scholarly journals G-Quadruplex Structures Colocalize with Transcription Factories and Nuclear Speckles Surrounded by Acetylated and Dimethylated Histones H3

2021 ◽  
Vol 22 (4) ◽  
pp. 1995
Author(s):  
Denisa Komůrková ◽  
Alena Svobodová Kovaříková ◽  
Eva Bártová
Keyword(s):  
Rna Polymerase Ii ◽  
Embryonic Stem ◽  
Mouse Cell ◽  
Telomere Maintenance ◽  
Nuclear Speckles ◽  
Helical Structures ◽  
Transcription Factories ◽  
Pml Bodies ◽  
Rnap Ii ◽  
Genomic Regions

G-quadruplexes (G4s) are four-stranded helical structures that regulate several nuclear processes, including gene expression and telomere maintenance. We observed that G4s are located in GC-rich (euchromatin) regions and outside the fibrillarin-positive compartment of nucleoli. Genomic regions around G4s were preferentially H3K9 acetylated and H3K9 dimethylated, but H3K9me3 rarely decorated G4 structures. We additionally observed the variability in the number of G4s in selected human and mouse cell lines. We found the highest number of G4s in human embryonic stem cells. We observed the highest degree of colocalization between G4s and transcription factories, positive on the phosphorylated form of RNA polymerase II (RNAP II). Similarly, a high colocalization rate was between G4s and nuclear speckles, enriched in pre-mRNA splicing factor SC-35. PML bodies, the replication protein SMD1, and Cajal bodies colocalized with G4s to a lesser extent. Thus, G4 structures seem to appear mainly in nuclear compartments transcribed via RNAP II, and pre-mRNA is spliced via the SC-35 protein. However, α-amanitin, an inhibitor of RNAP II, did not affect colocalization between G4s and transcription factories as well as G4s and SC-35-positive domains. In addition, irradiation by γ-rays did not change a mutual link between G4s and DNA repair proteins (G4s/γH2AX, G4s/53BP1, and G4s/MDC1), accumulated into DNA damage foci. Described characteristics of G4s seem to be the manifestation of pronounced G4s stability that is likely maintained not only via a high-order organization of these structures but also by a specific histone signature, including H3K9me2, responsible for chromatin compaction.

scholarly journals The Role of RNA Polymerase II Contiguity and Long-Range Interactions in the Regulation of Gene Expression in Human Pluripotent Stem Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Livia Eiselleova ◽  
Viktor Lukjanov ◽  
Simon Farkas ◽  
David Svoboda ◽  
Karel Stepka ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Long Range ◽  
Pluripotent Stem Cells ◽  
Human Pluripotent Stem Cells ◽  
Transcription Factories ◽  
Long Range Interactions ◽  
Rnap Ii

The eukaryotic nucleus is a highly complex structure that carries out multiple functions primarily needed for gene expression, and among them, transcription seems to be the most fundamental. Diverse approaches have demonstrated that transcription takes place at discrete sites known as transcription factories, wherein RNA polymerase II (RNAP II) is attached to the factory and immobilized while transcribing DNA. It has been proposed that transcription factories promote chromatin loop formation, creating long-range interactions in which relatively distant genes can be transcribed simultaneously. In this study, we examined long-range interactions between the POU5F1 gene and genes previously identified as being POU5F1 enhancer-interacting, namely, CDYL, TLE2, RARG, and MSX1 (all involved in transcriptional regulation), in human pluripotent stem cells (hPSCs) and their early differentiated counterparts. As a control gene, RUNX1 was used, which is expressed during hematopoietic differentiation and not associated with pluripotency. To reveal how these long-range interactions between POU5F1 and the selected genes change with the onset of differentiation and upon RNAP II inhibition, we performed three-dimensional fluorescence in situ hybridization (3D-FISH) followed by computational simulation analysis. Our analysis showed that the numbers of long-range interactions between specific genes decrease during differentiation, suggesting that the transcription of monitored genes is associated with pluripotency. In addition, we showed that upon inhibition of RNAP II, long-range associations do not disintegrate and remain constant. We also analyzed the distance distributions of these genes in the context of their positions in the nucleus and revealed that they tend to have similar patterns resembling normal distribution. Furthermore, we compared data created in vitro and in silico to assess the biological relevance of our results.

