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 33 for “"piwi"”.
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Mosquito Transposable Elements and piwi Genes
… subject focuses on the characterization of piwi genes in the dengue and yellow fever mosquito, Aedes aegypti. For the first subject we characterized Belly by identifying the two identical LTRs and one intact open reading frame. We also defined the target site duplications and boundaries of …
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Silencing Through Heterochromatin Formation: The Role of Piwi in Transposon Targeting
… I have engineered knockdown mutations of Piwi, a nuclear-localized small RNA binding protein, and demonstrated a loss of silencing and a corresponding loss of heterochromatin formation at targeted TE's. Genetic manipulations of Piwi and other components of the system confirm that small RNA …
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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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Roles of piwi-interacting RNAs and small interfering RNAs in regulating gene expression in Caenorhabditis elegans
… small RNAs found in animals: 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 …
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Drosophila Cyclin J And The Somatic Pirna Pathway Cooperate To Regulate Germline Stem Cells
… as well as two other piRNA pathway members (piwi and aub), revealed that CycJ genetically interacts with the piRNA pathways by enhancing their ability to regulate oogenesis. Double mutants of CycJ and mutants of piwi or armi produced mispackaged egg chambers containing an overabundance of …
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Biochemical and cell biological analysis of the mechanism of RNA interference in human cells
… sind und unterteilt diese in die Ago- und die Piwi-Subfamilie, die jeweils vier Mitglieder enthalten. Nur eines der Ago-Proteine ist zur siRNA/miRNA-geleiteten Spaltung von nahezu komplementären Ziel-RNAs imstande, wohingegen alle vier Ago-Subfamilienmitglieder die Translation partiell …
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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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piRNA-dependent transcriptional gene silencing during Drosophila oogenesis and embryogenesis
The PIWI-interacting RNA (piRNA) pathway is a small RNA based intracellular immune system protecting animal gonads from the deleterious effects of transposons, thus maintaining transgenerational genome integrity. In Drosophila melanogaster ovaries, piRNA-Piwi complexes localise to the nucleus and …
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The Role of Hiwi in Stem Cell Maintenance and Sarcomagenesis
… have identified elevated expression of the human Piwi homolog--called Hiwi--in a variety of human cancers, including gastric cancer, pancreatic cancer, gliomas and, most relevant for this dissertation, sarcomas. In sarcomas, Hiwi is highly expressed and elevated Hiwi prognosticates shorter patient …
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Functional analysis of the Argonaute family proteins during early embryonic and germ cell development in the mouse
… family to regulate 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 …
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The Role of Maelstrom in the Drosophila piRNA Pathway
… heterochromatin 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 …
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Analysis of the Role of Piwil2 gene in Tumorigenesis and Germline Stem Cell Metabolisms
Die Gene der piwi Familie werden durch ihre konservierte PAZ und Piwi Domäne charakterisiert und spielen eine wichtige Rolle bei der Stammzellselbsterneuerung , dem RNA silencing und der Translationsregulation in verschiedenen Organismen. Murine und humane Piwil2 Gene, Mitglieder der piwi …
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Mechanisms of piRNA-guided co-transcriptional gene silencing
… In *Drosophila* ovaries, this depends on Piwi, which is guided by a bound small RNA to nascent TE transcripts where it regulates the formation of transcriptionally repressive chromatin states. As well as numerous chromatin modifying proteins, this mechanism depends on the Panx-induced …
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RNAi-related genes in Toxoplasma gondii.
… we found significant homology between the Piwi domains of TgAgo and previously reported Argonaute proteins, but were unable to locate a PAZ domain. Polyclonal antibodies raised against TgAgo peptides have recognized a protein of the expected size (58.5 kDa), which was mainly localized in …
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Small regulatory RNAs in mammals : genomics, function and evolution
… in mammals: (1) the genomic 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 …
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Characterization of Small Non-Coding RNAs in the Seminal Plasma of Beef Bulls with Predicted High and Low Fertility
… of the genome plays 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 …
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Novel Small-RNA Mediated Gene Regulatory Mechanisms for Long-Term Memory
… are up-regulated. Importantly, we find that the piwi/piRNA complex facilitates serotonin-dependent methylation of a conserved CpG island in the promoter of CREB2, the major inhibitory constraint of memory in Aplysia, leading to the persistence of long-term synaptic facilitation. Taken together, …
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Small RNA studies in Drosophila melanogaster, Stylophora pistillata and Symbiodinium sp.
… (miRNAs), small interfering 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 …
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PERPETUATION OF NON-GENETIC CHANGES AT A TRANSGENE LOCUS IN C. ELEGANS
… RDE-1, mating-induced silencing required the Piwi-interacting Argonaute PRG-1. Both processes engaged the same germline Argonaute HRDE-1 to maintain heritable silencing suggesting that both processes trigger silencing independently but converge on the same pathway for maintenance. No other …
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Germline development in Platynereis dumerilii and its connection to embryonic patterning
… in totipotent and stem cells, such as pl10 and piwi, I suggest that there is an ancestral link between these processes, which is conserved in Platynereis. The third part of my thesis addresses the relationship between germline determination and axis formation. Here, I compared the expression …
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