Poly(ADP-ribosyl)ation is a very important posttranslational modification for many important biological processes in mammals including apoptosis/programmed cell death and DNA repair. However, clear and unified roles for poly(ADP-ribose) polymerases (PARPs) and poly(ADP-ribose) glycohydrolases (PARGs) are not yet defined. In order to gain information on PARPs potential role(s) during development and programmed cell death, we used the model organism Caenorhabditis elegans. A computational analysis of the genome of C. elegans using human PARP-1 amino acid sequence revealed the presence of four loci encoding putative poly(ADP-ribose) metabolism enzymes or PME. Loci Y71F9AL.18, and E02H1.4 contain
pme-1 and
pme-2 genes respectively. PME-1 gene product has a highly similar structure to human PARP-1 and PME-2 protein is similar to PARP-2. The transcript of
pme-1 was shown to be transspliced with splice leader SL1 and the transcript of
pme-2 is transspliced with splice leader SL2. Both transcript are expressed throughout the life cycle of the worm, although mainly present in the embryos, suggesting a role during this stage of development. A third locus, AC8.1, contains an almost identical copy of
pme-1. However, the putative transcript AC8.1 is shorter in size to PME-1 and was not detected on northern analysis, suggesting that AC8.1 may be a pseudogene. The recombinant enzymes rPME-1 and rPME-2 were shown to synthesize poly(ADP-ribose), confirming their identity as real PARP. A fourth locus, ZK1005.1 contains the gene
pme-5. PME-5 is a homolog of tankyrase 2 in mammals, a novel PARP localized to telomeres. Crude protein extracts from C. elegans contain specific PARG activity as shown on TLC plate analyses. In order to link the enzyme activity to specific gene(s), we analyzed the genome of C. elegans using human PARG amino acid sequence. Two distinct loci, F20C5.1 and H23L24.5, were found encoding two putative PARGs. The genes were named
pme-3 and
pme-4. PME-3 and PME-4 share identity at 35% and 30% with human PARG respectively. We also determine that
pme-3 encode two alternatively spliced transcripts, adding to the potential physiological role(s) for PARGs. We plan to address the role(s) of pme gene family members in development through a reverse genetics approach. Funding for this research is provided by the Natural Sciences and Engineering Research Council of Canada and the Fonds de la Recherche en Sant du Qubec.