Formation of co-transcriptional R-loops underlies replication fork stalling upon head-on transcription-replication encounters. Here, we demonstrate that RAD51-dependent replication fork reversal induced by R-loops is followed by the restart of semiconservative DNA replication mediated by RECQ1 and RECQ5 helicases, MUS81/EME1 endonuclease, RAD52 strand-annealing factor, the DNA ligase IV (LIG4)/XRCC4 complex, and the non-catalytic subunit of DNA polymerase δ, POLD3. RECQ5 disrupts RAD51 filaments assembled on stalled forks after RECQ1-mediated reverse branch migration, preventing a new round of fork reversal and facilitating fork cleavage by MUS81/EME1. MUS81-dependent DNA breaks accumulate in cells lacking RAD52 or LIG4 upon induction of R-loop formation, suggesting that RAD52 acts in concert with LIG4/XRCC4 to catalyze fork religation, thereby mediating replication restart. The resumption of DNA synthesis after R-loop-associated fork stalling also requires active transcription, the restoration of which depends on MUS81, RAD52, LIG4, and the transcription elongation factor ELL. These findings provide mechanistic insights into transcription-replication conflict resolution.

• MeSH
• DNA opravný a rekombinační protein Rad52 metabolismus   MeSH
• DNA vazebné proteiny metabolismus   MeSH
• DNA-ligasy metabolismus   MeSH
• DNA-polymerasa III metabolismus   MeSH
• endodeoxyribonukleasy metabolismus   MeSH
• endonukleasy genetika   metabolismus   MeSH
• genetická transkripce genetika   MeSH
• HeLa buňky MeSH
• helikasy RecQ metabolismus   fyziologie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• R-smyčka genetika   fyziologie   MeSH
• rekombinasa Rad51 genetika   metabolismus   fyziologie   MeSH
• replikace DNA genetika   fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The proper repair of deleterious DNA lesions such as double strand breaks prevents genomic instability and carcinogenesis. In yeast, the Rad52 protein mediates DSB repair via homologous recombination. In mammalian cells, despite the presence of the RAD52 protein, the tumour suppressor protein BRCA2 acts as the predominant mediator during homologous recombination. For decades, it has been believed that the RAD52 protein played only a back-up role in the repair of DSBs performing an error-prone single strand annealing (SSA). Recent studies have identified several new functions of the RAD52 protein and have drawn attention to its important role in genome maintenance. Here, we show that RAD52 activities are enhanced by interacting with a small and highly acidic protein called DSS1. Binding of DSS1 to RAD52 changes the RAD52 oligomeric conformation, modulates its DNA binding properties, stimulates SSA activity and promotes strand invasion. Our work introduces for the first time RAD52 as another interacting partner of DSS1 and shows that both proteins are important players in the SSA and BIR pathways of DSB repair.

• MeSH
• DNA opravný a rekombinační protein Rad52 genetika   MeSH
• DNA vazebné proteiny genetika   MeSH
• dvouřetězcové zlomy DNA MeSH
• genom lidský genetika   MeSH
• homologní rekombinace genetika   MeSH
• karcinogeneze genetika   MeSH
• lidé MeSH
• nestabilita genomu genetika   MeSH
• oprava DNA genetika   MeSH
• osteosarkom genetika   patologie   MeSH
• proteasomový endopeptidasový komplex genetika   MeSH
• protein BRCA2 genetika   MeSH
• Saccharomyces cerevisiae - proteiny genetika   MeSH
• Saccharomyces cerevisiae genetika   MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Aging may be characterized as the progressive increase of the risk of death caused by a decrease of almost all bodily functions. While a great number of model organism studies have established the role of DNA double strand breaks (DSBs) as one of the main causes of aging, few studies have examined whether common polymorphisms in human DSB repair genes influence aging and mortality. More importantly, to the best of our knowledge, no longitudinal study has thus far examined the link between polymorphisms in DSB repair and the risk of death. This longitudinal study thus analyses whether four common polymorphisms (rs2155209, rs7963551, rs17105278, rs2735383) in four selected DSB repair genes (MRE11A, RAD52, RAD51B, NBS1) influence the hazard of age-adjusted death in a cohort of patients with typical symptoms of ischemic heart disease. The results have shown that rs7963551 G/T heterozygotes exhibit a significantly increased hazard of death when compared with the combined GG and TT homozygotes (HR=1.42, 95% CI: 1.06-1.91, p=0.018). This study indicates that the SNP affecting efficiency of DSB repair may influence aging in humans.

