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SLX-1 is required for maintaining genomic integrity and promoting meiotic noncrossovers in the Caenorhabditis elegans germline
- Source :
- PLoS Genetics, Vol 8, Iss 8, p e1002888 (2012), PLoS Genetics
- Publication Year :
- 2012
- Publisher :
- Public Library of Science (PLoS), 2012.
-
Abstract
- Although the SLX4 complex, which includes structure-specific nucleases such as XPF, MUS81, and SLX1, plays important roles in the repair of several kinds of DNA damage, the function of SLX1 in the germline remains unknown. Here we characterized the endonuclease activities of the Caenorhabditis elegans SLX-1-HIM-18/SLX-4 complex co-purified from human 293T cells and determined SLX-1 germline function via analysis of slx-1(tm2644) mutants. SLX-1 shows a HIM-18/SLX-4–dependent endonuclease activity toward replication forks, 5′-flaps, and Holliday junctions. slx-1 mutants exhibit hypersensitivity to UV, nitrogen mustard, and camptothecin, but not gamma irradiation. Consistent with a role in DNA repair, recombination intermediates accumulate in both mitotic and meiotic germ cells in slx-1 mutants. Importantly, meiotic crossover distribution, but not crossover frequency, is altered on chromosomes in slx-1 mutants compared to wild type. This alteration is not due to changes in either the levels or distribution of double-strand breaks (DSBs) along chromosomes. We propose that SLX-1 is required for repair at stalled or collapsed replication forks, interstrand crosslink repair, and nucleotide excision repair during mitosis. Moreover, we hypothesize that SLX-1 regulates the crossover landscape during meiosis by acting as a noncrossover-promoting factor in a subset of DSBs.<br />Author Summary Crossover formation between homologous chromosomes is important for generating genetic diversity in subsequent generations, as well as for promoting accurate chromosome segregation during meiosis, which is a specialized cell division program that results in the formation of haploid gametes (sperm and eggs) from diploid parental germ cells. In the nematode Caenorhabditis elegans, a single off-centered crossover is formed on the chromosome arms between every pair of homologous chromosomes. Crossover formation at the central region of the chromosomes is suppressed by unknown mechanisms. By using high-resolution 3-D microscopy, we found that, while crossover distribution is biased to the arm regions along the chromosomes, DNA double-strand breaks (DSBs), which initiate the homologous recombination repair process, are evenly distributed along the chromosomes. These results suggest the existence of mechanisms that inhibit crossover formation after induction of DSBs at the central region of the chromosomes. In this study, our findings lead us to hypothesize that SLX-1, a structure-specific endonuclease, inhibits crossover formation at the central region of the chromosomes, probably via its resolution activity of the Holliday junctions, which are four-stranded recombination intermediates, to produce noncrossover products.
- Subjects :
- Genome instability
Male
Cancer Research
lcsh:QH426-470
DNA repair
Biology
Genomic Instability
Cell Line
03 medical and health sciences
Meiosis
Genetics
Holliday junction
Animals
Humans
Caenorhabditis elegans
Caenorhabditis elegans Proteins
Molecular Biology
Genetics (clinical)
Ecology, Evolution, Behavior and Systematics
030304 developmental biology
0303 health sciences
Deoxyribonucleases
Endodeoxyribonucleases
Genome
030302 biochemistry & molecular biology
DNA replication
DNA Helicases
MUS81
lcsh:Genetics
Homologous recombination
Nucleotide excision repair
DNA Damage
Research Article
Subjects
Details
- Language :
- English
- ISSN :
- 15537404 and 15537390
- Volume :
- 8
- Issue :
- 8
- Database :
- OpenAIRE
- Journal :
- PLoS Genetics
- Accession number :
- edsair.doi.dedup.....d30422dda6f9e5e337e08f9d9f757546