PARPs (poly ADP ribose polymerases) are DNA repair enzymes that promote single stranded break (SSB) repair by binding to DNA at the sites of SSBs and recruiting repair machinery. In humans, the PARP superfamily consists of 17 members, of which five play known roles in SSB repair. PARP-1, the most well-studied family member, is required for base excision repair and is thought to be responsible for 90% of PARP activity (5).