scholarly journals Genetic Inactivation ofATRXLeads to a Decrease in the Amount of Telomeric Cohesin and Level of Telomere Transcription in Human Glioma Cells

2015 ◽  
Vol 35 (16) ◽  
pp. 2818-2830 ◽  
Author(s):  
Rita Eid ◽  
Marie-Véronique Demattei ◽  
Harikleia Episkopou ◽  
Corinne Augé-Gouillou ◽  
Anabelle Decottignies ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Chromatin Immunoprecipitation ◽  
Glioma Cells ◽  
Telomere Maintenance ◽  
Telomeric Dna ◽  
Hairpin Rna ◽  
Genetic Inactivation ◽  
Alternative Lengthening ◽  
Rnap Ii ◽  
Subtelomeric Regions

Mutations in ATRX (alphathalassemia/mentalretardation syndromeX-linked), a chromatin-remodeling protein, are associated with the telomerase-independent ALT (alternative lengthening of telomeres) pathway of telomere maintenance in several types of cancer, including human gliomas. In telomerase-positive glioma cells, we found by immunofluorescence that ATRX localized not far from the chromosome ends but not exactly at the telomere termini. Chromatin immunoprecipitation (ChIP) experiments confirmed a subtelomeric localization for ATRX, yet short hairpin RNA (shRNA)-mediated genetic inactivation ofATRXfailed to trigger the ALT pathway. Cohesin has been recently shown to be part of telomeric chromatin. Here, using ChIP, we showed that genetic inactivation ofATRXprovoked diminution in the amount of cohesin in subtelomeric regions of telomerase-positive glioma cells. Inactivation ofATRXalso led to diminution in the amount of TERRAs, noncoding RNAs resulting from transcription of telomeric DNA, as well as to a decrease in RNA polymerase II (RNAP II) levels at the telomeres. Our data suggest that ATRX might establish functional interactions with cohesin on telomeric chromatin in order to control TERRA levels and that one or the other or both of these events might be relevant to the triggering of the ALT pathway in cancer cells that exhibit genetic inactivation ofATRX.

scholarly journals Herpes Simplex Virus Type 1 Infection Leads to Loss of Serine-2 Phosphorylation on the Carboxyl-Terminal Domain of RNA Polymerase II

2005 ◽  
Vol 79 (17) ◽  
pp. 11323-11334 ◽  
Author(s):  
Kathryn A. Fraser ◽  
Stephen A. Rice
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Rna Polymerase Ii ◽  
Mrna Processing ◽  
Nuclear Speckles ◽  
Carboxyl Terminal ◽  
Rnap Ii ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT Previous studies have shown that herpes simplex virus type 1 (HSV-1) infection alters the phosphorylation of the carboxyl-terminal domain (CTD) of RNA polymerase II (RNAP II), creating a new form of the enzyme known as RNAP III. However, the specific phosphorylation changes induced by HSV-1 have not been characterized. In this study, we used phospho-specific anti-CTD antibodies to probe the structure of the postinfection RNAP II. We find that RNAP III is phosphorylated on serine-5 (Ser-5) of the CTD consensus repeat but generally lacks phosphorylation on serine-2 (Ser-2). Since Ser-2 phosphorylation is normally associated with efficient transcriptional elongation and the recruitment of pre-mRNA processing factors, our results suggest that RNAP III may have altered elongation properties and decreased interactions with the mRNA processing machinery. The viral factors responsible for the reduction in Ser-2 CTD phosphorylation were studied. We found that viral immediate-early (IE) gene expression is required and sufficient, in the context of infection, for loss of Ser-2 phosphorylation. However, studies with viral mutants failed to implicate a single IE protein (among ICP0, ICP4, ICP22, and ICP27) in this process. Although most Ser-2-phosphorylated RNAP II is lost after infection, our immunofluorescence analyses identified a small subfraction that escapes loss and relocalizes to splicing antigen-rich nuclear speckles. A similar phenomenon is seen in uninfected cells after various treatments that inhibit RNAP II transcription. We hypothesize that the HSV-1-induced relocalization of residual Ser-2-phosphorylated RNAP II to nuclear speckles reflects a host response to the inhibition of cellular gene transcription.

