Genome-wide profiles of replication initiation, single-stranded DNA accumulation, and Rad52 binding in cells exposed to replication stress
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ABSTRACT:
ORGANISM(S): Schizosaccharomyces pombe
PROVIDER: GSE98462 | GEO | 2018/05/31
REPOSITORIES: GEO
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Project description:Genome-wide profiles of replication initiation, single-stranded DNA accumulation, and Rad52 binding in cells exposed to replication stress
| PRJNA385162 | ENA
Project description:Checkpoints are cellular surveillance and signaling pathways that regulate responses to DNA damage and perturbations of DNA replication. Here we show that high levels of sumoylated Rad52 are present in the mec1 sml1 and rad53 sml1 checkpoint mutants exposed to DNA damaging agents such as methyl methanesulfonate (MMS) or the DNA replication inhibitor hydroxyurea (HU). The kinase-defective mutant rad53-K227A also showed high levels of Rad52 sumoylation. Elevated levels of Rad52 sumoylation occur in checkpoint mutants proceeding S phase being exposed DNA-damaging agent. Interestingly, ChIP on chip analyses revealed non-canonical chromosomal localization of Rad52 in the HU-treated rad53-K227A cells arrested in early S phase: Rad52 localization at dormant and early DNA replication origins. However, such unusual localization was not dependent on the sumoylation of Rad52. In addition, we also found that Rad52 could be highly sumoylated in the absence of Rad51. Double deletion of RAD51 and RAD53 exhibited the similar levels of Rad52 sumoylation to RAD51 single deletion. The significance and regulation mechanism of Rad52 sumoylation by checkpoint pathways will be discussed. Keywords: ChIP-chip ⢠The goal of the experiment Genome-wide localization of Rad52 binding sites in Saccharomyces cerevisiae ⢠Experimental factor Distribution of Rad52 on chromosome III, IV, and V and the right arm of chromosome VI Strain: wild type, rad53 mutant, and rad53 siz2 mutant (W303 background, expressing myc tagged protein from its native promoter) Cell condition 1: G1 arrest with alpha-factor Cell condition 2: HU treatment ⢠Experimental design ChIP analyses: ChIP using anti-c-Myc antibody. ChIP-chip analyses: In all cases, hybridization data of ChIP fraction was compared with WCE (whole cell extract) fraction. Saccharomyces cerevisiae affymetrix genome tiling array (SC3456a520015F) were used. ⢠Quality control steps taken Confirmation of several loci by quantitative real time PCR. Wild type cells expressing non-tagged Rad52 were used as a negative control of DNA amplification.
2010-05-18 | E-GEOD-14761 | biostudies-arrayexpress
Project description:Replication gaps can arise as a consequence of perturbed DNA replication and their accumulation might undermine the stability of the genome. Loss of RAD52, a protein involved in the regulation of fork reversal, promotes accumulation of parental ssDNA gaps during replication perturbation. Here, we demonstrate that this is due to the engagement of Polα downstream of the extensive degradation of perturbed replication forks after their reversal, and is not dependent on PrimPol. Polα is hyper-recruited at parental ssDNA in the absence of RAD52, and this recruitment is dependent on fork reversal enzymes and RAD51. Of note, we report that the interaction between Polα and RAD51 is stimulated by RAD52 inhibition, and Polα-dependent gap accumulation requires nucleation of RAD51 suggesting that it occurs downstream strand invasion. Altogether, our data indicate that RAD51-Polα-dependent repriming is essential to promote fork restart and limit DNA damage accumulation when RAD52 function is disabled.
