title: Formation of a new DNA replication intermediate in novobiocin-treated human melanoma cells.
abstract: The effect of novobiocin on the formation of DNA replication intermediates in human melanoma cells was investigated. This drug reduces DNA synthesis in all probability by interfering with the DNA gyrases (enzymes that are involved in the supercoiling of the DNA). The single-stranded DNA replication intermediates were released from the parental DNA by lysing the cells in dilute alkali and were then fractionated by agarose gel electrophoresis. In the untreated cells one can detect replication intermediates ranging in size from Okazaki-fragments up to 10 kb. However, in novobiocin-treated cells, apart from the already known intermediates, formation of a new replication intermediate with the size of about 20 kb was also detected. The 20-kb DNA shows a similar discrete appearance in the agarose gel as the 10-kb DNA intermediate.
mesh_terms: D002478:Cells, Cultured; D004247:DNA; D004261:DNA Replication / Q000187:drug effects*; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D004273:DNA, Neoplasm / Q000096:biosynthesis / Q000378:metabolism; D004587:Electrophoresis, Agar Gel; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology; D008545:Melanoma / Q000378:metabolism; D009675:Novobiocin / Q000494:pharmacology*
chemical_list: D004273:DNA, Neoplasm; C022262:Okazaki fragments; D009675:Novobiocin; D004247:DNA; D004250:DNA Topoisomerases, Type II; D006918:Hydroxyurea