Project description:More than 98% of the mammalian genome is noncoding and interspersed transposable elements account for ~50% of noncoding space. Here, we demonstrate that a specific interaction between the Polycomb protein, EZH2, and RNA made from B2 SINE retrotransposons controls stress-responsive genes in mouse cells. In the heat shock model, B2 RNA binds stress genes and suppresses their transcription. Upon stress, EZH2 is recruited and triggers cleavage of B2 RNA. B2 degradation in turn upregulates stress genes. Evidence indicates that B2 RNA operates as "speed bumps" against advancement of RNA Polymerase II and temperature stress releases the brakes on transcriptional elongation. These data attribute a new function to EZH2 that is independent of its histone methyltransferase activity and reconcile how EZH2 can be associated with both gene repression and activation. Our study reveals that EZH2 and B2 together control activation of a large network of genes involved in thermal stress.
Project description:More than 98% of the mammalian genome is noncoding and approximately half is made up of transposable elements. One of the most abundant is the short interspersed nuclear elements (SINE). Among the million copies of SINEs, B2 accounts for ~350,000 in the mouse genome and have garnered special interest because of emerging roles in gene regulation. Our recent work demonstrated that B2 RNA normally binds stress genes to retard transcription elongation. Though epigenetically silenced, B2s become massively upregulated during thermal stress. Specifically, an interaction between B2 RNA and the Polycomb protein, EZH2, results in cleavage of B2 RNA, release of B2 RNA from RNA Polymerase II, and activation of the stress genes. Although an established RNA-binding protein and histone methyltransferase, EZH2 is not known to be a nuclease. Here, we provide evidence for the surprising conclusion that B2 is a self-cleaving RNA. Contact with EZH2 accelerates cleavage rate by >100-fold, suggesting that EZH2 may assist cleavage as an RNA chaperone. Modification-interference analysis demonstrate that phosphorothioate changes at A and C nucleotides can substitute for EZH2’s function. B2 mutagenesis indicate that nucleotides around positions 45-55 and 100-101 are critical for cleavage reaction. Finally, we demonstrate that another family of SINEs, the ALU elements produce also a self-cleaving RNA. ALUs are intrinsically more auto-reactive than B2s. We propose that the B2/ALU SINEs are a new class of ribozymes whose activity is accelerated by EZH2.
Project description:We report the comparison between SINE B2-AS transcriptome profiling and Dicer1-deficient-cell transcriptome profiling using RNA-seq analysis. We report that thousands of SINE B2 copies encode long B2-AS transcripts, which are constantly degraded by Dicer1. This new class of B2-AS transcripts regulates the expression of SINE B2 sense (B2-S) transcripts. Long B2-S is the main cause of cellular toxicity likely mediated by the multifunctional protein TSPO. Some B2-AS transcripts are putative miRNAs interconnected with the RNAi system. We propose that B2-AS transcripts have evolved as a self-defense mechanism to subvert the host RNAi system.
Project description:Global identification of activated GR and p65 binding sites and target genes using ChIP-seq in HeLa B2 cells. generation genome-wide chromatin state-maps of GR, p65 and RNAPII in HeLa B2 cells under conditions 1) DMSO (control); 2) TA 1M-BM-5M 4hr; 3) TNFM-NM-1 10ng/ml ; 4) TA 1M-BM-5M 4hr at at third hour 10ng/ml TNF M-NM-1 was added
Project description:The diffuse invasion of glioblastoma (GBM) cells into healthy brain tissue is a main contributor for the high lethality of this most frequent form of malignant brain tumor. Plexins are cell surface receptors for semaphorins and control cell adhesion and cytoskeletal dynamics in development and in adult physiology. Gene expression of Plexin-B2 is upregulated in GBM and correlates with its lethality. We show here that Plexin-B2 activity can reduce the cohesiveness of GBM cells, which facilitates their invasive capacity. Targeted deletion of Plexin-B2 in GBM cells increased their cohesion to each other, revealing that a major function of Plexin-B2 activity is to downregulate cell-cell adhesion, possibly by downregulating other cell adhesion systems. In an in vivo intracranial transplant model, invasion of Plexin-B2 mutant GBM cells was impaired, with cells invading shorter distances. Interestingly, the loss of Plexin-B2 also changed the migration mode of cells, with the balance of cells in brain stroma vs. capillary space shifted: Plexin-B2 mutant cells were more likely to adhere to the vasculature. Our structure-function analyses revealed that the Ras-GAP domain of Plexin-B2 that is the main functional output responsible for the cohesion regulating function of Plexin-B2. Transcriptomic analyses of Plexin-B2 KO cells suggests that Plexin-B2 loss in different GBM cell lines has no direct transcriptional target genes, however, consistently, cell adhesion molecules were changed in expression, suggesting that cells compensate for loss of Plexin-B2. Thus, Plexin-B2 acts as a key regulator of the cohesiveness of GBM cells, thereby facilitating their invasiveness.
Project description:ChIP-seq for H3K4me3 and H3K27me3 were conducted for iPS cells of human-1 (409-B2/HPS0076), human-2 (Nips-B2/HPS0223), chimpanzee-1 (kiku/0138F-1), and chimpanzee-2 (mari/0274F-2). The reads were mapped to the respective genomes (hg38 for human and panTro5 for chimpanzee).
Project description:Analysis of A549 cells treated with bradyikinin. In this dataset, we include the expression data obtained from A549 cells after treatment with bradykinin. We confirmed that A540 cells expressed bradykinin B2 receptor. Results provide insight into the effect of bradykin on MAP kinase pathway.
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.
2022-09-19 | GSE182247 | GEO
Project description:Effect of purging and buffer on cucumber fermentation, B2