Robust homology-directed repair within mouse mammary tissue is not specifically affected by Brca2 mutation

Kass, Elizabeth M.; Lim, Pei Xin; Helgadottir, Hildur R.; Moynahan, Mary Ellen; Jasin, Maria

doi:10.1038/ncomms13241

Cited by 39 publications

(37 citation statements)

References 46 publications

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“…One possibility is that breast and ovarian cells are more reliant on HDR than other tissues. This hypothesis was supported by recent in vivo observations of particularly robust HDR activity in proliferative mammary cells compared to other proliferative tissues (Kass et al 2016a). Despite more robust HDR overall, all tissues examined in this study show a similar reliance on BRCA2 for repair of a particular lesion, consistent with BRCA2 having a general role in HDR.…”

Section: Tissue Tropism Of Brca-mutated Cancers and Cell Of Originsupporting

confidence: 66%

Homology-Directed Repair and the Role of BRCA1, BRCA2, and Related Proteins in Genome Integrity and Cancer

Chen

Feng

Lim

et al. 2018

Annu. Rev. Cancer Biol.

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258

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Germ-line and somatic mutations in genes that promote homology-directed repair (HDR), especially BRCA1 and BRCA2, are frequently observed in several cancers, in particular, breast and ovary but also prostate and other cancers. HDR is critical for the error-free repair of DNA double-strand breaks and other lesions, and HDR factors also protect stalled replication forks. As a result, loss of BRCA1 or BRCA2 poses significant risks to genome integrity, leading not only to cancer predisposition but also to sensitivity to DNA-damaging agents, affecting therapeutic approaches. Here we review recent advances in our understanding of BRCA1 and BRCA2, including how they genetically interact with other repair factors, how they protect stalled replication forks, how they affect the response to aldehydes, and how loss of their functions links to mutation signatures. Importantly, given the recent advances with poly(ADP-ribose) polymerase inhibitors (PARPi) for the treatment of HDR-deficient tumors, we discuss mechanisms by which BRCA-deficient tumors acquire resistance to PARPi and other agents.

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Section: Tissue Tropism Of Brca-mutated Cancers and Cell Of Originsupporting

confidence: 66%

Homology-Directed Repair and the Role of BRCA1, BRCA2, and Related Proteins in Genome Integrity and Cancer

Chen

Feng

Lim

et al. 2018

Annu. Rev. Cancer Biol.

Self Cite

258

221

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“…We further quantified HDR in primary ear fibroblasts from Sws1 -/and Swsap1 -/mice containing the DR-GFP reporter 24 and found that HDR levels are similar to controls, as measured directly by the fraction of GFP positive cells or taking into account total I-SceI site-loss ( Supplementary Fig. 5b).…”

Section: Hdr In Mitotic Cells Does Not Require Efficient Rad51 Focusmentioning

confidence: 92%

“…The percent GFP + cells were analyzed 48 h later by flow cytometry. Site-loss were determined using the previously described protocol24 .All mouse ES cell lines were cultured in DMEM-HG medium supplemented with 12.5% stem cell grade FBS (Gemini), 1X Pen-Strep, 1X MEM/NEAA, 1X L-Gln, 833 U/ml LIF (Gemini Cat # 400-495), and 0.1 mM β-mercaptoethanol. Culture dishes were pre-coated with 0.1% gelatin.…”

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confidence: 99%

Distinct pathways of homologous recombination controlled by the SWS1-SWSAP1-SPIDR complex

