title: Extensive regions of single-stranded DNA in aphidicolin-treated melanoma cells.
abstract: We have looked for the presence of single-stranded DNA in human melanoma cells. Single-stranded DNA was observed by lysis of cells in dilute alkali (to partly denature the DNA) followed by CsCl gradient centrifugations. In normally growing cells we did not observe single-stranded DNA whereas large amounts were present in cells treated with aphidicolin (an inhibitor of DNA polymerase alpha). The single-stranded DNA is much larger (greater than 20 kb) than Okazaki fragments. When the cells were washed free of aphidicolin, the single-stranded DNA was converted to high molecular weight DNA. Furthermore, when DNA synthesis is recovering after drug treatment, the single-stranded DNA disappears. The single-stranded DNA represents a transient step during the maturation of newly synthesized DNA.
mesh_terms: D016590:Aphidicolin; D004261:DNA Replication / Q000187:drug effects*; D004273:DNA, Neoplasm / Q000187:drug effects* / Q000302:isolation & purification; D004277:DNA, Single-Stranded / Q000187:drug effects* / Q000302:isolation & purification; D004224:Diterpenes / Q000494:pharmacology*; D006801:Humans; D008545:Melanoma; D008970:Molecular Weight; D014407:Tumor Cells, Cultured / Q000187:drug effects*
chemical_list: D004273:DNA, Neoplasm; D004277:DNA, Single-Stranded; D004224:Diterpenes; D016590:Aphidicolin