Project description:Various small RNA libraries from purified microtubules or Xiwi immunoprecipitates or total extract from X.tropicalis or X.laevis egg extract. Various small RNA libraries from single X.tropicalis eggs. Analysis of this series of files is described in the manuscript "Systematic and single cell analysis of Xenopus Piwi-interacting RNAs and Xiwi".
Project description:Various small RNA libraries from purified microtubules or Xiwi immunoprecipitates or total extract from X.tropicalis or X.laevis egg extract. Various small RNA libraries from single X.tropicalis eggs. Analysis of this series of files is described in the manuscript "Systematic and single cell analysis of Xenopus Piwi-interacting RNAs and Xiwi". Small RNAs were ligated with linkers and converted to cDNA by reverse transcription. cDNA library was amplified by PCR and was sequenced with either the 454 Genome Sequencer FLX platform or the Illumina GA-II platform.
Project description:Small noncoding (snc) RNAs represent a growing family of transcripts that regulate key cellular processes, including mRNA degradation, translational repression and transcriptional gene silencing. Among these, the PIWI-interacting RNAs (piRNAs), a major class of sncRNAs initially identified in the germline of a variety of species, are now being found to be functionally active also in somatic cells. However, whether the Piwi/piRNA pathway is associated with fundamental biological processes, such as cell cycle progression, remains elusive. Here we investigated the possibility that piRNAs are expressed in liver and modulated during regenerative proliferation of this organ. To this aim, smallRNA-Seq was applied to identify and quantitate expression of these RNAs in rat liver before, during and after the wave of cell proliferation that follows partial hepatectomy (PH). Q-PCR analysis revealed the presence in rat liver of two PIWI (PIWI-Like) subfamily members (PIWIL2/HILI and, to a much lower level, PIWIL4/HIWI2) and other components of the piRNA biogenesis pathways, suggesting that this is present and functional in hepatocytes. Indeed, ~1400 piRNAs originally identified in rat and other mammalian germline cells are expressed in adult rat liver, including 72 that show timed changes in expression during cell cycle progression. Most piRNAs are up-regulated 24-48h after hepatectomy, a timing that corresponds to cell transition through the S phase, and return to basal levels by 168 h, when organ regeneration is completed and hepatocytes reach quiescence. These results indicate that the piRNA pathway is active in somatic cells and, more important, that it is subject to regulation during physiological processes, such as cell proliferation, when piRNAs may exert their regulatory functions on the cell genome and transcriptome. smallRNA-Seq was applied to identify and quantitate expression of RNAs in rat liver before and after partial hepatectomy (PH).
Project description:PIWI-interacting RNAs (piRNAs) are small non-coding RNAs that partner with PIWI proteins to protect germline tissues from destabilizing transposon activity. While the aberrant expression of PIWI proteins has been linked with poor outcomes for many cancers, less is known about the expression or function of piRNAs in cancer. We performed array-based piRNA expression profiling in seven pairs of normal and glioblastoma multiforme (GBM) tissue specimens and identified expression of ~350 piRNAs in both tissues and a subset with dysregulated expression in GBM. Several down-regulated piRNAs inhibited proliferation when transfected into glioma cell lines while those equivalently expressed in tumor and normal tissues did not, consistent with piRNA-specific tumor-suppressive roles. Upregulation of the most underexpressed piRNA, piR-8041, was found to induce cell cycle arrest and apoptosis and to alter transcriptional levels of several genes involved in stress and cell survival pathways. Additionally, the volume of intracranial mouse xenograft tumors was significantly reduced for approximately ten days after pre-implantation transfection with piR-8041. Taken together, our study reveals a previously unidentified functional role for piRNAs as tumor suppressors in gliomagenesis, and suggests that restoration of piRNA levels may be a potential strategy for GBM therapy.
Project description:There have been substantial researches focused on the roles of microRNAs (miRNA) and Piwi-interacting RNAs (piRNA) delivered from mammalian spermatozoa, comparatively little is known about the role of sperm-delivered miRNAs and piRNAs within cockerels’ (breeding cock) sperm. A small RNA library of cockerels’ sperm was constructed using Illumine high-throughput sequencing technology.
Project description:Small noncoding (snc) RNAs represent a growing family of transcripts that regulate key cellular processes, including mRNA degradation, translational repression and transcriptional gene silencing. Among these, the PIWI-interacting RNAs (piRNAs), a major class of sncRNAs initially identified in the germline of a variety of species, are now being found to be functionally active also in somatic cells. However, whether the Piwi/piRNA pathway is associated with fundamental biological processes, such as cell cycle progression, remains elusive. Here we investigated the possibility that piRNAs are expressed in liver and modulated during regenerative proliferation of this organ. To this aim, smallRNA-Seq was applied to identify and quantitate expression of these RNAs in rat liver before, during and after the wave of cell proliferation that follows partial hepatectomy (PH). Q-PCR analysis revealed the presence in rat liver of two PIWI (PIWI-Like) subfamily members (PIWIL2/HILI and, to a much lower level, PIWIL4/HIWI2) and other components of the piRNA biogenesis pathways, suggesting that this is present and functional in hepatocytes. Indeed, ~1400 piRNAs originally identified in rat and other mammalian germline cells are expressed in adult rat liver, including 72 that show timed changes in expression during cell cycle progression. Most piRNAs are up-regulated 24-48h after hepatectomy, a timing that corresponds to cell transition through the S phase, and return to basal levels by 168 h, when organ regeneration is completed and hepatocytes reach quiescence. These results indicate that the piRNA pathway is active in somatic cells and, more important, that it is subject to regulation during physiological processes, such as cell proliferation, when piRNAs may exert their regulatory functions on the cell genome and transcriptome.
Project description:Background: PIWI-interacting RNAs (piRNAs), the largest class of noncoding RNAs in mammals, cooperate with PIWI proteins to safeguard the genome from insertional mutations during germline development. Although a growing number studies have linked the PIWI-piRNA pathway to carcinogenesis, the role of piRNAs in glioma has not been explored. Methods: Utilizing directly measured and imputed genotypes from the GliomaScan genome-wide association study (1,840 cases and 2,401 controls), genetic variants in 1,428 piRNAs were analyzed for association with glioma risk. In vitro assays were performed to interrogate the functional impact of a top identified piRNA and its variant allele. Results: Variants in five piRNAs were considered to be associations of interest and four of these showed narrow clusters of enhanced association signals surrounding the index variant. Functional analyses of one of these piRNAs, piR-598, revealed that transfection of the wild-type piRNA impacted expression of genes involved in cell death/survival, and reduced glioma cell viability and colony formation. However, upon delivery of piR-598 containing the variant allele at rs147061479 (OR=1.80; 95% CI: 1.33-2.46; P=1.69 x 10-4), cell proliferation was sharply increased. Conclusions: These findings suggest that variant rs147061479 in piR-598 increases glioma risk by abolishing the tumor-suppressive function of piR-598, instead conferring growth-promoting properties that may result from a shift in piRNA targets. Impact: This transdisciplinary study demonstrates a role of piRNAs in gliomagenesis by evidence from both post-GWAS and in vitro functional analyses, and supports expanded investigation into the link between the PIWI-piRNA pathway and cancer.