82 research outputs found
Functional long non-coding RNA transcription in Schizosaccharomyces pombe
Eukaryotic genomes are pervasively transcribed and frequently generate long noncoding
RNAs (lncRNAs). However, most lncRNAs remain uncharacterized. In this
work, a set of positionally conserved intergenic lncRNAs in the fission yeast
Schizosaccharomyces pombe genome are selected for further analysis. Deleting
one of these lncRNA genes (ncRNA.1343) exhibited a clear phenotype: increased
drug sensitivity. Further analyses revealed that deleting ncRNA.1343 also disrupted
a previously unannotated lncRNA, termed nc-tgp1, transcribed in the opposite
orientation of the predicted ncRNA.1343 gene and into the promoter of the
phosphate-responsive permease gene tgp1+. Detailed analyses revealed that the
act of transcribing nc-tgp1 into the tgp1+ promoter increases nucleosome density
and prevents transcription factor access. Decreased nc-tgp1 transcription permits
tgp1+ expression upon phosphate starvation, while nc-tgp1 loss induces tgp1+ in
repressive phosphate-rich conditions. Notably, drug sensitivity results directly from
tgp1+ expression in the absence of nc-tgp1 transcription. Similarly, lncRNA
transcription upstream of pho1+, another phosphate-regulated gene, increases
nucleosome density and prevents transcription factor binding to repress pho1+ in
phosphate-replete cells. Importantly, the regulation of tgp1+ and pho1+ by upstream
lncRNA transcription occurs in the absence of RNAi and heterochromatin
components. Instead, the regulation of tgp1+ and pho1+ by upstream lncRNA
transcription resembles examples of transcriptional interference reported in other
organisms. Thus, tgp1+ and pho1+ are the first documented examples of genes
regulated by transcriptional interference in S. pombe
The Cyclin-dependent Kinase Activator, Spy1A, Is Targeted for Degradation by the Ubiquitin Ligase NEDD4
Spy1A is a cyclin-like protein required for progression through the G(1)/S phase of the cell cycle. Elevated Spy1A protein levels have been implicated in tumorigenesis and are attributed to overriding the DNA damage response and enhancing cell proliferation. Understanding how Spy1A is produced and degraded is essential in resolving how it contributes to normal and abnormal growth processes. Herein, we demonstrate that Spy1A is degraded in a cell cycle-dependent manner during mitosis via the ubiquitin-proteasome system. We have resolved the E3 ligase and essential phosphorylation sites mediating Spy1A degradation. Furthermore, we have determined that non-degradable forms of Spy1A do not trigger cell cycle arrest but, rather, contribute to uncontrolled cell growth. Further investigation into the regulation of Spy1A may reveal novel strategies for understanding the etiology and progression of specific growth disorders
Transcriptional read-through of the long non-coding RNA SVALKA governs plant cold acclimation
The function of most lncRNA is unknown. Here, the authors show that transcriptional read-through at the Arabidopsis SVALKA locus produces a cryptic lncRNA that overlaps with the neighboring cold-responsive CBF1 gene and limits CBF1 expression via an RNA polymerase II collision-based mechanism
Transcription-coupled changes to chromatin underpin gene silencing by transcriptional interference
Long non-coding RNA (lncRNA) transcription into a downstream promoter frequently results in transcriptional interference. However, the mechanism of this repression is not fully understood. We recently showed that drug tolerance in fission yeast Schizosaccharomyces pombe is controlled by lncRNA transcription upstream of the tgp1(+) permease gene. Here we demonstrate that transcriptional interference of tgp1(+) involves several transcription-coupled chromatin changes mediated by conserved elongation factors Set2, Clr6CII, Spt6 and FACT. These factors are known to travel with RNAPII and establish repressive chromatin in order to limit aberrant transcription initiation from cryptic promoters present in gene bodies. We therefore conclude that conserved RNAPII-associated mechanisms exist to both suppress intragenic cryptic promoters during genic transcription and to repress gene promoters by transcriptional interference. Our analyses also demonstrate that key mechanistic features of transcriptional interference are shared between S. pombe and the highly divergent budding yeast Saccharomyces cerevisiae. Thus, transcriptional interference is an ancient, conserved mechanism for tightly controlling gene expression. Our mechanistic insights allowed us to predict and validate a second example of transcriptional interference involving the S. pombe pho1(+) gene. Given that eukaryotic genomes are pervasively transcribed, transcriptional interference likely represents a more general feature of gene regulation than is currently appreciated
Transcription-driven chromatin repression of Intragenic transcription start sites
