Gen Homolog 1, Endonuclease (GEN1)

The human GEN1 gene encodes a 103-kD protein that contains a Rad2/XPG nuclease domain. The human Holliday junction resolvase GEN1 and its yeast ortholog Yen1 were independently identified using 2 distinct experimental approaches: GEN1 was identified by mass spectrometry following extensive fractionation of HeLa cell-free extracts, whereas Yen1 was detected by screening a yeast gene fusion library for nucleases capable of Holliday junction resolution. The eukaryotic Holliday junction resolvases represent a new subclass of the Rad2/XPG family of nucleases. Recombinant GEN1 and Yen1 resolve Holliday junctions by the introduction of symmetrically related cuts across the junction point, to produce nicked duplex products in which the nicks can be readily ligated.