scholarly journals Characterization of Arabidopsis thaliana promoter bidirectionality and antisense RNAs by depletion of nuclear RNA decay enzymes

2019 ◽  
Author(s):  
Axel Thieffry ◽  
Jette Bornholdt ◽  
Maxim Ivanov ◽  
Peter Brodersen ◽  
Albin Sandelin
Keyword(s):  
Arabidopsis Thaliana ◽  
Rna Polymerase Ii ◽  
Rna Decay ◽  
Gene Promoters ◽  
Alternative Promoters ◽  
Control Of Gene Expression ◽  
Antisense Rnas ◽  
Nuclear Rna ◽  
Reverse Strand ◽  
Clear Cases

ABSTRACTIn animals, transcription by RNA polymerase II initiates bidirectionally from gene promoters to produce pre-mRNAs on the forward strand and promoter upstream transcripts (PROMPTs) on the reverse strand. PROMPTs are rapidly degraded by the nuclear exosome. Similarly, active enhancer regions in animals initiate transcription of exosome-sensitive enhancer RNAs (eRNAs). Previous studies based on nascent RNA approaches concluded that Arabidopsis thaliana does not produce PROMPTs. Here, we used steady-state RNA sequencing methods in mutants defective in nuclear RNA decay, including by the exosome, to reassess the existence of PROMPTs and eRNAs in A. thaliana. While PROMPTs are overall rare in A. thaliana, about 100 clear cases of exosome-sensitive PROMPTs and 113 loci producing eRNA-like transcripts were identified. In addition, we found ∼200 transcription start sites within 3’-UTR-encoding regions that produce unspliced exosome-sensitive antisense RNAs covering much of the cognate pre-mRNA. A typical representative of this class of RNAs is the previously characterized non-coding RNA controlling the expression of the key seed dormancy regulator, DELAY OF GERMINATION1. Exosome-sensitive antisense RNAs are overrepresented in transcription factor genes, suggesting a potential for widespread control of gene expression. Lastly, we assess the use of alternative promoters in A. thaliana and compare the accuracy of existing TSS annotations.

scholarly journals Characterization of Arabidopsis thaliana Promoter Bidirectionality and Antisense RNAs by Inactivation of Nuclear RNA Decay Pathways

2020 ◽  
Vol 32 (6) ◽  
pp. 1845-1867 ◽  
Author(s):  
Axel Thieffry ◽  
Maria Louisa Vigh ◽  
Jette Bornholdt ◽  
Maxim Ivanov ◽  
Peter Brodersen ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Rna Decay ◽  
Antisense Rnas ◽  
Nuclear Rna

scholarly journals Cryptic Transcription and Early Termination in the Control of Gene Expression

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Jessie Colin ◽  
Domenico Libri ◽  
Odil Porrua
Keyword(s):  
Gene Expression ◽  
Rna Polymerase Ii ◽  
Regulatory Function ◽  
Large Set ◽  
Control Of Gene Expression ◽  
Alternative Transcription ◽  
Cryptic Transcription ◽  
Nuclear Exosome ◽  
The Impact

Recent studies on yeast transcriptome have revealed the presence of a large set of RNA polymerase II transcripts mapping to intergenic and antisense regions or overlapping canonical genes. Most of these ncRNAs (ncRNAs) are subject to termination by the Nrd1-dependent pathway and rapid degradation by the nuclear exosome and have been dubbed cryptic unstable transcripts (CUTs). CUTs are often considered as by-products of transcriptional noise, but in an increasing number of cases they play a central role in the control of gene expression. Regulatory mechanisms involving expression of a CUT are diverse and include attenuation, transcriptional interference, and alternative transcription start site choice. This review focuses on the impact of cryptic transcription on gene expression, describes the role of the Nrd1-complex as the main actor in preventing nonfunctional and potentially harmful transcription, and details a few systems where expression of a CUT has an essential regulatory function. We also summarize the most recent studies concerning other types of ncRNAs and their possible role in regulation.

scholarly journals HSFs drive stress type-specific transcription of genes and enhancers

2021 ◽  
Author(s):  
Samu V Himanen ◽  
Mikael C Puustinen ◽  
Alejandro J Da Silva ◽  
Anniina Vihervaara ◽  
Lea Sistonen
Keyword(s):  
Oxidative Stress ◽  
Heat Shock ◽  
Rna Polymerase Ii ◽  
Molecular Mechanisms ◽  
Gene Promoters ◽  
Heat Shock Factors ◽  
Pol Ii ◽  
Bona Fide ◽  
Stressed Cells ◽  
First Time

