Browsing by Author "Breese, Marcus R."

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    Alt Event Finder: a tool for extracting alternative splicing events from RNA-seq data.
    (BMC, 2012) Zhou, Ao; Breese, Marcus R.; Hao, Yangyang; Edenberg, Howard J.; Li, Lang; Skaar, Todd C.; Liu, Yunlong
    BACKGROUND: Alternative splicing increases proteome diversity by expressing multiple gene isoforms that often differ in function. Identifying alternative splicing events from RNA-seq experiments is important for understanding the diversity of transcripts and for investigating the regulation of splicing. RESULTS: We developed Alt Event Finder, a tool for identifying novel splicing events by using transcript annotation derived from genome-guided construction tools, such as Cufflinks and Scripture. With a proper combination of alignment and transcript reconstruction tools, Alt Event Finder is capable of identifying novel splicing events in the human genome. We further applied Alt Event Finder on a set of RNA-seq data from rat liver tissues, and identified dozens of novel cassette exon events whose splicing patterns changed after extensive alcohol exposure. CONCLUSIONS: Alt Event Finder is capable of identifying de novo splicing events from data-driven transcript annotation, and is a useful tool for studying splicing regulation.
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    Identification of putative targets of Nkx2-5 in Xenopus laevis using cross-species annotation and microarray gene expression analysis
    (2011-10) Breese, Marcus R.; Edenberg, Howard J.; Hurley, Thomas D., 1961-; Rhodes, Simon J.; Skalnik, David Gordon
    The heart is the first organ to form during development in vertebrates and Nkx2-5 is the first marker of cardiac specification. In Xenopus laevis, Nkx2-5 is essential for heart formation, but early targets of this homeodomain transcription factor have not been fully characterized. In order to discover potential early targets of Nkx2-5, synthetic Nkx2-5 mRNA was injected into eight-cell Xenopus laevis embryos and changes in gene expression measured using microarray analysis. While Xenopus laevis is a commonly used model organism for developmental studies, its genome remains poorly annotated. To compensate for this, a cross-species annotation database called CrossGene was constructed. CrossGene was created by exhaustively comparing UniGene transcripts from Homo sapiens, Mus musculus, Rattus norvegicus, Gallus gallus, Xenopus laevis, Danio rerio, Drosophila melanogaster, and Caenorhabditis elegans using the BLAST family of algorithms. Networks were then assembled by recursively combining reciprocal best matches into groups of orthologous genes. Gene ontology annotation from all organisms could then be applied to all members of the reciprocal group. In this way, the CrossGene database was used to augment the existing genomic annotation of Xenopus laevis. Combining cross-species annotation with differential gene expression analysis of Nkx2-5 overexpression led to the discovery of 99 potential targets of Nkx2-5.