Proteasome-mediated degradation of long-range nucleases negatively regulates resection of DNA double-strand breaks.

Homologous recombination is initiated by the nucleolytic degradation (resection) of DNA double-strand breaks (DSBs). DSB resection is a two-step process. In the short-range step, the MRX (Mre11-Rad50-Xrs2) complex, together with Sae2, incises the 5'-terminated strand at the DSB end and resects back toward the DNA end.

First Data on the (Poly)phenolic Profiling of Farmacista Honorati Persimmon Fruit ( Thunb.) at Commercial Harvest and after Treatments for Astringency Removal.

This study aims to provide the first report on the soluble and polyphenolic profiles of "Farmacista Honorati" (FH) persimmons, which is a marketed cultivar with no existing data on its nutraceutical value. Total soluble tannins (TSTs) and major soluble (poly)phenols in FH fruits before and after post-harvest commercial treatments with carbon dioxide and ethylene were analyzed. Fruits at commercial harvest had a TST content of 1022 ± 286 mg GAL/100 g d.

The multistep path to replicative senescence onset: zooming on triggering and inhibitory events at telomeric DNA.

Replicative senescence is an essential cellular process playing important physiological functions, but it is better known for its implications in aging, cancer, and other pathologies. One of the main triggers of replicative senescence is telomere shortening and/or its dysfunction and, therefore, a deep understanding of the molecular determinants is crucial. However, replicative senescence is a heterogeneous and hard to study process, especially in mammalian cells, and some important questions still need an answer.

To Fix or Not to Fix: Maintenance of Chromosome Ends Versus Repair of DNA Double-Strand Breaks.

Early work by Muller and McClintock discovered that the physical ends of linear chromosomes, named telomeres, possess an inherent ability to escape unwarranted fusions. Since then, extensive research has shown that this special feature relies on specialized proteins and structural properties that confer identity to the chromosome ends, thus allowing cells to distinguish them from intrachromosomal DNA double-strand breaks. Due to the inability of conventional DNA replication to fully replicate the chromosome ends and the downregulation of telomerase in most somatic human tissues, telomeres shorten as cells divide and lose this protective capacity.

Interplay between Sae2 and Rif2 in the regulation of Mre11-Rad50 activities at DNA ends.

DNA double-strand breaks (DSBs) can be repaired by non-homologous end-joining (NHEJ) or homologous recombination (HR). HR is initiated by nucleolytic degradation of the DSB ends in a process termed resection. The Mre11-Rad50-Xrs2/NBS1 (MRX/N) complex is a multifunctional enzyme that, aided by the Sae2/CtIP protein, promotes DSB resection and maintains the DSB ends tethered to each other to facilitate their re-ligation.

The 9-1-1 Complex Controls Mre11 Nuclease and Checkpoint Activation during Short-Range Resection of DNA Double-Strand Breaks.

Homologous recombination is initiated by nucleolytic degradation (resection) of DNA double-strand breaks (DSBs). DSB resection is a two-step process in which an initial short-range step is catalyzed by the Mre11-Rad50-Xrs2 (MRX) complex and limited to the vicinity of the DSB end. Then the two long-range resection Exo1 and Dna2-Sgs1 nucleases extend the resected DNA tracts.

DNA binding modes influence Rap1 activity in the regulation of telomere length and MRX functions at DNA ends.

The cellular response to DNA double-strand breaks (DSBs) is initiated by the Mre11-Rad50-Xrs2 (MRX) complex that has structural and catalytic functions. MRX association at DSBs is counteracted by Rif2, which is known to interact with Rap1 that binds telomeric DNA through two tandem Myb-like domains. Whether and how Rap1 acts at DSBs is unknown.

Processing of DNA Double-Strand Breaks by the MRX Complex in a Chromatin Context.

DNA double-strand breaks (DSBs) are highly cytotoxic lesions that must be repaired to ensure genomic stability and avoid cell death. The cellular response to DSBs is initiated by the evolutionarily conserved Mre11-Rad50-Xrs2/NBS1 (MRX/MRN) complex that has structural and catalytic functions. Furthermore, it is responsible for DSB signaling through the activation of the checkpoint kinase Tel1/ATM.

Mapping the allosteric network within a SH3 domain.

