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???displayArticle.abstract??? Piwi proteins and Piwi-interacting RNAs (piRNAs) are essential for germ cell development, but analysis of the molecular mechanisms of these ribonucleoproteins remains challenging in most animal germ cells. To address this challenge, we systematically characterized Xiwi, a Xenopus Piwi homologue, and piRNAs from Xenopus eggs and oocytes. We used the large size of Xenopus eggs to analyze small RNAs at the single cell level, and find abundant piRNAs and large piRNA clusters in the Xenopus tropicalis genome, some of which resemble the Drosophila piRNA-generating flamenco locus. Although most piRNA clusters are expressed simultaneously in an egg, individual frogs show distinct profiles of cluster expression. Xiwi is associated with microtubules and the meiotic spindle, and is localized to the germ plasm--a cytoplasmic determinant of germ cell formation. Xiwi associates with translational regulators in an RNA-dependent manner, but Xenopus tudor interacts with Xiwi independently of RNA. Our study adds insight to piRNA transcription regulation by showing that individual animals can have differential piRNA expression profiles. We suggest that in addition to regulating transposable elements, Xiwi may function in specifying RNA localization in vertebrate oocytes.
Allison,
Two distinct Staufen isoforms in Xenopus are vegetally localized during oogenesis.
2004, Pubmed,
Xenbase
Allison,
Two distinct Staufen isoforms in Xenopus are vegetally localized during oogenesis.
2004,
Pubmed
,
Xenbase
Aravin,
Developmentally regulated piRNA clusters implicate MILI in transposon control.
2007,
Pubmed
Aravin,
The Piwi-piRNA pathway provides an adaptive defense in the transposon arms race.
2007,
Pubmed
Aravin,
A piRNA pathway primed by individual transposons is linked to de novo DNA methylation in mice.
2008,
Pubmed
Aravin,
A novel class of small RNAs bind to MILI protein in mouse testes.
2006,
Pubmed
Batista,
PRG-1 and 21U-RNAs interact to form the piRNA complex required for fertility in C. elegans.
2008,
Pubmed
Boswell,
tudor, a gene required for assembly of the germ plasm in Drosophila melanogaster.
1985,
Pubmed
Brennecke,
An epigenetic role for maternally inherited piRNAs in transposon silencing.
2008,
Pubmed
Brennecke,
Discrete small RNA-generating loci as master regulators of transposon activity in Drosophila.
2007,
Pubmed
Brodersen,
Widespread translational inhibition by plant miRNAs and siRNAs.
2008,
Pubmed
Brown,
Xenopus tropicalis egg extracts provide insight into scaling of the mitotic spindle.
2007,
Pubmed
,
Xenbase
Carmell,
MIWI2 is essential for spermatogenesis and repression of transposons in the mouse male germline.
2007,
Pubmed
Chang,
Localization of RNAs to the mitochondrial cloud in Xenopus oocytes through entrapment and association with endoplasmic reticulum.
2004,
Pubmed
,
Xenbase
Cox,
A novel class of evolutionarily conserved genes defined by piwi are essential for stem cell self-renewal.
1998,
Pubmed
Deng,
miwi, a murine homolog of piwi, encodes a cytoplasmic protein essential for spermatogenesis.
2002,
Pubmed
Desai,
The use of Xenopus egg extracts to study mitotic spindle assembly and function in vitro.
1999,
Pubmed
,
Xenbase
Ferrell,
Xenopus oocyte maturation: new lessons from a good egg.
1999,
Pubmed
,
Xenbase
Ghildiyal,
Endogenous siRNAs derived from transposons and mRNAs in Drosophila somatic cells.
2008,
Pubmed
Girard,
A germline-specific class of small RNAs binds mammalian Piwi proteins.
2006,
Pubmed
Griffiths-Jones,
miRBase: tools for microRNA genomics.
2008,
Pubmed
Grivna,
MIWI associates with translational machinery and PIWI-interacting RNAs (piRNAs) in regulating spermatogenesis.
2006,
Pubmed
Gunawardane,
A slicer-mediated mechanism for repeat-associated siRNA 5' end formation in Drosophila.
2007,
Pubmed
Hinrichs,
The UCSC Genome Browser Database: update 2006.
2006,
Pubmed
Hiyoshi,
Involvement of Xtr (Xenopus tudor repeat) in microtubule assembly around nucleus and karyokinesis during cleavage in Xenopus laevis.
