Publications by authors named "Ray-Chaudhuri A"

Neonatal sepsis causes substantial morbidity and mortality, the burden of which is carried by low-income countries (LICs). The emergence of multidrug-resistant pathogens in vulnerable neonatal populations poses an urgent threat to infant survival. spp.

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Laboratory automation and quantitative high-content imaging are pivotal in advancing diverse scientific fields. These innovative techniques alleviate the burden of manual labour, facilitating large-scale experiments characterized by exceptional reproducibility. Nonetheless, the seamless integration of such systems continues to pose a constant challenge in many laboratories.

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Targeting poly(ADP-ribose) glycohydrolase (PARG) is currently explored as a therapeutic approach to treat various cancer types, but we have a poor understanding of the specific genetic vulnerabilities that would make cancer cells susceptible to such a tailored therapy. Moreover, the identification of such vulnerabilities is of interest for targeting BRCA2;p53-deficient tumors that have acquired resistance to poly(ADP-ribose) polymerase inhibitors (PARPi) through loss of PARG expression. Here, by performing whole-genome CRISPR/Cas9 drop-out screens, we identify various genes involved in DNA repair to be essential for the survival of PARG;BRCA2;p53-deficient cells.

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Article Synopsis
  • DNA combing and DNA spreading are techniques used to study DNA replication fork dynamics at a single-molecule level by arranging labeled DNA on slides for analysis.
  • The study aims to determine if these methods can effectively resolve adjacent sister chromatids during DNA replication, which is crucial for observing how replication dynamics vary between individual strands.
  • Results indicate that DNA combing can differentiate sister chromatids and identify strand-specific changes, while DNA spreading does not provide this level of detail, impacting how replication dynamics are interpreted.
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DNA combing and DNA spreading are two central approaches for studying DNA replication fork dynamics genome-wide at single-molecule resolution by distributing labeled genomic DNA on coverslips or slides for immunodetection. Perturbations in DNA replication fork dynamics can differentially affect either leading or lagging strand synthesis, for example in instances where replication is blocked by a lesion or obstacle on only one of the two strands. Thus, we sought to investigate whether the DNA combing and/or spreading approaches are suitable for resolving adjacent sister chromatids during DNA replication, thereby enabling the detection of DNA replication dynamics within individual nascent strands.

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The Dahl Concept describes the re-establishment of occlusal contacts after the provision of a planned localised appliance or restoration in supraocclusion. Initially developed to create space for prosthetic rehabilitation of anterior teeth suffering from localised wear, the principle has later been successfully applied to a variety of situations, including the Hall technique and resin-bonded bridges cemented in supraocclusion. Despite high levels of success seen in the relevant literature and widespread adoption in specialist care, the wider profession appears to be far more cautious in its use.

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Sister chromatid exchanges (SCEs) are products of joint DNA molecule resolution, and are considered to form through homologous recombination (HR). Indeed, SCE induction upon irradiation requires the canonical HR factors BRCA1, BRCA2 and RAD51. In contrast, replication-blocking agents, including PARP inhibitors, induce SCEs independently of BRCA1, BRCA2 and RAD51.

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Inhibitors of poly(ADP-ribose) (PAR) polymerase (PARPi) have entered the clinic for the treatment of homologous recombination (HR)-deficient cancers. Despite the success of this approach, preclinical and clinical research with PARPi has revealed multiple resistance mechanisms, highlighting the need for identification of novel functional biomarkers and combination treatment strategies. Functional genetic screens performed in cells and organoids that acquired resistance to PARPi by loss of 53BP1 identified loss of LIG3 as an enhancer of PARPi toxicity in BRCA1-deficient cells.

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Article Synopsis
  • The tumor suppressor gene plays a crucial role in DNA repair and interacts with other genes like BRCA2 and PALB2, which are important for preventing breast cancer.
  • A specific variant of the BRCA1 gene, p.L1363P, disrupts its interaction with PALB2 and causes embryonic lethality in animal models.
  • This variant results in a different type of mammary tumor that is still responsive to certain cancer treatments, highlighting its significance in breast cancer risk and therapy.
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Correct transcription is crucial for life. However, DNA damage severely impedes elongating RNA polymerase II, causing transcription inhibition and transcription-replication conflicts. Cells are equipped with intricate mechanisms to counteract the severe consequence of these transcription-blocking lesions.

