scholarly journals Arabidopsis cyclophilins direct plasmodesmata-targeting of mobile mRNA via organelle hitchhiking

Author(s):  
Kai-Ren Luo ◽  
Nien-Chen Huang ◽  
Yu-Hsin Chang ◽  
Tien-Shin Yu

Abstract Plants selectively transport mobile mRNAs through intercellular pores, plasmodesmata (PD), to distribute spatial information for synchronizing meristematic differentiation with environmental dynamics. However, how plants recognize and deliver mobile mRNAs to PD remains unknown. Here, by using RNA-live cell imaging, we show that mobile mRNAs hitchhike on organelle trafficking to transport to PD. Perturbed cytoskeleton organization or organelle trafficking severely disrupts the subcellular distribution of mobile mRNAs. We further show that Arabidopsis rotamase cyclophilins (ROCs), which are organelle-localized RNA-binding proteins (RBPs), specifically bind mobile mRNAs on the surface of organelles to direct PD-targeting. Arabidopsis roc quadruple mutants showed reduced in PD-targeting of mobile mRNAs, along with phenotype alterations. ROCs can move intercellularly and form RNA-protein complexes in phloem, suggesting the roles of ROCs in delivery of mobile mRNAs through PD. Our results highlight that an RBP-mediated hitchhiking system is purposely recruited to orient plant-mobile mRNAs to PD for intercellular transport.

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.


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.


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.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Da-Qiao Ding ◽  
Kasumi Okamasa ◽  
Yuki Katou ◽  
Eriko Oya ◽  
Jun-ichi Nakayama ◽  
...  

AbstractPairing of homologous chromosomes in meiosis is essential for sexual reproduction. We have previously demonstrated that the fission yeast sme2 RNA, a meiosis-specific long noncoding RNA (lncRNA), accumulates at the sme2 chromosomal loci and mediates their robust pairing in meiosis. However, the mechanisms underlying lncRNA-mediated homologous pairing have remained elusive. In this study, we identify conserved RNA-binding proteins that are required for robust pairing of homologous chromosomes. These proteins accumulate mainly at the sme2 and two other chromosomal loci together with meiosis-specific lncRNAs transcribed from these loci. Remarkably, the chromosomal accumulation of these lncRNA–protein complexes is required for robust pairing. Moreover, the lncRNA–protein complexes exhibit phase separation properties, since 1,6-hexanediol treatment reversibly disassembled these complexes and disrupted the pairing of associated loci. We propose that lncRNA–protein complexes assembled at specific chromosomal loci mediate recognition and subsequent pairing of homologous chromosomes.


2021 ◽  
Author(s):  
Isaac Angert ◽  
Siddarth Reddy Karuka ◽  
Louis Mansky ◽  
Joachim Mueller

The cell cortex plays a crucial role in cell mechanics, signaling, and development. However, little is known about the influence of the cortical meshwork on the spatial distribution of cytoplasmic biomolecules. Here, we describe a new fluorescence microscopy method to infer the intracellular distribution of labeled biomolecules with sub-resolution accuracy. Unexpectedly, we find that RNA-binding proteins are partially excluded from the cytoplasmic volume adjacent to the plasma membrane that corresponds to the actin cortex. Complementary diffusion measurements of RNA-protein complexes suggest that a rudimentary model based on excluded volume interactions can explain this partitioning effect. Our results suggest the actin cortex meshwork may play a role in regulating the biomolecular content of the volume immediately adjacent to the plasma membrane.


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.


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.


2021 ◽  
Vol 12 ◽  
Author(s):  
Hongjiang Liu ◽  
Yundong Zou ◽  
Chen Chen ◽  
Yundi Tang ◽  
Jianping Guo

Systemic lupus erythematosus (SLE) is a common and potentially fatal autoimmune disease that affects multiple organs. To date, its etiology and pathogenesis remains elusive. Circular RNAs (circRNAs) are a novel class of endogenous non-coding RNAs with covalently closed loop structure. Growing evidence has demonstrated that circRNAs may play an essential role in regulation of gene expression and transcription by acting as microRNA (miRNA) sponges, impacting cell survival and proliferation by interacting with RNA binding proteins (RBPs), and strengthening mRNA stability by forming RNA-protein complexes duplex structures. The expression patterns of circRNAs exhibit tissue-specific and pathogenesis-related manner. CircRNAs have implicated in the development of multiple autoimmune diseases, including SLE. In this review, we summarize the characteristics, biogenesis, and potential functions of circRNAs, its impact on immune responses and highlight current understanding of circRNAs in the pathogenesis of SLE.


Sign in / Sign up

Export Citation Format

Share Document