• MeSH
• DNA opravný a rekombinační protein Rad52 genetika   fyziologie   MeSH
• DNA vazebné proteiny genetika   MeSH
• dvouřetězcové zlomy DNA MeSH
• genetická predispozice k nemoci MeSH
• genotyp MeSH
• heterozygot MeSH
• jednonukleotidový polymorfismus * MeSH
• kardiovaskulární nemoci genetika   mortalita   MeSH
• kohortové studie MeSH
• lidé středního věku MeSH
• lidé MeSH
• longitudinální studie MeSH
• multivariační analýza MeSH
• mutace MeSH
• oprava DNA MeSH
• poškození DNA MeSH
• proporcionální rizikové modely MeSH
• riziko MeSH
• senioři MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Homologous recombination (HR) is essential for maintenance of genome stability through double-strand break (DSB) repair, but at the same time HR can lead to loss of heterozygosity and uncontrolled recombination can be genotoxic. The post-translational modification by SUMO (small ubiquitin-like modifier) has been shown to modulate recombination, but the exact mechanism of this regulation remains unclear. Here we show that SUMOylation stabilizes the interaction between the recombination mediator Rad52 and its paralogue Rad59 in Saccharomyces cerevisiae. Although Rad59 SUMOylation is not required for survival after genotoxic stress, it affects the outcome of recombination to promote conservative DNA repair. In some genetic assays, Rad52 and Rad59 SUMOylation act synergistically. Collectively, our data indicate that the described SUMO modifications affect the balance between conservative and non-conservative mechanisms of HR.

• MeSH
• chromozomy hub genetika   MeSH
• DNA opravný a rekombinační protein Rad52 chemie   metabolismus   MeSH
• DNA vazebné proteiny chemie   metabolismus   MeSH
• homologní rekombinace * MeSH
• lysin metabolismus   MeSH
• mitóza genetika   MeSH
• poškození DNA MeSH
• proteinové domény MeSH
• Saccharomyces cerevisiae - proteiny chemie   metabolismus   MeSH
• Saccharomyces cerevisiae cytologie   genetika   metabolismus   MeSH
• sumoylace * MeSH
• Publikační typ
• časopisecké články MeSH

Genetic variations in 3' untranslated regions of target genes may affect microRNA binding, resulting in differential protein expression. microRNAs regulate DNA repair, and single-nucleotide polymorphisms in miRNA binding sites (miRSNPs) may account for interindividual differences in the DNA repair capacity. Our hypothesis is that miRSNPs in relevant DNA repair genes may ultimately affect cancer susceptibility and impact prognosis.In the present study, we analysed the association of polymorphisms in predicted microRNA target sites of double-strand breaks (DSBs) repair genes with colorectal cancer (CRC) risk and clinical outcome. Twenty-one miRSNPs in non-homologous end-joining and homologous recombination pathways were assessed in 1111 cases and 1469 controls. The variant CC genotype of rs2155209 in MRE11A was strongly associated with decreased cancer risk when compared with the other genotypes (OR 0.54, 95% CI 0.38-0.76, p = 0.0004). A reduced expression of the reporter gene was observed for the C allele of this polymorphism by in vitro assay, suggesting a more efficient interaction with potentially binding miRNAs. In colon cancer patients, the rs2155209 CC genotype was associated with shorter survival while the TT genotype of RAD52 rs11226 with longer survival when both compared with their respective more frequent genotypes (HR 1.63, 95% CI 1.06-2.51, p = 0.03 HR 0.60, 95% CI 0.41-0.89, p = 0.01, respectively).miRSNPs in DSB repair genes involved in the maintenance of genomic stability may have a role on CRC susceptibility and clinical outcome.

