The elongation of primed DNA templates by DNA polymerase delta and DNA polymerase epsilon requires the accessory proteins proliferating cell nuclear antigen (PCNA) and replication factor C (RFC). RFC, also named activator 1, is a protein complex consisting of five distinct subunits of 140, 40, 38, 37, and 36 kD. This gene encodes the 38 kD subunit. This subunit is essential for the interaction between the 140 kD subunit and the core complex that consists of the 36, 37, and 40 kD subunits. Alternatively spliced transcript variants encoding distinct isoforms have been described.