scholarly journals Repeated evolution of inactive pseudonucleases in a fungal branch of the Dis3/RNase II family of nucleases

2020 ◽  
Author(s):  
Elizabeth R Ballou ◽  
Atlanta G Cook ◽  
Edward W J Wallace
Keyword(s):  
Active Site ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Degradation ◽  
Growth Stages ◽  
Pathogenic Yeast ◽  
Evolutionary Origins ◽  
Sequence Of Events ◽  
Domains Of Life ◽  
Rnase Ii

Abstract The RNase II family of 3′-5′ exoribonucleases are present in all domains of life, and eukaryotic family members Dis3 and Dis3L2 play essential roles in RNA degradation. Ascomycete yeasts contain both Dis3 and inactive RNase II-like “pseudonucleases”. The latter function as RNA-binding proteins that affect cell growth, cytokinesis, and fungal pathogenicity. However, the evolutionary origins of these pseudonucleases are unknown: what sequence of events led to their novel function, and when did these events occur? Here, we show how RNase II pseudonuclease homologs, including Saccharomyces cerevisiae Ssd1, are descended from active Dis3L2 enzymes. During fungal evolution, active site mutations in Dis3L2 homologs have arisen at least four times, in some cases following gene duplication. In contrast, N-terminal cold-shock domains and regulatory features are conserved across diverse dikarya and mucoromycota, suggesting that the non-nuclease function requires these regions. In the basidiomycete pathogenic yeast Cryptococcus neoformans, the single Ssd1/Dis3L2 homolog is required for cytokinesis from polyploid “titan” growth stages. This phenotype of C. neoformans Ssd1/Dis3L2 deletion is consistent with those of inactive fungal pseudonucleases, yet the protein retains an active site sequence signature. We propose that a nuclease-independent function for Dis3L2 arose in an ancestral hyphae-forming fungus. This second function has been conserved across hundreds of millions of years, while the RNase activity was lost repeatedly in independent lineages.

scholarly journals Repeated evolution of inactive pseudonucleases in a fungal branch of the Dis3/RNase II family of nucleases

2020 ◽  
Author(s):  
Elizabeth R Ballou ◽  
Atlanta G Cook ◽  
Edward W. J. Wallace
Keyword(s):  
Active Site ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Degradation ◽  
Growth Stages ◽  
Pathogenic Yeast ◽  
Fungal Evolution ◽  
Domains Of Life ◽  
Repeated Evolution ◽  
Rnase Ii

The RNase II family of 3'-5' exoribonucleases are present in all domains of life, and eukaryotic family members Dis3 and Dis3L2 play essential roles in RNA degradation. Ascomycete yeasts contain both Dis3 and inactive RNase II-like "pseudonucleases". These function as RNA-binding proteins that affect cell growth, cytokinesis, and fungal pathogenicity. Here, we show how these pseudonuclease homologs, including Saccharomyces cerevisiae Ssd1, are descended from active Dis3L2 enzymes. During fungal evolution, active site mutations in Dis3L2 homologs have arisen at least four times, in some cases following gene duplication. The N-terminal cold-shock domains and regulatory features are conserved across diverse dikarya and mucoromycota, suggesting that the non-nuclease function require this region. In the basidiomycete pathogenic yeast Cryptococcus neoformans, the single Ssd1/Dis3L2 homolog is required for cytokinesis from polyploid "titan" growth stages and yet retains an active site sequence signature. We propose that that a nuclease-independent function for Dis3L2 arose in an ancestral hyphae-forming fungus. This second function has been conserved across hundreds of millions of years, while the RNase activity was lost repeatedly in independent lineages.

scholarly journals Systematic discovery of endogenous human ribonucleoprotein complexes

2018 ◽  
Author(s):  
Anna L. Mallam ◽  
Wisath Sae-Lee ◽  
Jeffrey M. Schaub ◽  
Fan Tu ◽  
Anna Battenhouse ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein Complexes ◽  
Embryonic Stem ◽  
Human Protein ◽  
Disease States ◽  
Ribonucleoprotein Complexes ◽  
Associated Proteins ◽  
Domains Of Life ◽  
Factor C

AbstractRNA-binding proteins (RBPs) play essential roles in biology and are frequently associated with human disease. While recent studies have systematically identified individual RBPs, their higher order assembly intoRibonucleoprotein (RNP) complexes has not been systematically investigated. Here, we describe a proteomics method for systematic identification of RNP complexes in human cells. We identify 1,428 protein complexes that associate with RNA, indicating that over 20% of known human protein complexes contain RNA. To explore the role of RNA in the assembly of each complex, we identify complexes that dissociate, change composition, or form stable protein-only complexes in the absence of RNA. Importantly, these data also provide specific novel insights into the function of well-studied protein complexes not previously known to associate with RNA, including replication factor C (RFC) and cytokinetic centralspindlin complex. Finally, we use our method to systematically identify cell-type specific RNA-associated proteins in mouse embryonic stem cells. We distribute these data as a resource, rna.MAP (rna.proteincomplexes.org) which provides a comprehensive dataset for the study of RNA-associated protein complexes. Our system thus provides a novel methodology for further explorations across human tissues and disease states, as well as throughout all domains of life.SummaryAn exploration of human protein complexes in the presence and absence of RNA reveals endogenous ribonucleoprotein complexes

