RNF8 ubiquitylation of XRN2 facilitates R-loop resolution and restrains genomic instability in BRCA1 mutant cells
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ABSTRACT:
PROVIDER: PRJNA837125 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR19166100_1.fastq.gz | Fastqsanger.gz | |||
| SRR19166100_2.fastq.gz | Fastqsanger.gz | |||
| SRR19166101_1.fastq.gz | Fastqsanger.gz | |||
| SRR19166101_2.fastq.gz | Fastqsanger.gz | |||
| SRR19166102_1.fastq.gz | Fastqsanger.gz |
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Project description:Breast cancer linked with BRCA1/2 mutations commonly recur and resist current therapies, including PARP inhibitors. Given the lack of effective targeted therapies for BRCA1-mutant cancers, we sought to identify novel targets to selectively kill these cancers. Here, we report that loss of RNF8 significantly protects Brca1-mutant mice against mammary tumorigenesis. RNF8 deficiency in human BRCA1-mutant breast cancer cells was found to promote R-loop accumulation and replication fork instability, leading to increased DNA damage, senescence, and synthetic lethality. Mechanistically, RNF8 interacts with XRN2, which is crucial for transcription termination and R-loop resolution. We report that RNF8 ubiquitylates XRN2 to facilitate its recruitment to R-loop-prone genomic loci and that RNF8 deficiency in BRCA1-mutant breast cancer cells decreases XRN2 occupancy at R-loop-prone sites, thereby promoting R-loop accumulation, transcription-replication collisions, excessive genomic instability, and cancer cell death. Collectively, our work identifies a synthetic lethal interaction between RNF8 and BRCA1, which is mediated by a pathological accumulation of R-loops.
2023-09-14 | GSE202723 | GEO
Project description:Breast cancer linked with BRCA1/2 mutations commonly recur and resist current therapies, including PARP inhibitors. Given the lack of effective targeted therapies for BRCA1-mutant cancers, we sought to identify novel targets to selectively kill these cancers. Here, we report that loss of RNF8 significantly protects Brca1-mutant mice against mammary tumorigenesis. RNF8 deficiency in human BRCA1-mutant breast cancer cells was found to promote R-loop accumulation and replication fork instability, leading to increased DNA damage, senescence, and synthetic lethality. Mechanistically, RNF8 interacts with XRN2, which is crucial for transcription termination and R-loop resolution. We report that RNF8 ubiquitylates XRN2 to facilitate its recruitment to R-loop-prone genomic loci and that RNF8 deficiency in BRCA1-mutant breast cancer cells decreases XRN2 occupancy at R-loop-prone sites, thereby promoting R-loop accumulation, transcription-replication collisions, excessive genomic instability, and cancer cell death. Collectively, our work identifies a synthetic lethal interaction between RNF8 and BRCA1, which is mediated by a pathological accumulation of R-loops.
| S-EPMC10602868 | biostudies-literature
Project description:BRCA1/BARD1 is a tumor suppressor E3 ubiquitin (Ub) ligase with roles in DNA damage repair and in transcriptional regulation. BRCA1/BARD1 RING domains interact with nucleosomes to facilitate mono-ubiquitylation of distinct residues on the C-terminal tail of histone H2A. These enzymatic domains constitute a small fraction of the heterodimer, raising the possibility of functional chromatin interactions involving other regions such as the BARD1 C-terminal domains that bind nucleosomes containing the DNA damage signal H2A K15-Ub and H4 K20me0, or portions of the expansive intrinsically disordered regions found in both subunits. Herein, we reveal novel interactions that support robust H2A ubiquitylation activity mediated through a high-affinity, intrinsically disordered DNA-binding region of BARD1. These interactions support BRCA1/BARD1 recruitment to chromatin and sites of DNA damage in cells and contribute to their survival. We also reveal distinct BRCA1/BARD1 complexes that depend on the presence of H2A K15-Ub, including a complex where a single BARD1 subunit spans adjacent nucleosome units. Our findings identify an extensive network of multivalent BARD1-nucleosome interactions that serve as a platform for BRCA1/BARD1-associated functions on chromatin.
