Spatial control of the GEN1 Holliday junction resolvase ensures genome stability

• Published in: Nature communications 2014-09, Vol.5 (1), p.4844-4844, Article 4844
• Main Authors: Chan, Ying Wai, West, Stephen C.
• Format: Article
• Language: English
• Subjects: 13/105; 14; 38/22; 631/337/1427/2190; 631/80/389; 631/80/641/1655; 82; 82/1; Active Transport, Cell Nucleus; Cell Nucleus - metabolism; DNA-Binding Proteins - genetics; Endonucleases - genetics; Genomic Instability; HEK293 Cells; Holliday Junction Resolvases - metabolism; Humanities and Social Sciences; Humans; multidisciplinary; Nuclear Export Signals; Phenotype; Phosphorylation; Protein Transport; RecQ Helicases - genetics; Science; Science (multidisciplinary); Sister Chromatid Exchange - genetics
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms5844

Holliday junction (HJ) resolvases are necessary for the processing of persistent recombination intermediates before cell division. Their actions, however, need to be restricted to the late stages of the cell cycle to avoid the inappropriate cleavage of replication intermediates. Control of the yeast HJ resolvase, Yen1, involves phosphorylation changes that modulate its catalytic activity and nuclear import. Here, we show that GEN1, the human ortholog of Yen1, is regulated by a different mechanism that is independent of phosphorylation. GEN1 is controlled exclusively by nuclear exclusion, driven by a nuclear export signal (NES) that restricts GEN1 actions to mitosis when the nuclear membrane breaks down. Construction of a nuclear-localized version of GEN1 revealed that its premature actions partially suppress phenotypes associated with loss of BLM and MUS81, but cause elevated crossover formation. The spatial control of GEN1 therefore contributes to genome stability, by avoiding competition with non-crossover promoting repair pathways. The human Holliday junction resolvase GEN1 functions during anaphase to eliminate recombination intermediates that block proper chromosome segregation. Here, the authors demonstrate that GEN1 activity is regulated independently of its phosphorylation status and relies on its active exclusion from the nucleus.