scholarly journals Conceptual Advances in Control of Inflammation by the RNA-Binding Protein Tristetraprolin

2021 ◽  
Vol 12 ◽  
Author(s):  
Pavel Kovarik ◽  
Annika Bestehorn ◽  
Jeanne Fesselet
Keyword(s):  
Immune Responses ◽  
Mrna Stability ◽  
Binding Sites ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Degradation ◽  
Decay Rates ◽  
Mrna Destabilization

Regulated changes in mRNA stability are critical drivers of gene expression adaptations to immunological cues. mRNA stability is controlled mainly by RNA-binding proteins (RBPs) which can directly cleave mRNA but more often act as adaptors for the recruitment of the RNA-degradation machinery. One of the most prominent RBPs with regulatory roles in the immune system is tristetraprolin (TTP). TTP targets mainly inflammation-associated mRNAs for degradation and is indispensable for the resolution of inflammation as well as the maintenance of immune homeostasis. Recent advances in the transcriptome-wide knowledge of mRNA expression and decay rates together with TTP binding sites in the target mRNAs revealed important limitations in our understanding of molecular mechanisms of TTP action. Such orthogonal analyses lead to the discovery that TTP binding destabilizes some bound mRNAs but not others in the same cell. Moreover, comparisons of various immune cells indicated that an mRNA can be destabilized by TTP in one cell type while it remains stable in a different cell linage despite the presence of TTP. The action of TTP extends from mRNA destabilization to inhibition of translation in a subset of targets. This article will discuss these unexpected context-dependent functions and their implications for the regulation of immune responses. Attention will be also payed to new insights into the role of TTP in physiology and tissue homeostasis.

scholarly journals Neurogenesis: Regulation by Alternative Splicing and Related Posttranscriptional Processes

2016 ◽  
Vol 23 (5) ◽  
pp. 466-477 ◽  
Author(s):  
Enrique Lara-Pezzi ◽  
Manuel Desco ◽  
Alberto Gatto ◽  
María Victoria Gómez-Gaviro
Keyword(s):  
Alternative Splicing ◽  
Protein Function ◽  
Posttranscriptional Regulation ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Degradation ◽  
Protein Isoforms ◽  
Mammalian Brain ◽  
Nonsense Mediated Decay

The complexity of the mammalian brain requires highly specialized protein function and diversity. As neurons differentiate and the neuronal circuitry is established, several mRNAs undergo alternative splicing and other posttranscriptional changes that expand the variety of protein isoforms produced. Recent advances are beginning to shed light on the molecular mechanisms that regulate isoform switching during neurogenesis and the role played by specific RNA binding proteins in this process. Neurogenesis and neuronal wiring were recently shown to also be regulated by RNA degradation through nonsense-mediated decay. An additional layer of regulatory complexity in these biological processes is the interplay between alternative splicing and long noncoding RNAs. Dysregulation of posttranscriptional regulation results in defective neuronal differentiation and/or synaptic connections that lead to neurodevelopmental and psychiatric disorders.

scholarly journals An exon DNA element modulates heterochromatin spreading in the master regulator for sexual commitment in malaria parasites

2020 ◽  
Author(s):  
Carlos Cordon-Obras ◽  
Anna Barcons-Simon ◽  
Christine Scheidig-Benatar ◽  
Aurelie Claës ◽  
Valentin Sabatet ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Rna Binding ◽  
Antigenic Variation ◽  
Rna Binding Proteins ◽  
Protein Complexes ◽  
Heterochromatin Protein 1 ◽  
Master Regulator ◽  
Heterochromatin Protein

ABSTRACTHeterochromatin is essential in all eukaryotes to maintain genome integrity, long-term gene repression and to help chromosome segregation during mitosis. However, heterochromatin regions must be restricted by boundary elements to avoid its spreading over actively transcribed loci. In Plasmodium falciparum, facultative heterochromatin is important to regulate parasite virulence, antigenic variation and transmission. However, the underlying molecular mechanisms regulating repressive regions remain unknown. To investigate this topic, we chose the ap2-g gene, which forms a strictly delimited and independent heterochromatin island. Using electrophoretic motility shift assay (EMSA) we identified an ap2-g exon element at the 3’ end binding nuclear protein complexes. Upon replacement of this region by a gfp gene, we observed a shift in the heterochromatin boundary resulting in HP1 (Heterochromatin Protein 1) spreading over ∼2 additional kb downstream. We used this DNA element to purify candidate proteins followed by proteomic analysis. The identified complexes were found to be enriched in RNA-binding proteins, pointing to a potential role of RNA in the regulation of the ap2-g 3’ heterochromatin boundary. Our results provide insight into the unexplored topic of heterochromatin biology in P. falciparum and identify a DNA element within the master regulator of sexual commitment modulating heterochromatin spreading.

