Project description:Dosage Compensation is required to correct for uneven gene dose between the sexes. We utilized global run-on sequencing (GRO-seq) to examine how Caenorhabditis elegans dosage compensation reduces transcription of X-linked genes. To facilitate these experiments, we required accurate 5M-bM-^@M-^Y-ends of genes that have been missing due to a co-transcriptional trans-splicing event common in nematodes. We developed a modified GRO-seq protocol to identify TSSs that are supported by transcription, and determined that TSSs lie more than 1 kb upstream of the previously annotated TSS for nearly one-quarter of all genes. We then investigated the changes that occur in transcriptionally engaged RNA Polymerase when dosage compensation is disrupted, and find that dosage compensation controls recruitment of RNA Polymerase to X-linked genes. GRO-cap reactions were performed with TAP, and without TAP as a control.
Project description:Dosage Compensation is required to correct for uneven gene dose between the sexes. We utilized global run-on sequencing (GRO-seq) to examine how Caenorhabditis elegans dosage compensation reduces transcription of X-linked genes. To facilitate these experiments, we required accurate 5M-bM-^@M-^Y-ends of genes that have been missing due to a co-transcriptional trans-splicing event common in nematodes. We developed a modified GRO-seq protocol to identify TSSs that are supported by transcription, and determined that TSSs lie more than 1 kb upstream of the previously annotated TSS for nearly one-quarter of all genes. We then investigated the changes that occur in transcriptionally engaged RNA Polymerase when dosage compensation is disrupted, and find that dosage compensation controls recruitment of RNA Polymerase to X-linked genes. GRO-seq experiments (two biological replicates) were performed in nuclei from many wild-type states and a dosage compensation mutant
Project description:Production of mRNA depends critically on the rate of RNA polymerase II (Pol II) elongation. To dissect Pol II dynamics in mouse ES cells, we inhibited Pol II transcription at either initiation or promoter-proximal pause escape with Triptolide or Flavopiridol, and tracked Pol II kinetically using GRO-seq. Both inhibitors block transcription of more than 95% of genes, showing that pause escape, like initiation, is a ubiquitous and crucial step within the transcription cycle. Moreover, paused Pol II is relatively stable, as evidenced from half-life measurements at ~3200 genes. Finally, tracking the progression of Pol II after drug treatment establishes Pol II elongation rates at over 1,000 genes. Notably, Pol II accelerates dramatically while transcribing through genes, but slows at exons. Furthermore, intergenic variance in elongation rates is substantial, and is influenced by a positive effect of H3K79me2 and negative effects of exon density and CG content within genes. We isolated replicates of nuclei of untreated mESCs and cells treated for 2, 5, 12.5, 25 and 50 min with 300nM flavopiridol, as well as nuclei treated for 12.5, 25, and 50 min with 500nM triptolide and performed GRO-seq with these.
Project description:Densely sampled time course GRO-seq analysis was performed to determine global transcriptional activities at both enhancers and promoters upon Sendai Virus infection.
Project description:Inhibition of transcriptional elongation plays an important role in gene regulation in metazoans, including C. elegans, which lacks Negative Elongation Factor homologs. Here we combine genomic and biochemical approaches to dissect a novel role of C. elegans AF10 homolog, ZFP-1, in transcriptional control. We show that ZFP-1 and its interacting partner DOT-1.1 have a global role in negatively modulating the level of Pol II transcription on essential widely expressed genes. Moreover,the ZFP-1/DOT-1.1 complex contributes to progressive Pol II stalling on essential genes during development and to rapid Pol II stalling during stress response. The slowing down of Pol II transcription by ZFP-1/DOT-1.1 is associated with an increase in H3K79 methylation and a decrease in H2B monoubiquitination, which promotes transcription. We propose a model where recruitment of ZFP-1/DOT-1.1 and deposition of H3K79 methylation at highly expressed genes initiates a negative feedback mechanism for modulation of their expression. GRO-seq (Global Run-On sequening) for nascent transcript detectiong on WT and zfp-1(ok554) mutant nematode (C. elegans) larvae in L3 stage, performed in duplicate per condition (4 samples total).
