Project description:We have defined the mechanism of action of lurbinectedin, a marine-derived drug exhibiting a potent anti-tumorigenic activity across several cancer cell lines and tumor xenografts. This drug currently undergoing clinical evaluation in ovarian, breast and small-cell lung cancer patients inhibits the transcription process through (1) its binding to CG rich sequences, mainly located around the promoter of protein coding genes; (2) the irreversible stalling of elongating RNA polymerase II (Pol II) on the DNA template and its specific degradation by the ubiquitin/proteasome machinery and (3) the generation of DNA breaks. The finding that inhibition of Pol II phosphorylation prevents its degradation and the formation of DNA breaks after drug treatment underscores the connection between transcription elongation and DNA repair. Our results not only help to better understand the high specificity of this drug in cancer therapy but also improve our understanding of an important transcription regulation mechanism.
Project description:Various modes of DNA repair counteract genotoxic DNA double-strand breaks (DSBs) to maintain genome stability. Recent findings suggest that the human DNA damage response (DDR) utilises damage-induced small RNA for efficient repair of DSBs. However, production and processing of RNA is poorly understood. Here we show that localised induction of DSBs triggers phosphorylation of RNA polymerase II (RNAPII) on carboxy-terminal domain (CTD) residue tyrosine-1 in an Mre11-Rad50-Nbs1 (MRN) complex-dependent manner. CTD Tyr1-phosphorylated RNAPII synthetises, strand-specific, damage-responsive transcripts (DARTs). DART synthesis occurs via formation of transient RNA-DNA hybrid (R-loop) intermediates. Impaired R-loop formation attenuates DART synthesis, impairs recruitment of repair factors and delays the DDR. Collectively, we provide mechanistic insight in RNA-dependent DSB repair.
Project description:In mammals, the carboxy-terminal domain (CTD) of RNA polymerase (Pol) II consists of 52 conserved heptapeptide repeats containing the consensus sequence Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7. Post-translational modifications of the CTD coordinate the transcription cycle and various steps of mRNA maturation. Here we describe Tyr1 phosphorylation (Tyr1P) as a hallmark of initiating Pol II in mammalian cells, in contrast to what was described in yeast. Tyr1P is predominantly found in antisense orientation at promoters but is also specifically enriched at active enhancers. Mutation of Tyr1 to phenylalanine (Y1F) prevents the formation of the hyper-phosphorylated Pol IIO form, induces degradation of Pol II to the Pol IIB form and results in a lethal phenotype. Our results suggest that Tyr1P has evolved specialized and essential functions in higher eukaryotes associated with antisense promoter and enhancer transcription, and Pol II stability.
Project description:In mammals, the carboxy-terminal domain (CTD) of RNA polymerase (Pol) II consists of 52 conserved heptapeptide repeats containing the consensus sequence Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7. Post-translational modifications of the CTD coordinate the transcription cycle and various steps of mRNA maturation. Here we describe Tyr1 phosphorylation (Tyr1P) as a hallmark of initiating Pol II in mammalian cells, in contrast to what was described in yeast. Tyr1P is predominantly found in antisense orientation at promoters but is also specifically enriched at active enhancers. Mutation of Tyr1 to phenylalanine (Y1F) prevents the formation of the hyper-phosphorylated Pol IIO form, induces degradation of Pol II to the Pol IIB form and results in a lethal phenotype. Our results suggest that Tyr1P has evolved specialized and essential functions in higher eukaryotes associated with antisense promoter and enhancer transcription, and Pol II stability. This study was performed in a human Raji cell line. It contains ChIP-seq data for H3K36me3 (two replicates), H3K4me1 (two replicates), H3K4me3 (two replicates), Pol II (three replicates), Ser2P (two replicates), Ser5P (two replicates), Ser7P (two replicates), Tyr1P 3D12 (two replicates) and Tyr1P 8G5 (one replicate). MNase-experiment for nucleosomes was performed in paired-end sequencing on one replicate, 4 replicates for the input genomic DNA was used and one replicate was generated for the short strand specific RNA experiment.
Project description:One major class of anti-cancer drugs targets topoisomerase II to induce DNA double-strand breaks and cell death of fast growing cells. Here, we compare three members of this class - the antracyclines doxorubicin and aclarubicin, and a chemically unrelated compound, etoposide. Aclarubicin does not induce DNA breaks. We define a new activity for the antracyclines: unsupported histone eviction from ´open´ or loosely packed chromosomal areas reflecting exon and promoter regions. Comparison of histone H3K4me3 of cells post topoisomerase II inhibitors treatment to un-treated ones by ChIP-seq. Comparison of phosphorylated histone H2AX of cells post topoisomerase II inhibitors doxorubicin and etoposide treatment to un-treated ones by ChIP-seq.
