Implementing a Research Data Policy at Leiden University

In this paper, we discuss the various stages of the institution-wide project that lead to the adoption of the data management policy at Leiden University in 2016. We illustrate this process by highlighting how we have involved all stakeholders. Each organisational unit was represented in the project teams. Results were discussed in a sounding board with both academic and support staff. Senior researchers acted as pioneers and raised awareness and commitment among their peers. By way of example, we present pilot projects from two faculties. We then describe the comprehensive implementation programme that will create facilities and services that must allow implementing the policy as well as monitoring and evaluating it. Finally, we will present lessons learnt and steps ahead. The engagement of all stakeholders, as well as explicit commitment from the Executive Board, has been an important key factor for the success of the project and will continue to be an important condition for the steps ahead

Dot1 binding induces chromatin rearrangements by histone methylation-dependent and -independent mechanisms

<p>Abstract</p> <p>Background</p> <p>Methylation of histone H3 lysine 79 (H3K79) by Dot1 is highly conserved among species and has been associated with both gene repression and activation. To eliminate indirect effects and examine the direct consequences of Dot1 binding and H3K79 methylation, we investigated the effects of targeting Dot1 to different positions in the yeast genome.</p> <p>Results</p> <p>Targeting Dot1 did not activate transcription at a euchromatic locus. However, chromatin-bound Dot1 derepressed heterochromatin-mediated gene silencing over a considerable distance. Unexpectedly, Dot1-mediated derepression was established by both a H3K79 methylation-dependent and a methylation-independent mechanism; the latter required the histone acetyltransferase Gcn5. By monitoring the localization of a fluorescently tagged telomere in living cells, we found that the targeting of Dot1, but not its methylation activity, led to the release of a telomere from the repressive environment at the nuclear periphery. This probably contributes to the activity-independent derepression effect of Dot1.</p> <p>Conclusions</p> <p>Targeting of Dot1 promoted gene expression by antagonizing gene repression through both histone methylation and chromatin relocalization. Our findings show that binding of Dot1 to chromatin can positively affect local gene expression by chromatin rearrangements over a considerable distance.</p

Two Dot1 isoforms in Saccharomyces cerevisiae as a result of leaky scanning by the ribosome

Dot1 is a conserved histone methyltransferase that methylates histone H3 on lysine 79. We previously observed that in Saccharomyces cerevisiae, a single DOT1 gene encodes two Dot1 protein species. Here, we show that the relative abundance of the two isoforms changed under nutrient-limiting conditions. A mutagenesis approach showed that the two Dot1 isoforms are produced from two alternative translation start sites as a result of leaky scanning by the ribosome. The leaky scanning was not affected by the 5′- or 3′-untranslated regions of DOT1, indicating that translation initiation is determined by the DOT1 coding sequence. Construction of yeast strains expressing either one of the isoforms showed that both were sufficient for Dot1’s role in global H3K79 methylation and telomeric gene silencing. However, the absence of the long isoform of Dot1 altered the resistance of yeast cells to the chitin-binding drug Calcofluor White, suggesting that the two Dot1 isoforms have a differential function in cell wall biogenesis

A Modified Epigenetics Toolbox to Study Histone Modifications on the Nucleosome Core

In the eukaryotic cell nucleus, the DNA is packaged in a structure called chromatin. The fundamental building block of chromatin is the nucleosome, which is composed of DNA wrapped around an octamer of four distinct histone proteins. Post-translational modifications (PTMs) of histone proteins can affect chromatin structure and function and thereby play critical roles in regulating gene expression. Most histone PTMs are found in unstructured histone tails that protrude from the nucleosome core. As a consequence, (synthetic) peptide truncations of these tails provide convenient substrates for the analysis of histone binding proteins and modifying enzymes. Modifications located on residues that reside in the nucleosome core are more difficult to study because short peptides do not recapitulate this defined structured state well. Methylation of histone H3 on Lys79 (H3K79), mediated by the Dot1 enzyme, is an example of such a core PTM. This modification, which is highly conserved, is linked to human leukemia, and pharmacological modulation of Dot1 activity could be a strategy to treat leukemia. Here we review the available and emerging genetic, biochemical, and chemical methods that together are starting to reveal the function and regulation of this and other histone modifications on the nucleosome core. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim