scholarly journals The Developmentally Active and Stress-Inducible Noncoding hsrω Gene Is a Novel Regulator of Apoptosis in Drosophila

Genetics ◽  
2009 ◽  
Vol 183 (3) ◽  
pp. 831-852 ◽  
Author(s):  
Moushami Mallik ◽  
Subhash C. Lakhotia

The large nucleus limited noncoding hsrω-n RNA of Drosophila melanogaster is known to associate with a variety of heterogeneous nuclear RNA-binding proteins (hnRNPs) and certain other RNA-binding proteins to assemble the nucleoplasmic omega speckles. In this article, we show that RNAi-mediated depletion of this noncoding RNA dominantly suppresses apoptosis, in eye and other imaginal discs, triggered by induced expression of Rpr, Grim, or caspases (initiator as well as effector), all of which are key regulators/effectors of the canonical caspase-mediated cell death pathway. We also show, for the first time, a genetic interaction between the noncoding hsrω transcripts and the c-Jun N-terminal kinase (JNK) signaling pathway since downregulation of hsrω transcripts suppressed JNK activation. In addition, hsrω-RNAi also augmented the levels of Drosophila Inhibitor of Apoptosis Protein 1 (DIAP1) when apoptosis was activated. Suppression of induced cell death following depletion of hsrω transcripts was abrogated when the DIAP1-RNAi transgene was coexpressed. Our results suggest that the hsrω transcripts regulate cellular levels of DIAP1 via the hnRNP Hrb57A, which physically interacts with DIAP1, and any alteration in levels of the hsrω transcripts in eye disc cells enhances association between these two proteins. Our studies thus reveal a novel regulatory role of the hsrω noncoding RNA on the apoptotic cell death cascade through multiple paths. These observations add to the diversity of regulatory functions that the large noncoding RNAs carry out in the cells' life.

Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 207 ◽  
Author(s):  
Leandro Lucero ◽  
Jeremie Bazin ◽  
Johan Rodriguez Melo ◽  
Fernando Ibañez ◽  
Martín D. Crespi ◽  
...  

RNA-Binding Protein 1 (RBP1) was first identified as a protein partner of the long noncoding RNA (lncRNA) ENOD40 in Medicago truncatula, involved in symbiotic nodule development. RBP1 is localized in nuclear speckles and can be relocalized to the cytoplasm by the interaction with ENOD40. The two closest homologs to RBP1 in Arabidopsis thaliana were called Nuclear Speckle RNA-binding proteins (NSRs) and characterized as alternative splicing modulators of specific mRNAs. They can recognize in vivo the lncRNA ALTERNATIVE SPLICING COMPETITOR (ASCO) among other lncRNAs, regulating lateral root formation. Here, we performed a phylogenetic analysis of NSR/RBP proteins tracking the roots of the family to the Embryophytes. Strikingly, eudicots faced a reductive trend of NSR/RBP proteins in comparison with other groups of flowering plants. In Medicago truncatula and Lotus japonicus, their expression profile during nodulation and in specific regions of the symbiotic nodule was compared to that of the lncRNA ENOD40, as well as to changes in alternative splicing. This hinted at distinct and specific roles of each member during nodulation, likely modulating the population of alternatively spliced transcripts. Our results establish the basis to guide future exploration of NSR/RBP function in alternative splicing regulation in different developmental contexts along the plant lineage.


2019 ◽  
Vol 20 (16) ◽  
pp. 3926 ◽  
Author(s):  
Xing Zhao ◽  
Yujie Cai ◽  
Jianzhen Xu

CircRNAs are a class of noncoding RNA species with a circular configuration that is formed by either typical spliceosome-mediated or lariat-type splicing. The expression of circRNAs is usually abnormal in many cancers. Several circRNAs have been demonstrated to play important roles in carcinogenesis. In this review, we will first provide an introduction of circRNAs biogenesis, especially the regulation of circRNA by RNA-binding proteins, then we will focus on the recent findings of circRNA molecular mechanisms and functions in cancer development. Finally, some open questions are also discussed.


2020 ◽  
Vol 48 (9) ◽  
pp. e52-e52 ◽  
Author(s):  
Ziheng Zhang ◽  
Weiping Sun ◽  
Tiezhu Shi ◽  
Pengfei Lu ◽  
Min Zhuang ◽  
...  

Abstract No RNA is completely naked from birth to death. RNAs function with and are regulated by a range of proteins that bind to them. Therefore, the development of innovative methods for studying RNA–protein interactions is very important. Here, we developed a new tool, the CRISPR-based RNA-United Interacting System (CRUIS), which captures RNA–protein interactions in living cells by combining the power of CRISPR and PUP-IT, a novel proximity targeting system. In CRUIS, dCas13a is used as a tracker to target specific RNAs, while proximity enzyme PafA is fused to dCas13a to label the surrounding RNA-binding proteins, which are then identified by mass spectrometry. To identify the efficiency of CRUIS, we employed NORAD (Noncoding RNA activated by DNA damage) as a target, and the results show that a similar interactome profile of NORAD can be obtained as by using CLIP (crosslinking and immunoprecipitation)-based methods. Importantly, several novel NORAD RNA-binding proteins were also identified by CRUIS. The use of CRUIS facilitates the study of RNA–protein interactions in their natural environment, and provides new insights into RNA biology.


2015 ◽  
Vol 210 (4) ◽  
pp. 529-539 ◽  
Author(s):  
Sven Hennig ◽  
Geraldine Kong ◽  
Taro Mannen ◽  
Agata Sadowska ◽  
Simon Kobelke ◽  
...  

Prion-like domains (PLDs) are low complexity sequences found in RNA binding proteins associated with the neurodegenerative disorder amyotrophic lateral sclerosis. Recently, PLDs have been implicated in mediating gene regulation via liquid-phase transitions that drive ribonucleoprotein granule assembly. In this paper, we report many PLDs in proteins associated with paraspeckles, subnuclear bodies that form around long noncoding RNA. We mapped the interactome network of paraspeckle proteins, finding enrichment of PLDs. We show that one protein, RBM14, connects key paraspeckle subcomplexes via interactions mediated by its PLD. We further show that the RBM14 PLD, as well as the PLD of another essential paraspeckle protein, FUS, is required to rescue paraspeckle formation in cells in which their endogenous counterpart has been knocked down. Similar to FUS, the RBM14 PLD also forms hydrogels with amyloid-like properties. These results suggest a role for PLD-mediated liquid-phase transitions in paraspeckle formation, highlighting this nuclear body as an excellent model system for understanding the perturbation of such processes in neurodegeneration.


2016 ◽  
Vol 113 (12) ◽  
pp. 3221-3226 ◽  
Author(s):  
Nara Lee ◽  
Therese A. Yario ◽  
Jessica S. Gao ◽  
Joan A. Steitz

Epstein–Barr virus (EBV) produces a highly abundant noncoding RNA called EBV-encoded RNA 2 (EBER2) that interacts indirectly with the host transcription factor paired box protein 5 (PAX5) to regulate viral latent membrane protein 1/2 (LMP1/2) gene expression as well as EBV lytic replication. To identify intermediary proteins, we isolated EBER2–PAX5-containing complexes and analyzed the protein components by mass spectrometry. The top candidates include three host proteins splicing factor proline and glutamine rich (SFPQ), non-POU domain-containing octamer-binding protein (NONO), and RNA binding motif protein 14 (RBM14), all reported to be components of nuclear bodies called paraspeckles. In vivo RNA–protein crosslinking indicates that SFPQ and RBM14 contact EBER2 directly. Binding studies using recombinant proteins demonstrate that SFPQ and NONO associate with PAX5, potentially bridging its interaction with EBER2. Similar to EBER2 or PAX5 depletion, knockdown of any of the three host RNA-binding proteins results in the up-regulation of viral LMP2A mRNA levels, supporting a physiologically relevant interaction of these newly identified factors with EBER2 and PAX5. Identification of these EBER2-interacting proteins enables the search for cellular noncoding RNAs that regulate host gene expression in a manner similar to EBER2.


