GEN1

This gene encodes a member of the Rad2/xeroderma pigmentosum group G nuclease family, whose members are characterized by N-terminal and internal xeroderma pigmentosum group G nuclease domains followed by helix-hairpin-helix domains and disordered C-terminal domains. The protein encoded by this gene is involved in resolution of Holliday junctions, which are intermediate four-way structures that covalently link DNA during homologous recombination and double-strand break repair. The protein resolves Holliday junctions by creating dual incisions across the junction to produce nicked duplex products that can be ligated. In addition, this protein has been found to localize to centrosomes where it has been implicated in regulation of centrosome integrity. Alternative splicing results in multiple transcript variants.

Full Name

GEN1, Holliday Junction 5' Flap Endonuclease

Function

Endonuclease which resolves Holliday junctions (HJs) by the introduction of symmetrically related cuts across the junction point, to produce nicked duplex products in which the nicks can be readily ligated. Four-way DNA intermediates, also known as Holliday junctions, are formed during homologous recombination and DNA repair, and their resolution is necessary for proper chromosome segregation (PubMed:19020614, PubMed:26682650).

Cleaves HJs by a nick and counter-nick mechanism involving dual coordinated incisions that lead to the formation of ligatable nicked duplex products. Cleavage of the first strand is rate limiting, while second strand cleavage is rapid. Largely monomeric, dimerizes on the HJ and the first nick occurs upon dimerization at the junction (PubMed:26578604).

Efficiently cleaves both single and double HJs contained within large recombination intermediates. Exhibits a weak sequence preference for incision between two G residues that reside in a T-rich region of DNA (PubMed:28049850).

Has also endonuclease activity on 5'-flap and replication fork (RF) DNA substrates (PubMed:26578604).

Biological Process

Double-strand break repair via homologous recombination Source: UniProtKB
Positive regulation of mitotic cell cycle spindle assembly checkpoint Source: UniProtKB
Regulation of centrosome duplication Source: UniProtKB
Replication fork processing Source: UniProtKB
Resolution of mitotic recombination intermediates Source: UniProtKB
Resolution of recombination intermediates Source: UniProtKB

Cellular Location

Nucleus