scholarly journals Grad-seq identifies KhpB as a global RNA-binding protein in Clostridioides difficile that regulates toxin production

microLife ◽  
2021 ◽  
Author(s):  
Vanessa Lamm-Schmidt ◽  
Manuela Fuchs ◽  
Johannes Sulzer ◽  
Milan Gerovac ◽  
Jens Hör ◽  
...  

Abstract Much of our current knowledge about cellular RNA-protein complexes in bacteria is derived from analyses in gram-negative model organisms, with the discovery of RNA-binding proteins (RBPs) generally lagging behind in gram-positive species. Here, we have applied Grad-seq analysis of native RNA-protein complexes to a major gram-positive human pathogen, Clostridioides difficile, whose RNA biology remains largely unexplored. Our analysis resolves in-gradient distributions for ∼88% of all annotated transcripts and ∼50% of all proteins, thereby providing a comprehensive resource for the discovery of RNA-protein and protein-protein complexes in C. difficile and related microbes. The sedimentation profiles together with pulldown approaches identify KhpB, previously identified in Streptococcus pneumoniae, as an uncharacterized, pervasive RBP in C. difficile. Global RIP-seq analysis establishes a large suite of mRNA and small RNA targets of KhpB, similar to the scope of the Hfq targetome in C. difficile. The KhpB-bound transcripts include several functionally related mRNAs encoding virulence-associated metabolic pathways and toxin A whose transcript levels are observed to be increased in a khpB deletion strain. Moreover, the production of toxin protein is also increased upon khpB deletion. In summary, this study expands our knowledge of cellular RNA protein interactions in C. difficile and supports the emerging view that KhpB homologues constitute a new class of globally acting RBPs in gram-positive bacteria.

2019 ◽  
Author(s):  
Cornelia Kilchert ◽  
Tea Kecman ◽  
Emily Priest ◽  
Svenja Hester ◽  
Krzysztof Kus ◽  
...  

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.


Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2270
Author(s):  
Ronja Weissinger ◽  
Lisa Heinold ◽  
Saira Akram ◽  
Ralf-Peter Jansen ◽  
Orit Hermesh

Multiple cellular functions are controlled by the interaction of RNAs and proteins. Together with the RNAs they control, RNA interacting proteins form RNA protein complexes, which are considered to serve as the true regulatory units for post-transcriptional gene expression. To understand how RNAs are modified, transported, and regulated therefore requires specific knowledge of their interaction partners. To this end, multiple techniques have been developed to characterize the interaction between RNAs and proteins. In this review, we briefly summarize the common methods to study RNA–protein interaction including crosslinking and immunoprecipitation (CLIP), and aptamer- or antisense oligonucleotide-based RNA affinity purification. Following this, we focus on in vivo proximity labeling to study RNA–protein interactions. In proximity labeling, a labeling enzyme like ascorbate peroxidase or biotin ligase is targeted to specific RNAs, RNA-binding proteins, or even cellular compartments and uses biotin to label the proteins and RNAs in its vicinity. The tagged molecules are then enriched and analyzed by mass spectrometry or RNA-Seq. We highlight the latest studies that exemplify the strength of this approach for the characterization of RNA protein complexes and distribution of RNAs in vivo.


2021 ◽  
Vol 7 (1) ◽  
pp. 11 ◽  
Author(s):  
André P. Gerber

RNA–protein interactions frame post-transcriptional regulatory networks and modulate transcription and epigenetics. While the technological advances in RNA sequencing have significantly expanded the repertoire of RNAs, recently developed biochemical approaches combined with sensitive mass-spectrometry have revealed hundreds of previously unrecognized and potentially novel RNA-binding proteins. Nevertheless, a major challenge remains to understand how the thousands of RNA molecules and their interacting proteins assemble and control the fate of each individual RNA in a cell. Here, I review recent methodological advances to approach this problem through systematic identification of proteins that interact with particular RNAs in living cells. Thereby, a specific focus is given to in vivo approaches that involve crosslinking of RNA–protein interactions through ultraviolet irradiation or treatment of cells with chemicals, followed by capture of the RNA under study with antisense-oligonucleotides and identification of bound proteins with mass-spectrometry. Several recent studies defining interactomes of long non-coding RNAs, viral RNAs, as well as mRNAs are highlighted, and short reference is given to recent in-cell protein labeling techniques. These recent experimental improvements could open the door for broader applications and to study the remodeling of RNA–protein complexes upon different environmental cues and in disease.