2005,
Pubmed
,
Xenbase
Houwing,
A role for Piwi and piRNAs in germ cell maintenance and transposon silencing in Zebrafish.
2007,
Pubmed
Jurka,
Repetitive sequences in complex genomes: structure and evolution.
2007,
Pubmed
Jurka,
Repbase Update, a database of eukaryotic repetitive elements.
2005,
Pubmed
King,
Putting RNAs in the right place at the right time: RNA localization in the frog oocyte.
2005,
Pubmed
,
Xenbase
Kirino,
Arginine methylation of Piwi proteins catalysed by dPRMT5 is required for Ago3 and Aub stability.
2009,
Pubmed
,
Xenbase
Klattenhoff,
Biogenesis and germline functions of piRNAs.
2008,
Pubmed
Klenov,
Repeat-associated siRNAs cause chromatin silencing of retrotransposons in the Drosophila melanogaster germline.
2007,
Pubmed
Kloc,
RNA localization mechanisms in oocytes.
2005,
Pubmed
Kotaja,
Interplay of PIWI/Argonaute protein MIWI and kinesin KIF17b in chromatoid bodies of male germ cells.
2006,
Pubmed
Kuramochi-Miyagawa,
DNA methylation of retrotransposon genes is regulated by Piwi family members MILI and MIWI2 in murine fetal testes.
2008,
Pubmed
Kuramochi-Miyagawa,
Mili, a mammalian member of piwi family gene, is essential for spermatogenesis.
2004,
Pubmed
Lau,
Characterization of the piRNA complex from rat testes.
2006,
Pubmed
Malone,
Specialized piRNA pathways act in germline and somatic tissues of the Drosophila ovary.
2009,
Pubmed
Michalak,
Testis-derived microRNA profiles of African clawed frogs (Xenopus) and their sterile hybrids.
2008,
Pubmed
,
Xenbase
O'Donnell,
Mighty Piwis defend the germline against genome intruders.
2007,
Pubmed
Okamura,
Endogenous small interfering RNAs in animals.
2008,
Pubmed
Parry,
A whole-genome RNAi Screen for C. elegans miRNA pathway genes.
2007,
Pubmed
Rodriguez,
Seawi--a sea urchin piwi/argonaute family member is a component of MT-RNP complexes.
2005,
Pubmed
Saffman,
Germline development in vertebrates and invertebrates.
1999,
Pubmed
,
Xenbase
Saito,
Specific association of Piwi with rasiRNAs derived from retrotransposon and heterochromatic regions in the Drosophila genome.
2006,
Pubmed
Sprangers,
High-resolution X-ray and NMR structures of the SMN Tudor domain: conformational variation in the binding site for symmetrically dimethylated arginine residues.
2003,
Pubmed
Tam,
Pseudogene-derived small interfering RNAs regulate gene expression in mouse oocytes.
2008,
Pubmed
Thomson,
Isolation of new polar granule components in Drosophila reveals P body and ER associated proteins.
2008,
Pubmed
Unhavaithaya,
MILI, a PIWI-interacting RNA-binding protein, is required for germ line stem cell self-renewal and appears to positively regulate translation.
2009,
Pubmed
Vagin,
A distinct small RNA pathway silences selfish genetic elements in the germline.
2006,
Pubmed
Vasileva,
Tdrd6 is required for spermiogenesis, chromatoid body architecture, and regulation of miRNA expression.
2009,
Pubmed
Voeltz,
A novel embryonic poly(A) binding protein, ePAB, regulates mRNA deadenylation in Xenopus egg extracts.
2001,
Pubmed
,
Xenbase
Wang,
Mili interacts with tudor domain-containing protein 1 in regulating spermatogenesis.
2009,
Pubmed
Watanabe,
Endogenous siRNAs from naturally formed dsRNAs regulate transcripts in mouse oocytes.
2008,
Pubmed
Wheeler,
Database resources of the National Center for Biotechnology Information.
2005,
Pubmed
Wilczynska,
Two Piwi proteins, Xiwi and Xili, are expressed in the Xenopus female germline.
2009,
Pubmed
,
Xenbase
Yin,
An epigenetic activation role of Piwi and a Piwi-associated piRNA in Drosophila melanogaster.
2007,
Pubmed
