Mechanistic insights on the inhibition of c5 DNA methyltransferases by zebularine.
PLoS One
; 5(8): e12388, 2010 Aug 24.
Article
en En
| MEDLINE
| ID: mdl-20808780
ABSTRACT
In mammals DNA methylation occurs at position 5 of cytosine in a CpG context and regulates gene expression. It plays an important role in diseases and inhibitors of DNA methyltransferases (DNMTs)--the enzymes responsible for DNA methylation--are used in clinics for cancer therapy. The most potent inhibitors are 5-azacytidine and 5-azadeoxycytidine. Zebularine (1-(beta-D-ribofuranosyl)-2(1H)- pyrimidinone) is another cytidine analog described as a potent inhibitor that acts by forming a covalent complex with DNMT when incorporated into DNA. Here we bring additional experiments to explain its mechanism of action. First, we observe an increase in the DNA binding when zebularine is incorporated into the DNA, compared to deoxycytidine and 5-fluorodeoxycytidine, together with a strong decrease in the dissociation rate. Second, we show by denaturing gel analysis that the intermediate covalent complex between the enzyme and the DNA is reversible, differing thus from 5-fluorodeoxycytidine. Third, no methylation reaction occurs when zebularine is present in the DNA. We confirm that zebularine exerts its demethylation activity by stabilizing the binding of DNMTs to DNA, hindering the methylation and decreasing the dissociation, thereby trapping the enzyme and preventing turnover even at other sites.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Citidina
/
ADN (Citosina-5-)-Metiltransferasas
/
Inhibidores Enzimáticos
Límite:
Animals
/
Humans
Idioma:
En
Revista:
PLoS One
Asunto de la revista:
CIENCIA
/
MEDICINA
Año:
2010
Tipo del documento:
Article
País de afiliación:
Francia
Pais de publicación:
EEUU
/
ESTADOS UNIDOS
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ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
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US
/
USA