Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1018221 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Purified endogenous mouse MIWI fails to cleave mismatched targets in vitro. Surprisingly, here we find using knock-in mouse models that piRNA target sites with cleavage-site mismatches are precisely sliced in vivo. This is identical to the slicing outcome in knock-in mice where targets are identified by perfect complementarity base-pairing with the piRNA. Additionally, we find that such pachytene piRNA-guided MIWI/MILI slicing in vivo failed to initiate phased piRNA production from the specific target mRNA we studied. Instead, the two slicer cleavage fragments were retained in PIWI proteins as a pre-piRNA and 17-19 nt by-product fragments. Our results indicate that PIWI slicing rules established in vitro are not respected in vivo, and that all targets of PIWI slicing are not substrates for piRNA biogenesis.
2023-10-23 | GSE219200 | GEO
Project description:Small RNA was isolated from neuronal cultures transduced with different shRNA constructs direct against shNogoA with and without mismatches in the seed region
2020-12-31 | GSE156879 | GEO
Project description:In mice, the PIWI-piRNA pathway is essential to re-establish transposon silencing during male germline reprogramming. The cytoplasmic PIWI protein MILI mediates piRNA-guided transposon RNA cleavage as well as piRNA amplification. MIWI2-bound piRNAs and its nuclear localization are proposed to be dependent upon MILI function. Here, we demonstrate the existence of a piRNA biogenesis pathway that in the absence of MILI that sustains partial MIWI2 function and reprogramming activity.
2017-04-25 | E-MTAB-5561 | biostudies-arrayexpress
Project description:The bacterial CRISPR-Cas9 system has been widely adapted for RNA-guided genome editing and gene regulation in diverse organisms yet its in vivo target specificity is poorly understood. Here we provide the first genome-wide binding maps of nuclease-deactivated Cas9 loaded with guide RNAs in mammalian cells. We find a 5-nucleotide seed region in the guide RNA targets Cas9 to thousands of sites in the genome. Chromatin accessibility limits binding to the other hundreds of thousands sites with matching seed sequences, and consequently 70% of off-target binding sites are associated with genes. U-rich seeds have low numbers of off-target sites limited by both low guide RNA abundance and scarcity of complimentary sites in accessible chromatin. Unexpectedly, off-target sites show little evidence of cleavage, supporting a two-state model reminiscent of eukaryotic RNAi machinery where a short seed match triggers binding but extensive pairing is required for cleavage. ChIP-seq of HA-dCas9 loaded with 4 sgRNAs (Phc1-sg1, Phc1-sg2, Nanog-sg2, and Nanog-sg3) in mouse, and 2 sgRNAs in human (EMX1-sg1 and EMX1-sg3)
2014-04-20 | E-GEOD-54745 | biostudies-arrayexpress
Project description:The experiments were conducted to check whether mismatches and wobble base pairs in the upper stem of pri-miRNAs affects the DROSHA cleavage and thereby miRNA biogenesis.
2020-02-28 | GSE142136 | GEO
Project description:The bacterial CRISPR-Cas9 system has been widely adapted for RNA-guided genome editing and gene regulation in diverse organisms yet its in vivo target specificity is poorly understood. Here we provide the first genome-wide binding maps of nuclease-deactivated Cas9 loaded with guide RNAs in mammalian cells. We find a 5-nucleotide seed region in the guide RNA targets Cas9 to thousands of sites in the genome. Chromatin accessibility limits binding to the other hundreds of thousands sites with matching seed sequences, and consequently 70% of off-target binding sites are associated with genes. U-rich seeds have low numbers of off-target sites limited by both low guide RNA abundance and scarcity of complimentary sites in accessible chromatin. Unexpectedly, off-target sites show little evidence of cleavage, supporting a two-state model reminiscent of eukaryotic RNAi machinery where a short seed match triggers binding but extensive pairing is required for cleavage.
