Zinc-binding domain of poly(ADP-ribose)polymerase participates in the recognition of single strand breaks on DNA.
Poly(ADP-ribose)polymerase is a chromatin-associated enzyme of eukaryotic cell nuclei that catalyses the covalent attachment of ADP-ribose units from NAD+ to various nuclear acceptor proteins. This post-translational modification has been postulated to influence several chromatin functions, particularly those where nicking and rejoining of DNA occur. Poly(ADP-ribosyl)ation reactions are strictly dependent upon the presence of interruptions on DNA. We have recently demonstrated that the DNA-binding domain of the protein containing two putative "zinc-fingers" binds DNA in a zinc-dependent manner. The basis for the recognition of the DNA strand breaks by this enzyme, and more precisely, its 29,000 Mr N-terminal part, which contains the metal binding sites, needed to be clarified. DNA probes harbouring a single strand interruption at a defined position were constructed from synthetic oligonucleotides. DNase I protection studies show that poly(ADP-ribose)polymerase specifically binds to a DNA single-strand break by its metal-binding domain depending upon the presence of Zn(II). These results support the idea that the enzyme participates to the maintenance of DNA integrity in eukaryotes.
Ménissier-de Murcia
J
J
Institut de Biologie Moléculaire et Cellulaire du CNRS, Laboratoire de Biochimie 2, Strasbourg, France.
Molinete
M
M
Gradwohl
G
G
Simonin
F
F
de Murcia
G
G
D001483:Base Sequence; D001665:Binding Sites; D015342:DNA Probes; D004260:DNA Repair; D004277:DNA, Single-Stranded / Q000378:metabolism*; D003850:Deoxyribonuclease I; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism*
D015342:DNA Probes; D004277:DNA, Single-Stranded; D009838:Oligodeoxyribonucleotides; D011065:Poly(ADP-ribose) Polymerases; D003850:Deoxyribonuclease I; D015032:Zinc