Project description:Argonaute proteins and their small RNA co-factors short interfering RNAs (siRNAs) are known to inhibit gene expression at the transcriptional and post-transcriptional levels. In Caenorhabditis elegans, the Argonaute CSR-1 binds thousands of endogenous siRNAs (endo-siRNAs) antisense to germline transcripts and associates with chromatin in a siRNA-dependent manner. However, its role in gene expression regulation remains controversial. Here, we used a genome-wide profiling of nascent RNA transcripts to demonstrate that the CSR-1 RNAi pathway promotes sense-oriented Pol II transcription. Moreover, a loss of CSR-1 function resulted in global increase in antisense transcription and ectopic transcription of silent chromatin domains, which led to reduced chromatin incorporation of centromere-specific histone H3. Based on these findings, we propose that the CSR-1 pathway has a role in maintaining the directionality of active transcription thereby propagating the distinction between transcriptionally active and silent genomic regions. GRO-seq (Global Run-On sequencing) for detection of nascent transcripts. Two biological replicates were generated for csr-1 hypomorphic mutant and the corresponding WT samples using ~300,000 worms for each experiment, and two biological replicates were prepared for drh-3 (ne4253) mutant and the corresponding WT samples using ~100,000 worms for each experiment. The GRO-seq were performed in late L3/early L4 stage worms. (8 samples total)
Project description:Study of the POU-homeodomain transcription factor, has revealed that, binding of Pit1-occupied enhancers to a nuclear matrin-3-rich network/architecture is a key event in effective activation of the Pit1-regulated enhancer / coding gene transcriptional program. All ChIP-seq(s) were designed to understand the unique features, associated molecular mechanisms and functions of Matrin3 in the Homeodomain transcription study. Gro-seq Samples are used to detect gene expression between knockdown control and knockdown two key factors in our study.
Project description:Substantial evidence supports the hypothesis that enhancers are critical regulators of cell type determination, orchestrating both positive and negative transcriptional programs; however, the basic mechanisms by which enhancers orchestrate interactions with cognate promoters during activation and repression events remain incompletely understood. Here we report the required actions of the LIM domain binding protein, LDB1/CLIM2/NLI, interacting with the enhancer binding protein, ASCL1, to mediate looping to target gene promoters and target gene regulation in corticotrope cells. LDB1-mediated enhancer:promoter looping appears to be required for both activation and repression of these target target gene promoter genes. While LDB1-dependend activated genes are regulated at the level of transcriptional initiation, the LDB1-dependent repressed transcription units appear to be regulated primarily at the level of promoter pausing, with LDB1 regulating recruitment of MTA2, a component of the NuRD complex, on these negative enhancers, required for the repressive enhancer function. These results indicate that LDB1-dependent looping events can deliver repressive cargo to cognate promoters to mediate promoter pausing events in a pituitary cell type. Global Run On (GRO) assay followed by high throughput sequencing (GRO-seq)
Project description:Distal enhancers characterized by H3K4me1 mark play critical roles in developmental and transcriptional programs. However, potential roles of specific distal regulatory elements in regulating RNA Polymerase II (Pol II) promoter-proximal pause release remain poorly investigated. Here we report that a unique cohort of jumonji C domain-containing protein 6 (JMJD6) and bromodomain-containing protein 4 (Brd4) co-bound distal enhancers, termed anti-pause enhancers (A-PEs), regulate promoter-proximal pause release of a large subset of transcription units via long-range interactions. Brd4-dependent JMJD6 recruitment on A-PEs mediates erasure of H4R3me2(s), which is directly read by 7SK snRNA, and decapping/demethylation of 7SK snRNA, ensuring the dismissal of the 7SKsnRNA/HEXIM inhibitory complex. The interactions of both JMJD6 and Brd4 with the P-TEFb complex permit its activation and pause release of regulated coding genes. The functions of JMJD6/ Brd4-associated dual histone and RNA demethylase activity on anti-pause enhancers have intriguing implications for these proteins in development, homeostasis and disease. All Gro-seq(s) were designed to reveal the transcriptional targets of JMJD6 and Brd4, and assess the role of JMJD6 and Brd4 in Pol II promoter-proximal pause release. All ChIP-seq(s) were designed to understand the unique features, associated molecular mechanisms and functions of the anti-pause enhancers (A-PEs) discovered in the current study.
Project description:Investigating transcriptional changes after autophagy induction by rapamycin to compare changes in autophagy-related genes to changes in histone modifications.