GEMC1, a novel factor required for chromosomal DNA replication

In eukaryotic cells DNA replication begins from multiple origins. During the process of initiation, the DNA replication fork is established at each origin. In lower eukaryotes many factors required for chromosomal DNA replication have been identified. However, the regulation of DNA replication in complex multi-cellular organisms is still poorly understood. In this thesis I report the identification of GEMC1 (GEMinin Coiled-coil containing protein 1), a novel vertebrate factor belonging to a new protein family required to initiate chromosomal DNA replication. GEMC1 contains a domain similar to Geminin, a fundamental regulator of DNA replication (McGarry and Kirschner, 1998). GEMC1 is highly conserved in vertebrates and is preferentially expressed in proliferating cells. I show that Xenopus GEMC1 (XlGEMC1) binds the checkpoint and replication factor TopBP1, which promotes XlGEMC1 binding to chromatin during pre-replication complex (pre-RC) assembly. Moreover, I demonstrate that XlGEMC1 directly interacts with the replication factors Cdc45 and Cdk2/CyclinE by which it is heavily phosphorylated. Phosphorylated XlGEMC1 stimulates initiation of DNA replication. Inhibition of XlGEMC1 function with XlGEMC1 neutralizing antibodies prevents DNA replication onset by blocking Cdc45 loading onto chromatin. Inhibition of XlGEMC1 expression by morpholino antisense oligos is lethal for embryonic development. Furthermore, down-regulation of mouse GEMC1 (mGEMC1) expression by siRNA (small interfering RNA) oligos prevents initiation of DNA replication in somatic vertebrate cells. Data presented in this thesis suggest that GEMC1 promotes initiation of chromosomal DNA replication in higher eukaryotes by mediating TopBP1 and Cdk2 dependent Cdc45 recruitment onto replication origins

Biomarkers of Sudden Unexpected Death in Epilepsy (SUDEP)

La SUDEP (Sudden Unexpected Death in Epilepsy) è una complicanza devastante dell’epilessia e rappresenta la più comune causa di mortalità prematura in epilessia. Studi volti alla definizione di fattori di rischio clinici hanno permesso di identificare gruppi ad alto rischio. Tuttavia al momento non esistono validati biomarkers genomici, elettrofisiologici o strutturali predittivi di aumentato rischio di SUDEP. Al fine di definire la base genetica della SUDEP, abbiamo condotto una analisi di sequenziamento esomico per esaminare la prevalenza di varianti con effetto deleterio in soggetti deceduti per SUDEP rispetto a pazienti epilettici non deceduti e controlli con altre patologie. Abbiamo riscontrato una prevalenza significativamente aumentata di varianti deleterie diffuse a livello dell’intero genoma nei soggetti deceduti per SUDEP in confronto agli altri gruppi. Un secondo studio di neuroimaging è stato dedicato alla valutazione di anomalie regionali del volume della sostanza grigia in soggetti deceduti per SUDEP, confrontati con soggetti epilettici viventi rispettivamente ad alto e basso rischio per SUDEP, e controlli sani. Abbiamo riscontrato un aumento del volume della sostanza grigia in emisfero destro a livello di amigdala, parte anteriore dell’ippocampo e paraippocampo nei soggetti deceduti per SUDEP e nei soggetti ad alto rischio, rispetto ai soggetti a basso rischio ed ai controlli. Sia il sequenziamento esomico sia il neuroimaging strutturale hanno fornito dati significativi per il profilo di rischio di SUDEP. La definizione dei meccanismi eziologici della SUDEP è fondamentale. La traslazione di tali dati in algoritmi predittivi di rischio individuale consente di promuovere la ‘medicina personalizzata’, allo scopo di adottare strategie preventive e ridurre il rischio individuale di SUDEP in pazienti con epilessia.SUDEP (Sudden Unexpected Death in Epilepsy) is the most devastating outcome in epilepsy and the commonest cause of epilepsy-related premature mortality. Studies of clinical risk factors have allowed identifying high-risk populations. However no genomic, electrophysiological or structural features have emerged as established biomarkers of an increased SUDEP risk. To elucidate the genetic architecture of SUDEP, we used an unbiased whole-exome sequencing approach to examine overall burden and over-representation of deleterious variants in people who died of SUDEP compared to living people with epilepsy and non-epilepsy disease controls. We found significantly increased genome-wide polygenic burden per individual in the SUDEP cohort when compared to epilepsy and non-epilepsy disease controls. The polygenic burden was driven both by the number of variants per individual, and overrepresentation of variants likely to be deleterious in the SUDEP cohort. To elucidate which brain regions may be implicated in SUDEP, we investigated whether regional abnormalities in grey matter volume appear in those who died of SUDEP, compared to subjects at high and low risk for SUDEP, and healthy controls. We identified increased grey matter volume in the right anterior hippocampus/amygdala and parahippocampus in SUDEP cases and people at high risk, when compared to those at low risk and controls. Compared to controls, posterior thalamic grey matter volume, an area mediating oxygen regulation, was reduced in SUDEP cases and subjects at high risk. It is fundamental to understand the range of SUDEP aetiological mechanisms. Our results suggest that both exome sequencing data and structural imaging features may contribute to generate SUDEP risk estimates. Translation of this knowledge into predictive algorithms of individual risk and preventive strategies would promote stratified medicine in epilepsy, with the aim of reducing an individual patient's risk of SUDEP

