Project description:B2-SINEs are noncoding RNAs which are transcribed by RNA polymerase III (Pol III) from short interspersed nuclear elements (SINEs), which are high copy number transposable elements in the mouse genome. Unexpectedly have observed significant induction of non-coding RNAs from the B2-SINE subclass of repeat element RNAs in DRG neurons following sciatic nerve injury. We next sought to identify intracellular targets of GI-SINEs, by protein pull-down from sciatic nerve axoplasm using biotinylated B2-SINE RNA as bait. We generated two constructs from the B2 consensus sequence, comprising 5’ (1-75nt) and 3’ (75-166nt) sequences, both predicted to retain their respective structures, and used the constructs to pull down axoplasm proteins for mass spectrometry analysis. Further confirmatory experiments were performed using the mentioned -175nt sequence vs a control U1 SL3+4 RNA
Project description:We identified 2 specific motifs that are enriched in GI-SINE RNA expressed in sciatic-nerve injured DRG neurons compared to non-regulated B2-SINE RNAs. We designed a mix of 5 ASOs (21nt phosphorothioate DNA with LNA-flanks) that target these motifs and transfected those into cultured dorsal root ganglia (DRG) neurons. Control ASO was based on a 21nt non-targetting sequence from shControl backbone (addgene plasmid #85741). Primary DRG neurons were transfected using Dharmafect-4 with ASO at 50nM final concentration 1 hour after plating. Cultures were processed for RNA extraction 48h after transfection for RNA sequencing to identify changes in B2-SINE expression.
Project description:Short interspersed element (SINE) RNAs are upregulated by cellular stresses1 (heat shock, DNA damage and viral infection) and accumulate in human diseases (macular degeneration2, lupus3, and Alzheimer’s disease4). These transcripts activate inflammasomes5, a family of cytoplasmic multiprotein complexes that sense danger molecules and initiate innate immune responses by activating caspase-1-dependent cytokine production and inflammatory death6, but the molecular sensor of SINE RNAs is unknown. Here, we identify DDX17, a member of the DEAD box family of RNA helicases7, as a sensor of SINE RNAs requisite for inflammasome activation. Induction of caspase-1 cleavage and release of IL-1 and IL-18 by SINE RNAs requires dual recruitment of NLRP3 and NLRC4 but proceeds independent of NAIPs, immune sensors required for canonical NLRC4 activation by bacterial proteins8,9. Instead, SINE RNAs trigger DDX17–NLRC4 interaction, which licenses inflammasome activation. We also report increased levels of DDX17 protein and association of DDX17 and NLRC4 in the retinal pigmented epithelium (RPE) of human eyes with an advanced, untreatable form of age-related macular degeneration (AMD). Disrupting DDX17–NLRC4 signalling blocks SINE RNA-induced inflammasome activation in human RPE cells and RPE degeneration in an animal model of AMD. Our findings uncover a non-canonical mode of inflammasome activation by endogenous retrotransposon transcripts, and provide new potential targets for macular degeneration and potentially other diseases.
Project description:Short interspersed nuclear elements (SINEs) are retrotransposons evolutionarily derived from endogenous RNA Polymerase III RNAs. Though SINE elements have undergone exaptation into gene regulatory elements, how transcribed SINE RNA impacts transcriptional and post-transcriptional regulation is largely unknown. This is partly due to a lack of information regarding which of the loci have transcriptional potential. Here, we present an approach (short interspersed nuclear element sequencing, SINE-seq), which selectively profiles RNA Polymerase III-derived SINE RNA, thereby identifying transcriptionally active SINE loci. Applying SINE-seq to monitor murine B2 SINE expression during a gammaherpesvirus infection revealed transcription from 28,270 SINE loci, with ~50% of active SINE elements residing within annotated RNA Polymerase II loci. Furthermore, B2 RNA can form intermolecular RNA-RNA interactions with complementary mRNAs, leading to nuclear retention of the targeted mRNA via a mechanism involving p54nrb. These findings illuminate a pathway for the selective regulation of mRNA export during stress via retrotransposon activation.
Project description:We identified a novel long non-coding RNA Lx8-SINE B2, that is a marker of pluripotency. Depletion of Lx8-SINE B2 impacts embryonic stem cell self-renewal. RNA-seq analysis of Lx8-SINE B2 depletion revealed that a number of glycolytic genes with decreased expression. Mechanistically, we found that the Lx8-SINE B2 activates the glycolysis pathway by binding to Eno1. Collectively, our data suggest that Lx8-SINE B2 maintains the self-renewal of mESCs through glycolysis.
Project description:We report genome-wide binding of the highly conserved TF Sine oculis (So), which is necessary for Drosophila eye development and has few previously known direct transcriptional targets. Our data identify novel putative targets of So-mediated regulation, including genes involved in multiple aspects of development. 2 biological replicates of ChIP-seq with anti-So antibody on chromatin from D. melanogaster third instar eye-antennal imaginal discs; negative control - same sample and ChIP-seq protocol without anti-So antibody
Project description:To identify the eye-enriched genes by comparing the mRNA expression profiles from wild type fly heads (CantonS) and eye-less fly heads (sine occulis).