Open Biology ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 190096 ◽  
Author(s):  
Anna Balcerak ◽  
Alicja Trebinska-Stryjewska ◽  
Ryszard Konopinski ◽  
Maciej Wakula ◽  
Ewa Anna Grzybowska

RNA–protein interactions are crucial for most biological processes in all organisms. However, it appears that the complexity of RNA-based regulation increases with the complexity of the organism, creating additional regulatory circuits, the scope of which is only now being revealed. It is becoming apparent that previously unappreciated features, such as disordered structural regions in proteins or non-coding regions in DNA leading to higher plasticity and pliability in RNA–protein complexes, are in fact essential for complex, precise and fine-tuned regulation. This review addresses the issue of the role of RNA–protein interactions in generating eukaryotic complexity, focusing on the newly characterized disordered RNA-binding motifs, moonlighting of metabolic enzymes, RNA-binding proteins interactions with different RNA species and their participation in regulatory networks of higher order.


1982 ◽  
Vol 60 (4) ◽  
pp. 490-496 ◽  
Author(s):  
Ross N. Nazar ◽  
Makoto Yaguchi ◽  
Gordon E. Willick

The ribosomal 5S RNA – protein complex appears to be an excellent model for studies on the evolution and structure of ribosomes. In eukaryotes this complex is composed of two components, the 5S rRNA and a single ribosomal protein which in yeast has a molecular weight of about 38 000. The primary protein-binding site is located in the 3′-end region of the 5S RNA together with a small portion of the 5′ end. The primary RNA-binding site appears to be situated in the C-terminal end of the protein (YL3 in yeast) but the binding specificity requires other structural elements in the N-terminal half of the molecule. When compared with prokaryotic 5S RNA – protein complexes, various physical and chemical studies suggest that the basic structure and interactions have been conserved in the course of evolution, but that the single larger eukaryotic 5S RNA binding protein has evolved through a fusion of genes for the multiple 5S RNA binding proteins in prokaryotes.


2014 ◽  
Author(s):  
Roland Pache ◽  
Patrick Aloy

Macromolecular assemblies play an important role in almost all cellular processes. However, despite several large-scale studies, our current knowledge about protein complexes is still quite limited, thus advocating the use of in silico predictions to gather information on complex composition in model organisms. Since protein-protein interactions present certain constraints on the functional divergence of macromolecular assemblies during evolution, it is possible to predict complexes based on orthology data. Here, we show that incorporating interaction information through network alignment significantly increases the precision of orthology-based complex prediction. Moreover, we performed a large-scale in silico screen for protein complexes in human, yeast and fly, through the alignment of hundreds of known complexes to whole organism interactomes. Systematic comparison of the resulting network alignments to all complexes currently known in those species revealed many conserved complexes, as well as several novel complex components. In addition to validating our predictions using orthogonal data, we were able to assign specific functional roles to the predicted complexes. In several cases, the incorporation of interaction data through network alignment allowed to distinguish real complex components from other orthologous proteins. Our analyses indicate that current knowledge of yeast protein complexes exceeds that in other organisms and that predicting complexes in fly based on human and yeast data is complementary rather than redundant. Lastly, assessing the conservation of protein complexes of the human pathogen Mycoplasma pneumoniae, we discovered that its complexes repertoire is different from that of eukaryotes, suggesting new points of therapeutic intervention, whereas targeting the pathogen’s Restriction enzyme complex might lead to adverse effects due to its similarity to ATP-dependent metalloproteases in the human host.


Author(s):  
Anastasia Shamustakimova

Study of RNA-protein interactions and identification of RNA targets are among the key aspects of understanding the RNA biology. Currently, various methods are available to investigate these interactions, in particular, RNA pulldown assay. In the present paper, a method based on the HaloTag technology is presented that is called Halo-RPD (HaloTag RNA PullDown). The proposed protocol uses plants with stable fusion protein expression and the MagneBeads magnetic beads to capture RNA-protein complexes directly from the cytoplasmic lysate of transgenic A. thaliana plants. The key stages described in the paper are as follows: 1) preparation of the magnetic beads 2) tissue homogenization and collection of control samples 3) precipitation and wash of RNA-protein complexes; 4) evaluation of protein binding efficacy; 5) RNA isolation; 6) analysis of the obtained RNA. Recommendations for better NGS assay designs are provided.


