Likely to be an auxiliary protein of DNA polymerase delta complex and is probably involved in the control of DNA replication and repair by increasing the polymerase's processibility. Homotrimer (PubMed:17087725). Forms a complex with activator 1 heteropentamer in the presence of ATP (By similarity). Interacts with E2f (PubMed:19081076). Interacts with the catalytic subunits of two DNA polymerase complexes: PolD1 from the delta complex and PolE1/DNApol-epsilon255 from the epsilon complex (PubMed:17087725). Colocalizes with crm in polytene nuclei during embryogenesis (PubMed:9310333). Increased association with chromatin in response to DNA damage caused by methyl methanesulfonate (MMS), hydrogen peroxide (H2O2) and UV (PubMed:17087725). Expressed at high levels in adult ovary. Expressed maternally and zygotically (PubMed:1968224). Expressed at high levels in embryos at 0-2 and 8-12 h of development (PubMed:17087725, PubMed:1968224). Moderate levels detected at later stages of embryogenesis, in unfertilized eggs and adult females, and relatively low levels of expression were detected in larvae and adult males (PubMed:17087725). Mutant flies show temperature-sensitive lethality, hypersensitivity to DNA-damaging agents such as ionizing radiation and methyl methanesulfonate, suppression of position-effect variegation and female sterility. Belongs to the PCNA family.