Conditional knockout of RAD51-related genes in Leishmania major reveals a critical role for homologous recombination during genome replication
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ABSTRACT:
PROVIDER: PRJEB35031 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| ERR3610780_1.fastq.gz | Fastqsanger.gz | |||
| ERR3610780_2.fastq.gz | Fastqsanger.gz | |||
| ERR3610790_1.fastq.gz | Fastqsanger.gz | |||
| ERR3610790_2.fastq.gz | Fastqsanger.gz | |||
| ERR3610800_1.fastq.gz | Fastqsanger.gz |
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Project description:RAD51, a multifunctional protein, plays a central role in DNA replication and homologous recombination repair, and is known to be involved in cancer development. We identified a novel role for RAD51 in innate immune response signaling. Defects in RAD51 lead to the accumulation of self-DNA in the cytoplasm, triggering a STING-mediated innate immune response after replication stress and DNA damage. Our data suggest that in addition to playing roles in homologous recombination-mediated DNA double-strand break repair and replication fork processing, RAD51 is also implicated in the suppression of innate immunity. Thus, our study reveals a previously uncharacterized role of RAD51 in initiating immune signaling, placing it at the hub of new interconnections between DNA replication, DNA repair, and immunity.
2017-02-18 | GSE95050 | GEO
Project description:The formation of RAD51/DMC1 filaments on single-stranded (ss)DNAs, which is essential for homology search and strand exchange in DNA double-strand break (DSB) repair and for the protection of stalled DNA replication forks, is tightly regulated in time and space. FIGNL1 AAA+++ ATPase plays positive and negative roles in the RAD51-mediated recombination in human cells. However, the role of FIGNL1 in gametogenesis remains unsolved. Here, we characterized a germ-line-specific conditional knockout (cKO) mouse of FIGNL1. The Fignl1 cKO male mice showed defective chromosome synapsis and impaired meiotic DSB repair with the accumulation of RAD51/DMC1 on chromosomes in mid-meiotic prophase I, supporting a role of FIGNL1 in a post-assembly stage of RAD51/DMC1 filaments. Fignl1 cKO spermatocytes accumulate RAD51 and DMC1 ensembles on chromosomes not only in early meiotic prophase I but also in meiotic S-phase. These RAD51/DMC1 assemblies are independent of meiotic DSB formation. Finally, we showed that purified FIGNL1 dismantles RAD51 filament on double-stranded (ds)DNA as well as ssDNA. These results suggest a critical role of FIGNL1 to limit the uncontrolled assembly of RAD51 and DMC1 on native dsDNAs during the meiotic S-phase and meiotic prophase I.
2023-03-31 | GSE227944 | GEO
Project description:Sister chromatid exchanges (SCEs) are a product of joint DNA molecules resolution, and are considered to require homologous recombination (HR). Canonical HR factors BRCA1, BRCA2 and RAD51 were indeed essential for SCE induction in response to irradiation-induced DNA breaks. By contrast, replication-blocking agents, including PARP inhibitors, induced SCEs independently of BRCA1, BRCA2 or RAD51. HR-independent SCEs were associated with incomplete DNA replication, as evidenced by post-replicative single-stranded DNA (ssDNA) accumulation and enrichment of PARP inhibitor-induced SCEs at common fragile sites (CFSs). Importantly, PARP-induced DNA lesions were transmitted into mitosis, pointing towards SCEs originating from mitotic processing of underreplicated DNA. We found polymerase theta to be associated to mitotic DNA lesions, to be required for SCE formation and to prevent chromosome fragmentation upon PARP inhibition in HR-defective cells. Combined, our data show that replication-blocking agents lead to underreplicated DNA in mitosis, which is processed into SCEs independently of canonical HR factors.
2023-03-11 | PXD028670 | Pride
Project description:Repair of DNA double-strand break (DSB) is critical for the maintenance of genome integrity. We have previously shown that a class of DSB-induced small RNAs (diRNAs) facilitates homologous recombination (HR)-mediated DSB repair in Arabidopsis thaliana. Here we show that INVOLVED IN DE NOVO 2 (IDN2), a double-stranded RNA (dsRNA) binding protein involved in small RNA-directed DNA methylation, is required for DSB repair in Arabidopsis. We find that IDN2 interacts with the heterotrimeric replication protein A (RPA) complex. Depletion of IDN2 or the diRNA-binding ARGONAUTE 2 (AGO2) leads to increased accumulation of RPA at DSB sites and mislocalization of the recombination factor RAD51. These findings support a model in which IDN2 interacts with RPA and facilitates the release of RPA from ssDNA tails and subsequent recruitment of RAD51 at DSB sites to promote DSB repair.