2014 ◽  
Author(s):  
Roland Pache ◽  
Patrick Aloy

Macromolecular assemblies play an important role in almost all cellular processes. However, despite several large-scale studies, our current knowledge about protein complexes is still quite limited, thus advocating the use of in silico predictions to gather information on complex composition in model organisms. Since protein-protein interactions present certain constraints on the functional divergence of macromolecular assemblies during evolution, it is possible to predict complexes based on orthology data. Here, we show that incorporating interaction information through network alignment significantly increases the precision of orthology-based complex prediction. Moreover, we performed a large-scale in silico screen for protein complexes in human, yeast and fly, through the alignment of hundreds of known complexes to whole organism interactomes. Systematic comparison of the resulting network alignments to all complexes currently known in those species revealed many conserved complexes, as well as several novel complex components. In addition to validating our predictions using orthogonal data, we were able to assign specific functional roles to the predicted complexes. In several cases, the incorporation of interaction data through network alignment allowed to distinguish real complex components from other orthologous proteins. Our analyses indicate that current knowledge of yeast protein complexes exceeds that in other organisms and that predicting complexes in fly based on human and yeast data is complementary rather than redundant. Lastly, assessing the conservation of protein complexes of the human pathogen Mycoplasma pneumoniae, we discovered that its complexes repertoire is different from that of eukaryotes, suggesting new points of therapeutic intervention, whereas targeting the pathogen’s Restriction enzyme complex might lead to adverse effects due to its similarity to ATP-dependent metalloproteases in the human host.


2020 ◽  
Author(s):  
Miao He ◽  
Rouxi Zhou ◽  
Sen Liu ◽  
Weijing Cheng ◽  
Wei Wang

ABSTRACTCircular RNAs (CircRNAs) are endogenous long non-coding RNAs. Unlike linear RNAs, they are structurally continuous and covalently closed, without 5 ’caps or 3’ polyadenylation tails. High-throughput RNA sequencing has enabled people to find several endogenous circRNAs in different species and tissues. circRNA mainly acts as a sponge for microRNAs in cytoplasm to regulates protein translation, or interacts with RNA-binding proteins to generate RNA protein complexes that control transcription. circRNAs are closely associated with diseases such as diabetes, neurological disorders, cardiovascular diseases and cancer, which indicates that circRNAs are closely related to and also play an important functional role in the occurrence and development of human diseases. Recent studies have shown that they are differentially expressed in healthy and diseased eye tissues. There lacks of biomarkers for early detection of diabetic retinopathy, and the newly discovered circRNAs seem to be an ideal candidate of novel molecular markers and therapeutic targets. However, the molecular mechanism of circRNAs activity in the occurrence and development of diabetic retinopathy are not clear yet. This systematic review aims to summarize the research status on function and mechanism of circRNAs in regulating the occurrence of diabetic retinopathy.


2018 ◽  
Author(s):  
Erika C Urdaneta ◽  
Carlos H Vieira-Vieira ◽  
Timon Hick ◽  
Hans-Herrmann Wessels ◽  
Davide Figini ◽  
...  

Recent methodological advances allowed the identification of an increasing number of RNA-binding proteins (RBPs) and their RNA-binding sites. Most of those methods rely, however, on capturing proteins associated to polyadenylated RNAs which neglects RBPs bound to non-adenylate RNA classes (tRNA, rRNA, pre-mRNA) as well as the vast majority of species that lack poly-A tails in their mRNAs (including all archea and bacteria). To overcome these limitations, we have developed a novel protocol, Phenol Toluol extraction (PTex), that does not rely on a specific RNA sequence or motif for isolation of cross-linked ribonucleoproteins (RNPs), but rather purifies them based entirely on their physicochemical properties. PTex captures RBPs that bind to RNA as short as 30 nt, RNPs directly from animal tissue and can be used to simplify complex workflows such as PAR-CLIP. Finally, we provide a first global RNA-bound proteome of human HEK293 cells and Salmonella Typhimurium as a bacterial species.


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