• MeSH
• 3' nepřekládaná oblast genetika   MeSH
• DNA opravný a rekombinační protein Rad52 genetika   MeSH
• dospělí MeSH
• genetická predispozice k nemoci MeSH
• genotyp MeSH
• homologní protein MRE11 genetika   MeSH
• jednonukleotidový polymorfismus * MeSH
• kolorektální nádory genetika   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mikro RNA genetika   MeSH
• míra přežití MeSH
• mladý dospělý MeSH
• nádorové biomarkery genetika   MeSH
• následné studie MeSH
• oprava DNA genetika   MeSH
• prognóza MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• vazebná místa MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Genetic variants located within the 12p13.33/RAD52 locus have been associated with lung squamous cell carcinoma (LUSC). Here, within 5,947 UADT cancers and 7,789 controls from 9 different studies, we found rs10849605, a common intronic variant in RAD52, to be also associated with upper aerodigestive tract (UADT) squamous cell carcinoma cases (OR = 1.09, 95% CI: 1.04-1.15, p = 6x10(-4)). We additionally identified rs10849605 as a RAD52 cis-eQTL inUADT(p = 1x10(-3)) and LUSC (p = 9x10(-4)) tumours, with the UADT/LUSC risk allele correlated with increased RAD52 expression levels. The 12p13.33 locus, encompassing rs10849605/RAD52, was identified as a significant somatic focal copy number amplification in UADT(n = 374, q-value = 0.075) and LUSC (n = 464, q-value = 0.007) tumors and correlated with higher RAD52 tumor expression levels (p = 6x10(-48) and p = 3x10(-29) in UADT and LUSC, respectively). In combination, these results implicate increased RAD52 expression in both genetic susceptibility and tumorigenesis of UADT and LUSC tumors.

• MeSH
• demografie MeSH
• DNA opravný a rekombinační protein Rad52 genetika   MeSH
• fyzikální mapování chromozomů MeSH
• genetická predispozice k nemoci * MeSH
• genetické lokusy * MeSH
• jednonukleotidový polymorfismus genetika   MeSH
• lidé středního věku MeSH
• lidé MeSH
• lidské chromozomy, pár 12 genetika   MeSH
• lokus kvantitativního znaku genetika   MeSH
• nádory hlavy a krku genetika   MeSH
• nádory plic genetika   MeSH
• počítačová simulace MeSH
• rizikové faktory MeSH
• spinocelulární karcinom genetika   MeSH
• studie případů a kontrol MeSH
• zárodečné buňky MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, N.I.H., Extramural MeSH

Most mitotic homologous recombination (HR) events proceed via a synthesis-dependent strand annealing mechanism to avoid crossing over, which may give rise to chromosomal rearrangements and loss of heterozygosity. The molecular mechanisms controlling HR sub-pathway choice are poorly understood. Here, we show that human RECQ5, a DNA helicase that can disrupt RAD51 nucleoprotein filaments, promotes formation of non-crossover products during DNA double-strand break-induced HR and counteracts the inhibitory effect of RAD51 on RAD52-mediated DNA annealing in vitro and in vivo. Moreover, we demonstrate that RECQ5 deficiency is associated with an increased occupancy of RAD51 at a double-strand break site, and it also causes an elevation of sister chromatid exchanges on inactivation of the Holliday junction dissolution pathway or on induction of a high load of DNA damage in the cell. Collectively, our findings suggest that RECQ5 acts during the post-synaptic phase of synthesis-dependent strand annealing to prevent formation of aberrant RAD51 filaments on the extended invading strand, thus limiting its channeling into potentially hazardous crossover pathway of HR.

