INGEBI   02650
INSTITUTO DE INVESTIGACIONES EN INGENIERIA GENETICA Y BIOLOGIA MOLECULAR "DR. HECTOR N TORRES"
Unidad Ejecutora - UE
artículos
Título:
TcPARP: a DNA damage-dependent poly(ADP-ribose) polymerase from T. cruzi.
Autor/es:
FERNÁNDEZ VILLAMIL, S.; BALTANÁS, R.; ALONSO, G.; TORRES, H.N.; FLAWIÁ, M.M.
Revista:
INTERNATIONAL JOURNAL FOR PARASITOLOGY
Editorial:
Elsevier
Referencias:
Año: 2007 vol. 38 p. 277 - 287
ISSN:
0020-7519
Resumen:
Abstract: Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme present in most eukaryotes and has been involved in processes such as DNA repair and gene expression. The poly(ADP-ribose) polymer (PAR) is mainly catabolized by poly(ADP-ribose) glycohydrolase. Here we describe the cloning and characterization of a PARP from Trypanosoma cruzi (TcPARP). The recombinant enzyme (Mr = 65), required DNA for catalytic activity, and it was strongly enhanced by nicked DNA. Histones purified from T. cruzi increased TcPARP activity and the covalent attachment of [32P]-ADP-ribose moieties to histones was demonstrated. TcPARP required no magnesium or any other metal ion cofactor for its activity. The enzyme was inhibited by 3-aminobenzamide, nicotinamide, theophylline, and thymidine but not by menadione. We demonstrated automodification reaction of TcPARP, and that the removal of attached PAR from this protein resulted in an increase of its activity. The enzyme was expressed in all parasite stages (amastigotes, epimastigotes and trypomastigotes). When T. cruzi epimastigotes were exposed to DNA-damaging agents such as hydrogen peroxide or â-lapachone, PAR drastically increased in the nucleus, thus confirming PAR synthesis in vivo and suggesting a physiological role of PARP in trypanosomatids DNA repair signaling.