Higher plants possess two structurally different poly(ADP‐ribose) polymerases

Abstract

SummaryOne of the immediate reactions of the mammalian cell to many environmental stresses is a massive synthesis of poly(ADP-ribose), catalyzed by poly(ADP-ribose) polymerase (PARP). Most of the biological functions attributed to PARP are inferred from experimentation with mammalian cells. In plants, the biology of PARP may be more complicated and diverse than was previously thought. Two poly(ADP-ribose) polymerase homologues were found in plants, the classical Zn-finger-containing polymerase (ZAP) and the structurally non-classical PARP proteins (APP and NAP), which lack the characteristic N-terminal Zn-finger domain. By enzymatic and cytological experiments the recombinant APP protein was shown to be located in the nucleus and to possess DNA-dependent poly(ADP-ribose) polymerase activity in yeast. The nuclear localization was further confirmed by the analysis of transgenic tobacco plants that expressed a translational gene fusion between APP and the bacterial β-glucuronidase. The app promoter was transcriptionally up-regulated in cells pre-determined to die because of deficiency in a DNA ligase I.

The Paralogous GenesRADICAL-INDUCED CELL DEATH1andSIMILAR TO RCD ONE1Have Partially Redundant Functions during Arabidopsis Development

“…S1A). Orthologs of PARP-1 and PARP-2, the DNA-dependent PARPs, AtPARP1 (At4g02390) and AtPARP2 (At2g31320), respectively, have been identified (Lepiniec et al, 1995;Babiychuk et al, 1998). These genes have been implicated in DNA repair (Doucet-Chabeaud et al, 2001;De Block et al, 2005) and have been shown to be associated with chromosomes through their N-terminal zinc fingers (Babiychuk et al, 2001).…”

A Nick-sensing DNA 3′-Repair Enzyme fromArabidopsis

“…5 Similar to its human homolog, the XRCC1-like polypeptide of Arabidopsis is predicted to contain multiple protein-protein interaction BRCT (BRCA1 C-terminal) modules. Interestingly, similar BRCT modules are also present in the putative DNA polymerase ␤ as well as in a member of one of the two PARP families thus far described in plants (21). No human polynucleotide kinase 3Ј-phosphatase homolog other than AtZDP is encoded in the Arabidopsis genome.…”

“…Genes encoding PARP-homologous proteins with a structural organization resembling that of animal PARPs have been described in higher plants (20,21). More recently, the first plant enzyme catalyzing the repair of DNA 3Ј-blocking lesions has been identified in maize (22).…”

Poly(ADP-ribose) polymerase-deficient mice are protected from streptozotocin-induced diabetes

“…Cultured fibroblasts from PARP Ϫ͞Ϫ mice display PARP activity Ϸ25% of wild-type levels, whereas cultured PARP Ϫ͞Ϫ primary embryonic cells display Ϸ3% of wild-type levels (37). Very recently, novel isoforms of PARP have been identified (38,39). The extent to which they contribute to PARP activity in various mammalian tissues has not been established.…”