title: Cloning and characterization of full-length cDNAs coding for the DNA topoisomerase II beta from Chinese hamster lung cells sensitive and resistant 9-OH-ellipticine.
abstract: DNA topoisomerase II beta cDNAs from Chinese hamster lung cells sensitive (DC-3F) and resistant to 9-OH-ellipticine (DC-3F/9O-HE) were isolated. In the sensitive cells, the sequence defines an open reading frame of 4839 nucleotides, and extends over a 323 nucleotides untranslated region up to the putative polyadenylation site. The deduced amino acid sequence predicts a protein with 1612 amino acids in length and a calculated molecular mass of approx. 182 kDa. The cDNAs from the resistant cells only differs by one mutation at position length and a calculated molecular mass of approx. 182 kDa. The cDNAs from the resistant cells only differs by one mutation at position 1710 which converts a Trp codon (TGG) to a stop codon (TGA). This mutation accounts for the loss of DNA topoisomerase II beta in the 9-OH-ellipticine resistant cells.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D001483:Base Sequence; D015139:Blotting, Southern; D002460:Cell Line; D003001:Cloning, Molecular; D003062:Codon / Q000235:genetics; D006224:Cricetinae; D003412:Cricetulus; D004250:DNA Topoisomerases, Type II / Q000235:genetics*; D018076:DNA, Complementary; D004351:Drug Resistance; D004611:Ellipticines / Q000494:pharmacology*; D007527:Isoenzymes / Q000235:genetics; D008168:Lung; D008969:Molecular Sequence Data; D017354:Point Mutation; D014364:Tryptophan
chemical_list: D000964:Antimetabolites, Antineoplastic; D003062:Codon; D018076:DNA, Complementary; D004611:Ellipticines; D007527:Isoenzymes; D014364:Tryptophan; C008009:9-hydroxyellipticine; D004250:DNA Topoisomerases, Type II