2017-02-28 | GSE94305 | GEO
Project description:The proper maintenance of genetic material is essential for the survival of living organisms. One of the main safeguards of genome stability is homologous recombination involved in the faithful repair of DNA double-strand breaks, the restoration of collapsed replication forks, and the bypass of replication barriers. Homologous recombination relies on the formation of Rad51 nucleofilaments which are responsible for the homology-based interactions between DNA strands. Here we demonstrate that without the regulation of these filaments by Srs2 and Rad54, which are known to remove Rad51 from single-stranded and double-stranded DNA respectively, the filaments strongly inhibit damage-associated DNA synthesis during DNA repair. Furthermore, this regulation is essential for cell survival under normal growth conditions as in the srs2Δ rad54Δ mutants unregulated Rad51 nucleofilaments cause activation of the DNA damage checkpoint, formation of mitotic bridges and loss of genetic material. These genome instability features may stem from the problems at stalled replication forks as the lack of Srs2 and Rad54 in the presence of Rad51 nucleofilaments impedes cell recovery from replication stress. This study demonstrates that the timely and efficient disassembly of recombination machinery is essential for genome maintenance and cell survival.
2023-03-16 | GSE227383 | GEO
Project description:ARF is a tumour suppressor activated by oncogenic stress, which stabilizes p53. Although p53 is a key component of the response to DNA damage, a similar function for ARF has not been ascribed. In this work we show that homologous recombination (HR) -deficient primary mouse and human cells accumulate DNA damage, which triggers checkpoint signalling and ARF activation. We also show that in the absence of ARF p53 is induce in response to DNA damage, but surprisingly fails to trigger senescence. The hypothesis tested in this study was that ARF deficiency alters the spectrum of genes activated by p53 in response to HR deficiency. Using mRNA microarray analysis and expression profiling, we identified genes upregulated in wild type primary MEFs treated with RAD51 shRNA, whose expression was not induced in similarly treated Arf -/- primary MEFs. Clustering analysis of p53 transcriptional targets with increased expression in RAD51-depleted cells revealed three groups: genes requiring functional ARF for their expression, genes transcribed in an ARF-independent manner and genes that are upregulated in both ARF-proficient and ARF-deficient cells. Among the genes in the last group we found Cdkn1a(p21), encoding the p21 inhibitor of cyclindependent kinases and well-characterized effector of the p53 role in promoting senescence. The subset of p53 targets requiring ARF for their transcription was specifically upregulated in response to RAD51 inhibition in wild type, but not Arf -/- MEFs. Among these genes, two encoded the dual specificity phosphatase (DUSP) family members DUSP4 and DUSP7, which act as ERK phosphatases and negative regulators of the MAPK kinase pathway in mammalian cells. Four samples were analysed (WT or ARF negative cells transfected with GFP or RAD51 shRNAs) in duplicate. Samples treated with GFP shRNA are the reference samples and the ones treated with RAD51 shRNA are the experimental ones (RAD51 depletion leads to HR deficiency). The WT cell line is our control cell line to study the effect of HR deficiency on the transcription of p53 target genes
2014-12-04 | E-GEOD-51354 | biostudies-arrayexpress
Project description:Homologous recombination (HR) has an intimate relationship with genome replication, both during repair of DNA lesions that might prevent DNA synthesis and in tackling stalls to the replication fork. Recent studies led us to ask if HR might have a more central role in replicating the genome of Leishmania, a eukaryotic parasite. Conflicting evidence has emerged regarding whether or not HR genes are essential, and genome-wide mapping has provided evidence for an unorthodox organisation of DNA replication initiation sites, termed origins. To answer this question, we have employed a combined CRISPR/Cas9 and DiCre approach to rapidly generate and assess the effect of conditional ablation of RAD51 and three RAD51-related proteins in Leishmania major. Using this approach, we demonstrate that loss of any of these HR factors is not immediately lethal but in each case growth slows with time and leads to DNA damage and accumulation of cells with aberrant DNA content. Despite these similarities, we show that only loss of RAD51 or RAD51-3 impairs DNA synthesis and causes elevated levels of genome-wide mutation. Furthermore, we show that these two HR factors act in distinct ways, since ablation of RAD51, but not RAD51-3, has a profound effect on DNA replication, causing loss of initiation at the major origins and increased DNA synthesis at subtelomeres. Our work clarifies questions regarding the importance of HR to survival of Leishmania and reveals an unanticipated, central role for RAD51 in the programme of genome replication in a microbial eukaryote.