Project description:Phf5a regulates transcription elongation in mouse embryonic stem cells (ESCs), through regulation of the Paf1 complex. In this study we assayed for genome-wide localization of Ser-5-phosphorylated RNA polymerase II and Ser-2-phosphorylated RNA polymerase II in mouse ESCs under conditions of shControl and shPhf5a knockdown. These results revealed that downregualtion of Phf5a results in the increase of the initiating form of RNA polymerase II (Ser5-phosphorylated) and in the aberrant loss of the elongating form of RNA polymerase II (Ser2-phosphorylated) of pluripotency genes in ESCs.
Project description:The regulation of gene expression by RNA polymerase II (Pol II) is a multistep process requiring the concerted action of diverse transcription factors. Very little is known about in vivo function of transcription factor SPT5 as its deletion results in loss of viability. To circumvent this issue and define in vivo mechanism of action for SPT5, we employed acute degradation of SPT5 and studied its consequence on transcription. We find that SPT5 loss triggers degradation of the core Pol II subunit RPB1, a process which we show to be evolutionarily conserved from yeast to human. This RPB1 degradation requires the E3 ubiquitin ligase Cullin 3, the unfoldase VCP/p97 and a novel form of CDK9 kinase complex. SPT5 specifically stabilizes Pol II at promoter proximal regions, permitting Pol II release from promoters to gene bodies. Our findings provide mechanistic insight into the in vivo function of SPT5 in stabilization of promoter-proximal Pol II prior to release into gene bodies for safeguarding accurate gene expression.
Project description:RNA Polymerase II transcribes protein-coding and many non-coding RNA genes in eukaryotes. The largest subunit of RNA Polymerase II, Rpb1, contains a hepta-peptide repeat on its C-terminal tail with three potential phosphorylation sites (Serine 2, Serine 5 and Serine 7). Mammalian Rpb1 contains 52 repeats. The phosphorylation events are catalyzed by specific protein kinases where the phosphorylation of specific residues is coupled to the transcription cycle. For example, the Cdk7 subunit of TFIIH phosphorylates both Serine 5 and Serine 7 during intiation and the Cdk9 subunit of P-TEFb phosphorylates Serine 2 during the transition into productive elongation. The dataset presented here is the genome-wide distribution of RNA Pol II with Serine 7 of the CTD phosphorylated in murine embryonic stem cells. This data, in addition to phospho-specific datasets generated in the same cell type in Rahl et al. Cell 2010 and Seila et al. Science 2008, represents the genome-wide distribution of multiple RNA Pol II isoforms in murine embryonic stem cells: total Pol II, hypophosphorylated CTD Pol II, Serine 2 phosphorylated CTD Pol II, Serine 5 phosphorylated CTD Pol II and Serine 7 phosphorylated CTD Pol II. An antibody specific to RNA Pol II Serine 7 phosphorylated CTD (gift of Dirk Eick; Chapman et al. Science 2008) was used to enrich for DNA fragments associated with this Pol II isoform in murine embryonic stem cells. DNA was purified and prepared for Illumina/Solexa sequencing following their standard protocol. This is a single dataset but together with datasets from Rahl et al. Cell 2010 and Seila et al. Science 2008, these datasets represent the genome-wide distribution of multiple RNA Pol II isoforms in murine embryonic stem cells: total Pol II, hypophosphorylated CTD Pol II, Serine 2 phosphorylated CTD Pol II, Serine 5 phosphorylated CTD Pol II and Serine 7 phosphorylated CTD Pol II.
Project description:ChIP-chip profiles of RNA Polymerase II phosphorylated on serine 2 in Drosophila S2 cells. RNA Polymerase II phosphorylated on serine 2 ChIP in Drosophila S2 cells. 3 biological replicates with dye-swaps.
Project description:Neuronal activity causes the rapid expression of immediate early genes that are crucial for experience driven changes to synapses, learning, and memory. Here, using both molecular and genome-wide next generation sequencing methods, we report that neuronal activity stimulation triggers the formation of DNA double strand breaks (DSBs) in the promoters of a subset of early-response genes, including Fos, Npas4, and Egr1. Generation of targeted DNA DSBs within Fos and Npas4 promoters is sufficient to induce their expression even in the absence of an external stimulus. Activity-dependent DSB formation is likely mediated by the type II topoisomerase, Topoisomerase IIb (Topo IIb), and knockdown of Topo IIb attenuates both DSB formation and early response gene expression following neuronal stimulation. Our results suggest that DSB formation is a physiological event that rapidly resolves topological constraints to early-response gene expression in neurons. Generation of sequencing data from ChIP-seq with antibodies against γH2AX and Topo IIβ after neuronal activity stimulation, and RNA-seq after etoposide treatment