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 31 for “"piRNA"”.
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Evolutionary conservation of unistrand piRNA clusters and characterisation of the piRNA precursor export machinery in Drosophila
The PIWI-interacting RNA (piRNA) pathway prevents endogenous genomic parasites, transposable elements, from damaging the genetic material of animal gonadal cells. Specific regions in the genome, called piRNA clusters, are thought to define each species’ piRNA repertoire and therefore its capacity …
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Mechanisms of piRNA-guided co-transcriptional gene silencing
… Nxt1. PICTS operates at the interface between piRNA-guided Piwi and heterochromatin effectors. While the N-terminal region of Panx is known to deliver the transcriptional silencing signal, the molecular mechanism by which PICTS induces heterochromatin formation at TE insertions is not fully …
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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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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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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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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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Determinants of piRNA precursor transcription and export in Drosophila melanogaster
The piRNA pathway is a conserved, small RNA-based immune system that guards genomic integrity against the harmful effects of transposon mobilisation in animal gonads. The majority of piRNAs originates from discrete source loci named piRNA clusters. In Drosophila germ cells, most piRNAs are produced …
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Transcriptional regulation of the piRNA pathway in animal ovarian germ cells
The PIWI-interacting RNA (piRNA) pathway is a deeply conserved mechanism by which animals guard their genomes against the activity of mobile genetic elements. The gene-regulatory networks controlling the expression of the germline piRNA pathway components within the gonads of metazoan species …
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Mechanisms of piRNA biogenesis and co-transcriptional silencing of transposable elements in Drosophila
… safeguard genome integrity. Among these is the piRNA pathway, a gonad-specific system based on small non-coding RNAs that recognise active transposons and instruct their silencing. Ultimately, piRNAs trigger epigenetic silencing of transposon loci. The work in this thesis investigates the …
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Drosophila Cyclin J And The Somatic Pirna Pathway Cooperate To Regulate Germline Stem Cells
… in a genetic interaction with neighboring piRNA pathway gene, armitage (armi). Here I assessed oogenesis in CycJ null in the presence or absence of mutations in armi or other piRNA pathway genes. Although CycJ null flies had decreased egg laying and hatching rates, ovaries appeared normal …
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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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Mechanisms governing transposable element expression in the Drosophila germ line
… notably including the PIWI-interacting RNA (piRNA) pathway, which acts to repress its targets through both chromatin-mediated silencing and post-transcriptional slicing. The P-element is a classic example of an active transposon that has been highly successful in invading new populations and …
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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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Transcriptional and developmental consequences of aneuploidy during male meiosis
… in the male germline involves the expression of piRNAs, a class of small non-coding RNAs that are commonly found in the germline of animals where they defend cells against transposable elements. Profiling the expression of small RNAs in the Tc1 mouse showed that conserved human piRNA clusters can …
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The organization and evolution of heterochromatin in the Anopheles gambiae complex
… study also looks at the Piwi-interacting RNA (piRNA) pathway and its role in An. gambiae. The piRNA pathway is associated with transposable element (TE) suppression in many species, where clusters of vestigial TEs provide some of the RNA necessary for the pathway to function. These clusters are …
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P53 Genes Act to Restrain Mobile Elements
… genetically interacted with components of the piRNA pathway and, in complementation studies, normal human p53 alleles restrained these mobile elements, but mutant p53 alleles from cancer patients could not. Consistent with these results, we also found patterns of unrestrained retrotransposons …
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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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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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Rearrangements of 7q11.23: disorders of the epigenome
… of Fkbp6, a gene involved in meiosis and piRNA biogenesis, in mouse and human cortical tissue, which may contribute to parent-of-origin dependent expression of phenotypes in WS. These data suggest WS and Dup7 are disorders of the epigenome, and that DNA methylation may be an important …
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Large replisome-dependent heterochromatic domains defining the transgenerational regulatory landscape
… region and the high H3K9me3 region is rich in piRNA loci and poor RNA PolII binding. Interestingly, these “corrie” domains tend to contain Helitron elements at the activation peak rich in periodic An/Tn sequences, which protect endogenous genes from sRNA silencing. This research highlights the …
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