Tet3 CXXC Domain and Dioxygenase Activity Cooperatively Regulate Key Genes for Xenopus Eye and Neural Development

Ten-Eleven Translocation (Tet) family of dioxygenases offers a new mechanism for dynamic regulation of DNA methylation and has been implicated in cell lineage differentiation and oncogenesis. Yet their functional roles and mechanisms of action in gene regulation and embryonic development are largely unknown. Here, we report that Xenopus Tet3 plays an essential role in early eye and neural development by directly regulating a set of key developmental genes. Tet3 is an active 5mC hydroxylase regulating the 5mC/5hmC status at target gene promoters. Biochemical and structural studies further reveal a novel DNA binding mode of the Tet3 CXXC domain that is critical for specific Tet3 targeting. Finally, we show that the enzymatic activity and CXXC domain are crucial for Tet3’s biological function. Together, these findings define Tet3 as a novel transcription factor and reveal a molecular mechanism by which the 5mC hydroxylase and DNA binding activities of Tet3 cooperate to control target gene expression and embryonic development

Balancing managerial and professional demands : school principals as evaluation brokers

The evaluation trend in the global education field implies new professional challenges for school principals. The purpose of this article is to describe and analyse Swedish school principals’ experiences of prevailing evaluations and the implications for the profession. Specifically, we examine: a) how principals respond to evaluations and their consequences in their schools; and b) the implications of the evaluations for the profession in light of professional responsibility and accountability. The interviewed principals are ascribed huge evaluation responsibilities and are in this respect key actors but to some extent are also ‘victims’ of external pressures. All schools are embedded in a web of evaluation systems. They share the view that evaluations that are useful for improving teaching, student achievement and everyday school life are those conducted close to practice, and involve teachers. Most of them are also aware of the risks for the reduction of the broad goals of schooling and for work overload. The principals express a desire to protect the fundamental values of professional responsibility but the total demands of the local evaluation web have involved.a shift in their professional role towards professional accountability

A Bayesian Network Approach for Modeling the Influence of Contextual Variables on Scientific Problem Solving

A challenge for intelligent tutoring is to develop methodologies for transforming streams of performance data into insights and models about underlying learning mechanisms. Such modeling at different points in time could provide evidence of a student’s changing understanding of a task, and given sufficient detail, could extend our understanding of how gender, prior achievement, classroom practices and other student/contextual characteristics differentially influence performance and participation in complex problem-solving environments. If the models had predictive properties, they could also provide a framework for directing feedback to improve learning. In this paper we describe the causal relationships between students’ problem-solving effectiveness (i.e. reaching a correct solution) and strategy (i.e. approach) and multiple contextual variables including experience, gender, classroom environment, and task difficulty. Performances of the IMMEX problem set Hazmat (n ~ 33,000) were first modeled by Item Response Theory analysis to provide a measure of effectiveness and then by self-organizing artificial neural networks and hidden Markov modeling to provide measures of strategic efficiency. Correlation findings were then used to link the variables into a Bayesian network representation. Sensitivity analysis indicated that whether a problem was solved or not was most likely influenced by findings related to the problem under investigation and the classroom environment while strategic approaches were most influenced by the actions taken, the classroom environment and the number of problems previously performed. Subsequent testing with unknown performances indicated that the strategic approaches were most easily predicted (17% error rate), whereas whether the problem was solved was more difficult (32% error rate)