The Infinite Learning Chain. Flipped Professional Labs for Learning and Knowledge Co-Creation

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Troya historiada en The Book of the Duchess y The House of Fame

En este trabajo propongo analizar The Book of the Duchess y The House of Fame a partir de los problemas que introduce la presencia de la historia troyana. El famoso relato está invocado a través de escenas pintadas en paredes o en ventanales, presentados como escenografía. No están incluidos para añadirles nuevas interpretaciones, ni para completar faltantes de información o conciliar versiones divergentes, sino que son utilizados para capitalizar sus resonancias como objeto cultural, incorporado a la memoria social, frente al cual Chaucer construye un universo de sentido para su propia poesía e indaga en los principios que autorizan su texto

Sounding the Arctic in Chantal Bilodeau’s Climate Change Plays

Quebec-born playwright Chantal Bilodeau has been responding to the challenges of dramatizing anthropogenic climate change by developing an eight-part Arctic Cycle, each play of which is set in one of the nations that claims Arctic territory. Sila (2014) immerses audiences into a complex network of humans, animals, and mythical beings crisscrossing the Canadian Arctic. These movements circle around the Inuit concept of sila, which is the life-giving force of breath and voice. Thus, the sonic world of Sila focuses on voices speaking words, on performance poetry, and on the sounds of breath and wind. Bilodeau’ s second Arctic Cycle play, Forward (2016), addresses the long-term impact of Fridtjof Nansen’s polar exploration of the 1890s on Norway’s economy and society. In terms of sound, Forward features multiple musical performances rangingfrom traditional songs to European opera arias and Lieder to contemporary Norwegian electro-pop. The sonic features of both plays stress interdependence across time, space, as well as (non-)human, earthly, and metaphysical realms. Sila and Forward address climate change in a non-universalizing manner which promotes a heterarchical (rather than hierarchical) aesthetic fit for a growing awareness of planetary relationality

Audit of use of stiripentol in adults with Dravet syndrome

OBJECTIVES: There are very few data available in the literature on the use of stiripentol in adults with Dravet syndrome (DS). DS cases are increasingly recognized in adulthood, and more children with DS now survive to adulthood. The aim of the study was to document the effectiveness and tolerability of stiripentol in adults with DS. MATERIAL AND METHODS: We conducted an observational clinical audit in the epilepsy service of the National Hospital for Neurology and Neurosurgery, London (UK). RESULTS: We included 13 adult subjects with DS (eight females, five males). The responder (defined as more than 50% reduction in all seizure types) rate was 3/13 (23%) at 36 months. The following other outcomes were reported: seizure exacerbation (3/13, 23%), no change (3/13, 23%), less than 50% reduction in seizures (2/13, 15%), more than 50% reduction in generalized tonic-clonic seizures but no other seizure types (1/13, 8%), undefined response (1/13, 8%). The retention rate was 62% after 1 year and 31% after 5 years. Adverse effects were reported in 7/13 (54%): the most frequent were anorexia, weight loss, unsteadiness and tiredness. Withdrawal due to adverse effects occurred in 3/13 (23%). CONCLUSIONS: Compared with previous studies on children with DS, our results show a lower responder rate and a similar tolerability profile. Stiripentol can be effective with a good tolerability profile. Our audit is small, but supports the use of stiripentol in adults with DS when first-line treatments are ineffective or not tolerated, in keeping with published guidelines

Cell wall remodeling in mycorrhizal symbiosis: a way towards biotrophism

Cell walls are deeply involved in the molecular talk between partners during plant and microbe interactions, and their role in mycorrhizae, i.e., the widespread symbiotic associations established between plant roots and soil fungi, has been investigated extensively. All mycorrhizal interactions achieve full symbiotic functionality through the development of an extensive contact surface between the plant and fungal cells, where signals and nutrients are exchanged. The exchange of molecules between the fungal and the plant cytoplasm takes place both through their plasma membranes and their cell walls; a functional compartment, known as the symbiotic interface, is thus defined. Among all the symbiotic interfaces, the complex intracellular interface of arbuscular mycorrhizal (AM) symbiosis has received a great deal of attention since its first description. Here, in fact, the host plasmamembrane invaginates and proliferates around all the developing intracellular fungal structures, and cell wall material is laid down between this membrane and the fungal cell surface. By contrast, in ectomycorrhizae (ECM), where the fungus grows outside and between the root cells, plant and fungal cell walls are always in direct contact and form the interface between the two partners. The organization and composition of cell walls within the interface compartment is a topic that has attracted widespread attention, both in ecto- and endomycorrhizae. The aim of this review is to provide a general overview of the current knowledge on this topic by integrating morphological observations, which have illustrated cell wall features during mycorrhizal interactions, with the current data produced by genomic and transcriptomic approaches