scholarly journals The Role of lncRNAs in Gene Expression Regulation through mRNA Stabilization

2021 ◽  
Vol 7 (1) ◽  
pp. 3
Author(s):  
Maialen Sebastian-delaCruz ◽  
Itziar Gonzalez-Moro ◽  
Ane Olazagoitia-Garmendia ◽  
Ainara Castellanos-Rubio ◽  
Izortze Santin
Keyword(s):  
Gene Expression ◽  
Mrna Stability ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Gene Expression Regulation ◽  
Rna Binding Proteins ◽  
Regulation Of Gene Expression ◽  
Mrna Stabilization ◽  
Living Organisms ◽  
Almost All

mRNA stability influences gene expression and translation in almost all living organisms, and the levels of mRNA molecules in the cell are determined by a balance between production and decay. Maintaining an accurate balance is crucial for the correct function of a wide variety of biological processes and to maintain an appropriate cellular homeostasis. Long non-coding RNAs (lncRNAs) have been shown to participate in the regulation of gene expression through different molecular mechanisms, including mRNA stabilization. In this review we provide an overview on the molecular mechanisms by which lncRNAs modulate mRNA stability and decay. We focus on how lncRNAs interact with RNA binding proteins and microRNAs to avoid mRNA degradation, and also on how lncRNAs modulate epitranscriptomic marks that directly impact on mRNA stability.

scholarly journals Computational Mapping of the Human-SARS-CoV-2 Protein-RNA Interactome

2021 ◽  
Author(s):  
Marc Horlacher ◽  
Svitlana Oleshko ◽  
Yue Hu ◽  
Mahsa Ghanbari ◽  
Ernesto Elorduy Vergara ◽  
...  
Keyword(s):  
Deep Learning ◽  
Viral Replication ◽  
Binding Sites ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Stability ◽  
Experimental Studies ◽  
Viral Rna ◽  
Virus Binding

It is well known that viruses make extensive use of the host cell's machinery, hijacking it for the purpose of viral replication and interfere with the activity of master regulatory proteins - including RNA binding proteins (RBPs). RBPs recognize and bind RNA molecules to control several steps of cellular RNA metabolism, such as splicing, transcript stability, translation and others, and recognize their targets by means of sequence or structure motifs. Host RBPs are critical factors for viral replication, especially for RNA viruses, and have been shown to influence viral RNA stability, replication and escape of host immune response. While current research efforts have been centered around identifying mechanisms of host cell-entry, the role of host RBPs in the context of SARS-CoV-2 replication remains poorly understood. Few experimental studies have started mapping the SARS-CoV-2 RNA-protein interactome in infected human cells, but they are limited in the resolution and exhaustivity of their output. On the other hand, computational approaches enable screening of large numbers of human RBPs for putative interactions with the viral RNA, and are thus crucial to prioritize candidates for further experimental investigation. Here, we investigate the role of RBPs in the context of SARS-CoV-2 by constructing a first single-nucleotide \textit{in silico} map of human RBP / viral RNA interactions by using deep learning models trained on RNA sequences. Our framework is based on Pysster and DeepRiPe, two deep learning method which use a convolutional neural network to learn sequence-structure preferences of a specific RBP. Models were trained using eCLIP and PAR-CLIP datasets for >150 RBP generated on human cell lines and applied cross-species to predict the propensity of each RBP to bind the SARS-CoV-2 genome. After extensive validation of predicted binding sites, we generate RBP binding profiles across different SARS-CoV-2 variants and 6 other betacoronaviruses. We address the questions of (1) conservation of binding between pathogenic betacoronaviruses, (2) differential binding across viral strains and (3) gain and loss of binding events in novel mutants which can be linked to disease severity and spread in the population. In addition, we explore the specific pathways hijacked by the virus, by integrating host factors linked to these virus-binding RBPs through protein-protein interaction networks or genome wide CRISPR screening. We believe that identifying viral RBP binding sites will give valuable insights into the mechanisms of host-virus interaction, thus giving us a deeper understanding of the life cycle of SARS-CoV-2 but also opening new avenues for the development of new therapeutics.

