Holliday junctions in the eukaryotic nucleus: resolution in sight?

• Published in: Trends in biochemical sciences (Amsterdam. Regular ed.) Vol. 28; no. 10; pp. 548 - 557
• Main Authors: Heyer, Wolf-Dietrich, Ehmsen, Kirk T, Solinger, Jachen A
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2003
• Subjects: Alleles; Animals; Bacterial Proteins - metabolism; Cell Nucleus - metabolism; DNA Repair; DNA Replication; DNA topoisomerase III; DNA-Binding Proteins - chemistry; Humans; Nucleic Acid Conformation; Phenotype; Recombination, Genetic; resolvase; Substrate Specificity
• ISSN: 0968-0004; 1362-4326
• DOI: 10.1016/j.tibs.2003.08.011

The Holliday junction is a key recombination intermediate whose resolution generates crossovers. Interplay between recombination, repair and replication has moved the Holliday junction to the center stage of nuclear DNA metabolism. Holliday junction resolvases in the eukaryotic nucleus have long eluded identification. The endonucleases Mus81/Mms4-Eme1 and XPF-MEI-9/MUS312 are structurally related to the archaeal resolvase Hjc and were found to be involved in crossover formation in budding yeast and flies, respectively. Although these endonucleases might represent one class of eukaryotic resolvases, their substrate preference opens up the possibility that junctions other than classical Holliday junctions might contribute to crossovers. Holliday junction resolution to non-crossover products can also be achieved topologically, for example, by the action of RecQ-like DNA helicases combined with topoisomerase III.