Dataset Information

TFIP11 competes with the Bloom syndrome helicase for binding to stalled replication forks to preserve genome stability

ABSTRACT: Replication fork reversal is a key protective mechanism against replication stress in higher eukaryotic cells and occurs via a series of coordinated enzymatic reactions. The Bloom syndrome gene product, BLM, is a member of the highly conserved RecQ helicase family and has been implicated in this process, but its precise regulation and role remain poorly understood. Here, we show that, upon replication stress, the GCFC domain-containing protein TFIP11 competes with the BLM helicase for association with stalled replication forks, thereby facilitates RAD51-mediated stalled fork reversal. Consequently, loss of TFIP11 results in aberrant accumulation of BLM at stalled forks, which in turn compromises RAD51 recruitment, impairs replication stress-induced fork reversal and slowing, hypersensitizes cells to replication stress-inducing agents, and enhances chromosomal instability. These findings reveal a previously unidentified regulatory mechanism that modulates the activities of BLM and RAD51 at stalled forks and thus genome integrity.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: Junliang Chen

LAB HEAD: Ting Liu

PROVIDER: PXD042222 | Pride | 2024-05-24

REPOSITORIES: Pride

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			Action	DRS
	TFIP1_1_2023_05_14.raw	Raw
	TFIP1_1_2023_05_14.txt	Txt

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Publications

TFIP11 promotes replication fork reversal to preserve genome stability.

Chen Junliang J Wu Mingjie M Yang Yulan Y Ruan Chunyan C Luo Yi Y Song Lizhi L Wu Ting T Huang Jun J Yang Bing B Liu Ting T

Nature communications 20240210 1

Replication fork reversal, a critical protective mechanism against replication stress in higher eukaryotic cells, is orchestrated via a series of coordinated enzymatic reactions. The Bloom syndrome gene product, BLM, a member of the highly conserved RecQ helicase family, is implicated in this process, yet its precise regulation and role remain poorly understood. In this study, we demonstrate that the GCFC domain-containing protein TFIP11 forms a complex with the BLM helicase. TFIP11 exhibits a p ...[more]

PMID: 38341452

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Project description:The proteins from the Fanconi Anemia (FA) pathway of DNA repair maintain DNA replication fork integrity by preventing the unscheduled degradation of nascent DNA at regions of stalled replication forks. Here, we ask if the bacterial pathogen H. pylori exploits the fork stabilisation machinery to generate double stand breaks (DSBs) and genomic instability. Specifically, we study if the H. pylori virulence factor CagA generates host genomic DSBs through replication fork destabilisation and collapse. An inducible gastric cancer model was used to examine global CagA-dependent transcriptomic and proteomic alterations, using RNA sequencing and SILAC-based mass spectrometry, respectively. The transcriptional alterations were confirmed in gastric cancer cell lines infected with H. pylori. Functional analysis was performed using chromatin fractionation, pulsed-field gel electrophoresis (PFGE), and single molecule DNA replication/repair fiber assays. We found a core set of 31 DNA repair factors including the FA genes FANCI, FANCD2, BRCA1, and BRCA2 that were downregulated following CagA expression. H. pylori infection of gastric cancer cell lines showed downregulation of the aforementioned FA genes in a CagA-dependent manner. Consistent with FA pathway downregulation, chromatin purification studies revealed impaired levels of Rad51 but higher recruitment of the nuclease MRE11 on the chromatin of CagA-expressing cells, suggesting impaired fork protection. In line with the above data, fibre assays revealed higher fork degradation, lower fork speed, daughter strands gap accumulation, and impaired re-start of replication forks in the presence of CagA, indicating compromised genome stability. By downregulating the expression of key DNA repair genes such as FANCI, FANCD2, BRCA1, and BRCA2, H. pylori CagA compromises host replication fork stability and induces DNA DSBs through fork collapse. These data unveil an intriguing example of a bacterial virulence factor that induces genomic instability by interfering with the host replication fork stabilisation machinery.