scholarly journals RNA-stabilization factors in chloroplasts of vascular plants

2018 ◽  
Vol 62 (1) ◽  
pp. 51-64 ◽  
Author(s):  
Nikolay Manavski ◽  
Lisa-Marie Schmid ◽  
Jörg Meurer
Keyword(s):  
Stress Responses ◽  
Vascular Plants ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Degradation ◽  
Decay Rates ◽  
Transcriptional Level ◽  
Chloroplast Gene Expression ◽  
Chloroplast Rna

In contrast to the cyanobacterial ancestor, chloroplast gene expression is predominantly governed on the post-transcriptional level such as modifications of the RNA sequence, decay rates, exo- and endonucleolytic processing as well as translational events. The concerted function of numerous chloroplast RNA-binding proteins plays a fundamental and often essential role in all these processes but our understanding of their impact in regulation of RNA degradation is only at the beginning. Moreover, metabolic processes and post-translational modifications are thought to affect the function of RNA protectors. These protectors contain a variety of different RNA-recognition motifs, which often appear as multiple repeats. They are required for normal plant growth and development as well as diverse stress responses and acclimation processes. Interestingly, most of the protectors are plant specific which reflects a fast-evolving RNA metabolism in chloroplasts congruent with the diverging RNA targets. Here, we mainly focused on the characteristics of known chloroplast RNA-binding proteins that protect exonuclease-sensitive sites in chloroplasts of vascular plants.

scholarly journals Profiling the binding sites of RNA-binding protein by LACE-seq

2021 ◽  
Author(s):  
Ruibao Su ◽  
Di Wang ◽  
Changchang Cao ◽  
Yuanchao Xue
Keyword(s):  
Binding Sites ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Transcription Termination ◽  
Early Embryo ◽  
Linear Amplification ◽  
Single Nucleotide ◽  
Nucleotide Resolution ◽  
Single Nucleotide Resolution

Abstract RNA-binding proteins (RBPs) directly interact with various RNAs in living cells to regulate their processing, translation, and stability. Identifying the precise binding sites of RBPs is critical for appreciating their physiological or pathological roles in germline and early embryo development. Current methods typically need millions of cells to map RBP binding positions, which prevents us from appreciating the crucial role of RBPs in early development. Here, we present the LACE-seq method for unbiased mapping of RBP-binding sites at single-nucleotide resolution in fewer cells or even single oocytes. LACE-seq depends on RBP-mediated reverse transcription termination, and linear amplification of the cDNA ends for deep sequencing. To further promote its application, we describe a step-by-step protocol about how to construct a successful LACE-seq library.

scholarly journals Dynamic regulation of HYL1 provides new insights into its multifaceted role in Arabidopsis

2018 ◽  
Author(s):  
Prakash Kumar Bhagat ◽  
Deepanjali Verma ◽  
Raghuram Badmi ◽  
Alok Krishna Sinha
Keyword(s):  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Phosphorylation Site ◽  
Terminal Region ◽  
Mirna Biogenesis ◽  
Dynamic Regulation ◽  
Double Stranded Rna ◽  
Microprocessor Complex

SummaryMicroRNAs (miRNAs) are 21 to 24 nucleotide non-coding RNAs that regulate gene expression. Biogenesis of miRNAs is fine-tuned by specialized microprocessor complex, the regulation of which is being continuously understood. Recruitment of HYL1 to the microprocessor complex is crucial for accurate primary-miRNA (pri-miRNA) processing and accumulation of mature miRNA in Arabidopsis thaliana. HYL1 is a double-stranded RNA binding protein also termed as DRB1, has two double-stranded RNA binding domain at N-terminal and a highly disordered C-terminal region. Also, the biological activity of HYL1 is dynamically regulated through transition from hyperphosphorylation to hypophosphorylation state. HYL1 is known to be phosphorylated by a MAP kinase MPK3 and SnRK2. However, the precise role of its phosphorylation are still unknown. Recently, the stability of HYL1 protein has been shown to be regulated by an unknown protease X. However, the identity of the protease and its molecular mechanisms are poorly understood. Here, we describe, three functionally important facets of HYL1, which provide a better picture of its association with molecular processes. First, we identified a conserved MPK3 phosphorylation site on HYL1 and its possible role in the miRNA biogenesis. Secondly, the C-terminal region of HYL1 displays tendencies to bind dsDNA. Lastly, the role of C-terminal region of HYL1 in the regulation of its protein stability and the regulation of miRNA biogenesis is documented. We show the unexplored role of C-terminal and hypothesize the novel functions of HYL1 in addition to miRNA biogenesis. We anticipate that the data presented in this study, will open a new dimension of understanding the role of double stranded RNA binding proteins in diverse biological processes of plants and animal.

