text: Flap endonuclease 1 (FEN1) is responsible for processing Okazaki fragments. It works with DNA polymerase to remove the RNA primer of an Okazaki fragment and can remove the 5 ribonucleotide and 5 flaps when DNA polymerase displaces the strands during lagging strand synthesis. The removal of these flaps involves a process called nick translation and creates a nick for ligation. Thus, FEN1's function is necessary to Okazaki fragment maturation in forming a long continuous DNA strand. Likewise, during DNA base repair, the damaged nucleotide is displaced into a flap and subsequently removed by FEN1.