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N‐terminal and core‐domain random mutations in human topoisomerase II α conferring bisdioxopiperazine resistance
Author(s) -
Jensen Lars H,
Wessel Irene,
Møller Marianne,
Nitiss John L,
Sehested Maxwell,
Jensen Peter B
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01934-7
Subject(s) - topoisomerase , mutagenesis , biology , recombinant dna , mutation , microbiology and biotechnology , complementary dna , in vitro , enzyme , dna , genetics , biochemistry , gene
Random mutagenesis of human topoisomerase II α cDNA followed by functional expression in yeast cells lacking endogenous topoisomerase II activity in the presence of ICRF‐187, identified five functional mutations conferring cellular bisdioxopiperazine resistance. The mutations L169F, G551S, P592L, D645N, and T996L confer >37, 37, 18, 14, and 19 fold resistance towards ICRF‐187 in a 24 h clonogenic assay, respectively. Purified recombinant L169F protein is highly resistant towards catalytic inhibition by ICRF‐187 in vitro while G551S, D645N, and T996L proteins are not. This demonstrates that cellular bisdioxopiperazine resistance can result from at least two classes of mutations in topoisomerase II; one class renders the protein non‐responsive to bisdioxopiperazine compounds, while an other class does not appear to affect the catalytic sensitivity towards these drugs. In addition, our results indicate that different protein domains are involved in mediating the effect of bisdioxopiperazine compounds.