Extensive regions of single-stranded DNA in aphidicolin-treated melanoma cells |
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Authors: | U L?nn S L?nn |
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Affiliation: | Department of Histology, Karolinska Institutet, Stockholm, Sweden. |
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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. |
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