PARP1 gene knockout suppresses expression of DNA Base Excision Repair genes
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE218871 | GEO | 2022/12/01
REPOSITORIES: GEO
Similar Datasets
Project description:Mammalian DNA base excision repair (BER) is accelerated by poly(ADP-ribose) polymerases (PARPs) and the scaffold protein XRCC1. PARPs are sensors that detect single-strand break intermediates, but the critical role of XRCC1 during BER is unknown. Here, we show that protein complexes containing DNA polymerase β and DNA ligase III that are assembled by XRCC1 prevent excessive engagement and activity of PARP1 during BER. As a result, PARP1 becomes "trapped" on BER intermediates in XRCC1-deficient cells in a manner similar to that induced by PARP inhibitors, including in patient fibroblasts from XRCC1-mutated disease. This excessive PARP1 engagement and trapping renders BER intermediates inaccessible to enzymes such as DNA polymerase β and impedes their repair. Consequently, PARP1 deletion rescues BER and resistance to base damage in XRCC1-/- cells. These data reveal excessive PARP1 engagement during BER as a threat to genome integrity and identify XRCC1 as an "anti-trapper" that prevents toxic PARP1 activity.
| S-EPMC8294329 | biostudies-literature
Project description:Poly(ADP-ribose) polymerases (PARP1 and PARP2) contribute to DNA base excision repair (BER) and DNA demethylation and has been implicated in epigenetic programming in early mammalian development. Recently, proteomic analyses identified BER proteins to be covalently poly-ADP-ribosylated by PARPs. The role of this posttranslational modification in the BER process is unknown. Here, we show that PARP1 senses AP-sites and SSBs generated during TET-TDG mediated active DNA demethylation and covalently attaches PAR to each BER protein engaged. Covalent PARylation dissociates BER proteins from DNA, which accelerates completion of the repair process. Consistently, inhibition of PARylation in mESC resulted both in reduced locus specific TET-TDG-targeted DNA demethylation, and in reduced general repair of random DNA damage. Our findings establish a critical function of covalent protein PARylation in coordinating molecular processes associated with dynamic DNA methylation.
2023-11-08 | GSE166963 | GEO
Project description:Genetic defects in the repair of DNA single-strand breaks (SSBs) can result in neurological disease triggered by toxic activity of the single-strand-break sensor protein PARP1. However, the mechanism(s) by which this toxic PARP1 activity triggers cellular dysfunction are unclear. Here we show that human cells lacking XRCC1 fail to rapidly recover transcription following DNA base damage, a phenotype also observed in patient-derived fibroblasts with XRCC1 mutations and Xrcc1-/- mouse neurons. This defect is caused by excessive/aberrant PARP1 activity during DNA base excision repair, resulting from the loss of PARP1 regulation by XRCC1. We show that aberrant PARP1 activity suppresses transcriptional recovery during base excision repair by promoting excessive recruitment and activity of the ubiquitin protease USP3, which as a result reduces the level of monoubiquitinated histones important for normal transcriptional regulation. Importantly, inhibition and/or deletion of PARP1 or USP3 restores transcriptional recovery in XRCC1-/- cells, highlighting PARP1 and USP3 as possible therapeutic targets in neurological disease.
| S-EPMC8683375 | biostudies-literature
Project description:Base excision repair (BER) corrects DNA damage from oxidation, deamination and alkylation. Such base lesions cause little distortion to the DNA helix structure. BER is initiated by a DNA glycosylase that recognizes and removes the damaged base, leaving an abasic site that is further processed by short-patch repair or long-patch repair that largely uses different proteins to complete BER. At least 11 distinct mammalian DNA glycosylases are known, each recognizing a few related lesions, frequently with some overlap in specificities. Impressively, the damaged bases are rapidly identified in a vast excess of normal bases, without a supply of energy. BER protects against cancer, aging, and neurodegeneration and takes place both in nuclei and mitochondria. More recently, an important role of uracil-DNA glycosylase UNG2 in adaptive immunity was revealed. Furthermore, other DNA glycosylases may have important roles in epigenetics, thus expanding the repertoire of BER proteins.
| S-EPMC3683898 | biostudies-literature
Project description:The A-type lamins (lamin A/C), encoded by the Lmna gene, are important structural components of the nuclear lamina. Lmna mutations lead to degenerative disorders, including the premature aging disease Hutchinson-Gilford progeria syndrome (HGPS). In addition, altered lamin A/C expression is found in various cancers. Reports indicate that lamin A/C plays a role in DNA double strand break repair, but a role in DNA base excision repair (BER) has not been described. We provide evidence for reduced BER efficiency in lamin A/C-depleted cells. The mechanism involves impairment of the APE1 and POLβ enzyme activities in BER. Also, Lmna null mouse fibroblasts displayed reduced expression of several core BER enzymes (PARP1, LIG3, and POLβ). Moreover, the robustness of APE1 and POLβ activities and the rate of BER were enhanced by lamin A/C-augmented poly(ADP-ribose) polymer formation (PARylation). Finally, we report that HGPS fibroblasts are defective in BER. Collectively, our results provide novel insights into the functional interplay between the nuclear lamina and cellular defenses against oxidative DNA damage, with implications for human cancer and aging.