| S-EPMC7360064 | biostudies-literature
Project description:To achieve drug resistance Leishmania parasite alters gene copy number by using its repeated sequences widely distributed through the genome. Even though homologous recombination (HR) is ascribed to maintain genome stability, this eukaryote exploits this potent mechanism driven by the Rad51 recombinase to form beneficial extrachromosomal circular amplicons. Here, we provide insights on the formation of these circular amplicons by analyzing the functions of the Rad51 paralogs. We purified three Leishmania infantum Rad51 paralogs homologs (LiRad51-3, LiRad51-4 and LiRad51-6) all of which directly interact with LiRad51. LiRad51-3, LiRad51-4 and LiRad51-6 show differences in DNA binding and annealing capacities. Moreover, it is also noteworthy that LiRad51-3 and LiRad51-4 are able to stimulate Rad51-mediated D-loop formation. In addition, we succeed to inactivate the LiRad51-4 gene and report a decrease of circular amplicons in this mutant. The LiRad51-3 gene was found to be essential for cell viability. Thus, we propose that the LiRad51 paralogs play crucial functions in extrachromosomal circular DNA amplification to circumvent drug actions and preserve survival.
| S-EPMC4357719 | biostudies-literature
Project description:53BP1 activity drives genome instability and embryonic lethality in BRCA1-deficient cells by inhibiting homologous recombination (HR).53BP1’s anti-recombinogenic functions require phosphorylation-dependent interactions with two effector complexes, PTIP and RIF1/Shieldin. While RIF1/Shieldin is thought to block 5’-3’ nucleolytic processing of DNA ends, it remains unclear how PTIP antagonizes HR. Here we show that mutation of the PTIP interaction site in 53BP1 (S25A) increases Shieldin association with DNA damage. Despite excessive Shieldin “end-blocking” activity, the mutant protein allows end resection sufficient to rescue the lethality of BRCA1D11 mice. End resection in BRCA1D1153BP1S25A mice is rewired in a manner driven by DNA2 since Shieldin blocks EXO1-mediated nucleolytic processing. Despite ample resection, mutant cells fail to complete HR, as 53BP1/Shieldin also inhibits RNF168-mediated loading of PALB2/RAD51 onto ssDNA post-resection. As a result, BRCA1D1153BP1S25A mice exhibit hallmark features of HR insufficiency, including increased developmental neuronal apoptosis, premature aging and hypersensitivity to PARP inhibitors. Disruption of Shieldin or forced targeting of PALB2 to ssDNA in BRCA1D1153BP1S25A cells restores RNF168 recruitment, RAD51 nucleofilament formation, and PARPi resistance. Our study supports a model in which RIF1/Shieldin and PTIP associate independently with 53BP1 to regulate distinct end-resection pathways, and reveals a critical function of 53BP1/Shieldin post-resection that limits RNF168-mediated loading of RAD51.
2019-10-22 | GSE133806 | GEO
Project description:53BP1 activity drives genome instability and embryonic lethality in BRCA1-deficient cells by inhibiting homologous recombination (HR).53BP1’s anti-recombinogenic functions require phosphorylation-dependent interactions with two effector complexes, PTIP and RIF1/Shieldin. While RIF1/Shieldin is thought to block 5’-3’ nucleolytic processing of DNA ends, it remains unclear how PTIP antagonizes HR. Here we show that mutation of the PTIP interaction site in 53BP1 (S25A) increases Shieldin association with DNA damage. Despite excessive Shieldin “end-blocking” activity, the mutant protein allows end resection sufficient to rescue the lethality of BRCA1D11 mice. End resection in BRCA1D1153BP1S25A mice is rewired in a manner driven by DNA2 since Shieldin blocks EXO1-mediated nucleolytic processing. Despite ample resection, mutant cells fail to complete HR, as 53BP1/Shieldin also inhibits RNF168-mediated loading of PALB2/RAD51 onto ssDNA post-resection. As a result, BRCA1D1153BP1S25A mice exhibit hallmark features of HR insufficiency, including increased developmental neuronal apoptosis, premature aging and hypersensitivity to PARP inhibitors. Disruption of Shieldin or forced targeting of PALB2 to ssDNA in BRCA1D1153BP1S25A cells restores RNF168 recruitment, RAD51 nucleofilament formation, and PARPi resistance. Our study supports a model in which RIF1/Shieldin and PTIP associate independently with 53BP1 to regulate distinct end-resection pathways, and reveals a critical function of 53BP1/Shieldin post-resection that limits RNF168-mediated loading of RAD51.
2019-10-22 | GSE133805 | GEO