Nuclear bodies

2019 ◽  
pp. 153-162
Author(s):  
John C. Lucchesi
Keyword(s):  
Rna Polymerase Ii ◽  
Messenger Rna ◽  
Nuclear Bodies ◽  
Nuclear Speckles ◽  
Suppressor Activity ◽  
Transcription Factories ◽  
Pml Nuclear Bodies ◽  
Tumor Suppressor Activity ◽  
Nuclear Regions ◽  
Dynamic Exchange

The nucleus is subdivided into a number of compartments that are not enclosed by membranes and whose main functions are transcriptional regulation and RNA processing. Many of the same proteins are found in different compartments, highlighting the dynamic exchange of components. The perinuclear compartment (PNC) is a hallmark of a number of different cancers. Cajal bodies (CBs) are sites of assembly of small nuclear ribonucleic particles (snRNPs) that function in messenger RNA (mRNA) or ribosomal RNA (rRNA) processing and in the biogenesis of telomerase. Nuclear speckles contain pre-mRNA splicing components and proteins involved in every aspect of gene regulation. Paraspeckles are involved in the processing and maturation of micro RNAs (miRNAs). Promyelocytic leukemia (PML) nuclear bodies contain the PML protein that has tumor suppressor activity by preventing the inactivation of p53. Under conditions of stress, the number and size of PML nuclear bodies increases. Transcription factories are nuclear regions where several RNA polymerase II (RNAPII) complexes are transcribing several genes. The co-localization of genes in transcription factories may lead to their co-regulation.

scholarly journals Functional dissection of the catalytic mechanism of mammalian RNA polymerase II

2005 ◽  
Vol 83 (4) ◽  
pp. 497-504 ◽  
Author(s):  
Benoit Coulombe ◽  
Marie-France Langelier
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Catalytic Mechanism ◽  
Mutational Analysis ◽  
Structural Elements ◽  
Catalytic Mechanisms ◽  
Rnap Ii ◽  
Affinity Peptide

High resolution X-ray crystal structures of multisubunit RNA polymerases (RNAP) have contributed to our understanding of transcriptional mechanisms. They also provided a powerful guide for the design of experiments aimed at further characterizing the molecular stages of the transcription reaction. Our laboratory used tandem-affinity peptide purification in native conditions to isolate human RNAP II variants that had site-specific mutations in structural elements located strategically within the enzyme's catalytic center. Both in vitro and in vivo analyses of these mutants revealed novel features of the catalytic mechanisms involving this enzyme.Key words: RNA polymerase II, transcriptional mechanisms, mutational analysis, mRNA synthesis.

scholarly journals The Temporal Order of DNA Replication Shaped by Mammalian DNA Methyltransferases

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 266
Author(s):  
Shin-ichiro Takebayashi ◽  
Tyrone Ryba ◽  
Kelsey Wimbish ◽  
Takuya Hayakawa ◽  
Morito Sakaue ◽  
...  
Keyword(s):  
Dna Replication ◽  
Temporal Order ◽  
Expression System ◽  
Embryonic Stem ◽  
Replication Timing ◽  
Dna Methyltransferases ◽  
Dna Hypomethylation ◽  
Transcriptional Changes ◽  
A Cell ◽  
Genomic Regions

