Induction of Topoisomerase I Cleavage Complexes by the Vinyl Chloride Adduct 1, N 6 -Ethenoadenine - Inserm - Institut national de la santé et de la recherche médicale Accéder directement au contenu
Article Dans Une Revue Journal of Biological Chemistry Année : 1998

Induction of Topoisomerase I Cleavage Complexes by the Vinyl Chloride Adduct 1, N 6 -Ethenoadenine

Résumé

We used purified mammalian topoisomerases I (top1) and oligonucleotides to study top1-mediated cleavage and religation in the presence of a potent carcinogenic adduct, 1,N6-ethenoadenosine (epsilonA) incorporated immediately downstream of a unique top1 cleavage site. We found tha epsilonA markedly enhanced top1 cleavage complexes when it was incorporated at the +1 position of the top1 cleavage. This enhancement was due to a reduction of the religation step of the top1 reaction. In addition, epsilonA reduced the top1-mediated cleavage and decreased binding of the enzyme to DNA. We also studied the effects of the epsilonA adduct on top1 trapping by camptothecin (CPT), a well known top1 inhibitor. CPT was inactive when epsilonA was present at the +1 position. Alkylation of the top1 cleavage complex by 7-chloromethyl-10,11-methylenedioxycamptothecin (7-ClMe-MDO-CPT) was also blocked by the epsilonA adduct. Altogether, these results demonstrate that the epsilonA carcinogenic adduct can efficiently trap human top1 and mimic CPT effects. Normal hydrogen bonding of the base pairs immediately downstream from the top1 cleavage site is probably essential for efficient DNA religation and binding of camptothecins in the top1 cleavage complex.
Fichier principal
Vignette du fichier
PIIS0021925819596648.pdf (391.22 Ko) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

inserm-02438248 , version 1 (27-05-2021)

Licence

Paternité

Identifiants

Citer

Philippe Pourquier, Mary-Ann Bjornsti, Yves Pommier. Induction of Topoisomerase I Cleavage Complexes by the Vinyl Chloride Adduct 1, N 6 -Ethenoadenine. Journal of Biological Chemistry, 1998, 273 (42), pp.27245-27249. ⟨10.1074/jbc.273.42.27245⟩. ⟨inserm-02438248⟩
38 Consultations
37 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More