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Project description:Analyzing XRN2-mediated transcriptome changes of glioblastoma multiforme cell lines
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Project description:Brca1 mutation predisposes women to early onset of breast and ovarian cancers.Through its diverse functions in DNA damage repair, cell cycle control, transcription regulation, ubiquitination and so on, BRCA1 acts as a very significant tumor suppressor and genomic safeguard. Brca1 deficiency induces severe cellular stress, when occurring in the mammary glands, it impairs the regular developmental process and eventually causes tumorigenesis due to accumulation of genome instability and other mechanisms. The Brca1-defiencient mouse mammary tumor were characterized with great tumoral heterogeneity, which is in line with the human breast cancers carrying BRCA1 mutations. Here we studied the molecular complexicity of Brca1-deficient mouse mammary tumors vie RNA sequencing.
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Project description:LARP7 is a substrate of BRCA1 that regulats genome instability and tumorigenesis
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Project description:The tumor suppressor BRCA1 regulates DNA damage responses and multiple other processes. Among these, BRCA1 heterodimerizes with BARD1 to ubiquitylate targets via its N-terminal RING domain. Here we show that BRCA1 promotes oxidative metabolism via degradation of Oct1, a transcription factor with pro-glycolytic/tumorigenic effects. BRCA1 E3 ubiquitin ligase mutation skews cells towards a glycolytic metabolic profile while elevating Oct1 protein. CRISPR-mediated Oct1 deletion reverts the glycolytic phenotype. RNAseq confirms the deregulation of metabolic genes. BRCA1 mediates direct Oct1 ubiquitylation and degradation, and mutation of two ubiquitylated Oct1 lysines insulates the protein against BRCA1-mediated destabilization. Oct1 deletion in MCF-7 breast cancer cells does not perturb growth in standard culture, but inhibits growth in soft agar and xenografts. Oct1 protein levels correlate positively with tumor aggressiveness, and inversely with BRCA1, in primary breast cancer samples. These results identify BRCA1 as an Oct1 ubiquitin ligase that catalyzes Oct1 degradation to promote oxidative metabolism.
2017-11-30 | GSE98831 | GEO
Project description:We analysed the effect of depriving the human cell of the catalytic activity of the nuclear 5’ to 3’ exoribonuclease XRN2. Catalytic amino acids in this protein had been defined previously, so it was possible to design a mutated catalytically inactive form of the protein (XRN2D233A-D235A) (PMID: 19194460). We created 293 Flp-In T-REx stable cell lines that induciby silence endogenous XRN2, and concomitantly express wild-type or inactive XRN2 in fusion with EGFP at the C-terminus. Thus, complementation of silencing of endogenous XRN2 with the expression of mutant version of the protein allows to directly link potential phenotypes with the lack of XRN2 enzymatic activity. To this end we isolated total RNA from tetracycline-treated cells, depleted it from rRNA and conducted strand-specific deep sequencing.
2018-04-17 | GSE99421 | GEO
Project description:XRN2 is a conserved 5â??-->3â?? exoribonuclease that complexes with XTB-domain containing proteins. Thus, in Caenorhabditis elegans (C. elegans), the XTBD-protein PAXT-1 stabilizes XRN2 to retain its activity. XRN2 activity is also promoted by 3'(2'),5'-bisphosphate nucleotidase 1 (BPNT1) through its hydrolysis of 3â??-phosphoadenosine-5'-bisphosphate (PAP), an endogenous XRN inhibitor. Here, we find through unbiased screening that loss of bpnt-1 function suppresses lethality caused by paxt-1 deletion. This unexpected finding is explained by XRN2 autoregulation, which occurs through repression of a cryptic promoter activity and destabilization of the xrn-2 transcript. Autoregulation appears to be triggered at different thresholds of XRN2 inactivation, such that more robust XRN2 perturbation, by elimination of both PAXT-1 and BPNT1, is less detrimental to worm viability than absence of PAXT-1 alone. Like more than 15% of C. elegans genes, xrn-2 occurs in an operon, and we identify additional operons under its control, consistent with a broader function of XRN2 in polycistronic gene regulation. Regulation occurs through intercistronic regions that link genes in an operon, but similar mechanisms may allow XRN2 to operate on monocistronic genes in organisms lacking operons. Wild-type C. elegans worms were subjected to mock or xrn-2 RNAi from L1 to L4 stage at 20°C. Total RNA was extracted from the worms, and polyadenylated RNA was analyzed.
2016-08-25 | E-GEOD-79994 | biostudies-arrayexpress