2014-04-20 | GSE54745 | GEO
Project description:During embryonic germ cell development in mice, transposon-enriched, piwi-interacting RNAs (piRNAs) guide MILI and MIWI2 to direct silencing of potentially active mobile element families. In contrast, we know much less about the function of the highly abundant and extremely diverse class of piRNAs, which partner with MIWI and MILI during meiosis. Both MIWI and its catalytic activity are required for successful spermatogenesis, strongly indicating that piRNA-guided cleavage is critical for germ cell development. To gain an understanding of meiotic piRNA targets, we augmented the mouse piRNA repertoire by introducing an entire human meiotic piRNA cluster. This triggered a spermatogenesis defect, presumably by inappropriately targeting the piRNA machinery to mouse RNAs essential for germ cell development. Through an analysis of such de novo targets, we derived a signature for pachytene piRNA target recognition. This enabled identification of both transposable elements and meiotically expressed protein coding genes as targets of native piRNAs. Cleavage of genic targets begins at the pachytene stage when meiotic piRNAs first appear. As such, target mRNA levels attenuate starting from the pachytene stage and are further repressed throughout meiosis. Target mRNA-piRNA pairs also show evidence of an ongoing cleavage-dependent amplification cycle, which is not normally a strong feature of meiotic piRNAs. Our data support the idea that meiotic piRNA populations must be strongly selected to enable successful spermatogenesis, both driving the response away from essential genes and directing the pathway toward mRNA targets that are regulated by small RNAs in meiotic cells. 48 samples
2015-05-22 | E-GEOD-64138 | biostudies-arrayexpress
Project description:Ribosomal-depleted total RNA was isolated from neuronal cultures transduced with different shRNA constructs direct against shNogoA with and without mismatches in the seed region
2020-12-31 | GSE156878 | GEO
Project description:PIWI-interacting RNAs (piRNAs) guide PIWI proteins to suppress transposable elements in animal gonads. Here we demonstrate that in the mouse embryonic male germline, endonucleolytic cleavage (slicing) of a transcript by cytosolic MILI acts as a trigger to initiate its further 5??3? processing into non-overlapping fragments. These fragments accumulate as new piRNAs within the nuclear PIWI protein MIWI2. We identify Exonuclease domain-containing 1 (EXD1) as a partner of the established MIWI2 piRNA biogenesis factor TDRD12. Although EXD1 homodimers are inactive as a nuclease, it functions as an RNA adapter within a PET (PIWI-EXD1-Tdrd12) complex. Loss of Exd1 impacts biogenesis of MIWI2 piRNAs and displays a reduction in sequences generated by MILI slicing. This results in selective depletion of repeat piRNAs that target active retrotransposons like LINE1, which are de-repressed in the mutant. We propose that PIWI slicing and EXD1 promote coordination of nucleo-cytoplasmic silencing via piRNA biogenesis. Immunoprecipitated or total small RNAs were purified and sequenced from P0 mouse testis of Exd1+/- and Exd1 -/- mice. Testes of three males were pooled together and MILI and MIWI2 immunoprecipitation was performed or total small RNAs were purified. Two replicas from different pools were prepared. For Rosa26-pi reporter mouse P0 testes of three males were pooled together and MILI and MIWI2 immunoprecipitation was performed.
2015-12-04 | E-GEOD-74423 | biostudies-arrayexpress
Project description:We present “centered sites,” a class of microRNA target sites that lacks both perfect seed pairing and 3'-compensatory pairing and instead has 11–12 contiguous Watson–Crick pairs to the center of the microRNA. In elevated Mg2+, centered sites impart mRNA cleavage, but in cells, centered sites repress protein output without consequential Agronaute-catalyzed cleavage. Our study also identified novel extensively paired sites that are cleavage substrates in cultured cells and human brain. This expanded repertoire of cleavage targets and the identification of the centered site type help explain why central regions of many microRNAs are evolutionarily conserved.
2010-06-25 | GSE22068 | GEO