Regulation of blocked-DSB repair by DNA-PKcs and ATM kinases

Dada la amenaza que suponen las roturas del ADN de doble cadena para la integridad del genoma, conocer los mecanismos moleculares implicados de su reparación es extremadamente relevante. En particular, las estructuras de los extremos que presentan las roturas de doble cadena definen su complejidad y son consideradas posibles determinantes de la elección de la ruta por las que van a ser reparadas y del resultado de dicha reparación. Sin embargo, esta cuestión no ha sido suficientemente esclarecida debido a la dificultad de inducir roturas homogéneas con extremos que presenten estructuras definidas. Gracias al reciente desarrollo de un método genético para inducir roturas con extremos homogéneos, hemos diseccionado las rutas requeridas para reparar las roturas de doble cadena inducidas por la Topoisomerasa 2 cuando los extremos se encuentran específicamente limpios o bloqueados en G0/G1. Para ello, hemos caracterizado la implicación de factores identificados en escrutinios genéticos realizados con la técnica CRISPR/Cas9 y otros candidatos relacionados con los factores previamente identificados. De esta manera, hemos identificado que existe una preferencia para reparar las roturas producidas por la Topoisomerasa 2 a través de la actividad de TDP2 en vez del procesamiento llevado a cabo por las nucleasas, que sólo son necesarias cuando los extremos están bloqueados de una forma irreversible. Esta jerarquía contribuye a asegurar la estabilidad del genoma y no se mantiene en ausencia de DNA-PKcs. También demostramos que la función de ATM en la reparación de las roturas bloqueadas está principalmente relacionada con la ruta nucleolítica, aunque también podría estar implicada en la protección de los extremos frente a un excesivo procesamiento. Además, demostramos que esta jerarquía que prioriza la actividad de TDP2 impide la transformación a células malignas y el desarrollo de cáncer

An End to a Means: How DNA-End Structure Shapes the Double-Strand Break Repair Process

Endogenously-arising DNA double-strand breaks (DSBs) rarely harbor canonical 5'-phosphate, 3'-hydroxyl moieties at the ends, which are, regardless of the pathway used, ultimately required for their repair. Cells are therefore endowed with a wide variety of enzymes that can deal with these chemical and structural variations and guarantee the formation of ligatable termini. An important distinction is whether the ends are directly "unblocked" by specific enzymatic activities without affecting the integrity of the DNA molecule and its sequence, or whether they are "processed" by unspecific nucleases that remove nucleotides from the termini. DNA end structure and configuration, therefore, shape the repair process, its requirements, and, importantly, its final outcome. Thus, the molecular mechanisms that coordinate and integrate the cellular response to blocked DSBs, although still largely unexplored, can be particularly relevant for maintaining genome integrity and avoiding malignant transformation and cancer.España, Junta de Andalucía SAF2017-89619-R, CVI-7948European Research Council (ERC-CoG-2014-647359

La formación de voluntariado en el ciclo formativo de Animación Sociocultural y Turística

En este Trabajo Fin de Master se desarrolla un proyecto educativo sobre la unidad de trabajo de Voluntariado en el ciclo formativo de Animación Sociocultural y Turística. Partiendo de una base teórica donde se exponen diferentes teorías explicativas del aprendizaje, se propone una guía metodológica basada en la participación activa del alumnado y en la importancia de "aprender a aprender", a través de diversas técnicas, actividades y procedimientos de evaluación. Se motiva la capacidad de transmisión, por parte del profesorado, de conocimientos que permitan trabajar competencias, habilidades, capacidades, así como valores y actitudes para lograr un óptimo desarrollo del alumno como persona y como profesional en aquellos ámbitos relacionados con las actividades voluntarias.Máster en Profesor de Educación Secundaria Obligatoria y Bachillerato, Formación Profesional y Enseñanzas de Idioma

Lithium sulfur battery exploiting material design and electrolyte chemistry: 3D graphene framework and diglyme solution

Herein we investigate a lithium sulfur battery suitably combining alternative cathode design and relatively safe, highly conductive electrolyte. The composite cathode is formed by infiltrating sulfur in a N-doped 3D graphene framework prepared by a microwave assisted solvothermal approach, while the electrolyte is obtained by dissolving lithium bis(trifluoromethane)sulfonimide (LiTFSI) in diethylene glycol dimethyl ether (DEGDME), and upgraded by addition of lithium nitrate (LiNO3) as a film forming agent. The particular structure of the composite cathode, studied in this work by employing various techniques, well enhances the lithium-sulfur electrochemical process leading to very stable cycling trend and specific capacity ranging from 1000 mAh g−1 at the highest rate to 1400 mAh g−1 at the lowest one. The low resistance of the electrode/electrolyte interphase, driven by an enhanced electrode design and a suitable electrolyte, is considered one of the main reasons for the high performance which may be of interest for achieving a promising lithium-sulfur battery. Furthermore, the study reveals a key bonus of the cell represented by the low flammability of the diglyme electrolyte, while comparable conductivity and interface resistance, with respect to the most conventional solution used for the lithium sulfur cell

Untreated Natural Graphite as a Graphene Source for High-Performance Li-Ion Batteries

Graphene nanosheets (GNS) are synthesized from untreated natural graphite (NG) foruse as electroactive materials in Li-ion batteries (LIBs), which avoids the pollution-generating stepsof purifying graphite. Through a modified Hummer method and subsequent thermal exfoliation,graphitic oxide and graphene were synthesized and characterized structurally, morphologicallyand chemically. Untreated natural graphite samples contain 45–50% carbon by weight; the rest iscomposed of different elements such as aluminium, calcium, iron, silicon and oxygen, which arepresent as calcium carbonate and silicates of aluminium and iron. Our results confirm that in the GOand GNS synthesized, calcium is removed due to oxidation, though other impurities are maintainedbecause they are not affected by the synthesis. Despite the remaining mineral phases, the energystorage capacity of GNS electrodes is very promising. In addition, an electrochemical comparisonbetween GNS and NG demonstrated that the specific capacity in GNS is higher during the wholecycling process, 770 mA·g−1at 100th cycle, which is twice that of graphite