| S-EPMC10120653 | biostudies-literature
Project description:Checkpoints are cellular surveillance and signaling pathways that regulate responses to DNA damage and perturbations of DNA replication. Here we show that high levels of sumoylated Rad52 are present in the mec1 sml1 and rad53 sml1 checkpoint mutants exposed to DNA damaging agents such as methyl methanesulfonate (MMS) or the DNA replication inhibitor hydroxyurea (HU). The kinase-defective mutant rad53-K227A also showed high levels of Rad52 sumoylation. Elevated levels of Rad52 sumoylation occur in checkpoint mutants proceeding S phase being exposed DNA-damaging agent. Interestingly, ChIP on chip analyses revealed non-canonical chromosomal localization of Rad52 in the HU-treated rad53-K227A cells arrested in early S phase: Rad52 localization at dormant and early DNA replication origins. However, such unusual localization was not dependent on the sumoylation of Rad52. In addition, we also found that Rad52 could be highly sumoylated in the absence of Rad51. Double deletion of RAD51 and RAD53 exhibited the similar levels of Rad52 sumoylation to RAD51 single deletion. The significance and regulation mechanism of Rad52 sumoylation by checkpoint pathways will be discussed. Keywords: ChIP-chip
2009-05-26 | GSE14761 | GEO
Project description:oriC is a region of the bacterial chromosome at which the initiator protein DnaA interacts with specific sequences, leading to DNA unwinding and the initiation of chromosome replication. The general architecture of oriCs is universal; however, the structure of oriC and the mode of orisome assembly differ in distantly related bacteria. In this work, we characterized oriC of Helicobacter pylori, which consists of two DnaA box clusters and a DNA unwinding element (DUE); the latter can be subdivided into a GC-rich region, a DnaA-trio and an AT-rich region. We show that the DnaA-trio submodule is crucial for DNA unwinding, possibly because it enables proper DnaA oligomerization on ssDNA. However, we also observed the reverse effect: DNA unwinding, enabling subsequent DnaA-ssDNA oligomer formation-stabilized DnaA binding to box ts1. This suggests the interplay between DnaA binding to ssDNA and dsDNA upon DNA unwinding. Further investigation of the ts1 DnaA box revealed that this box, together with the newly identified c-ATP DnaA box in oriC1, constitute a new class of ATP-DnaA boxes. Indeed, in vitro ATP-DnaA unwinds H. pylori oriC more efficiently than ADP-DnaA. Our results expand the understanding of H. pylori orisome formation, indicating another regulatory pathway of H. pylori orisome assembly.
| S-EPMC8235120 | biostudies-literature
Project description:The eukaryotic single-stranded DNA-binding protein, replication protein A (RPA), is essential in DNA metabolism and is phosphorylated in response to DNA-damaging agents. Rad52 and RPA participate in the repair of double-stranded DNA breaks (DSBs). It is known that human RPA and Rad52 form a complex, but the molecular mass, stoichiometry, and exact role of this complex in DSB repair are unclear. In this study, absolute molecular masses of individual proteins and complexes were measured in solution using analytical size-exclusion chromatography coupled with multiangle light scattering, the protein species present in each purified fraction were verified via sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)/Western analyses, and the presence of biotinylated ssDNA in the complexes was verified by chemiluminescence detection. Then, employing UV cross-linking, the protein partner holding the ssDNA was identified. These data show that phosphorylated RPA promoted formation of a complex with monomeric Rad52 and caused the transfer of ssDNA from RPA to Rad52. This suggests that RPA phosphorylation may regulate the first steps of DSB repair and is necessary for the mediator function of Rad52.
| S-EPMC2710861 | biostudies-literature
Project description:Initiation of DNA replication requires binding of the initiator protein, DnaA, to specific binding sites in the chromosomal origin of replication, oriC. In low G+C Gram-positive bacteria, the primosomal proteins DnaD and DnaB, in conjunction with loader ATPase DnaI, load the replicative helicase at oriC, and this depends on DnaA. DnaD and DnaB are also required to load the replicative helicase outside of oriC during replication restart, in a DnaA-independent manner. DnaA also binds to many sites around the chromosome, outside of oriC, and acts as a transcription factor at several of these. Using chromatin immunoprecipitation, we found that DnaD and DnaB, but not the replicative helicase, are associated with many of the chromosomal regions bound by DnaA in vivo in Bacillus subtilis. This association was dependent on DnaA and the order of recruitment was the same as that at oriC, but was independent of a functional oriC. The presence of DnaD and DnaB at the secondary (non-oriC) targets of DnaA in the absence of helicase loading indicates a possible role for DnaD and DnaB in modulating the activity of DnaA. The genome-wide binding profiles of DnaA, DnaD, DnaB and DnaC were determined. Binding profiles were determined in exponentially growing cells with and without HPUra treatment. Three biological replicates were analyzed per protein/treatment (one per array). Enrichment in immunoprecipitated samples versus total genomic DNA were determined.
