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e One of the most striking epigenetic alterations that occurs at the level of the nucleosome is the complete exchange of the canonical H2A histones for the macroH2A variant. Here, we provide insight into the poorly recognized function of macroH2A in transcriptional activation and demonstrate its relevance in embryonic and adult stem cells. Knockdown of macroH2A1 in mouse embryonic stem (mES) cells limited their capacity to differentiate but not their self-renewal. The loss of macroH2A1 interfered with the proper activation of differentiation genes, most of which are direct target genes of macroH2A. Additionally, macroH2A1-deficient mES cells displayed incomplete inactivation of pluripotency genes and formed defective embryoid bodies. In vivo, macroH2A1-deficient teratomas contained a massive expansion of malignant, undifferentiated carcinoma tissue. In the heterogeneous culture of primary human keratinocytes, macroH2A1 levels negatively correlated with the self-renewal capacity of the pluripotent compartment. Together these results establish macroH2A1 as a critical chromatin component that regulates the delicate balance between self-renewal and differentiation of embryonic and adult stem cells.

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The influence of metal cations (M = Cu+, Ca2+ and Cu2+) coordinated to N7 of guanine on the intermolecular proton-transfer reaction in guanine−cytosine base pair has been analyzed using the B3LYP density functional approach. Gas phase metal cation interaction stabilizes the ion pair structure derived from the N1−N3 single-proton-transfer reaction, the effects being more pronounced for the divalent cations than for the monovalent one. For Cu2+GC the reaction is largely favored due to both electrostatic and oxidative effects. Hydration of the metal cation disfavors the reaction due to the screening of electrostatic effects. However, for Cu2+ the reaction can still be easily produced, especially for certain local environments of the metal cation for which Cu2+ induces the oxidation of guanine. Therefore, the ability of Cu2+ to oxidize guanine turns out to be a key factor for this mutagenic process.

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Artículo de publicación ISIThe purpose of this paper is to analyse the factors that influence female entrepreneurship in Spain, using institutional economics as the theoretical framework. The empirical research uses Spanish regional-level panel data (Global Entrepreneurship Monitor and National Statistics Institute of Spain) covering the period 2003-2010. The main findings indicate that informal factors (recognition of entrepreneurial career and female networks) are more relevant for female entrepreneurship than formal factors (education, family context and differential of income level). The research contributes both theoretically (advancing knowledge with respect to environmental factors that affect female entrepreneurship), and practically (for the design of support policies and educational programmes to foster female entrepreneurial activity).Spanish Ministry of Economy & Competitiveness, Economy & Knowledge Department-Catalan Government

The intramolecular proton transfer in cationized glycine and chlorine substituted derivatives with M = Na+, Mg2+, Ni+, Cu+, and Cu2+ has been studied with the three parameter B3LYP density functional method. The coordination of metal cations to the oxygens of the carboxylic group of glycine stabilizes the zwitterionic structure. For all monocations the intramolecular proton transfer occurs readily with small energy barriers (1-2 kcalmol(-1)). For the dication Mg2+ and Cu2+ systems, the zwitterionic structure becomes very stable. However, whereas for Mg2+, the proton transfer process takes place spontaneously, for Cu2+ the reaction occurs with an important energy barrier. The substitution of the hydrogens of the amino group by chlorine atoms decreases the basicity of nitrogen, which destabilizes the zwitterionic structure. For monosubstituted glycine complexed with Na+, the zwitterionic structure still exists as a minimum, but for disubstituted glycine no minimum appears for this structure. In contrast, for Mg2+ complexed to mono- and disubstituted glycine, the zwitterionic structure remains the only minimum, since the enhanced electrostatic interaction with the dication overcomes the destabilizing effect of the chlorine atoms.

Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThis article investigates the influence of informal and formal institutions on the university students' decision of becoming employer entrepreneurs in the context of Catalonia. A sample of 1,207 students from the Universitat Autònoma de Barcelona (UAB) and the Universitat Oberta de Catalunya were surveyed for the period of 2012-2015, and probit regressions over pooled data were used. The main findings suggest that formal factors (university's lack of incentives to create a new business, entrepreneurial knowledge, training and skills, and entrepreneurship education) are higher correlated with the student employer entrepreneurs than informal institutions (role models, entrepreneur's social image and fear of failure). Despite that the entrepreneur's social image does not seem to have an influence on the entrepreneurial decision of university students, the other variables analysed are statistically significant, correlated with entrepreneurship as a choice. Specifically, entrepreneurship education is the most relevant variable in explaining the decision of university students becoming employer entrepreneurs. The paper contributes with policy discussions in order to extend the current debate about the role of the universities in the entrepreneurial process and also the importance of entrepreneurial universities to the society.2