Reprogramming of transcription is critical for the survival under cellular stress. Heat shock has provided an excellent model to investigate nascent transcription in stressed cells, but the molecular mechanisms orchestrating RNA synthesis during other types of stress are unknown. We utilized PRO-seq and ChIP-seq to study how Heat Shock Factors, HSF1 and HSF2, coordinate transcription at genes and enhancers upon oxidative stress and heat shock. We show that pause-release of RNA polymerase II (Pol II) is a universal mechanism regulating gene transcription in stressed cells, while enhancers are activated at the level of Pol II recruitment. Moreover, besides functioning as conventional promoter-binding transcription factors, HSF1 and HSF2 bind to stress-induced enhancers to trigger Pol II pause-release from poised gene promoters. Importantly, HSFs act at distinct genes and enhancers in a stress type-specific manner. HSF1 binds to many chaperone genes upon oxidative and heat stress but activates them only in heat-shocked cells. Under oxidative stress, HSF1 and HSF2 trans-activate genes independently of each other, demonstrating, for the first time, that HSF2 is a bona fide transcription factor. Taken together, we show that HSFs function as multi-stress-responsive factors that activate specific genes and enhancers when encountering changes in temperature and redox state.

scholarly journals Diminished nuclear RNA decay upon Salmonella infection upregulates antibacterial noncoding RNA s

2018 ◽  
Vol 37 (13) ◽  
Author(s):  
Katsutoshi Imamura ◽  
Akiko Takaya ◽  
Yo‐ichi Ishida ◽  
Yayoi Fukuoka ◽  
Toshiki Taya ◽  
...  
Keyword(s):  
Noncoding Rna ◽  
Rna Decay ◽  
Salmonella Infection ◽  
Nuclear Rna

Transient activity assays of the Trypanosoma brucei variant surface glycoprotein gene promoter: control of gene expression at the posttranscriptional level

1991 ◽  
Vol 11 (1) ◽  
pp. 338-343
Author(s):  
D Jefferies ◽  
P Tebabi ◽  
E Pays
Keyword(s):  
Trypanosoma Brucei ◽  
Gene Promoter ◽  
Surface Glycoprotein ◽  
Variant Surface Glycoprotein ◽  
Gene Promoters ◽  
Control Of Gene Expression ◽  
Transient Activity ◽  
Expression Site ◽  
Cat Gene ◽  
Cat Expression

The putative promoter of the variant surface glycoprotein (VSG) gene of Trypanosoma brucei was cloned into a plasmid containing the chloramphenicol acetyltransferase (CAT) gene. After electroporation into trypanosomes, this construct directed the expression of the CAT reporter gene. The essential region for promoter activity was found to reside within 88 bp upstream of the putative transcription start site. Transcription of the CAT construct occurred at approximately the same level in both bloodstream and procyclic forms and was resistant to alpha-amanitin. However, CAT expression appeared to be modulated in the two forms of the parasite. Sequences 3' to the gene seemed to be important in this respect, as CAT activity in bloodstream forms was readily detectable only when the 3' region of a VSG cDNA was placed downstream of the CAT gene. Two separate VSG gene promoter sequences, both cloned from T. brucei AnTat 1.3A, were equally able to direct CAT expression, which suggests that there are a number of potential VSG gene promoters in the genome, although usually only one expression site is fully active at any one time.

Introns encode dsRNAs undetected by RIG-I/MDA5/interferons and sensed via RNase L

2021 ◽  
Vol 118 (46) ◽  
pp. e2102134118
Author(s):  
Alisha Chitrakar ◽  
Kristina Solorio-Kirpichyan ◽  
Eliza Prangley ◽  
Sneha Rath ◽  
Jin Du ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Immune Responses ◽  
Innate Immune ◽  
Rna Decay ◽  
Antiviral Defense ◽  
Rnase L ◽  
Innate Immune Responses ◽  
Double Stranded Rna ◽  
Turn On ◽  
Nuclear Rna

Double-stranded RNA (dsRNA), a hallmark viral material that activates antiviral interferon (IFN) responses, can appear in human cells also in the absence of viruses. We identify phosphorothioate DNAs (PS DNAs) as triggers of such endogenous dsRNA (endo-dsRNA). PS DNAs inhibit decay of nuclear RNAs and induce endo-dsRNA via accumulation of high levels of intronic and intergenic inverted retroelements (IIIR). IIIRs activate endo-dsRNA responses distinct from antiviral defense programs. IIIRs do not turn on transcriptional RIG-I/MDA5/IFN signaling, but they trigger the dsRNA-sensing pathways of OAS3/RNase L and PKR. Thus, nuclear RNA decay and nuclear-cytosolic RNA sorting actively protect from these innate immune responses to self. Our data suggest that the OAS3/RNase L and PKR arms of innate immunity diverge from antiviral IFN responses and monitor nuclear RNA decay by sensing cytosolic escape of IIIRs. OAS3 provides a receptor for IIIRs, whereas RNase L cleaves IIIR-carrying introns and intergenic RNAs.

