Chromatin ubiquitination by the ubiquitin ligase RNF168 is critical to regulate the DNA damage response (DDR). DDR deficiencies lead to cancer-prone syndromes, but whether this reflects DNA repair defects is still elusive. We identified key factors of the RNF168 pathway as essential mediators of efficient DNA replication in unperturbed S phase. We found that loss of RNF168 leads to reduced replication fork progression and to reversed fork accumulation, particularly evident at repetitive sequences stalling replication. Slow fork progression depends on MRE11-dependent degradation of reversed forks, implicating RNF168 in reversed fork protection and restart. Consistent with regular nucleosomal organization of reversed forks, the replication function of RNF168 requires H2A ubiquitination. As this novel function is shared with the key DDR players ATM, γH2A.X, RNF8, and 53BP1, we propose that double-stranded ends at reversed forks engage classical DDR factors, suggesting an alternative function of this pathway in preventing genome instability and human disease.

OBJECTIVE -The International Diabetes Federation (IDF) has recently established a worldwide consensus definition of the metabolic syndrome. No prospective data are available on the cardiovascular risk associated with this new metabolic syndrome definition. RESEARCH DESIGN AND METHODS-In a prospective study of 750 coronary patients, we recorded vascular events over 4 years.RESULTS -From our patients, 37.3% (n ϭ 280) had the metabolic syndrome according to the Adult Treatment Panel III (ATPIII) definition and 45.5% (n ϭ 341) according to the IDF definition. The metabolic syndrome as defined by the ATPIII criteria significantly predicted vascular events (adjusted hazard ratio 1.745 [95% CI 1.255-2.427]; P ϭ 0.001), but the metabolic syndrome as defined by IDF criteria did not (1.189 [0.859 -1.646]; P ϭ 0.297). Accordingly, event-free survival was significantly lower among patients who fulfilled the ATPIII but not the IDF criteria than among those who met the IDF but not the ATPIII criteria (P ϭ 0.012). The metabolic syndrome as defined by ATPIII criteria remained significantly predictive of vascular events after adjustment for type 2 diabetes but not after additional adjustment for the metabolic syndrome components high triglycerides and low HDL cholesterol. These lipid traits in turn proved significantly predictive of vascular events even after adjustment for the metabolic syndrome.CONCLUSIONS -The ATPIII definition of the metabolic syndrome confers a significantly higher risk of vascular events than the IDF definition. However, among angiographied coronary patients, even the ATPIII definition of the metabolic syndrome does not provide prognostic information beyond its dyslipidemic features. Diabetes Care 29:901-907, 2006T he term metabolic syndrome refers to a cluster of cardiovascular risk factors associated with insulin resistance (1,2). During the past decade, there have been various attempts to standardize the definition of the metabolic syndrome as a diagnostic category, with several institutions proposing various criteria (3-7).The definition of the metabolic syndrome that has most often been used in the literature was proposed by the National Cholesterol Education Program's Adult Treatment Panel III (ATPIII) 4 years ago (4). According to this definition, the metabolic syndrome is diagnosed in the presence of any three of five markers: central obesity, high triglycerides, low HDL cholesterol, high fasting glucose, and high blood pressure.Recently, the concept of the metabolic syndrome as an entity with clinical implications over and above its single constituents has been challenged (8,9). However, efforts continue to integrate the individual metabolic syndrome traits into an overall diagnosis, and the International Diabetes Federation (IDF) has now established a worldwide consensus definition of the metabolic syndrome (10,11).This new definition basically agrees with the component features of the ATPIII definition but introduces some important changes: the cutoff for a waist circumference defining central o...

It has been shown from an evaluation of the inverse reading of the dosemeter (1/M) against the inverse of the polarizing voltage (1/V), obtained with a number of commercially available ionization chambers, using dose per pulse values between 0.16 and 5 mGy, that a linear relationship between the recombination correction factor kS and dose per pulse (DPP) can be found. At dose per pulse values above 1 mGy the method of a general equation with coefficients dependent on the chamber type gives more accurate results than the Boag method. This method was already proposed by Burns and McEwen (1998, Phys. Med. Biol. 43 2033) and avoids comprehensive and time-consuming measurements of Jaffé plots which are a prerequisite for the application of the multi-voltage analysis (MVA) or the two-voltage analysis (TVA). We evaluated and verified the response of ionization chambers on the recombination effect in pulsed accelerator beams for both photons and electrons. Our main conclusions are: (1) The correction factor k(S) depends only on the DPP and the chamber type. There is no influence of radiation type and energy. (2) For all the chambers investigated there is a linear relationship between kS and DPP up to 5 mGy/pulse, and for two chambers we could show linearity up to 40 mGy/pulse. (3) A general formalism, such as that of Boag, characterizes chambers exclusively by the distance of the electrodes and gives a trend for the correction factor, and therefore (4) a general formalism has to reflect the influence of the chamber construction on the recombination by the introduction of chamber-type dependent coefficients.

DNA replication is highly regulated by the ubiquitin system, which plays key roles upon stress. The ubiquitin-like modifier ISG15 (interferon-stimulated gene 15) is induced by interferons, bacterial and viral infection, and DNA damage, but it is also constitutively expressed in many types of cancer, although its role in tumorigenesis is still largely elusive. Here, we show that ISG15 localizes at the replication forks, in complex with PCNA and the nascent DNA, where it regulates DNA synthesis. Indeed, high levels of ISG15, intrinsic or induced by interferon-β, accelerate DNA replication fork progression, resulting in extensive DNA damage and chromosomal aberrations. This effect is largely independent of ISG15 conjugation and relies on ISG15 functional interaction with the DNA helicase RECQ1, which promotes restart of stalled replication forks. Additionally, elevated ISG15 levels sensitize cells to cancer chemotherapeutic treatments. We propose that ISG15 up-regulation exposes cells to replication stress, impacting genome stability and response to genotoxic drugs.