Protein ZGRF1 is a protein  encoded in the human by the ZGRF1 gene also known as C4orf21, that has a weight of 236.6 kDa. The ZGRF1 gene product localizes to the cell nucleus and promotes DNA repair by stimulating homologous recombination. This gene shows relatively low expression in most human tissues, with increased expression in situations of chemical dependence. ZGRF1 is orthologous to nearly all eukaryotes. Functional domains of this protein link it to a series of helicases, most notably the AAA_12 and AAA_11 domains.