Sensitivity to camptothecin in Aspergillus nidulans identifies a novel gene, scaA+, related to the cellular DNA damage response

G. C M Bruschi, C. C. De Souza, M. R V Z K Fagundes, M. A C Dani, M. H S Goldman, N. R. Morris, Leroy-Fong Liu, G. H. Goldman

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

The anti-cancer drug camptothecin targets eukaryotic DNA topoisomerase I by trapping the covalent complex formed between the catalytically active enzyme and DNA. We are interested in identifying factors, other than topoisomerase I, that are involved in mediating cellular sensitivity to camptothecin. To this end, we have isolated eighteen mutants that are sensitive to camptothecin (sca) in the filamentous fungus Aspergillus nidulans and characterised one of them, sca299. The mutant sca299 is hypersensitive to camptothecin, and sensitive to several different mutagenic agents and to actinomycin D. Using temperature-sensitive mutations in genes that are known to regulate the cell cycle, we showed that the camptothecin sensitivity of the mutant sca299 is not affected by a mitotic block. The abnormal nuclear morphology observed in the sca299 mutant strain suggests that the germlings might be undergoing mitosis in the presence of unrepaired DNA damage, which would result in mitotic catastrophe. The hypersensitivity of the sca299 mutant to camptothecin does not result from elevated levels of topoisomerase I mRNA or from alterations in enzyme activity. Using DNA-mediated complementation of the sca299 mutant phenotype, the scaA+ gene was cloned. This gene encodes a 594-amino acid product; moderate structural similarity suggests that the scaA gene product may be related to the human nibrin gene which encodes a product involved in DNA double-strand break repair. Strains disrupted in the scaA gene were sensitive to the anti-topoisomerase I agent berberine, the DNA cross-linking agents mitomycin C and cis-platinum, and also to t-butyl hydroperoxide, which is an inducer of oxidative stress.

Original languageEnglish
Pages (from-to)264-275
Number of pages12
JournalMolecular and General Genetics
Volume265
Issue number2
Publication statusPublished - 2001
Externally publishedYes

Fingerprint

Aspergillus nidulans
Camptothecin
DNA Damage
Type I DNA Topoisomerase
Genes
DNA
Berberine
tert-Butylhydroperoxide
Double-Stranded DNA Breaks
Dactinomycin
Mitomycin
Enzymes
Mitosis
Cisplatin
Cell Cycle
Hypersensitivity
Oxidative Stress
Fungi
Phenotype
Amino Acids

Keywords

  • Aspergillus nidulans
  • Camptothecin
  • DNA damage
  • DNA repair

ASJC Scopus subject areas

  • Genetics

Cite this

Bruschi, G. C. M., De Souza, C. C., Fagundes, M. R. V. Z. K., Dani, M. A. C., Goldman, M. H. S., Morris, N. R., ... Goldman, G. H. (2001). Sensitivity to camptothecin in Aspergillus nidulans identifies a novel gene, scaA+, related to the cellular DNA damage response. Molecular and General Genetics, 265(2), 264-275.

Sensitivity to camptothecin in Aspergillus nidulans identifies a novel gene, scaA+, related to the cellular DNA damage response. / Bruschi, G. C M; De Souza, C. C.; Fagundes, M. R V Z K; Dani, M. A C; Goldman, M. H S; Morris, N. R.; Liu, Leroy-Fong; Goldman, G. H.

In: Molecular and General Genetics, Vol. 265, No. 2, 2001, p. 264-275.

Research output: Contribution to journalArticle

Bruschi, GCM, De Souza, CC, Fagundes, MRVZK, Dani, MAC, Goldman, MHS, Morris, NR, Liu, L-F & Goldman, GH 2001, 'Sensitivity to camptothecin in Aspergillus nidulans identifies a novel gene, scaA+, related to the cellular DNA damage response', Molecular and General Genetics, vol. 265, no. 2, pp. 264-275.
Bruschi GCM, De Souza CC, Fagundes MRVZK, Dani MAC, Goldman MHS, Morris NR et al. Sensitivity to camptothecin in Aspergillus nidulans identifies a novel gene, scaA+, related to the cellular DNA damage response. Molecular and General Genetics. 2001;265(2):264-275.
Bruschi, G. C M ; De Souza, C. C. ; Fagundes, M. R V Z K ; Dani, M. A C ; Goldman, M. H S ; Morris, N. R. ; Liu, Leroy-Fong ; Goldman, G. H. / Sensitivity to camptothecin in Aspergillus nidulans identifies a novel gene, scaA+, related to the cellular DNA damage response. In: Molecular and General Genetics. 2001 ; Vol. 265, No. 2. pp. 264-275.
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abstract = "The anti-cancer drug camptothecin targets eukaryotic DNA topoisomerase I by trapping the covalent complex formed between the catalytically active enzyme and DNA. We are interested in identifying factors, other than topoisomerase I, that are involved in mediating cellular sensitivity to camptothecin. To this end, we have isolated eighteen mutants that are sensitive to camptothecin (sca) in the filamentous fungus Aspergillus nidulans and characterised one of them, sca299. The mutant sca299 is hypersensitive to camptothecin, and sensitive to several different mutagenic agents and to actinomycin D. Using temperature-sensitive mutations in genes that are known to regulate the cell cycle, we showed that the camptothecin sensitivity of the mutant sca299 is not affected by a mitotic block. The abnormal nuclear morphology observed in the sca299 mutant strain suggests that the germlings might be undergoing mitosis in the presence of unrepaired DNA damage, which would result in mitotic catastrophe. The hypersensitivity of the sca299 mutant to camptothecin does not result from elevated levels of topoisomerase I mRNA or from alterations in enzyme activity. Using DNA-mediated complementation of the sca299 mutant phenotype, the scaA+ gene was cloned. This gene encodes a 594-amino acid product; moderate structural similarity suggests that the scaA gene product may be related to the human nibrin gene which encodes a product involved in DNA double-strand break repair. Strains disrupted in the scaA gene were sensitive to the anti-topoisomerase I agent berberine, the DNA cross-linking agents mitomycin C and cis-platinum, and also to t-butyl hydroperoxide, which is an inducer of oxidative stress.",
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