• MeSH
• buněčné linie MeSH
• DNA opravný a rekombinační protein Rad52 metabolismus   MeSH
• DNA metabolismus   MeSH
• dvouřetězcové zlomy DNA * MeSH
• helikasy RecQ metabolismus   MeSH
• jednovláknová DNA metabolismus   MeSH
• lidé MeSH
• rekombinační oprava DNA * MeSH
• rekombinasa Rad51 metabolismus   MeSH
• výměna sesterských chromatid MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Homologous recombination (HR) plays a vital role in DNA metabolic processes including meiosis, DNA repair, DNA replication and rDNA homeostasis. HR defects can lead to pathological outcomes, including genetic diseases and cancer. Recent studies suggest that the post-translational modification by the small ubiquitin-like modifier (SUMO) protein plays an important role in mitotic and meiotic recombination. However, the precise role of SUMOylation during recombination is still unclear. Here, we characterize the effect of SUMOylation on the biochemical properties of the Saccharomyces cerevisiae recombination mediator protein Rad52. Interestingly, Rad52 SUMOylation is enhanced by single-stranded DNA, and we show that SUMOylation of Rad52 also inhibits its DNA binding and annealing activities. The biochemical effects of SUMO modification in vitro are accompanied by a shorter duration of spontaneous Rad52 foci in vivo and a shift in spontaneous mitotic recombination from single-strand annealing to gene conversion events in the SUMO-deficient Rad52 mutants. Taken together, our results highlight the importance of Rad52 SUMOylation as part of a 'quality control' mechanism regulating the efficiency of recombination and DNA repair.

• MeSH
• DNA opravný a rekombinační protein Rad52 chemie   metabolismus   MeSH
• jednovláknová DNA metabolismus   MeSH
• lysin metabolismus   MeSH
• oprava DNA MeSH
• protein SUMO-1 metabolismus   MeSH
• rekombinace genetická MeSH
• rekombinasa Rad51 metabolismus   MeSH
• replikační protein A metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny chemie   metabolismus   MeSH
• terciární struktura proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

The replication protein A (RPA) is involved in most, if not all, nuclear metabolism involving single-stranded DNA. Here, we show that RPA is involved in genome maintenance at stalled replication forks by the homologous recombination repair system in humans. Depletion of the RPA protein inhibited the formation of RAD51 nuclear foci after hydroxyurea-induced replication stalling leading to persistent unrepaired DNA double-strand breaks (DSBs). We demonstrate a direct role of RPA in homology directed recombination repair. We find that RPA is dispensable for checkpoint kinase 1 (Chk1) activation and that RPA directly binds RAD52 upon replication stress, suggesting a direct role in recombination repair. In addition we show that inhibition of Chk1 with UCN-01 decreases dissociation of RPA from the chromatin and inhibits association of RAD51 and RAD52 with DNA. Altogether, our data suggest a direct role of RPA in homologous recombination in assembly of the RAD51 and RAD52 proteins. Furthermore, our data suggest that replacement of RPA with the RAD51 and RAD52 proteins is affected by checkpoint signalling.

• MeSH
• aktivace enzymů MeSH
• CDC geny MeSH
• DNA opravný a rekombinační protein Rad52 genetika   metabolismus   MeSH
• hydroxymočovina metabolismus   MeSH
• inhibitory syntézy nukleových kyselin metabolismus   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• oprava DNA * MeSH
• poškození DNA MeSH
• proteinkinasy genetika   metabolismus   MeSH
• rekombinasa Rad51 metabolismus   MeSH
• replikace DNA * MeSH
• replikační protein A genetika   metabolismus   MeSH
• signální transdukce * fyziologie   MeSH
• Check Tag
• lidé MeSH