SH3 domains are very abundant protein-protein interactions modules, involved in the regulation of several cellular processes. Whilst they have been associated to allosteric communication pathways between contiguous domains in multi-domain proteins, there is lack of information regarding the intra-domain allosteric cross-talk within the SH3 moiety. Here we scrutinize the presence of an allosteric network in the C-terminal SH3 domain of Grb2 protein, upon binding the Grb2-associated binding 2 protein.

Protocol for a Randomised controlled trial to Evaluate the effectiveness and cost benefit of prescribing high dose FLuoride toothpaste in preventing and treating dEntal Caries in high-risk older adulTs (reflect trial).

Background: Dental caries in the expanding elderly, predominantly-dentate population is an emerging public health concern. Elderly individuals with heavily restored dentitions represent a clinical challenge and significant financial burden for healthcare systems, especially when their physical and cognitive abilities are in decline. Prescription of higher concentration fluoride toothpaste to prevent caries in older populations is expanding in the UK, significantly increasing costs for the National Health Services (NHS) but the effectiveness and cost benefit of this intervention are uncertain.

Understanding Intramolecular Crosstalk in an Intrinsically Disordered Protein.

The interaction between N and XD from the measles virus represents a paradigmatic example of molecular recognition between an intrinsically disordered protein and a folded partner. By binding to XD, a small portion of N (classically denoted as MoRE) undergoes a disorder-to-order transition, populating an α-helical structure, while the reminder of the protein remains disordered. Here, we demonstrate an unexpected crosstalk between such a disordered region and the adjacent molecular recognition element (MoRE).

Uncoupling Sae2 Functions in Downregulation of Tel1 and Rad53 Signaling Activities.

The Mre11-Rad50-Xrs2 (MRX) complex acts together with the Sae2 protein to initiate resection of DNA double-strand breaks (DSBs) and to regulate a checkpoint response that couples cell cycle progression with DSB repair. Sae2 supports resistance to DNA damage and downregulates the signaling activities of MRX, Tel1, and Rad53 checkpoint proteins at the sites of damage. How these functions are connected to each other is not known.

The psychological and physiological health effects of fatigue.

Background: The issue of employee fatigue is becoming increasingly prominent, particularly in safety-critical industries.

Aims: To produce an in-depth review collating the known psychological and physiological health and work effects of fatigue to guide mitigation strategies in safety-critical industries.

Methods: Literature searches were conducted via scientific databases using appropriate filters and keywords.

Exploring the feasibility of general health promotion in UK dental primary care: ENGAGE in Scotland.

Introduction Despite UK dental guidance recommending opportunistic health promotion, it's rare for GDPs to discuss more than oral hygiene with their patients. The ENGAGE intervention incorporates UK guidance and evidence-based behaviour change techniques to motivate patients to make lifestyle changes (reduce smoking, alcohol consumption and/or improve diet). It was designed to take less than five minutes and be delivered during a routine dental check-up, and includes a take-home patient handout signposting to free NHS lifestyle counselling helpline services.

Processing of DNA Ends in the Maintenance of Genome Stability.

DNA double-strand breaks (DSBs) are particularly hazardous lesions as their inappropriate repair can result in chromosome rearrangements, an important driving force of tumorigenesis. DSBs can be repaired by end joining mechanisms or by homologous recombination (HR). HR requires the action of several nucleases that preferentially remove the 5'-terminated strands at both DSB ends in a process called DNA end resection.

A Carboxylate to Amide Substitution That Switches Protein Folds.

Metamorphic proteins are biomolecules prone to adopting alternative conformations. Because of this feature, they represent ideal systems to investigate the general rules allowing primary structure to dictate protein topology. A comparative molecular dynamics study was performed on the denatured states of two proteins, sharing nearly identical amino-acid sequences (88 %) but different topologies, namely an all-α-helical bundle protein named G 88 and an α+β-protein named G 88.

Folding Mechanism of the SH3 Domain from Grb2.

SH3 domains are small protein modules involved in the regulation of important cellular pathways. These domains mediate protein-protein interactions recognizing motifs rich in proline on the target protein. The SH3 domain from Grb2 (Grb2-SH3) presents the typical structure of an SH3 domain composed of two three-stranded antiparallel β-sheets orthogonally packed onto each other, to form a single hydrophobic core.