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 The Escherichia coli major exoribonuclease RNase II is a component of the RNA degradosome

2014 ◽  
Vol 34 (6) ◽  
Author(s):  
Feng Lu ◽  
Aziz Taghbalout
Keyword(s):  
Escherichia Coli ◽  
Rna Processing ◽  
Binding Sites ◽  
Rna Degradation ◽  
The Other ◽  
Polynucleotide Phosphorylase ◽  
Cell Extracts ◽  
Domains Of Life ◽  
Rna Degradosome ◽  
Rnase Ii

Multiprotein complexes that carry out RNA degradation and processing functions are found in cells from all domains of life. In Escherichia coli, the RNA degradosome, a four-protein complex, is required for normal RNA degradation and processing. In addition to the degradosome complex, the cell contains other ribonucleases that also play important roles in RNA processing and/or degradation. Whether the other ribonucleases are associated with the degradosome or function independently is not known. In the present work, IP (immunoprecipitation) studies from cell extracts showed that the major hydrolytic exoribonuclease RNase II is associated with the known degradosome components RNaseE (endoribonuclease E), RhlB (RNA helicase B), PNPase (polynucleotide phosphorylase) and Eno (enolase). Further evidence for the RNase II-degradosome association came from the binding of RNase II to purified RNaseE in far western affinity blot experiments. Formation of the RNase II–degradosome complex required the degradosomal proteins RhlB and PNPase as well as a C-terminal domain of RNaseE that contains binding sites for the other degradosomal proteins. This shows that the RNase II is a component of the RNA degradosome complex, a previously unrecognized association that is likely to play a role in coupling and coordinating the multiple elements of the RNA degradation pathways.

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 Structural elucidation of a novel mechanism for the bacteriophage-based inhibition of the RNA degradosome

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
An Van den Bossche ◽  
Steven W Hardwick ◽  
Pieter-Jan Ceyssens ◽  
Hanne Hendrix ◽  
Marleen Voet ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Degradation ◽  
Rnase E ◽  
Effective Inhibition ◽  
Domains Of Life ◽  
Infected Cells ◽  
Rna Degradosome ◽  
Host Infection ◽  
Structural Homologues ◽  
Unique Mechanism

In all domains of life, the catalysed degradation of RNA facilitates rapid adaptation to changing environmental conditions, while destruction of foreign RNA is an important mechanism to prevent host infection. We have identified a virus-encoded protein termed gp37/Dip, which directly binds and inhibits the RNA degradation machinery of its bacterial host. Encoded by giant phage фKZ, this protein associates with two RNA binding sites of the RNase E component of the Pseudomonas aeruginosa RNA degradosome, occluding them from substrates and resulting in effective inhibition of RNA degradation and processing. The 2.2 Å crystal structure reveals that this novel homo-dimeric protein has no identifiable structural homologues. Our biochemical data indicate that acidic patches on the convex outer surface bind RNase E. Through the activity of Dip, фKZ has evolved a unique mechanism to down regulate a key metabolic process of its host to allow accumulation of viral RNA in infected cells.

scholarly journals Small regulatory bacterial RNAs regulating the envelope stress response

2017 ◽  
Vol 45 (2) ◽  
pp. 417-425 ◽  
Author(s):  
Gracjana Klein ◽  
Satish Raina
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Degradation ◽  
Feedback Mechanism ◽  
Transcriptional Factors ◽  
Membrane Composition ◽  
Envelope Stress ◽  
Small Regulatory Rnas ◽  
Two Component Systems ◽  
Regulatory Rnas

Most bacteria encode a large repertoire of RNA-based regulatory mechanisms. Recent discoveries have revealed that the expression of many genes is controlled by a plethora of base-pairing noncoding small regulatory RNAs (sRNAs), regulatory RNA-binding proteins and RNA-degrading enzymes. Some of these RNA-based regulated processes respond to stress conditions and are involved in the maintenance of cellular homeostasis. They achieve it by either direct posttranscriptional repression of several mRNAs, including blocking access to ribosome and/or directing them to RNA degradation when the synthesis of their cognate proteins is unwanted, or by enhanced translation of some key stress-regulated transcriptional factors. Noncoding RNAs that regulate the gene expression by binding to regulatory proteins/transcriptional factors often act negatively by sequestration, preventing target recognition. Expression of many sRNAs is positively regulated by stress-responsive sigma factors like RpoE and RpoS, and two-component systems like PhoP/Q, Cpx and Rcs. Some of these regulatory RNAs act via a feedback mechanism on their own regulators, which is best reflected by recent discoveries, concerning the regulation of cell membrane composition by sRNAs in Escherichia coli and Salmonella, which are highlighted here.

scholarly journals N6-methyladenosine dynamics during early vertebrate embryogenesis

