Search results for "piRNA"
showing 7 items of 7 documents
Function and Evolution of Nematode RNAi Pathways
2019
Selfish genetic elements, like transposable elements or viruses, are a threat to genomic stability. A variety of processes, including small RNA-based RNA interference (RNAi)-like pathways, has evolved to counteract these elements. Amongst these, endogenous small interfering RNA and Piwi-interacting RNA (piRNA) pathways were implicated in silencing selfish genetic elements in a variety of organisms. Nematodes have several incredibly specialized, rapidly evolving endogenous RNAi-like pathways serving such purposes. Here, we review recent research regarding the RNAi-like pathways of Caenorhabditis elegans as well as those of other nematodes, to provide an evolutionary perspective. We argue tha…
PIWIL3 Forms a Complex with TDRKH in Mammalian Oocytes.
2019
P-element induced wimpy testis (PIWIs) are crucial guardians of genome integrity, particularly in germ cells. While mammalian PIWIs have been primarily studied in mouse and rat, a homologue for the human PIWIL3 gene is absent in the Muridae family, and hence the unique function of PIWIL3 in germ cells cannot be effectively modeled by mouse knockouts. Herein, we investigated the expression, distribution, and interaction of PIWIL3 in bovine oocytes. We localized PIWIL3 to mitochondria, and demonstrated that PIWIL3 expression is stringently controlled both spatially and temporally before and after fertilization. Moreover, we identified PIWIL3 in a mitochondrial-recruited three-membered complex…
Piwi proteins and piRNAs in mammalian oocytes and early embryos: From sample to sequence
2015
AbstractThe role of the Piwi/piRNA pathway during mammalian oogenesis has remained enigmatic thus far, especially since experiments with Piwi knockout mice did not reveal any phenotypic defects in female individuals. This is in striking contrast with results obtained from other species including flies and zebrafish. In mouse oocytes, however, only low levels of piRNAs are found and they are not required for their function. We recently demonstrated dynamic expression of PIWIL1, PIWIL2, and PIWIL3 during mammalian oogenesis and early embryogenesis. In addition, small RNA analysis of human, crab-eating macaque and cattle revealed that piRNAs are also expressed in the female germline and closel…
RNAs That Behave Like Prions
2020
The term “prion” was originally coined to describe the proteinaceous infectious agents involved in mammalian neurological disorders. More recently, a prion has been defined as a nonchromosomal, protein-based genetic element that is capable of converting the copies of its own benign variant into the prion form, with the new phenotypic effects that can be transmitted through the cytoplasm. Some prions are toxic to the cell, are able to aggregate and/or form amyloid structures, and may be infectious in the wild, but none of those traits are seen as an integral property of all prions. We propose that the definition of prion should be expanded, to include the inducible transmissible entities und…
Intrinsically disordered protein PID-2 modulates Z granules and is required for heritable piRNA-induced silencing in the Caenorhabditis elegans embryo
2020
Abstract In Caenorhabditis elegans, the piRNA (21U RNA) pathway is required to establish proper gene regulation and an immortal germline. To achieve this, PRG‐1‐bound 21U RNAs trigger silencing mechanisms mediated by RNA‐dependent RNA polymerase (RdRP)‐synthetized 22G RNAs. This silencing can become PRG‐1‐independent and heritable over many generations, a state termed RNA‐induced epigenetic gene silencing (RNAe). How and when RNAe is established, and how it is maintained, is not known. We show that maternally provided 21U RNAs can be sufficient for triggering RNAe in embryos. Additionally, we identify PID‐2, a protein containing intrinsically disordered regions (IDRs), as a factor required …
unitas: the universal tool for annotation of small RNAs
2017
AbstractBackgroundNext generation sequencing is a key technique in small RNA biology research that has led to the discovery of functionally different classes of small non-coding RNAs in the past years. However, reliable annotation of the extensive amounts of small non-coding RNA data produced by high-throughput sequencing is time-consuming and requires robust bioinformatics expertise. Moreover, existing tools have a number of shortcomings including a lack of sensitivity under certain conditions, limited number of supported species or detectable sub-classes of small RNAs.ResultsHere we introduce unitas, an out-of-the-box ready software for complete annotation of small RNA sequence datasets, …
Extensive nuclear gyration and pervasive non-genic transcription during primordial germ cell development in zebrafish.
2020
ABSTRACT Primordial germ cells (PGCs) are the precursors of germ cells, which migrate to the genital ridge during early development. Relatively little is known about PGCs after their migration. We studied this post-migratory stage using microscopy and sequencing techniques, and found that many PGC-specific genes, including genes known to induce PGC fate in the mouse, are only activated several days after migration. At this same time point, PGC nuclei become extremely gyrated, displaying general broad opening of chromatin and high levels of intergenic transcription. This is accompanied by changes in nuage morphology, expression of large loci (PGC-expressed non-coding RNA loci, PERLs) that ar…