PAP1 [poly(A) polymerase 1] homozygosity and hyperadenylation are major determinants of increased mRNA stability of CDR1 in azole-resistant clinical isolates of Candida albicans

Microbiology ◽  
2010 ◽  
Vol 156 (2) ◽  
pp. 313-326 ◽  
Author(s):  
Raman Manoharlal ◽  
Jyotsna Gorantala ◽  
Monika Sharma ◽  
Dominique Sanglard ◽  
Rajendra Prasad
Keyword(s):  
Drug Resistance ◽  
Candida Albicans ◽  
Transcriptional Activation ◽  
Mrna Stability ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Dominant Negative ◽  
Clinical Isolates ◽  
Single Type

Using genetically matched azole-susceptible (AS) and azole-resistant (AR) clinical isolates of Candida albicans, we recently demonstrated that CDR1 overexpression in AR isolates is due to its enhanced transcriptional activation and mRNA stability. This study examines the molecular mechanisms underlying enhanced CDR1 mRNA stability in AR isolates. Mapping of the 3′ untranslated region (3′ UTR) of CDR1 revealed that it was rich in adenylate/uridylate (AU) elements, possessed heterogeneous polyadenylation sites, and had putative consensus sequences for RNA-binding proteins. Swapping of heterologous and chimeric lacZ–CDR1 3′ UTR transcriptional reporter fusion constructs did not alter the reporter activity in AS and AR isolates, indicating that cis-acting sequences within the CDR1 3′ UTR itself are not sufficient to confer the observed differential mRNA decay. Interestingly, the poly(A) tail of the CDR1 mRNA of AR isolates was ∼35–50 % hyperadenylated as compared with AS isolates. C. albicans poly(A) polymerase (PAP1), responsible for mRNA adenylation, resides on chromosome 5 in close proximity to the mating type-like (MTL) locus. Two different PAP1 alleles, PAP1-a/PAP1-α, were recovered from AS (MTL-a/MTL-α), while a single type of PAP1 allele (PAP1-α) was recovered from AR isolates (MTL-α/MTL-α). Among the heterozygous deletions of PAP1-a (Δpap1-a/PAP1-α) and PAP1-α (PAP1-a/Δpap1-α), only the former led to relatively enhanced drug resistance, to polyadenylation and to transcript stability of CDR1 in the AS isolate. This suggests a dominant negative role of PAP1-a in CDR1 transcript polyadenylation and stability. Taken together, our study provides the first evidence, to our knowledge, that loss of heterozygosity at the PAP1 locus is linked to hyperadenylation and subsequent increased stability of CDR1 transcripts, thus contributing to enhanced drug resistance.

The role of 3'UTR of RNA viruses on mRNA stability and translation enhancement

2021 ◽  
Vol 21 ◽  
Author(s):  
Mahsa Rasekhian ◽  
Farzin Roohvand ◽  
Solomon Habtemariam ◽  
Marzieh Marzbany ◽  
Monireh Kazemimanesh
Keyword(s):  
Mrna Stability ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Viruses ◽  
Nucleotide Composition ◽  
Rna Molecules ◽  
A Genome ◽  
Functional Product ◽  
Positive Sense

: The central dogma of molecular biology explains the flow of genetic information from DNA to functional products such as proteins. In most cases, a linear relationship with high correlation coefficient exists between the concentration of mRNA, the middle man, and the functional product. Untranslated regions (UTRs) of RNA form considerable base pairing that contributes to the secondary and tertiary structures of mRNA. The interaction between the mRNA secondary structures (cis-elements), RNA-binding proteins (RBP) and miRs (trans-element) are critical determinants of mRNAs' fate and stability. Among different viral families, the positive sense (+) RNA viruses use the simplest possible strategy of replication and expression; as the same molecule functions both as a genome and mRNA. Additionally, nucleotide composition and codon usage of +RNA viruses are the closest to human codon adaptation index (CAI). Since the origin of replication of viral intermediate RNA molecules is at the 3'-end of the genome, the 3'UTR plays a role in viral RNA replication. Moreover, the messenger role of RNA likely places functional demands on the 3'UTR to serve a role typical of cellular mRNA. This article reviews the effect of 3'UTR of RNA viruses with positive sense and genomes on mRNA stability and translation improvement. A range of animal (e.g., Dengue, Sindbis, Corona and Polio) and plant (Barley yellow dwarf, Brome mosaic, Turnip crinkle, Tobacco mosaic, Cowpea mosaic and Alfalfa mosaic) viruses are examined to highlight the role of 3'UTR in viral survival and as a potential target for pharmaceutical applications.

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