Proliferating cell nuclear antigen (PCNA) is a homo-trimeric clamp complex that serves as the molecular hub for various DNA transactions, including DNA synthesis and post-replicative mismatch repair. Its timely loading and unloading are critical for genome stability. PCNA loading is catalyzed by Replication factor C (RFC) and the Ctf18 RFC-like complex (Ctf18-RLC), and its unloading is catalyzed by Atad5/Elg1-RLC.
View Article and Find Full Text PDFAdv Health Sci Educ Theory Pract
September 2024
Research has demonstrated erosion of empathy in students during medical education. Particularly, U.S.
View Article and Find Full Text PDF: It has been known for many years that in metazoan cells, replication origins are organised into clusters where origins within each cluster fire near-synchronously. Despite clusters being a fundamental organising principle of metazoan DNA replication, the genomic location of origin clusters has not been documented. : We synchronised human U2OS by thymidine block and release followed by L-mimosine block and release to create a population of cells progressing into S phase with a high degree of synchrony.
View Article and Find Full Text PDFBackground: Removal of a well-fixed uncemented femoral component in revision hip arthroplasty is challenging. A modular head-neck adapter provides an option to optimise the femoral offset and anteversion, avoiding the need for femoral stem revision.
Aim: To present the clinical results following revision arthroplasty with the Bioball head-neck adapter in the elderly American Society of Anaesthesiologists (ASA) Grade II, III & IV patients.
Background: TFMT stems are modular porous coated stems widely used in revision hip arthroplasty. Although TFMT stems are popular due to its proven advantage in the setting of severe bone deficiency, subsidence is a concern in these stem designs. We used two TFMT stems between 2013 and 2019, ARCOS(Zimmer Biomet) and Reclaim(Depuy Synthes).
View Article and Find Full Text PDFThe maintenance of genomic stability during the mitotic cell-cycle not only demands that the DNA is duplicated and repaired with high fidelity, but that following DNA replication the chromatin composition is perpetuated and that the duplicated chromatids remain tethered until their anaphase segregation. The coordination of these processes during S phase is achieved by both cyclin-dependent kinase, CDK, and Dbf4-dependent kinase, DDK. CDK orchestrates the activation of DDK at the G1-to-S transition, acting as the 'global' regulator of S phase and cell-cycle progression, whilst 'local' control of the initiation of DNA replication and repair and their coordination with the re-formation of local chromatin environments and the establishment of chromatid cohesion are delegated to DDK.
View Article and Find Full Text PDFHealthy eating and physical activity (PA) necessitate interventions designed to increase these behaviors. Self-Determination Theory (SDT) posits addressing psychological needs to promote intrinsic motivation, while the Transtheoretical Model (TTM) posits progression through stages of change consistent with contemplating processes of change. Previous findings suggest the efficacy of combining these approaches to understand, initiate, and maintain behavior.
View Article and Find Full Text PDFTreslin/Ticrr is required for the initiation of DNA replication and binds to MTBP (Mdm2 Binding Protein). Here, we show that in egg extract, MTBP forms an elongated tetramer with Treslin containing two molecules of each protein. Immunodepletion and add-back experiments show that Treslin-MTBP is rate limiting for replication initiation.
View Article and Find Full Text PDFSmall-molecule-induced protein depletion technologies, also called inducible degrons, allow degradation of genetically engineered target proteins within cells and animals. Here, we design and develop the BromoTag, a new inducible degron system comprising a Brd4 bromodomain L387A variant as a degron tag that allows direct recruitment by heterobifunctional bumped proteolysis targeting chimeras (PROTACs) to hijack the VHL E3 ligase. We describe extensive optimization and structure-activity relationships of our bump-and-hole-PROTACs using a CRISPR knock-in cell line expressing model target BromoTag-Brd2 at endogenous levels.
View Article and Find Full Text PDFObjectives: The socioeconomic disparity in childhood and early adult obesity prevalence has been well characterised. Takeaway outlets may cluster in lower socioeconomic areas and their proximity to schools is of concern. This study aimed to map takeaway food outlets, characterise takeaway types and their proximity to educational institutions within a low socioeconomic ward in Manchester.
View Article and Find Full Text PDFThe full licensing of replication origins in late G1 is normally enforced by the licensing checkpoint. In this issue, Matson et al. (2019.
View Article and Find Full Text PDFObjectives: Takeaway foods form a growing proportion of the UK diet. This consumption is linked with poor health outcomes due to their adverse nutritional profile. However, there is little research regarding the sociocultural context surrounding the consumption of takeaway meals.
