PIWI proteins and PIWI-interacting RNAs (piRNAs) mediate repression of transposons in the animal gonads. Primary processing converts long single-stranded into ∼30-nt piRNAs, but their entry biogenesis pathway is unknown. Here, we demonstrate that an RNA element at 5′ end a piRNA cluster—which termed trigger sequence (PTS)—can induce primary any downstream sequence. We propose such signals are triggers for generation original pool piRNAs. also endonucleolytic cleavage transcript by cytosolic...

A relationship exists between nuclear architecture and gene activity it has been proposed that the of ongoing RNA polymerase II transcription determines genome organization in mammalian cell nucleus. Recently developed 3C 4C technology allowed us to test importance for architecture. We demonstrate upon inhibition binding regulatory elements is severely reduced. However, contacts DNA genes β-globin locus are unaffected still interacts with same genomic regions elsewhere on chromosome. This a...

ABSTRACT Animal germ cells deploy a specialized small RNA-based silencing system, called the PIWI-interacting RNA (piRNA) pathway, to prevent unwanted expression of transposable elements and maintain genome integrity. In Drosophila cells, majority piRNA populations originate from dual-strand clusters, genomic regions highly enriched in transposon fragments, via an elaborate protein machinery centred on heterochromatin 1 homolog, Rhino. Although Rhino binds peptides carrying trimethylated...

For species survival, the germline must faithfully transmit genetic information to progeny. Transposable elements (TEs) constitute a significant threat genome stability due their mobility. In metazoan germline, mobilization is limited by class of small RNAs called PIWI-interacting (piRNAs) produced dedicated genomic loci piRNA clusters. Although pathway an adaptive immunity system, it remains unclear how gains protection from new transposon invasion. To address this question, we analyze...

Gap junctions allow the exchange of small molecules between cells. How this function could be used to promote cell growth is not yet fully understood. During Drosophila ovarian follicle development, germ cells, which are surrounded by epithelial somatic undergo massive growth. We found that depends on gap these populations, with a requirement for Innexin4 and Innexin2, in cells respectively. Translatomic analyses revealed express enzymes transporters involved amino acid metabolism absent...

Microsporidian genomes are the leading models to understand streamlining in response a pathogenic lifestyle; they gene-poor and often possess small genomes. In this study, we show feature of microsporidian that contrasts pattern genome reduction. Specifically, investigations targeted at Anncaliia algerae, human pathogen with size 23 Mb, revealed presence hitherto undetected diversity transposable elements (TEs). A total 240 TE families per were identified, exceeding found many free-living...

PIWI-interacting RNAs (piRNAs) are effectors of transposable element (TE) silencing in the reproductive apparatus. In Drosophila ovarian somatic cells, piRNAs arise from longer single-stranded RNA precursors that processed cytoplasm presumably within Yb-bodies. piRNA encoded by flamenco (flam) cluster accumulate a single focus away their sites transcription. this study, we identify exportin complex containing Nxf1 and Nxt1 as required for flam precursor nuclear export. Together with...

Abstract Background Retroviruses have evolved various mechanisms to optimize their transfer new target cells via late endosomes. Here, we analyzed the of ZAM, a retroelement from Drosophila melanogaster , ovarian follicle oocyte at stage 9–10 oogenesis, when an active yolk is occurring between these two cell types. Results Combining genetic and microscopic approaches, show that functional secretory apparatus required tether ZAM endosomal vesicles direct its transport apical side cells....

Abstract During Drosophila oogenesis, transposable element (TE) repression involves the Piwi-interacting RNA (piRNA) pathway which ensures genome integrity for next generation. We developed a transgenic model to study of Idefix retrotransposon in germline. Using candidate gene KD-approach, we identified differences spatio-temporal requirements piRNA components piRNA-mediated silencing. Some them (Aub, Vasa, Spn-E) are necessary very early stages oogenesis within germarium and appear be less...

Transposable elements (TEs) are major components of genomes. Their mobilization may affect genomic expression and be a threat to genetic stability. This is why they have tightly regulated by dedicated system. In the reproductive tissues large range organisms, repressed subclass small interfering RNAs called piRNAs (PIWI interacting RNAs). Drosophila melanogaster, produced both in ovarian germline cells their surrounding somatic cells. Accumulating evidence suggests that germinal piRNA...

