@article{OmidbakhshfardWinckArvidssonetal.2014, author = {Omidbakhshfard, Mohammad Amin and Winck, Flavia Vischi and Arvidsson, Samuel Janne and Riano-Pachon, Diego M. and M{\"u}ller-R{\"o}ber, Bernd}, title = {A step-by-step protocol for formaldehyde-assisted isolation of regulatory elements from Arabidopsis thaliana}, series = {Journal of integrative plant biology}, volume = {56}, journal = {Journal of integrative plant biology}, number = {6}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1672-9072}, doi = {10.1111/jipb.12151}, pages = {527 -- 538}, year = {2014}, abstract = {The control of gene expression by transcriptional regulators and other types of functionally relevant DNA transactions such as chromatin remodeling and replication underlie a vast spectrum of biological processes in all organisms. DNA transactions require the controlled interaction of proteins with DNA sequence motifs which are often located in nucleosome-depleted regions (NDRs) of the chromatin. Formaldehyde-assisted isolation of regulatory elements (FAIRE) has been established as an easy-to-implement method for the isolation of NDRs from a number of eukaryotic organisms, and it has been successfully employed for the discovery of new regulatory segments in genomic DNA from, for example, yeast, Drosophila, and humans. Until today, however, FAIRE has only rarely been employed in plant research and currently no detailed FAIRE protocol for plants has been published. Here, we provide a step-by-step FAIRE protocol for NDR discovery in Arabidopsis thaliana. We demonstrate that NDRs isolated from plant chromatin are readily amenable to quantitative polymerase chain reaction and next-generation sequencing. Only minor modification of the FAIRE protocol will be needed to adapt it to other plants, thus facilitating the global inventory of regulatory regions across species.}, language = {en} } @article{KlieNikoloskiSelbig2014, author = {Klie, Sebastian and Nikoloski, Zoran and Selbig, Joachim}, title = {Biological cluster evaluation for gene function prediction}, series = {Journal of computational biology}, volume = {21}, journal = {Journal of computational biology}, number = {6}, publisher = {Liebert}, address = {New Rochelle}, issn = {1066-5277}, doi = {10.1089/cmb.2009.0129}, pages = {428 -- 445}, year = {2014}, abstract = {Recent advances in high-throughput omics techniques render it possible to decode the function of genes by using the "guilt-by-association" principle on biologically meaningful clusters of gene expression data. However, the existing frameworks for biological evaluation of gene clusters are hindered by two bottleneck issues: (1) the choice for the number of clusters, and (2) the external measures which do not take in consideration the structure of the analyzed data and the ontology of the existing biological knowledge. Here, we address the identified bottlenecks by developing a novel framework that allows not only for biological evaluation of gene expression clusters based on existing structured knowledge, but also for prediction of putative gene functions. The proposed framework facilitates propagation of statistical significance at each of the following steps: (1) estimating the number of clusters, (2) evaluating the clusters in terms of novel external structural measures, (3) selecting an optimal clustering algorithm, and (4) predicting gene functions. The framework also includes a method for evaluation of gene clusters based on the structure of the employed ontology. Moreover, our method for obtaining a probabilistic range for the number of clusters is demonstrated valid on synthetic data and available gene expression profiles from Saccharomyces cerevisiae. Finally, we propose a network-based approach for gene function prediction which relies on the clustering of optimal score and the employed ontology. Our approach effectively predicts gene function on the Saccharomyces cerevisiae data set and is also employed to obtain putative gene functions for an Arabidopsis thaliana data set.}, language = {en} } @article{BalazadehSchildhauerAraujoetal.2014, author = {Balazadeh, Salma and Schildhauer, Joerg and Araujo, Wagner L. and Munne-Bosch, Sergi and Fernie, Alisdair R. and Proost, Sebastian and Humbeck, Klaus and M{\"u}ller-R{\"o}ber, Bernd}, title = {Reversal of senescence by N resupply to N-starved Arabidopsis thaliana: transcriptomic and metabolomic consequences}, series = {Journal of experimental botany}, volume = {65}, journal = {Journal of experimental botany}, number = {14}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0022-0957}, doi = {10.1093/jxb/eru119}, pages = {3975 -- 3992}, year = {2014}, abstract = {Leaf senescence is a developmentally controlled process, which is additionally modulated by a number of adverse environmental conditions. Nitrogen shortage is a well-known trigger of precocious senescence in many plant species including crops, generally limiting biomass and seed yield. However, leaf senescence induced by nitrogen starvation may be reversed when nitrogen is resupplied at the onset of senescence. Here, the transcriptomic, hormonal, and global metabolic rearrangements occurring during nitrogen resupply-induced reversal of senescence in Arabidopsis thaliana were analysed. The changes induced by senescence were essentially in keeping with those previously described; however, these could, by and large, be reversed. The data thus indicate that plants undergoing senescence retain the capacity to sense and respond to the availability of nitrogen nutrition. The combined data are discussed in the context of the reversibility of the senescence programme and the evolutionary benefit afforded thereby. Future prospects for understanding and manipulating this process in both Arabidopsis and crop plants are postulated.}, language = {en} }