Brahma Is Required for Proper Expression of the Floral Repressor FLC in Arabidopsis

This is an open-access article distributed under the terms of the Creative Commons Attribution License.[Background]: BRAHMA (BRM) is a member of a family of ATPases of the SWI/SNF chromatin remodeling complexes from Arabidopsis. BRM has been previously shown to be crucial for vegetative and reproductive development. [Methodology/Principal Findings]: Here we carry out a detailed analysis of the flowering phenotype of brm mutant plants which reveals that, in addition to repressing the flowering promoting genes CONSTANS (CO), FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CO1 (SOC1), BRM also represses expression of the general flowering repressor FLOWERING LOCUS C (FLC). Thus, in brm mutant plants FLC expression is elevated, and FLC chromatin exhibits increased levels of histone H3 lysine 4 tri-methylation and decreased levels of H3 lysine 27 tri-methylation, indicating that BRM imposes a repressive chromatin configuration at the FLC locus. However, brm mutants display a normal vernalization response, indicating that BRM is not involved in vernalization-mediated FLC repression. Analysis of double mutants suggests that BRM is partially redundant with the autonomous pathway. Analysis of genetic interactions between BRM and the histone H2A.Z deposition machinery demonstrates that brm mutations overcome a requirement of H2A.Z for FLC activation suggesting that in the absence of BRM, a constitutively open chromatin conformation renders H2A.Z dispensable. [Conclusions/Significance]: BRM is critical for phase transition in Arabidopsis. Thus, BRM represses expression of the flowering promoting genes CO, FT and SOC1 and of the flowering repressor FLC. Our results indicate that BRM controls expression of FLC by creating a repressive chromatin configuration of the locus.This work was supported by Ministerio de Educacin y Ciencia (BFU2008-00238, CSD2006-00049), and by Junta de Andaluca (P06-CVI-01400) to J.C.R. and by the National Institutes of Health (grant no. 1R01GM079525), and the National Science Foundation (grant no. 0446440) to R.A. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewe

The Chromatin Remodeler SPLAYED Regulates Specific Stress Signaling Pathways

Organisms are continuously exposed to a myriad of environmental stresses. Central to an organism's survival is the ability to mount a robust transcriptional response to the imposed stress. An emerging mechanism of transcriptional control involves dynamic changes in chromatin structure. Alterations in chromatin structure are brought about by a number of different mechanisms, including chromatin modifications, which covalently modify histone proteins; incorporation of histone variants; and chromatin remodeling, which utilizes ATP hydrolysis to alter histone-DNA contacts. While considerable insight into the mechanisms of chromatin remodeling has been gained, the biological role of chromatin remodeling complexes beyond their function as regulators of cellular differentiation and development has remained poorly understood. Here, we provide genetic, biochemical, and biological evidence for the critical role of chromatin remodeling in mediating plant defense against specific biotic stresses. We found that the Arabidopsis SWI/SNF class chromatin remodeling ATPase SPLAYED (SYD) is required for the expression of selected genes downstream of the jasmonate (JA) and ethylene (ET) signaling pathways. SYD is also directly recruited to the promoters of several of these genes. Furthermore, we show that SYD is required for resistance against the necrotrophic pathogen Botrytis cinerea but not the biotrophic pathogen Pseudomonas syringae. These findings demonstrate not only that chromatin remodeling is required for selective pathogen resistance, but also that chromatin remodelers such as SYD can regulate specific pathways within biotic stress signaling networks

Relational Capital in Universities: The “Ipazia” Observatory on Gender Issues

The purpose of this paper is twofold: first, to carry out a literature review in order to know whether and to what extent the studies conducted so far have addressed relational capital in universities and, then, to provide a new framework for good practice that combines research, education, external universities (third mission) and internal relations. Our investigation aims to answer the following RQ: “How is relational capital formed in universities? How is it managed?” From a methodological point of view, we start with a literature review on relational capital and then we develop a case study. As far as the literature review is concerned, a search on Scopus was conducted, using a set of selected keywords, because it guarantees a high quality for publications. Selected papers have been analysed in an attempt to identify the main issues. The case study is a research strategy particularly suitable for an in-depth examination of current real-life events. The case chosen focuses on the foundation and development of the scientific observatory on gender issues entitled “Ipazia”. All relationships built in order to merge research, teaching and third mission within universities will be analysed and discussed. The analysed case study allows us to investigate whether and how the use of relational capital enables universities to combine research, education and third mission. Meanwhile, our research highlights how “Ipazia” can be seen as an activator of relationships for gender studies. Our research project aims to extend the analysis of relational capital in universities. This project could allow us to gain a greater understanding of a relevant subject, especially for those, scholars or politicians, who are involved in developing, managing and measuring relational capital in universities. Finally, this paper contributes to the expansion of the literature on gender studies, and for this reason, it offers a new perspective applied to a topic of high relevance such as relational capital in universities