Specific genomic loci, termed Piwi-interacting RNA (piRNA) clusters, manufacture piRNAs that serve as guides for the inactivation of complementary transposable elements (TEs). The piRNA pathway has been accurately detailed in Drosophila melanogaster, while it remains poorly examined other insects. This is increasingly recognized critical germline development and reproduction. Understanding functions mosquitoes could offer an opportunity disease vector control by reduction their reproductive...

Transposable element (TE) activity is repressed in animal gonads by PIWI-interacting RNAs (piRNAs) produced piRNA clusters. Current models flies propose that germinal clusters are functionally defined the maternal inheritance of piRNAs during previous generation. Taking advantage an inactive, but ready to go, cluster P-element derived transgene insertions Drosophila melanogaster, we show here raising at high temperature (29°C) instead 25°C triggers stable conversion this locus from inactive...

The piRNA pathway protects genomes by silencing mobile elements. Despite advances in understanding the processing events that generate piRNAs for silencing, little is known about how primary transcripts are transported from their genomic clusters to centers. Using a model of Drosophila COM/flamenco locus ovarian somatic cells, we identified prominent nuclear structure called Dot COM, which enriched long but located far transcription sites. Remarkably, multiple accumulate at often juxtaposed...

Abstract Background High-throughput deep-sequencing technology has generated an unprecedented number of expressed sequence reads that offer the opportunity to get insight into biological systems. Several databases report small regulatory RNAs which play a prominent role in control transposable elements (TE). However, huge amount data reported these remains mostly unexplored because available tools are hard for biologists use. Results Here we NucBase, new program designed make exhaustive...

The field of small RNA is one the most investigated research areas since they were shown to regulate transposable elements and gene expression play essential roles in fundamental biological processes. Small deep sequencing (sRNA-seq) now routinely used for large-scale analyses RNA. Such high-throughput typically produces several millions reads. Here we present a computational pipeline (sRNAPipe: pipeline) based on Galaxy framework that takes as input fastq file RNA-seq reads performs...

Transposable elements (TEs) have invaded most genomes and constitute up to 50% of the human genome. Machinery based on small non-coding piRNAs has evolved inhibit their expression at transcriptional post-transcriptional levels. Surprisingly, this machinery is weakened during specific windows time in mice, flies or plants, allowing TEs germline cells. The function de-repression remains unknown. In Drosophila, we previously shown that developmental window characterized by a reduction Piwi...

Most Drosophila transposable elements are LTR retrotransposons, some of which belong to the genus Errantivirus and share structural functional characteristics with vertebrate endogenous retroviruses. Like retroviruses, it is unclear whether errantiviruses retain infectivity transposition capacity. We created conditions where control ZAM errantivirus through piRNA pathway was abolished leading its de novo reactivation in somatic gonadal cells. After reactivation, invaded oocytes severe...

Eukaryotic mRNAs are modified at the 5′ end with a methylated guanosine (m 7 G) that is attached to transcription start site (TSS) nucleotide. The TSS nucleotide 2′- O -methylated (Nm) by CMTR1 in organisms ranging from insects human. In mammals, adenosine can be further N 6 RNA polymerase II phosphorylated CTD-interacting factor 1 (PCIF1) create m Am. Curiously, fly ortholog of mammalian PCIF1 demonstrated catalytic-dead, and its functions not known. Here, we show Pcif1 mutant flies display...

A report on the 'Non-coding RNA, epigenetics and transgenerational inheritance' meeting, Churchill College, Cambridge, UK, 11-12 April 2013.

PIWI-interacting RNAs (piRNAs) target transcripts by sequence complementarity serving as guides for RNA slicing in animal germ cells. The piRNA pathway is increasingly recognized critical essential cellular functions such germline development and reproduction. In the Anopheles gambiae ovary, much 11% of piRNAs map to protein-coding genes. Here, we show that ovarian mRNAs long non-coding (lncRNAs) are processed into can direct other biogenesis pathway. Targeting fuel either ping-pong cycle...