q000096:biosynthesis; D004279:DNA, Viral / Q000096:biosynthesis*; D003851:Deoxyribonucleases; D004492:Edetic Acid / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D000882:Haplorhini; D007668:Kidney; D007700:Kinetics; D009690:Nucleic Acid Conformation; D009994:Osmolar Concentration; D011188:Potassium / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D013539:Simian virus 40 / Q000378:metabolism*; D013095:Spermidine / Q000494:pharmacology; D013096:Spermine / Q000494:pharmacology; D013431:Sulfates / Q000494:pharmacology; D013997:Time Factors
chemical_list: D002729:Chloromercuribenzoates; D004270:DNA, Circular; D004279:DNA, Viral; D013431:Sulfates; D013096:Spermine; D011189:Potassium Chloride; D004492:Edetic Acid; D003851:Deoxyribonucleases; D005033:Ethylmaleimide; D011188:Potassium; D000645:Ammonium Sulfate; D002118:Calcium; D013095:Spermidine