The NH2-terminal Jun kinases (JNKs) function in diverse roles through phosphorylation and activation of AP-1 components including ATF2 and c-Jun. However, the genes that mediate these processes are poorly understood. ...
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The NH2-terminal Jun kinases (JNKs) function in diverse roles through phosphorylation and activation of AP-1 components including ATF2 and c-Jun. However, the genes that mediate these processes are poorly understood. A model phenotype characterized by rapid activation of Jun kinase and enhanced DNA repair following cisplatin treatment was examined using chromatin immunoprecipitation with antibodies against ATF2 and c-Jun or their phosphorylated forms and hybridization to promoter arrays. Following genotoxic stress, we identified 269 genes whose promoters are bound upon phosphorylation of ATF2 and c-Jun. Binding did not occur following treatment with transplatin or the JNK inhibitor SP600125 or JNK-specific siRNA. Of 89 known DNA repair genes represented on the array, 23 are specifically activated by cisplatin treatment within 3-6 hr. Thus, the genotoxic stress response occurs at least partly via activation of ATF2 and c-Jun, leading to large-scale coordinate gene expression dominated by genes of DNA repair.
Whole genome microarrays allow assessment of the profile of genes expressed under particular experimental conditions, including external stimuti such as pH or temperature, and internal changes brought about by deletin...
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Whole genome microarrays allow assessment of the profile of genes expressed under particular experimental conditions, including external stimuti such as pH or temperature, and internal changes brought about by deleting or overexpressing a gene. Such experiments produce large data sets, for which sophisticated analysis software is available. What is tacking are toots for analysing data sets from different experiments, in order to test and generate hypotheses about the links between regulatory networks. We describe here a method for presenting results from different experiments as a directed graph constructed using an automated graph drawing program xneato, enhanced by a logic program designed to cluster data and aid in the generation of hypotheses about possible gene interactions. A web-based front-end to the system has been constructed to explore and manipulate the graphical displays produced. Results of microarray experiments on Mycobacterium tuberculosis were used to develop and evaluate the visualization too[ and initiate the development of an inference system for gene interactions based on such data. The GeneGraph project can be accessed at: *** (C) 2004 Elsevier Ltd. All rights reserved.
Motivation: Gene expression array technology has become increasingly widespread among researchers who recognize its numerous promises. At the same time, bench biologists and bioinformaticians have come to appreciate i...
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Motivation: Gene expression array technology has become increasingly widespread among researchers who recognize its numerous promises. At the same time, bench biologists and bioinformaticians have come to appreciate increasingly the importance of establishing a collaborative dialog from the onset of a study and of collecting and exchanging detailed information on the many experimental and computational procedures using a structured mechanism. This is crucial for adequate analyses of this kind of data. Results: The RNA Abundance database (RAD;http://***/RAD) provides a comprehensive MIAME-supportive infrastructure for gene expression data management and makes extensive use of ontologies. Specific details on protocols, biomaterials, study designs, etc. are collected through a user-friendly suite of web annotation forms. Software has been developed to generate MAGE-ML documents to enable easy export of studies stored in RAD to any other database accepting data in this format (e.g. ArrayExpress). RAD is part of a more general Genomics Unified Schema (http://***), which includes a richly annotated gene index (http://***), thus providing a platform that integrates genomic and transcriptomic data from multiple organisms. This infrastructure enables a large variety of queries that incorporate visualization and analysis tools and have been tailored to serve the specific needs of projects focusing on particular organisms or biological systems.
作者:
Troendle, JFKorn, ELMcShane, LMNICHHD
Div Epidemiol Stat & Prevent Res NIH Dept Hlth & Human Serv Bethesda MD 20892 USA NCI
Biometr Res Branch DHHS Bethesda MD 20892 USA
This article examines the use of bootstrap hypothesis tests for testing the equality of two multivariate distributions. The test statistic used is the maximum of the univariate two-sample t-statistics. Depending upon ...
