Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"piRNAs"”.
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Roles of piwi-interacting RNAs and small interfering RNAs in regulating gene expression in Caenorhabditis elegans
… microRNAs (miRNAs), piwi interacting RNAs (piRNAs), and small interfering RNAs (siRNAs). miRNAs are required throughout development, whereas piRNAs and siRNAs are best known for their roles in germline development and genome defense (see Chapter 1 for an overview of piRNA and siRNA …
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Insights into the piRNA pathway through 16 strains of mice
… such class of small RNAs - PIWI-interacting RNA (piRNAs) - are exclusively expressed in the germlines of mammals. This thesis provides an exhaustive bioinformatic exploration of piRNA biogenesis and dynamics utilising a large dual-sequencing dataset, which encompasses bulk RNA sequencing and …
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Novel Small-RNA Mediated Gene Regulatory Mechanisms for Long-Term Memory
… expression in brain of a 28-nt sized class of piRNAs, which had been thought to be germ-line specific. These piRNAs have unique biogenesis patterns and predominant nuclear localization. Moreover, we find that whereas miRNAs are down-regulated by exposure to serotonin, piRNAs are up-regulated. …
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Mechanisms of piRNA biogenesis and co-transcriptional silencing of transposable elements in Drosophila
… and instruct their silencing. Ultimately, piRNAs trigger epigenetic silencing of transposon loci. The work in this thesis investigates the molecular mechanisms by which piRNAs are produced from the correct substrates and how piRNAs can induce silencing of target loci in Drosophila …
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Analysis of variation in PIWI-interacting RNA (piRNA) expression in testes of different mouse strains
Piwi-interacting RNAs (piRNAs) are a class of small non-coding RNAs present in the germline of most animals which are responsible for silencing transposable elements (TEs) through base-pair complementarity. We performed an extensive study of the expression of piRNAs in the male germline of five …
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Studies on the mammalian piRNA pathway in cancer cells
Piwi-interacting RNAs (piRNAs) are a subset of noncoding RNAs that complex with members of the Argonaute protein family, the Piwi proteins. The Piwi/piRNA pathway is highly conserved in animals and is implicated in spermatogenesis, germline stem cell maintenance, and transposon suppression in the …
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Small regulatory RNAs in mammals : genomics, function and evolution
… origin of mammalian piwi-interacting RNAs (piRNAs), (2) the evolutionary and functional implication of the seed-based target recognition mechanism of microRNAs (miRNAs). First, we participated in the discovery of mammalian piRNAs from adult rat testes. Our initial characterization of …
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Characterization of Small Non-Coding RNAs in the Seminal Plasma of Beef Bulls with Predicted High and Low Fertility
… a role in male fertility. Piwi-interacting RNAs (piRNAs) are another class of germline-specific non-coding RNAs that form silencing complexes to maintain germline genome integrity. In bovine seminal plasma, piRNAs have not previously been characterized. Thus, the objective of this study was to …
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piRNA-dependent transcriptional gene silencing during Drosophila oogenesis and embryogenesis
… expression by using complementary antisense piRNAs as guides. Following target engagement, the gonad-specific protein Panoramix (Panx) is recruited and induces transcriptional gene silencing (TGS) by connecting to the general chromatin silencing machinery of the cell resulting in changes of …
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Determinants of piRNA precursor transcription and export in Drosophila melanogaster
… mobilisation in animal gonads. The majority of piRNAs originates from discrete source loci named piRNA clusters. In Drosophila germ cells, most piRNAs are produced from both genomic strands of so-called ‘dual-strand’ cluster loci. These loci, embedded in heterochromatin, are licenced by a …
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Biochemical and Structures Studies of tRNA Modificaton and Repair Enzymes
… shown to be responsible for the methylation of piRNAs, some siRNAs as well as endogenous siRNAs. Interestingly, a subset of bacteria also has a Hen1 homolog. Since bacteria do not have canonical RNAi, Hen1 in bacteria (bHen1) might play other biological roles, Our goals are to find out the …
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The Role of Hiwi in Stem Cell Maintenance and Sarcomagenesis
… RNA partners, called piwi-interacting RNAs (piRNAs). More specifically, Piwi/piRNA complexes in the germline are thought to maintain transposon silencing, and thus ensure genomic stability. A detailed mechanism by with Piwis suppress transposon migration in the germline remains an area of …
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Understanding Host Tolerance to Transposable Elements
… DNA damage. Although TE regulation through piRNAs is studied extensively, little is known about mechanisms of gametogenic tolerance to TE activity. To study tolerance I take advantage of a unique phenomenon called hybrid dysgenesis in Drosophila melanogaster where naïve females devoid of …
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Small RNA studies in Drosophila melanogaster, Stylophora pistillata and Symbiodinium sp.
… RNAs (siRNAs) and Piwi-interacting RNAs (piRNAs) play a big role in regulating gene expression in cells. In my work, I focus primarily on miRNAs, which represses the expression of the mRNA targets post-transcriptionally. For Drosophila melanogaster, I predicted the tissue-specific …
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Functional analysis of the Argonaute family proteins during early embryonic and germ cell development in the mouse
… gene expression, while Piwi-interacting RNAs (piRNAs) associate with PIWI proteins to silence transposons in the germ line.<br/>In mammals, genetic experiments revealed that Ago2 is the central effector for both siRNA and miRNA silencing pathways in several developmental processes. …
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The Role of Maelstrom in the Drosophila piRNA Pathway
… which prevents TE mobilisation. Piwi guided by piRNAs to nascent TE transcripts, it recruits factors necessary for creating transcriptionally repressive chromatin. Maelstrom, a protein that is involved in transposon silencing within the Drosophila germline, appears to function in both …
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Exploiting the Conflict Within: Examining Tripartite Interactions for Development of Next Generation Mosquito Microbiome Vector Control Strategies.
… RNAs (siRNAs) and PIWI-interacting RNAs (piRNAs). Additionally, 17 host miRNAs had altered levels across multiple time points. Finally, the mosquito RNAi response to ZIKV targeted the NS5 region, while ZIKV in response produced virus-derived piRNA-like small RNAs (vipRNAs). Together, these …
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Modulation of Alphaviruses by Small RNAs
… by ping-pong-dependent PIWI-interacting RNAs (piRNAs; ~24-30 nucleotides). The complexity of mosquito antiviral immunity has important implications for understanding how viruses both induce and modulate RNA-silencing responses in mosquito vectors. In mammals, viral RIs induce a range of …
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Elucidating the function and biogenesis of small non-coding RNAs using novel computational methods & machine learning.
… on the function and biogenesis of miRNAs and piRNAs, across multiple species, by employing advanced computational methods and machine learning. We first introduce a novel method (Chimira) for the identification of miRNAs from sets of animal and plant hairpin precursors along with …
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Evolutionary conservation of unistrand piRNA clusters and characterisation of the piRNA precursor export machinery in Drosophila
… approaches and deep sequencing of somatic piRNAs, me and my colleagues showed that these loci act as bona-fide unistrand piRNA clusters and are specifically organised to selectively silence *Gypsy*-family transposons, a class of endogenous retroviruses, in the soma. Notable, these …
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