2019-10-02 | GSE120389 | GEO
Project description:The A-type lamins (lamin A/C), encoded by the Lmna gene, are important structural components of the nuclear lamina. Lmna mutations lead to degenerative disorders, including the premature aging disease Hutchinson-Gilford progeria syndrome (HGPS). In addition, altered lamin A/C expression is found in various cancers. Reports indicate that lamin A/C plays a role in DNA double strand break repair, but a role in DNA base excision repair (BER) has not been described. We provide evidence for reduced BER efficiency in lamin A/C-depleted cells. The mechanism involves impairment of the APE1 and POLβ enzyme activities in BER. Also, Lmna null mouse fibroblasts displayed reduced expression of several core BER enzymes (PARP1, LIG3, and POLβ). Moreover, the robustness of APE1 and POLβ activities and the rate of BER were enhanced by lamin A/C-augmented poly(ADP-ribose) polymer formation (PARylation). Finally, we report that HGPS fibroblasts are defective in BER. Collectively, our results provide novel insights into the functional interplay between the nuclear lamina and cellular defenses against oxidative DNA damage, with implications for human cancer and aging.
2020-09-30 | GSE124465 | GEO
Project description:The repair of endogenously induced DNA damage is essential to maintain genomic integrity. It has been shown that XRCC1 and PARP1 are involved in the repair of base lesions and SSBs, although the exact mode of action has yet to be determined. Here we show that XRCC1 is involved in the repair of base lesions and SSBs independent of the cell cycle. However, the rate of repair of damage requiring XRCC1 does reflect the damage complexity. The repair of induced DNA damage occurs by PARP1-dependent and PARP1-independent sub-pathways of BER. It is suggested that the repair of SSBs and purine base damage is by a sub-pathway of BER that requires both XRCC1 and PARP1. Repair of pyrimidine base damage may require XRCC1 but does not require PARP1 activity. Therefore, although BER of simple lesions occurs rapidly, pathway choice and the involvement of PARP1 are highly dependent on the types of lesion induced.
| S-EPMC4417162 | biostudies-literature
Project description:In principle, a decline in base excision repair (BER) efficiency with age should lead to genomic instability and ultimately contribute to the onset of the aging phenotype. Although multiple studies have indicated a negative link between aging and BER, the change of BER efficiency with age in humans has not been systematically analyzed. Here, with foreskin fibroblasts isolated from 19 donors between 20 and 64 y of age, we report a significant decline of BER efficiency with age using a newly developed GFP reactivation assay. We further observed a very strong negative correlation between age and the expression levels of SIRT6, a factor which is known to maintain genomic integrity by improving DNA double strand break (DSB) repair. Our mechanistic study suggests that, similar to the regulatory role that SIRT6 plays in DNA DSB repair, SIRT6 regulates BER in a PARP1-depdendent manner. Moreover, overexpression of SIRT6 rescues the decline of BER in aged fibroblasts. In summary, our results uncovered the regulatory mechanisms of BER by SIRT6, suggesting that SIRT6 reactivation in aging tissues may help delay the process of aging through improving BER.
| S-EPMC4614943 | biostudies-literature
Project description:Oxaliplatin (OXA) resistance in the treatment of different types of cancer is an important and complex problem. The culture of tumor organoids derived from gastric cancer can help us to provide a deeper understanding of the underlying mechanisms that lead to OXA resistance. In this study, our purpose was to understand the mechanisms that lead to OXA resistance, and to provide survival benefits to patients with OXA through targeted combination therapies. Using sequence analysis of OXA-resistant and non-OXA-resistant organoids, we found that PARP1 is an important gene that mediates OXA resistance. Through the patients' follow-up data, it was observed that the expression level of PARP1 was significantly correlated with OXA resistance. This was confirmed by genetic manipulation of PARP1 expression in OXA-resistant organoids used in subcutaneous tumor formation. Results further showed that PARP1 mediated OXA resistance by inhibiting the base excision repair pathway. OXA also inhibited homologous recombination by CDK1 activity and importantly made cancers with normal BRCA1 function sensitive to PARP inhibition. As a result, combination of OXA and Olaparib (PARP-1/2/3 inhibitor), inhibited in vivo and in vitro OXA resistant organoid growth and viability.
| S-EPMC8419238 | biostudies-literature
Project description:PARP1 regulates the repair of DNA single-strand breaks generated directly, or during base excision repair (BER). However, the role of PARP2 in these and other repair mechanisms is unknown. Here, we report a requirement for PARP2 in stabilising replication forks that encounter BER intermediates through Fbh1-dependent regulation of Rad51. Whereas PARP2 is dispensable for tolerance of cells to SSBs or homologous recombination dysfunction, it is redundant with PARP1 in BER. Therefore, combined disruption of PARP1 and PARP2 leads to defective BER, resulting in elevated levels of replication-associated DNA damage owing to an inability to stabilise Rad51 at damaged replication forks and prevent uncontrolled DNA resection. Together, our results demonstrate how PARP1 and PARP2 regulate two independent, but intrinsically linked aspects of DNA base damage tolerance by promoting BER directly, and by stabilising replication forks that encounter BER intermediates.
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