2021 ◽  
Author(s):  
Jonathan ENRIQUEZ ◽  
Wenyue GUAN ◽  
Mathilde BOUCHET ◽  
Aurelien DARMAS

Neuronal stem cells produce a finite and stereotyped number of neuronal progenies. This process must be finely regulated during development and adult stages to ensure proper brain function. In Drosophila, stem cells, called Neuroblasts, produce an invariant number of neurons. Two RNA binding proteins, Imp and Syp, play a central role in controlling the speed of division and the end of the proliferative phase of individual NBs, two parameters that influences the final number of neurons produced. Here, we have discovered a novel function for Imp and Syp, where both RBPs shape the number of neurons produced by a stem cell by controlling program cell death (PCD) in immature neurons. By studying a neuroblast lineage, called Lin A/15, which produces motoneurons (MNs) and glia, we have demonstrated that Lin A/15 stem cell spends 40% of its time producing immature MNs which are eliminated by apoptosis. We have revealed that only the first born MNs (Imp +) survive while the last born MNs (Imp- Syp+) are eliminated by apoptosis. Both RBPs play a central role in neuronal survival, Imp promotes neuronal survival while Syp promotes cell death in immature motoneurons. Interestingly their opposite temporal gradient in Lin A/15 stem cell also determines the end of Lin A/15 stem cell neurogenesis by PCD. Both RNA binding proteins are conserved in vertebrates and seem to play a central role in the number of neurons produce during development. The Drosophila model and its genetic tools offer a unique chance to decipher their function in neural stem cell versus immature neurons.


2019 ◽  
Author(s):  
Li Li ◽  
Isana Veksler-Lublinsky ◽  
Anna Y. Zinovyeva

AbstractmicroRNAs (miRNAs) are potent regulators of gene expression that function in diverse developmental and physiological processes. Argonaute proteins loaded with miRNAs form the miRNA Induced Silencing Complexes (miRISCs) that repress gene expression at the post-transcriptional level. miRISCs target genes through partial sequence complementarity between the miRNA and the target mRNA’s 3’ UTR. In addition to being targeted by miRNAs, these mRNAs are also extensively regulated by RNA-binding proteins (RBPs) through RNA processing, transport, stability, and translation regulation. While the degree to which RBPs and miRISCs functionally interact to regulate gene expression is likely extensive, we have only begun to unravel these functional interactions. An RNAi-based screen of putative ALG-1 Argonaute interactors has identified a role for a conserved RNA binding protein, HRPK-1, in modulating miRNA activity during C. elegans development. Here, we report the physical and genetic interaction between HRPK-1 and ALG-1/miRNAs. Specifically, we report the genetic and molecular characterizations of hrpk-1 and its role in C. elegans development and miRNA-mediated target repression. We show that loss of hrpk-1 causes numerous developmental defects and enhances the mutant phenotypes associated with reduction of miRNA activity, including those of lsy-6, mir-35-family, and let-7-family miRNAs. In addition to hrpk-1 genetic interaction with these miRNA families, hrpk-1 is required for efficient regulation of lsy-6 target cog-1. We report that hrpk-1 may play a role in miRNA processing but is not globally required for mature miRNA biogenesis or ALG-1/AIN-1 miRISC assembly and confirm HRPK-1 ability to co-precipitate with ALG-1. We suggest that HRPK-1 may functionally interact with miRNAs on multiple levels to enhance miRNA/miRISC gene regulatory activity and present several models for its activity.Author summarymicroRNAs are small non-coding RNAs that regulate gene expression at the post-transcriptional level. The core microRNA Induced Silencing Complex (miRISC), composed of Argonaute, mature microRNA, and GW182 protein effector, assembles on the target messenger RNA and inhibits translation or leads to messenger RNA degradation. RNA binding proteins interface with miRNA pathways on multiple levels to coordinate gene expression regulation. Here, we report identification and characterization of HRPK-1, a conserved RNA binding protein, as a physical and functional interactor of miRNAs. We confirm the physical interaction between HRPK-1, an hnRNPK homolog, and Argonaute ALG-1. We report characterizations of hrpk-1 role in development and its functional interactions with multiple miRNA families. We suggest that HRPK-1 promotes miRNA activity on multiple levels in part by contributing to miRNA processing and by coordinating with miRISC at the level of target RNAs. This work contributes to our understanding of how RNA binding proteins and auxiliary miRNA cofactors may interface with miRNA pathways to modulate miRNA gene regulatory activity.


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