Prakash

Sandoval

Morati

et al. 2020

Preprint

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Homology-directed repair (HDR), a critical DNA repair pathway in mammalian cells, is complex, leading to multiple outcomes with different impacts on genomic integrity. However, the factors that control these different outcomes are often not well understood. Here we show that SWS1-SWSAP1-SPIDR controls distinct types of HDR. Despite their requirement for stable assembly of RAD51 recombinase at DNA damage sites, these proteins are not essential for intrachromosomal HDR, providing insight into why patients and mice with mutations are viable.However, SWS1-SWSAP1-SPIDR is critical for inter-homolog HDR, the first mitotic factor identified specifically for this function. Furthermore, SWS1-SWSAP1-SPIDR drives the high level of sister-chromatid exchange, promotes long-range loss of heterozygosity often involved with cancer initiation, and impels the poor growth of BLM helicase-deficient cells. The relevance of these genetic interactions is evident as SWSAP1 loss prolongs Blm-mutant embryo survival, suggesting a possible druggable target for the treatment of Bloom syndrome. MainDouble-strand breaks (DSBs) are among the most dangerous DNA lesions that can arise in cells and, if not repaired correctly, can lead to genomic instability and tumorigenesis 1 . Homologous recombination, also known as homology-directed repair (HDR), is the predominant pathway to repair DSBs in an error-free manner. The RAD51 recombinase plays a central role, whereby it forms filaments on single-stranded DNA at resected DNA ends through the activity of mediator proteins like BRCA2 2 and can be stabilized and/or remodeled by RAD51 paralogs, as shown for the yeast and worm proteins 3,4 . RAD51 nucleoprotein filaments subsequently invade a homologous template, typically the sister chromatid, to form a displacement loop (D loop), followed by repair synthesis. DNA helicases can unwind these D loops to promote HDR by the synthesis-dependent strand annealing pathway to result in noncrossovers. Alternatively, D loops that capture the other DNA end can mature into double Holliday junctions, which can be dissolved by BLM, a RECQ helicase deficient in individuals with Bloom syndrome, or resolved by structure-specific nucleases to form crossovers 5,6 . What controls the decision points for these various pathways is not well understood.SWS1-SWSAP1 is a recently identified complex that is critically important for HDR during meiosis in the mouse, promoting the stable assembly of both RAD51 and DMC1 nucleoprotein filaments at resected DNA ends in spermatocytes 7 . As a result, meiotic chromosomes in Sws1 and Swsap1 mutant mice often fail to synapse properly and mice are sterile. SWS1 homologs are readily

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“…Brca2 Δ27/Δ27 mice 36 causes an HR defect in somatic cells 37 , there is little discernible effect on RAD51 and DMC1 foci in early meiotic cells and cells progress to later prophase I stages ( Fig. 5a-g).…”

Section: Although Expression Of Brca2 Lacking the C-terminal Domain Inmentioning

confidence: 99%

Shu complex SWS1-SWSAP1 is required for mouse meiotic recombination in concert with the BRCA2 C terminus

Prakash

et al. 2017

Preprint

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Homology recognition and DNA-strand invasion ensure faithful homolog pairing and segregation during the first meiotic division 1 . RAD51 and DMC1 recombinases catalyze these steps 2 , with BRCA2 promoting their assembly into nuclear foci 3 . The recently identified human SWS1-SWSAP1 complex, related to the Shu complex in yeast, promotes RAD51 focus formation in cell lines 4,5 . We show here that mouse SWS1-SWSAP1 is critical for meiotic homologous recombination (HR) by promoting the assembly of RAD51 and DMC1 on early recombination intermediates. Absence of the complex perturbs meiotic progression in males and females and both sexes are sterile, although a fraction of meiocytes form crossovers. Remarkably, loss of the DNA damage checkpoint kinase CHK2 rescues fertility specifically in females without rescuing crossover numbers. Unlike the Shu complex, the BRCA2 C terminus (known to be required for RAD51 stabilization 6,7 ) is dispensible for RAD51 and DMC1 focus formation. However, concomitant loss of the BRCA2 C terminus aggravates the meiotic defects in Shu mutant spermatocytes. These results point to a complex interplay of factors that ensure recombinase function and hence meiotic progression in the mouse.Regulating the assembly, stabilization, and disassembly of nucleoprotein filaments of RAD51 and its meiosis-specific paralog DMC1 is critical for productive meiotic HR 2 .Transgenic mouse studies have shown that BRCA2, a multi-domain protein with several interaction sites for both recombinases 7-9 is necessary for RAD51 and DMC1 focus formation during meiosis, such that BRCA2 loss causes meiotic arrest and sterility 3 . Other proteins are also expected to play a role in this process, including the canonical RAD51 paralogs, but understanding their meiotic role has been hampered by the embryonic lethality of mutants 10 .More recently, "Shu" complexes have been identified in several organisms; these interact with RAD51 and RAD51 paralogs and modulate RAD51 11 . Shu complexes are comprised of a defining member with a conserved Zn-coordinating motif and one or more members with RAD51-like structural motifs 4,5,[11][12][13] . In budding yeast, mutations in any of the four subunits of the Shu complex suppress the slow growth and hydroxyurea sensitivity ("Shu") of sgs1 and top3

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Robust homology-directed repair within mouse mammary tissue is not specifically affected by Brca2 mutation

Cited by 39 publications

References 46 publications

Homology-Directed Repair and the Role of BRCA1, BRCA2, and Related Proteins in Genome Integrity and Cancer

Homology-Directed Repair and the Role of BRCA1, BRCA2, and Related Proteins in Genome Integrity and Cancer

Distinct pathways of homologous recombination controlled by the SWS1-SWSAP1-SPIDR complex

Shu complex SWS1-SWSAP1 is required for mouse meiotic recombination in concert with the BRCA2 C terminus

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