View Article and Find Full Text PDFThe decompaction and re-establishment of chromatin organization immediately after mitosis is essential for genome regulation. Mechanisms underlying chromatin structure control in daughter cells are not fully understood. Here we show that a chromatin compaction threshold in cells exiting mitosis ensures genome integrity by limiting replication licensing in G1 phase.
View Article and Find Full Text PDFTheoretically-based correlates of weight and waist circumference in an overweight/obese Hispanic sample were assessed. Two-hundred thirty-one participants completed questionnaires assessing constructs from self-determination theory and the transtheoretical model. Height, weight, and waist circumference were also measured.
View Article and Find Full Text PDFDuring late mitosis and the early G phase, the origins of replication are licensed by binding to double hexamers of MCM2-7. In this study, we investigated how licensing and proliferative commitment are coupled in the epithelium of the small intestine. We developed a method for identifying cells in intact tissue containing DNA-bound MCM2-7.
View Article and Find Full Text PDFMutations in PINK1, which impair its catalytic kinase activity, are causal for autosomal recessive early-onset Parkinson's disease (PD). Various studies have indicated that the activation of PINK1 could be a useful strategy in treating neurodegenerative diseases, such as PD. Herein, it is shown that the anthelmintic drug niclosamide and its analogues are capable of activating PINK1 in cells through the reversible impairment of the mitochondrial membrane potential.
View Article and Find Full Text PDFIn late mitosis and G, origins of DNA replication must be "licensed" for use in the upcoming S phase by being encircled by double hexamers of the minichromosome maintenance proteins MCM2-7. A "licensing checkpoint" delays cells in G until sufficient origins have been licensed, but this checkpoint is lost in cancer cells. Inhibition of licensing can therefore kill cancer cells while only delaying normal cells in G.
View Article and Find Full Text PDFDbf4-dependent kinases (DDKs) are required for the initiation of DNA replication, their essential targets being the MCM2-7 proteins. We show that, in Xenopus laevis egg extracts and human cells, hyper-phosphorylation of DNA-bound Mcm4, but not phosphorylation of Mcm2, correlates with DNA replication. These phosphorylations are differentially affected by the DDK inhibitors PHA-767491 and XL413.
View Article and Find Full Text PDFHere we discuss the important contributions that cell-free extracts have made to the study of complex biological processes. We provide a brief history of how cell-free extracts of frog eggs were developed to avoid many of the problems that can arise from the dilution and mixing of cellular components that typically occur when cell-free extracts are prepared. We briefly describe how Xenopus egg extracts have been fundamental to the study of many important cellular processes including DNA replication, cell cycle progression, nuclear protein import, nuclear assembly and chromosome organisation.
View Article and Find Full Text PDFThe replication of DNA is initiated at particular sites on the genome called replication origins (ROs). Understanding the constraints that regulate the distribution of ROs across different organisms is fundamental for quantifying the degree of replication errors and their downstream consequences. Using a simple probabilistic model, we generate a set of predictions on the extreme sensitivity of error rates to the distribution of ROs, and how this distribution must therefore be tuned for genomes of vastly different sizes.
View Article and Find Full Text PDFTo prevent rereplication of genomic segments, the eukaryotic cell cycle is divided into two nonoverlapping phases. During late mitosis and G1 replication origins are "licensed" by loading MCM2-7 double hexamers and during S phase licensed replication origins activate to initiate bidirectional replication forks. Replication forks can stall irreversibly, and if two converging forks stall with no intervening licensed origin-a "double fork stall" (DFS)-replication cannot be completed by conventional means.
View Article and Find Full Text PDFDuring S phase, following activation of the S phase CDKs and the DBF4-dependent kinases (DDK), double hexamers of Mcm2-7 at licensed replication origins are activated to form the core replicative helicase. Mcm10 is one of several proteins that have been implicated from work in yeasts to play a role in forming a mature replisome during the initiation process. Mcm10 has also been proposed to play a role in promoting replisome stability after initiation has taken place.
View Article and Find Full Text PDFThe cyclin-dependent kinase inhibitor p21(WAF1/CIP1) (p21) is a cell-cycle checkpoint effector and inducer of senescence, regulated by p53. Yet, evidence suggests that p21 could also be oncogenic, through a mechanism that has so far remained obscure. We report that a subset of atypical cancerous cells strongly expressing p21 showed proliferation features.
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