The DNA damage-inducible C. elegans tankyrase is a nuclear protein closely linked to chromosomes

Tankyrases are protein members of the poly(ADP-ribose) polymerase family bearing several ankyrin domain and a WGR domain. They have functional role in telomere maintenance, are found at centrosome, and are associated with vesicular secretion. This diversity in localization and function makes it difficult to identify a unified role for tankyrases. We have shown that the C. elegans orthologue PME-5 is among the most transcriptionally up-regulated genes following ionizing radiations, linking a tankyrase with DNA damage response. Our analysis showed that the up-regulation of PME-5 is translated at the protein level, suggesting an effective role in DNA damage response or DNA repair. In order to gain more information on the potential role of PME-5 in DNA damage response, we analyzed its sub-cellular localization. Using immunostaining as well as gfp reporter assay, we have shown a nuclear localization for PME-5. Moreover, we showed that PME-5 is a ubiquitous nuclear protein expressed throughout the development of the worm and is closely linked to chromatin and condensed chromosomes. Taken together, our data suggest that C. elegans can be used to study the nuclear roles of tankyrase.