2010-12-07 | E-GEOD-23686 | biostudies-arrayexpress
Project description:Initiation of DNA replication requires binding of the initiator protein, DnaA, to specific binding sites in the chromosomal origin of replication, oriC. In low G+C Gram-positive bacteria, the primosomal proteins DnaD and DnaB, in conjunction with loader ATPase DnaI, load the replicative helicase at oriC, and this depends on DnaA. DnaD and DnaB are also required to load the replicative helicase outside of oriC during replication restart, in a DnaA-independent manner. DnaA also binds to many sites around the chromosome, outside of oriC, and acts as a transcription factor at several of these. Using chromatin immunoprecipitation, we found that DnaD and DnaB, but not the replicative helicase, are associated with many of the chromosomal regions bound by DnaA in vivo in Bacillus subtilis. This association was dependent on DnaA and the order of recruitment was the same as that at oriC, but was independent of a functional oriC. The presence of DnaD and DnaB at the secondary (non-oriC) targets of DnaA in the absence of helicase loading indicates a possible role for DnaD and DnaB in modulating the activity of DnaA.
2010-12-07 | GSE23686 | GEO
Project description:Disrupting either the DNA annealing factor RAD52 or the A-family DNA polymerase POLQ can cause synthetic lethality with defects in BRCA1 and BRCA2, which are tumor suppressors important for homology-directed repair of DNA double-strand breaks (DSBs), and protection of stalled replication forks. A likely mechanism of this synthetic lethality is that RAD52 and/or POLQ are important for backup pathways for DSB repair and/or replication stress responses. The features of DSB repair events that require RAD52 vs. POLQ, and whether combined disruption of these factors causes distinct effects on genome maintenance, have been unclear. Using human U2OS cells, we generated a cell line with POLQ mutations upstream of the polymerase domain, a RAD52 knockout cell line, and a line with combined disruption of both genes. We also examined RAD52 and POLQ using RNA-interference. We find that combined disruption of RAD52 and POLQ causes at least additive hypersensitivity to cisplatin, and a synthetic reduction in replication fork restart velocity. We also examined the influence of RAD52 and POLQ on several DSB repair events. We find that RAD52 is particularly important for repair using ≥ 50 nt repeat sequences that flank the DSB, and that also involve removal of non-homologous sequences flanking the repeats. In contrast, POLQ is important for repair events using 6 nt (but not ≥ 18 nt) of flanking repeats that are at the edge of the break, as well as oligonucleotide microhomology-templated (i.e., 12-20 nt) repair events requiring nascent DNA synthesis. Finally, these factors show key distinctions with BRCA2, regarding effects on DSB repair events and response to stalled replication forks. These findings indicate that RAD52 and POLQ have distinct roles in genome maintenance, including for specific features of DSB repair events, such that combined disruption of these factors may be effective for genotoxin sensitization and/or synthetic lethal strategies.
| S-EPMC6695211 | biostudies-literature
Project description:In Escherichia coli, the replication origin oriC consists of two functional regions: the duplex unwinding element (DUE) and its flanking DnaA-assembly region (DAR). ATP-DnaA molecules multimerize on DAR, unwinding DUE for DnaB helicase loading. However, DUE-unwinding mechanisms and functional structures in DnaA-oriC complexes supporting those remain unclear. Here, using various in vitro reconstituted systems, we identify functionally distinct DnaA sub-complexes formed on DAR and reveal novel mechanisms in DUE unwinding. The DUE-flanking left-half DAR carrying high-affinity DnaA box R1 and the ATP-DnaA-preferential DnaA box R5, ?1-2 and I1-2 sites formed a DnaA sub-complex competent in DUE unwinding and ssDUE binding, thereby supporting basal DnaB loading activity. This sub-complex is further subdivided into two; the DUE-distal DnaA sub-complex formed on the ATP-DnaA-preferential sites binds ssDUE. Notably, the DUE-flanking, DnaA box R1-DnaA sub-complex recruits DUE to the DUE-distal DnaA sub-complex in concert with a DNA-bending nucleoid protein IHF, thereby promoting DUE unwinding and binding of ssDUE. The right-half DAR-DnaA sub-complex stimulated DnaB loading, consistent with in vivo analyses. Similar features are seen in DUE unwinding of the hyperthermophile, Thermotoga maritima, indicating evolutional conservation of those mechanisms.
| S-EPMC3287180 | biostudies-literature