Genomic instability in a PARP-1(-/-) cell line expressing PARP-1 DNA-binding domain.
Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear DNA binding protein that participates in processes involving nicking and resealing DNA strands. A genomically unstable subpopulation of PARP-1(-/-) cells has recently been described, which disappears after stable transfection of the cells with complete PARP-1 cDNA. Here we investigate the role played by PARP-1 in the maintenance of genomic stability, independently of its enzymatic activity. We used a PARP-1-deficient cell line to express a DNA construct encoding the PARP-1 DNA-binding domain (DBD) fragment and one encoding the mutant DBDbd-, defective in binding to DNA strand breaks. We found that, in the absence of DNA damage, expression of DBD or DBDbd- mutant induces increased genomic instability in the PARP-1(-/-) cells. These results suggest that the DBD fragment of PARP-1, apart from its classical role of nick detection and DNA binding, is likely to participate in molecular complexes with proteins involved in genomic integrity.
Cayuela
M L
ML
Transplant Unit, Surgery Department, University Hospital Virgen de la Arrixaca, El Palmar, 30120-Murcia, Spain.
Carrillo
A
A
Ramirez
P
P
Parrilla
P
P
Yélamos
J
J
D001483:Base Sequence; D001665:Binding Sites; D002453:Cell Cycle / Q000502:physiology* / Q000528:radiation effects; D002460:Cell Line; D003587:Cytomegalovirus / Q000235:genetics; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D017931:DNA Primers; D005720:Gamma Rays; D006801:Humans; D011065:Poly(ADP-ribose) Polymerases / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D017931:DNA Primers; D004247:DNA; D011065:Poly(ADP-ribose) Polymerases