INTERVAL (investigation of NICE technologies for enabling risk-variable-adjusted-length) dental recalls trial: a multicentre randomised controlled trial investigating the best dental recall interval for optimum, cost-effective maintenance of oral health in dentate adults attending dental primary care.

Background: Traditionally, patients at low risk and high risk of developing dental disease have been encouraged to attend dental recall appointments at regular intervals of six months between appointments. The lack of evidence for the effect that different recall intervals between dental check-ups have on patient outcomes, provider workload and healthcare costs is causing considerable uncertainty for the profession and patients, despite the publication of the NICE Guideline on dental recall. The need for primary research has been highlighted in the Health Technology Assessment Group's systematic review of routine dental check-ups, which found little evidence to support or refute the practice of encouraging 6-monthly dental check-ups in adults.

The effect of introducing a financial incentive to promote application of fluoride varnish in dental practice in Scotland: a natural experiment.

Background: Financial incentives are often used to influence professional practice, yet the factors which influence their effectiveness and their behavioural mechanisms are not fully understood. In keeping with clinical guidelines, Childsmile (Scotland's oral health improvement programme) advocates twice yearly fluoride varnish application (FVA) for children in dental practice. To support implementation Childsmile offered dental practitioners a fee-per-item payment for varnishing 2-5-year-olds' teeth through a pilot.

Improving the Quality of Dentistry (IQuaD): a cluster factorial randomised controlled trial comparing the effectiveness and cost-benefit of oral hygiene advice and/or periodontal instrumentation with routine care for the prevention and management of periodontal disease in dentate adults attending dental primary care.

Background: Periodontal disease is preventable but remains the most common oral disease worldwide, with major health and economic implications. Stakeholders lack reliable evidence of the relative clinical effectiveness and cost-effectiveness of different types of oral hygiene advice (OHA) and the optimal frequency of periodontal instrumentation (PI).

Objectives: To test clinical effectiveness and assess the economic value of the following strategies: personalised OHA versus routine OHA, 12-monthly PI (scale and polish) compared with 6-monthly PI, and no PI compared with 6-monthly PI.

[Risk assessment and its appropriateness supporting the physician in the certification of a suspected occupational disease.].

Objectives: The topic of appropriateness was defined as the new frontier of development of health interventions. RH Brook in an Editorial published in the BMJ in 1994 defines the appropriateness "… an intervention for which the expected benefits are greater (with a sufficient margin) the possible negative consequences … excluding economic considerations". In workplaces the goal of appropriateness should cover not only the actions of health surveillance and health protocols, but also and primarily all stages of the risk assessment process.

How Robust Is the Mechanism of Folding-Upon-Binding for an Intrinsically Disordered Protein?

The mechanism of interaction of an intrinsically disordered protein (IDP) with its physiological partner is characterized by a disorder-to-order transition in which a recognition and a binding step take place. Even if the mechanism is quite complex, IDPs tend to bind their partner in a cooperative manner such that it is generally possible to detect experimentally only the disordered unbound state and the structured complex. The interaction between the disordered C-terminal domain of the measles virus nucleoprotein (N) and the X domain (XD) of the viral phosphoprotein allows us to detect and quantify the two distinct steps of the overall reaction.

β-catenin knockdown promotes NHERF1-mediated survival of colorectal cancer cells: implications for a double-targeted therapy.

Nuclear activated β-catenin plays a causative role in colorectal cancers (CRC) but remains an elusive therapeutic target. Using human CRC cells harboring different Wnt/β-catenin pathway mutations in APC/KRAS or β-catenin/KRAS genes, and both genetic and pharmacological knockdown approaches, we show that oncogenic β-catenin signaling negatively regulates the expression of NHERF1 (Na/H exchanger 3 regulating factor 1), a PDZ-adaptor protein that is usually lost or downregulated in early dysplastic adenomas to exacerbate nuclear β-catenin activity. Chromatin immunoprecipitation (ChIP) assays demonstrated that β-catenin represses NHERF1 via TCF4 directly, while the association between TCF1 and the Nherf1 promoter increased upon β-catenin knockdown.