<div><p>Progression of RNA polymerase II (RNAPII) transcription relies on the appropriately positioned activities of elongation factors. The resulting profile of factors and chromatin signatures along transcription units provides a “positional information system” for transcribing RNAPII. Here, we investigate a chromatin-based mechanism that suppresses intragenic initiation of RNAPII transcription. We demonstrate that RNAPII transcription across gene promoters represses their function in plants. This repression is characterized by reduced promoter-specific molecular signatures and increased molecular signatures associated with RNAPII elongation. The conserved FACT histone chaperone complex is required for this repression mechanism. Genome-wide Transcription Start Site (TSS) mapping reveals thousands of discrete intragenic TSS positions in <i>fact</i> mutants, including downstream promoters that initiate alternative transcript isoforms. We find that histone H3 lysine 4 mono-methylation (H3K4me1), an <i>Arabidopsis</i> RNAPII elongation signature, is enriched at FACT-repressed intragenic TSSs. Our analyses suggest that FACT is required to repress intragenic TSSs at positions that are in part characterized by elevated H3K4me1 levels. In sum, conserved and plant-specific chromatin features correlate with the co-transcriptional repression of intragenic TSSs. Our insights into TSS repression by RNAPII transcription promise to inform the regulation of alternative transcript isoforms and the characterization of gene regulation through the act of pervasive transcription across eukaryotic genomes.</p></div
Transcript isoform sequencing reveals widespread promoter-proximal transcriptional termination in Arabidopsis
Analysis of Property Values, Local Government Finances and Reservation of Land for National Parks and Similar Purposes
The impact on local government finances of the reservation of land for national parks in local government areas has been a bone of contention. This article identifies conditions in which the reservation of land for national parks increases total rateable unimproved property values in a local government area. The level of a local government's receipts from rates tends to move in the same direction as the total value of rateable property in its local government area. Thus, even though national parks and similar natural areas are not rateable, it is possible that the reservation of some local government areas for such protection can increase revenue from rates. However this is not always so and conditions for an increase in local government revenue are specified. Local governments may wish to maximise their income for discretionary expenditures rather than total receipts. Conditions are specified in which the reservation of local areas for national parks fosters - and conflicts with - this objective. Depending upon the nature of the relevant functions, local government finances may benefit from the existence of national parks in a local government area or be adversely affected by their presence. As far as we are aware, the conditions for this have not been previously specified
Structure and proteomic analysis of the crown-of-thorns starfish (Acanthaster sp.) radial nerve cord
The nervous system of the Asteroidea (starfish or seastar) consists of radial nerve cords (RNCs) that interconnect with a ring nerve. Despite its relative simplicity, it facilitates the movement of multiple arms and numerous tube feet, as well as regeneration of damaged limbs. Here, we investigated the RNC ultrastructure and its molecular components within the of Pacific crown-of-thorns starfish (COTS; Acanthaster sp.), a well-known coral predator that in high-density outbreaks has major ecological impacts on coral reefs. We describe the presence of an array of unique small bulbous bulbs (40–100 μm diameter) that project from the ectoneural region of the adult RNC. Each comprise large secretory-like cells and prominent cilia. In contrast, juvenile COTS and its congener Acanthaster brevispinus lack these features, both of which are non-corallivorous. Proteomic analysis of the RNC (and isolated neural bulbs) provides the first comprehensive echinoderm protein database for neural tissue, including numerous secreted proteins associated with signalling, transport and defence. The neural bulbs contained several neuropeptides (e.g., bombyxin-type, starfish myorelaxant peptide, secretogranin 7B2-like, Ap15a-like, and ApNp35) and Deleted in Malignant Brain Tumor 1-like proteins. In summary, this study provides a new insight into the novel traits of COTS, a major pest on coral reefs, and a proteomics resource that can be used to develop (bio)control strategies and understand molecular mechanisms of regeneration.journal articl
anti-tick vaccines to prevent tick-borne diseases in Europe
Ixodes ricinus transmits bacterial, protozoal and viral pathogens, causing
disease and forming an increasing health concern in Europe. ANTIDotE is an
European Commission funded consortium of seven institutes, which aims to
identify and characterize tick proteins involved in feeding and pathogen
transmission. The knowledge gained will be used to develop and evaluate anti-
tick vaccines that may prevent multiple human tick-borne diseases. Strategies
encompassing anti-tick vaccines to prevent transmission of pathogens to
humans, animals or wildlife will be developed with relevant stakeholders with
the ultimate aim of reducing the incidence of tick-borne diseases in humans
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