Irreversible binding of poly(ADP)ribose polymerase cleavage product to DNA ends revealed by atomic force microscopy: possible role in apoptosis.
During apoptosis, DNA undergoes fragmentation and caspase-3 cleaves poly(ADP-ribose) polymerase (PARP) into both a 24-kDa fragment containing the DNA binding domain and an 89-kDa fragment containing the catalytic and automodification domains. Atomic force microscopy revealed that recombinant full-length PARP bound to plasmid DNA fragments and linked them into chainlike structures. Automodification of PARP in the presence of NAD+ resulted in its dissociation from the DNA fragments, which, nevertheless, remained physically aligned. A recombinant 28-kDa fragment of PARP containing the DNA binding domain but lacking the automodification domain irreversibly bound to and linked DNA fragments in the absence or presence of NAD+. Identical results were obtained on incubation of internucleosomal DNA fragments from apoptotic cells with the products of cleavage of recombinant PARP by purified caspase-3. The 24-kDa product of PARP cleavage by caspase-3 may contribute to the irreversibility of apoptosis by blocking the access of DNA repair enzymes to DNA strand breaks.
Department of Biochemistry and Molecular Biology, Georgetown University, Washington, DC 20007, USA.
M E
ME
Smulson
D
D
Pang
M
M
Jung
A
A
Dimtchev
S
S
Chasovskikh
A
A
Spoonde
C
C
Simbulan-Rosenthal
D
D
Rosenthal
A
A
Yakovlev
A
A
Dritschilo
D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D004247:DNA / Q000378:metabolism*; D053938:DNA Fragmentation; D051379:Mice; D018625:Microscopy, Atomic Force; D010957:Plasmids / Q000235:genetics; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*
D004247:DNA; D011065:Poly(ADP-ribose) Polymerases