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Background: Gingival tissue enlargement is a common side effect of antiepileptic medications (e.g. phenytoin and sodium valproate), immunosuppressing drugs (e.

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Homologous recombination (HR) and Fanconi Anemia (FA) pathway proteins in addition to their DNA repair functions, limit nuclease-mediated processing of stalled replication forks. However, the mechanism by which replication fork degradation results in genome instability is poorly understood. Here, we identify RIF1, a non-homologous end joining (NHEJ) factor, to be enriched at stalled replication forks.

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BRCA1 functions at two distinct steps during homologous recombination (HR). Initially, it promotes DNA end resection, and subsequently it recruits the PALB2 and BRCA2 mediator complex, which stabilizes RAD51-DNA nucleoprotein filaments. Loss of 53BP1 rescues the HR defect in BRCA1-deficient cells by increasing resection, suggesting that BRCA1's downstream role in RAD51 loading is dispensable when 53BP1 is absent.

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Besides its role in homologous recombination, the tumor suppressor BRCA2 protects stalled replication forks from nucleolytic degradation. Defective fork stability contributes to chemotherapeutic sensitivity of BRCA2-defective tumors by yet-elusive mechanisms. Using DNA fiber spreading and direct visualization of replication intermediates, we report that reversed replication forks are entry points for fork degradation in BRCA2-defective cells.

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Homologous recombination (HR) and the Fanconi Anemia (FA) pathways constitute essential repair pathways for DNA damage, which includes DNA double‐stranded breaks (DSB) and inter‐strand cross‐links (ICL), respectively. Germline mutations affecting a single copy of the HR factors BRCA1 and BRCA2 predispose individuals to cancers of the breast, ovary, prostate, and pancreas. Cells deficient for BRCA proteins display high levels of genome instability due to defective repair of endogenous DSBs and are also exquisitely sensitive to DNA‐damaging agents.

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Cells are exposed to various endogenous and exogenous insults that induce DNA damage, which, if unrepaired, impairs genome integrity and leads to the development of various diseases, including cancer. Recent evidence has implicated poly(ADP-ribose) polymerase 1 (PARP1) in various DNA repair pathways and in the maintenance of genomic stability. The inhibition of PARP1 is therefore being exploited clinically for the treatment of various cancers, which include DNA repair-deficient ovarian, breast and prostate cancers.

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Poly (ADP-ribose) polymerase (PARP) inhibitor (PARPi) olaparib has been approved for treatment of advanced ovarian cancer associated with BRCA1 and BRCA2 mutations. BRCA1- and BRCA2-mutated cells, which are homologous recombination (HR) deficient, are hypersensitive to PARPi through the mechanism of synthetic lethality. Here we examine the effect of PARPi on HR-proficient cells.

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Cells deficient in the Brca1 and Brca2 genes have reduced capacity to repair DNA double-strand breaks by homologous recombination and consequently are hypersensitive to DNA-damaging agents, including cisplatin and poly(ADP-ribose) polymerase (PARP) inhibitors. Here we show that loss of the MLL3/4 complex protein, PTIP, protects Brca1/2-deficient cells from DNA damage and rescues the lethality of Brca2-deficient embryonic stem cells. However, PTIP deficiency does not restore homologous recombination activity at double-strand breaks.

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The diagnosis and appropriate management of temporo-mandibular disorders (TMDs) remains controversial. Current scientific evidence highlights the importance of psychosocial factors in sufferers and the reducing emphasis on occlusal or dental/prosthetic factors. This paper describes the findings of a survey of 211 patients reporting pain from their temporo-mandibular joint area and associated structures.

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Poly(ADP-ribosyl)ation (PAR) has been implicated in various aspects of the cellular response to DNA damage and genome stability. Although 17 human poly(ADP-ribose) polymerase (PARP) genes have been identified, a single poly(ADP-ribosyl) glycohydrolase (PARG) mediates PAR degradation. Here we investigated the role of PARG in the replication of human chromosomes.

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Unlabelled: Dental plaque-induced periodontal diseases are common in children and adults. Guidelines were previously not available for the periodontal screening of under 18s. However, new guidelines have been introduced by the British Society of Periodontology and the British Society of Paediatric Dentistry which set out recommendations for the periodontal screening and management of under 18s in primary dental care.

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