492 research outputs found

    Allotopic RNA expression strategy to rescue an endogenous mitochondrial ATP6[1] mutation in Drosophila

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    Mitochondria are essential organelles in the cell. One of their most critical functions is the generation of cellular energy in the form of ATP. The presence of DNA in the mitochondrial matrix makes this organelle semi-autonomous. However, it relies heavily on the nucleus and cytosol to import ~99% of its proteins and some RNA molecules for its normal functioning. Mutations in the mitochondrial DNA (mtDNA) cause several devastating disorders. Due to their complexity and our incomplete understanding of mitochondrial disease pathogenesis, these disorders are difficult to diagnose and currently no pharmacological treatment exists. Further, gene therapy for these devastating disorders is impeded due to lack of mitochondrial genome manipulation techniques. Understanding the mechanism of pathogenesis and developing mtDNA manipulation strategies are key to developing remedial therapies. In my thesis, I investigated an RNA allotopic strategy of targeting RNA into the mitochondria in vivo in flies. In my first aim, I improved an in vivo mitochondrial-targeting tool (mtTRES vector) to manipulate proteins encoded by the mitochondrial DNA. This vector integrates into the nuclear genome and results in the transcription of a chimeric RNA consisting of a mitochondrial targeting signal sequence and a small non-coding antisense RNA. Previous studies have attempted allotopic expression via both protein and RNA import with mixed results. Only a few of them, however, have been tested in vivo and none have been examined for rescue in an animal model of mitochondrial disease. Since our lab has a well characterized mtDNA mutation fly model, ATP6[1], I had a unique opportunity to investigate rescue strategies in these models. In my second aim, I improved a unique set of mtTRESPro vectors for both flies and humans to target long coding RNAs into mitochondria. Once imported these long RNAs are designed to be endogenously translated in mitochondria. By targeting a wild type copy of the mutant ATP6 gene, I explored the rescuing potential of allotopic RNA import in vivo. Our data suggest the mtTRES and mtTRESPro mitochondrial manipulation tools have genuine potential to be developed into a mitochondrial disease gene therapy

    NASA space and Earth science data on CD-ROM

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    The National Space Science Data Center (NSSDC) is very interested in facilitating the widest possible use of the scientific data acquired through NASA spaceflight missions. Therefore, NSSDC has participated with projects and data management elements throughout the NASA science environment in the creation, archiving, and dissemination of data using Compact Disk-Read Only Memory (CD-ROM). This CD-ROM technology has the potential to enable the dissemination of very large data volumes at very low prices to a great many researchers, students and their teachers, and others. This catalog identifies and describes the scientific CD-ROM's now available from NSSDC including the following data sets: Einstein Observatory CD-ROM, Galileo Cruise Imaging on CD-ROM, International Halley Watch, IRAS Sky Survey Atlas, Infrared Thermal Mapper (IRTM), Magellan (MIDR), Magellan (ARCDR's), Magellan (GxDR's), Mars Digital Image Map (MDIM), Outer Planets Fields & Particles Data, Pre-Magellan, Selected Astronomical Catalogs, TOMS Gridded Ozone Data, TOMS Ozone Image Data, TOMS Update, Viking Orbiter Images of Mars, and Voyager Image

    Readers and Reading in the First World War

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    This essay consists of three individually authored and interlinked sections. In ‘A Digital Humanities Approach’, Francesca Benatti looks at datasets and databases (including the UK Reading Experience Database) and shows how a systematic, macro-analytical use of digital humanities tools and resources might yield answers to some key questions about reading in the First World War. In ‘Reading behind the Wire in the First World War’ Edmund G. C. King scrutinizes the reading practices and preferences of Allied prisoners of war in Mainz, showing that reading circumscribed by the contingencies of a prison camp created an unique literary community, whose legacy can be traced through their literary output after the war. In ‘Book-hunger in Salonika’, Shafquat Towheed examines the record of a single reader in a specific and fairly static frontline, and argues that in the case of the Salonika campaign, reading communities emerged in close proximity to existing centres of print culture. The focus of this essay moves from the general to the particular, from the scoping of large datasets, to the analyses of identified readers within a specific geographical and temporal space. The authors engage with the wider issues and problems of recovering, interpreting, visualizing, narrating, and representing readers in the First World War

    Severe acute respiratory syndrome coronavirus 3a protein activates the mitochondrial death pathway through p38 MAP kinase activation

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    The molecular mechanisms governing severe acute respiratory syndrome coronavirus-induced pathology are not fully understood. Virus infection and some individual viral proteins, including the 3a protein, induce apoptosis. However, the cellular targets leading to 3a protein-mediated apoptosis have not been fully characterized. This study showed that the 3a protein modulates the mitochondrial death pathway in two possible ways. Activation of caspase-8 through extrinsic signal(s) caused Bid activation. In the intrinsic pathway, there was activation of caspase-9 and cytochrome c release from the mitochondria. This was the result of increased Bax oligomerization and higher levels of p53 in 3a protein-expressing cells, which depended on the activation of p38 MAP kinase (MAPK) in these cells. For p38 activation and apoptosis induction, the 3a cytoplasmic domain was sufficient. In direct Annexin V staining assays, the 3a protein-expressing cells showed increased apoptosis that was attenuated with the p38 MAPK inhibitor SB203580. A block in nuclear translocation of the STAT3 transcription factor in cells expressing the 3a protein was also observed. These results have been used to present a model of 3a-mediated apoptosis

    Highly efficient 5\u27 capping of mitochondrial RNA with NAD+ and NADH by yeast and human mitochondrial RNA polymerase

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    Bacterial and eukaryotic nuclear RNA polymerases (RNAPs) cap RNA with the oxidized and reduced forms of the metabolic effector nicotinamide adenine dinucleotide, NAD+ and NADH, using NAD+ and NADH as non-canonical initiating nucleotides for transcription initiation. Here, we show that mitochondrial RNAPs (mtRNAPs) cap RNA with NAD+ and NADH, and do so more efficiently than nuclear RNAPs. Direct quantitation of NAD+- and NADH-capped RNA demonstrates remarkably high levels of capping in vivo: up to ~60% NAD+ and NADH capping of yeast mitochondrial transcripts, and up to ~15% NAD+ capping of human mitochondrial transcripts. The capping efficiency is determined by promoter sequence at, and upstream of, the transcription start site and, in yeast and human cells, by intracellular NAD+ and NADH levels. Our findings indicate mtRNAPs serve as both sensors and actuators in coupling cellular metabolism to mitochondrial transcriptional outputs, sensing NAD+ and NADH levels and adjusting transcriptional outputs accordingly. © 2018, Bird et al
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