Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA403795 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR6019600_1.fastq.gz | Fastqsanger.gz | |||
| SRR6019600_2.fastq.gz | Fastqsanger.gz | |||
| SRR6019610_1.fastq.gz | Fastqsanger.gz | |||
| SRR6019610_2.fastq.gz | Fastqsanger.gz | |||
| SRR6019620_1.fastq.gz | Fastqsanger.gz |
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Project description:Small ~10 kb microhomology-mediated tandem duplications (“Group 1 TDs”) are abundant in BRCA1-linked but not BRCA2-linked breast cancer genomes. Here, we define the mechanism underlying this rearrangement signature. We show that BRCA1, but not BRCA2, suppresses TDs at a Tus/Ter site-specific chromosomal replication fork barrier in primary mammalian cells. BRCA1 has no equivalent role at chromosomal double strand breaks, indicating specificity for the stalled fork response. Two motor proteins—FANCM and the Bloom’s syndrome helicase—suppress Tus/Ter-induced TDs in BRCA1 mutants, revealing the existence of a multi-gene TD suppressor network. TDs arise by a “replication restart-bypass” mechanism terminated by end joining or microhomology-mediated template switching, the latter forming complex TD breakpoints. We show that solitary DNA ends form directly at Tus/Ter, implicating misrepair of these lesions in TD formation. We find that BRCA1 inactivation is strongly associated with Group 1 TDs in ovarian cancer. The Group 1 TD phenotype may be a general signature of BRCA1-deficient cancer
2017-11-23 | GSE103624 | GEO
Project description:The accurate processing of stalled forks by the DNA2 nuclease is pivotal for replication fork restart, as excessive degradation poses a threat to genomic stability. However, the regulation of DNA2 activity at stalled forks remains elusive. Here, we demonstrate that, upon replication stress, RNA polymerase II (RNAPII) is recruited to stalled forks, actively promoting the transient formation of RNA-DNA hybrids. Furthermore, we provide evidence that DDX39A, functioning as an RNA-DNA resolver, unwinds these hybrids, allowing DNA2 access to stalled forks. This orchestrated process facilitates controlled DNA2-dependent stalled fork processing and restart. Nevertheless, premature removal of RNA-DNA hybrids at stalled forks leads to DNA2-dependent excessive degradation of nascent DNA. Finally, we reveal that loss of DDX39A enhances the protection of stalled forks in BRCA1/2-deficient cells, consequently conferring chemoresistance within this specific cellular context. Our results suggest that the dynamic regulation of RNA-DNA hybrid formation at stalled forks by RNAPII and DDX39A precisely governs the timing of DNA2 activation, contributing to stalled fork processing and restart, ultimately promoting genome stability.
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Project description:The accurate processing of stalled forks by the DNA2 nuclease is pivotal for replication fork restart, as excessive degradation poses a threat to genomic stability. However, the regulation of DNA2 activity at stalled forks remains elusive. Here, we demonstrate that, upon replication stress, RNA polymerase II (RNAPII) is recruited to stalled forks, actively promoting the transient formation of RNA-DNA hybrids. Furthermore, we provide evidence that DDX39A, functioning as an RNA-DNA resolver, unwinds these hybrids, allowing DNA2 access to stalled forks. This orchestrated process facilitates controlled DNA2-dependent stalled fork processing and restart. Nevertheless, premature removal of RNA-DNA hybrids at stalled forks leads to DNA2-dependent excessive degradation of nascent DNA. Finally, we reveal that loss of DDX39A enhances the protection of stalled forks in BRCA1/2-deficient cells, consequently conferring chemoresistance within this specific cellular context. Our results suggest that the dynamic regulation of RNA-DNA hybrid formation at stalled forks by RNAPII and DDX39A precisely governs the timing of DNA2 activation, contributing to stalled fork processing and restart, ultimately promoting genome stability.
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