Characterization of sPARP-1. An alternative product of PARP-1 gene with poly(ADP-ribose) polymerase activity independent of DNA strand breaks.
Poly(ADP-ribose) polymerase-1 (PARP-1) is an abundant nuclear enzyme that catalyzes the synthesis of poly(ADP-ribose) (pADPr) from its substrate NAD(+) upon binding to DNA strand breaks. Poly(ADP-ribosyl)ation has been implicated in many cellular processes including replication, transcription, and the maintenance of genomic stability. However, studies with mice and cells lacking PARP-1 reveal a critical role for the enzyme in the maintenance of genomic integrity only. Recently, a significant level of poly(ADP-ribose) polymerase activity has been detected in fibroblasts derived from mice lacking PARP-1 following treatment with genotoxic agents (Shieh, W. M., Amé, J-C., Wilson, M. V., Wang, Z-Q., Koh, D. W., Jacobson, M. K., and Jacobson, E. L. (1998) J. Biol. Chem. 273, 30069-30072). We have isolated a cDNA that originates from PARP-1 (-/-) fibroblasts and encodes a polypeptide of 493 amino acid residues bearing poly(ADP-ribose) polymerase activity. This protein, that we named sPARP-1 for short poly(ADP-ribose) polymerase-1, has a calculated mass of 55.3 kDa and is identical in deduced amino acid sequence to the catalytic domain of PARP-1. Radiation hybrid analysis assigned the sPARP-1 gene to the chromosome 1H5-H6 in an immediate proximity to the known location of PARP-1 gene, indicating that sPARP-1 and PARP-1 are most probably products of the same gene. Active sPARP-1 is present in both PARP-1 (+/+) and PARP-1 (-/-) cells as demonstrated by activity-Western blotting and immunostaining using a specific antibody developed against sPARP-1. Like PARP-1, sPARP-1 is localized in the cell nucleus, uses NAD(+) as a substrate and is inhibited by nicotinamide analogues. sPARP-1 produces pADPr of similar length and structure to that of PARP-1. However, contrary to PARP-1, sPARP-1 does not require DNA strand breaks for its activation, although it is stimulated following genotoxic treatments.
Sallmann
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FR
Poly(ADP-ribose) Metabolism Group, Health and Environment Unit, Laval University Medical Research Center, CHUQ, Laval University, Ste-Foy, Quebec, G1V 4G2 Canada.
Vodenicharov
M D
MD
Wang
Z Q
ZQ
Poirier
G G
GG
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D002874:Chromosome Mapping; D005347:Fibroblasts; D007700:Kinetics; D007739:L Cells; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics* / Q000378:metabolism* / Q000528:radiation effects; D014466:Ultraviolet Rays
D010446:Peptide Fragments; D008769:Methylnitronitrosoguanidine; D011065:Poly(ADP-ribose) Polymerases