2019 ◽  
Author(s):  
Håvard Aanes ◽  
Dominique Engelsen ◽  
Adeel Manaf ◽  
Endalkachew Ashenafi Alemu ◽  
Cathrine Broberg Vågbø ◽  
...  
Keyword(s):  
Translational Regulation ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Degradation ◽  
Translational Efficiency ◽  
Mrna Levels ◽  
Maternal Transcripts ◽  
Post Transcriptional Regulation ◽  
Genome Activation ◽  
Polyadenylated Mrna

AbstractEarly vertebrate embryogenesis is characterized by extensive post-transcriptional regulation during the maternal-to-zygotic transition. The N6-methyladenosine (m6A) modifications on mRNA have been shown to affect both translation and stability of transcripts. Here we investigate the m6A topology during early vertebrate embryogenesis and its association with polyadenylated mRNA levels. The majority (>70%) of maternal transcripts harbor m6A, and there is a substantial increase of m6A in the polyadenylated mRNA fraction between 0 and 2 hours post fertilization. Notably, we find strong associations between m6A, cytoplasmic polyadenylation and translational efficiency prior to zygotic genome activation (ZGA). Interestingly, the relationship between m6A and translation is strongest for peaks located in the 3’UTR, but not overlapping stop codons. Sequence analyses revealed enrichment of motifs for RNA binding proteins involved in translational regulation and RNA degradation. After ZGA, m6A seem to diminish the effect of miR-430 mediated degradation. The reported results improve our understanding of the combinatorial code behind post-transcriptional mRNA regulation during embryonic reprogramming and early differentiation.

scholarly journals Changes in mRNA abundance drive shuttling of RNA binding proteins, linking cytoplasmic RNA degradation to transcription

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Sarah Gilbertson ◽  
Joel D Federspiel ◽  
Ella Hartenian ◽  
Ileana M Cristea ◽  
Britt Glaunsinger
Keyword(s):  
Gene Expression ◽  
Rna Polymerase Ii ◽  
Mrna Decay ◽  
Binding Proteins ◽  
Rna Binding ◽  
Nuclear Translocation ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Protein Localization ◽  
Rna Degradation

Alterations in global mRNA decay broadly impact multiple stages of gene expression, although signals that connect these processes are incompletely defined. Here, we used tandem mass tag labeling coupled with mass spectrometry to reveal that changing the mRNA decay landscape, as frequently occurs during viral infection, results in subcellular redistribution of RNA binding proteins (RBPs) in human cells. Accelerating Xrn1-dependent mRNA decay through expression of a gammaherpesviral endonuclease drove nuclear translocation of many RBPs, including poly(A) tail-associated proteins. Conversely, cells lacking Xrn1 exhibited changes in the localization or abundance of numerous factors linked to mRNA turnover. Using these data, we uncovered a new role for relocalized cytoplasmic poly(A) binding protein in repressing recruitment of TATA binding protein and RNA polymerase II to promoters. Collectively, our results show that changes in cytoplasmic mRNA decay can directly impact protein localization, providing a mechanism to connect seemingly distal stages of gene expression.

scholarly journals System-wide analyses of the fission yeast poly(A)+ RNA interactome reveal insights into organisation and function of RNA-protein complexes

2019 ◽  
Author(s):  
Cornelia Kilchert ◽  
Tea Kecman ◽  
Emily Priest ◽  
Svenja Hester ◽  
Krzysztof Kus ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Protein Interactions ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein Complexes ◽  
Rna Degradation ◽  
Binding Activity ◽  
Rna Exosome ◽  
And Function ◽  
Rna Protein Complexes

AbstractProduction, function, and turnover of mRNA are orchestrated by multi-subunit machineries that play a central role in gene expression. Within these molecular machines, interactions with the target mRNA are mediated by RNA-binding proteins (RBPs), and the accuracy and dynamics of these RNA-protein interactions are essential for their function. Here, we show that fission yeast whole cell poly(A)+ RNA-protein crosslinking data provides system-wide information on the organisation and function of the RNA-protein complexes. We evaluate relative enrichment of cellular RBPs on poly(A)+ RNA to identify interactors with high RNA-binding activity and provide key information about the RNA-binding properties of large multi-protein complexes, such as the mRNA 3’ end processing machinery (cleavage and polyadenylation factor, CPF) and the RNA exosome. We demonstrate that different functional modules within CPF differ in their ability to interact with RNA. Importantly, we reveal that CPF forms additional contacts with RNA via the Fip1 subunit of the polyadenylation module and two subunits of the nuclease module. In addition, our data highlights the central role of the RNA helicase Mtl1 in RNA degradation by the exosome as mutations in Mtl1 lead to disengagement of the exosome from RNA. We examine how routes of substrate access to the complex are affected upon mutation of exosome subunits. Our results provide important insights into how different components of the exosome contribute to engagement of the complex with substrate RNA. Overall, our data uncover how multi-subunit cellular machineries interact with RNA, on a proteome-wide scale.

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