scholarly journals CDK7 inhibitors as anticancer drugs

2020 ◽  
Vol 39 (3) ◽  
pp. 805-823 ◽  
Author(s):  
Georgina P. Sava ◽  
Hailing Fan ◽  
R. Charles Coombes ◽  
Lakjaya Buluwela ◽  
Simak Ali
Keyword(s):  
Cell Cycle ◽  
Rna Polymerase Ii ◽  
Cancer Therapeutics ◽  
Model Systems ◽  
Current Status ◽  
Cancer Therapies ◽  
Gene Promoters ◽  
Normal Tissues ◽  
Bet Inhibitors ◽  
Cancer Types

Abstract Cyclin-dependent kinase 7 (CDK7), along with cyclin H and MAT1, forms the CDK-activating complex (CAK), which directs progression through the cell cycle via T-loop phosphorylation of cell cycle CDKs. CAK is also a component of the general transcription factor, TFIIH. CDK7-mediated phosphorylation of RNA polymerase II (Pol II) at active gene promoters permits transcription. Cell cycle dysregulation is an established hallmark of cancer, and aberrant control of transcriptional processes, through diverse mechanisms, is also common in many cancers. Furthermore, CDK7 levels are elevated in a number of cancer types and are associated with clinical outcomes, suggestive of greater dependence on CDK7 activity, compared with normal tissues. These findings identify CDK7 as a cancer therapeutic target, and several recent publications report selective CDK7 inhibitors (CDK7i) with activity against diverse cancer types. Preclinical studies have shown that CDK7i cause cell cycle arrest, apoptosis and repression of transcription, particularly of super-enhancer-associated genes in cancer, and have demonstrated their potential for overcoming resistance to cancer treatments. Moreover, combinations of CDK7i with other targeted cancer therapies, including BET inhibitors, BCL2 inhibitors and hormone therapies, have shown efficacy in model systems. Four CDK7i, ICEC0942 (CT7001), SY-1365, SY-5609 and LY3405105, have now progressed to Phase I/II clinical trials. Here we describe the work that has led to the development of selective CDK7i, the current status of the most advanced clinical candidates, and discuss their potential importance as cancer therapeutics, both as monotherapies and in combination settings. ClinicalTrials.gov Identifiers: NCT03363893; NCT03134638; NCT04247126; NCT03770494.

scholarly journals Pathogen Genetic Control of Transcriptome Variation in the Arabidopsis thaliana – Botrytis cinerea Pathosystem

Genetics ◽  
2020 ◽  
Vol 215 (1) ◽  
pp. 253-266 ◽  
Author(s):  
Nicole E. Soltis ◽  
Celine Caseys ◽  
Wei Zhang ◽  
Jason A. Corwin ◽  
Susanna Atwell ◽  
...  
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Botrytis Cinerea ◽  
Gene Expression Regulation ◽  
Expression Regulation ◽  
Necrotrophic Pathogen ◽  
Control Of Gene Expression ◽  
Genome Wide ◽  
Pathogen Control ◽  
Transcriptome Variation

In plant–pathogen relations, disease symptoms arise from the interaction of the host and pathogen genomes. Host–pathogen functional gene interactions are well described, whereas little is known about how the pathogen genetic variation modulates both organisms’ transcriptomes. To model and generate hypotheses on a generalist pathogen control of gene expression regulation, we used the Arabidopsis thaliana–Botrytis cinerea pathosystem and the genetic diversity of a collection of 96 B. cinerea isolates. We performed expression-based genome-wide association (eGWA) for each of 23,947 measurable transcripts in Arabidopsis (host), and 9267 measurable transcripts in B. cinerea (pathogen). Unlike other eGWA studies, we detected a relative absence of locally acting expression quantitative trait loci (cis-eQTL), partly caused by structural variants and allelic heterogeneity hindering their identification. This study identified several distantly acting trans-eQTL linked to eQTL hotspots dispersed across Botrytis genome that altered only Botrytis transcripts, only Arabidopsis transcripts, or transcripts from both species. Gene membership in the trans-eQTL hotspots suggests links between gene expression regulation and both known and novel virulence mechanisms in this pathosystem. Genes annotated to these hotspots provide potential targets for blocking manipulation of the host response by this ubiquitous generalist necrotrophic pathogen.

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