Please use this identifier to cite or link to this item: http://hdl.handle.net/2067/1713
Title: Evidence that camptothecin-induced aberrations in the G2 phase of cell cycle of Chinese hamster ovary (CHO) cell lines is associated with transcription
Authors: Mosesso, Pasquale
Pichierri, Pietro
Franchitto, Annapaola
Palitti, Fabrizio
Issue Date: 2000
Publisher: Elsevier
Source: Mosesso, P. et al. 2000. Evidence that camptothecin-induced aberrations in the G2 phase of cell cycle of Chinese hamster ovary (CHO) cell lines is associated with transcription. "Mutation Research" 452(2): 189-195
Abstract: 
It is widely accepted that camptothecin (CPT) is an S-dependent genotoxin. In this study, we aimed to elucidate the 'puzzling' induction of chromosomal damage by CPT in the G(2) phase of CHO cells, where no DNA synthesis is expected, focusing the attention on the possible role of the ongoing RNA synthesis, supposed to cause the conversion of CPT-single stranded cleavage complexes spaced closely on opposite DNA strands into DNA double strand breaks (DSB's) by the action of traversing RNA polymerase.CHO AA8 and its parental mutant EM9 cell lines were pre-treated with alpha-amanitin, which prevents transcription to pre-m-RNA and challenged cells with CPT for the last hour in culture to evaluate whether G(2)-CPT-induced aberrations would have been reduced or abolished in the absence of RNA synthesis compared with G(2)-CPT treatment alone. The results obtained indicated a marked and significant reduction of aberration yields, to almost the control values (alpha-amanitin alone) when inhibition of RNA synthesis was substantial (3h total alpha-amanitin). Partial inhibition of RNA synthesis (2h total alpha-amanitin) slightly reduced the CPT-induced aberrations yield only at the high dose-level employed of CPT (20mM). This finding strongly supports the hypothesis that CPT-single stranded cleavages complexes spaced closely on opposite DNA strands are converted into DNA double strand breaks by the action of traversing RNA polymerase.
Description: 
L'articolo è disponibile sul sito dell'editore: http://www.sciencedirect.com
URI: http://hdl.handle.net/2067/1713
ISSN: 0027-5107
Appears in Collections:DABAC - Archivio della produzione scientifica

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