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.
Smulson
M E
ME
Department of Biochemistry and Molecular Biology, Georgetown University, Washington, DC 20007, USA.
Pang
D
D
Jung
M
M
Dimtchev
A
A
Chasovskikh
S
S
Spoonde
A
A
Simbulan-Rosenthal
C
C
Rosenthal
D
D
Yakovlev
A
A
Dritschilo
A
A
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