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This article examines the use of bootstrap hypothesis tests for testing the equality of two multivariate distributions. The test statistic used is the maximum of the univariate two-sample t-statistics. Depending upon the type of bootstrap resampling used, the simulation studies show that the test levels are conservative or anti-conservative when the sample sizes are small and the number of variables is large. For small sample sizes, using the bootstrap resampling that preserves the Type I error can lead to a testing procedure that has lower power, sometimes dramatically lower, than a permutation test.
The genes having similar expression profiles are considered to have common regulatory mechanisms and are controlled by the binding of transcription factors to the regulatory elements present in their upstream regions....
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High-throughput experiments such as gene expression microarrays in the life sciences result in large datasets. In response, a wide variety of visualization tools have been created to facilitate data analysis. Biologis...
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ISBN:
(纸本)0780387791
High-throughput experiments such as gene expression microarrays in the life sciences result in large datasets. In response, a wide variety of visualization tools have been created to facilitate data analysis. Biologists often face a dilemma in choosing the best tool for their situation. The tool that works best for one biologist may not work well for another due to differences in the type of insight they seek from their data. A primary purpose of a visualization tool is to provide domain-relevant insight into the data. Ideally, any user wants maximum information in the least possible time. In this paper we identify several distinct characteristics of insight that enable us to recognize and quantify it. Based on this, we empirically evaluate five popular microarray visualization tools. Our conclusions can guide biologists in selecting the best tool for their data, and computer scientists in developing and evaluating visualizations.
We propose a statistical method for estimating a gene network based on Bayesian networks from microarray gene expression data together with biological knowledge including protein-protein interactions, protein-DNA inte...
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The advent of DNA microarray technologies has revolutionized the experimental study of gene expression. Clustering is the most popular approach of analyzing gene expression data and has indeed proven to be successful ...
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ISBN:
(纸本)0769521940
The advent of DNA microarray technologies has revolutionized the experimental study of gene expression. Clustering is the most popular approach of analyzing gene expression data and has indeed proven to be successful in many applications. Our work focuses on discovering a subset of genes which exhibit similar expression patterns along a subset of conditions in the gene expression matrix. Specifically, we are looking for the Order Preserving clusters (OP-Cluster), in each of which a subset of genes induce a similar linear ordering along a subset of conditions. The pioneering work of the OPSM model[3], which enforces the strict order shared by the genes in a cluster, is included in our model as a special case. Our model is more robust than OPSM because similarly expressed conditions are allowed to form order equivalent groups and no restriction is placed on the order within a group. Guided by our model, we design and implement a deterministic algorithm, namely OPC-Tree, to discover OP-Clusters. Experimental study on two real datasets demonstrates the effectiveness of the algorithm in the application of tissue classification and cell cycle identification. In addition, a large percentage of OP-Clusters exhibit significant enrichment of one or more function categories, which implies that OP-Clusters indeed carry significant biological relevance.
The ordinary-, penalized-, and bootstrap t-test, least squares and best linear unbiased prediction were compared for their false discovery rates (FDR), i.e. the fraction of falsely discovered genes, which was empirica...
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The ordinary-, penalized-, and bootstrap t-test, least squares and best linear unbiased prediction were compared for their false discovery rates (FDR), i.e. the fraction of falsely discovered genes, which was empirically estimated in a duplicate of the data set. The bootstrap-t-test yielded up to 80% lower FDRs than the alternative statistics, and its FDR was always as good as or better than any of the alternatives. Generally, the predicted FDR from the bootstrapped P-values agreed well with their empirical estimates, except when the number of mRNA samples is smaller than 16. In a cancer data set, the bootstrap-t-test discovered 200 differentially regulated genes at a FDR of 2.6%, and in a knock-out gene expression experiment 10 genes were discovered at a FDR of 3.2%. It is argued that, in the case of microarray data, control of the FDR takes sufficient account of the multiple testing, whilst being less stringent than Bonferoni-type multiple testing corrections. Extensions of the bootstrap simulations to more complicated test-statistics are discussed.
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