Physical activation of graphene: An effective, simple and clean procedure for obtaining microporous graphene for high-performance Li/S batteries

Graphene nanosheets are a promising scaffold to accommodate S for achieving high performanceLi/S battery. Nanosheet activation is used as a viable strategy to induce a micropore system and further improve the battery performance. Accordingly, chemical activation methods dominate despite the need of multiple stages, which slow down the process in addition to making them tiresome. Here, a three-dimensional (3D)N-doped graphene specimen was physically activated with CO2, a clean and single step process, and used for the preparation of a sulfur composite (A-3DNG/S). The A-3DNG/S composite exhibited outstanding electrochemical properties such as an excellent rate capability (1,000 mAh·g─1at 2C), high reversible capacity and cycling stability (average capacity ~ 800 mAh·g─1at 1C after 200cycles), values which exceed those measured in chemically activated graphene. Therefore, these results support the use of physical activation as a simple and efficient alternative to improve the performance of carbons as an S host for high-performance Li-S batteries

Effects of exercise timing on metabolic health

The increasing prevalence of metabolic syndrome is associated with major health and socioeconomic consequences. Currently, physical exercise, together with dietary interventions, is the mainstay of the treatment of obesity and related metabolic complications. Although exercise training includes different modalities, with variable intensity, duration, volume, or frequency, which may have a distinct impact on several characteristics related to metabolic syndrome, the potential effects of exercise timing on metabolic health are yet to be fully elucidated. Remarkably, promising results with regard to this topic have been reported in the last few years. Similar to other time-based interventions, including nutritional therapy or drug administration, time-of-day-based exercise may become a useful approach for the management of metabolic disorders. In this article, we review the role of exercise timing in metabolic health and discuss the potential mechanisms that could drive the metabolic-related benefits of physical exercise performed in a time-dependent manner.Funding for open access charge: Universidad de Málaga/CBUA

Comparative Analysis of Muscle Transcriptome between Pig Genotypes Identifies Genes and Regulatory Mechanisms Associated to Growth, Fatness and Metabolism.

Iberian ham production includes both purebred (IB) and Duroc-crossbred (IBxDU) Iberian pigs, which show important differences in meat quality and production traits, such as muscle growth and fatness. This experiment was conducted to investigate gene expression differences, transcriptional regulation and genetic polymorphisms that could be associated with the observed phenotypic differences between IB and IBxDU pigs. Nine IB and 10 IBxDU pigs were slaughtered at birth. Morphometric measures and blood samples were obtained and samples from Biceps femoris muscle were employed for compositional and transcriptome analysis by RNA-Seq technology. Phenotypic differences were evident at this early age, including greater body size and weight in IBxDU and greater Biceps femoris intramuscular fat and plasma cholesterol content in IB newborns. We detected 149 differentially expressed genes between IB and IBxDU neonates (p < 0.01 and Fold-Change > 1. 5). Several were related to adipose and muscle tissues development (DLK1, FGF21 or UBC). The functional interpretation of the transcriptomic differences revealed enrichment of functions and pathways related to lipid metabolism in IB and to cellular and muscle growth in IBxDU pigs. Protein catabolism, cholesterol biosynthesis and immune system were functions enriched in both genotypes. We identified transcription factors potentially affecting the observed gene expression differences. Some of them have known functions on adipogenesis (CEBPA, EGRs), lipid metabolism (PPARGC1B) and myogenesis (FOXOs, MEF2D, MYOD1), which suggest a key role in the meat quality differences existing between IB and IBxDU hams. We also identified several polymorphisms showing differential segregation between IB and IBxDU pigs. Among them, non-synonymous variants were detected in several transcription factors as PPARGC1B and TRIM63 genes, which could be associated to altered gene function. Taken together, these results provide information about candidate genes, metabolic pathways and genetic polymorphisms potentially involved in phenotypic differences between IB and IBxDU pigs associated to meat quality and production traits

Endogenous topoisomerase II-mediated DNA breaks drive thymic cancer predisposition linked to ATM deficiency

The ATM kinase is a master regulator of the DNA damage response to double-strand breaks (DSBs) and a well-established tumour suppressor whose loss is the cause of the neurodegenerative and cancer-prone syndrome Ataxia-Telangiectasia (A-T). A-T patients and Atm−/− mouse models are particularly predisposed to develop lymphoid cancers derived from deficient repair of RAG-induced DSBs during V(D)J recombination. Here, we unexpectedly find that specifically disturbing the repair of DSBs produced by DNA topoisomerase II (TOP2) by genetically removing the highly specialised repair enzyme TDP2 increases the incidence of thymic tumours in Atm−/− mice. Furthermore, we find that TOP2 strongly colocalizes with RAG, both genome-wide and at V(D)J recombination sites, resulting in an increased endogenous chromosomal fragility of these regions. Thus, our findings demonstrate a strong causal relationship between endogenous TOP2-induced DSBs and cancer development, confirming these lesions as major drivers of ATM-deficient lymphoid malignancies, and potentially other conditions and cancer types.Junta de Andalucía SAF2010-21017, SAF2013-47343-P, SAF2014-55532-R, SAF2017-89619-R, CVI-7948European Research Council ERC-CoG-2014-64735