Multiple epigenetic pathways underlie the temporal order of DNA replication (replication timing) in the contexts of development and disease. DNA methylation by DNA methyltransferases (Dnmts) and downstream chromatin reorganization and transcriptional changes are thought to impact DNA replication, yet this remains to be comprehensively tested. Using cell-based and genome-wide approaches to measure replication timing, we identified a number of genomic regions undergoing subtle but reproducible replication timing changes in various Dnmt-mutant mouse embryonic stem (ES) cell lines that included a cell line with a drug-inducible Dnmt3a2 expression system. Replication timing within pericentromeric heterochromatin (PH) was shown to be correlated with redistribution of H3K27me3 induced by DNA hypomethylation: Later replicating PH coincided with H3K27me3-enriched regions. In contrast, this relationship with H3K27me3 was not evident within chromosomal arm regions undergoing either early-to-late (EtoL) or late-to-early (LtoE) switching of replication timing upon loss of the Dnmts. Interestingly, Dnmt-sensitive transcriptional up- and downregulation frequently coincided with earlier and later shifts in replication timing of the chromosomal arm regions, respectively. Our study revealed the previously unrecognized complex and diverse effects of the Dnmts loss on the mammalian DNA replication landscape.

scholarly journals What’s all the phos about? Insights into the phosphorylation state of the RNA polymerase II C-terminal domain via mass spectrometry

2021 ◽  
Author(s):  
Blase Matthew LeBlanc ◽  
Rosamaria Yvette Moreno ◽  
Edwin Escobar ◽  
Mukesh Kumar Venkat Ramani ◽  
Jennifer S Brodbelt ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Phosphorylation State ◽  
Terminal Domain ◽  
Carboxy Terminal Domain ◽  
Protein Encoding ◽  
Small Nuclear Rnas ◽  
Rnap Ii ◽  
Carboxy Terminal ◽  
Encoding Genes

RNA polymerase II (RNAP II) is one of the primary enzymes responsible for expressing protein-encoding genes and some small nuclear RNAs. The enigmatic carboxy-terminal domain (CTD) of RNAP II and...

scholarly journals RNA Polymerase II-Association Factor 1 (Paf1/PD2) Maintains Self-renewal by Its Interaction with Oct3/4 in Mouse Embryonic Stem Cells

Stem Cells ◽  
2009 ◽  
pp. N/A-N/A ◽  
Author(s):  
Moorthy P. Ponnusamy ◽  
Shonali Deb ◽  
Parama Dey ◽  
Subhankar Chakraborty ◽  
Satyanarayana Rachagani ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Embryonic Stem ◽  
Mouse Embryonic Stem Cells ◽  
Self Renewal

scholarly journals FUS driven circCNOT6L biogenesis in mouse and human spermatozoa supports zygote development

2021 ◽  
Author(s):  
Teresa Chioccarelli ◽  
Geppino Falco ◽  
Donato Cappetta ◽  
Antonella De Angelis ◽  
Luca Roberto ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Rna Binding ◽  
Cannabinoid Receptor ◽  
Rna Binding Proteins ◽  
Embryonic Stem ◽  
Circular Rna ◽  
Physical Interaction ◽  
Knock Out ◽  
Maternal Contribution ◽  
Zygote Development

AbstractCircular RNA (circRNA) biogenesis requires a backsplicing reaction, promoted by inverted repeats in cis-flanking sequences and trans factors, such as RNA-binding proteins (RBPs). Among these, FUS plays a key role. During spermatogenesis and sperm maturation along the epididymis such a molecular mechanism has been poorly explored. With this in mind, we chose circCNOT6L as a study case and wild-type (WT) as well as cannabinoid receptor type-1 knock-out (Cb1−/−) male mice as animal models to analyze backsplicing mechanisms. Our results suggest that spermatozoa (SPZ) have an endogenous skill to circularize mRNAs, choosing FUS as modulator of backsplicing and under CB1 stimulation. A physical interaction between FUS and CNOT6L as well as a cooperation among FUS, RNA Polymerase II (RNApol2) and Quaking (QKI) take place in SPZ. Finally, to gain insight into FUS involvement in circCNOT6L biogenesis, FUS expression was reduced through RNA interference approach. Paternal transmission of FUS and CNOT6L to oocytes during fertilization was then assessed by using murine unfertilized oocytes (NF), one-cell zygotes (F) and murine oocytes undergoing parthenogenetic activation (PA) to exclude a maternal contribution. The role of circCNOT6L as an active regulator of zygote transition toward the 2-cell-like state was suggested using the Embryonic Stem Cell (ESC) system. Intriguingly, human SPZ exactly mirror murine SPZ.

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