scholarly journals Posttranscriptional regulation of human endogenous retroviruses by RNA-binding motif protein 4, RBM4

2020 ◽  
Vol 117 (42) ◽  
pp. 26520-26530
Author(s):  
Amir K. Foroushani ◽  
Bryan Chim ◽  
Madeline Wong ◽  
Andre Rastegar ◽  
Patrick T. Smith ◽  
...  

The human genome encodes for over 1,500 RNA-binding proteins (RBPs), which coordinate regulatory events on RNA transcripts. Most studies of RBPs have concentrated on their action on host protein-encoding mRNAs, which constitute a minority of the transcriptome. A widely neglected subset of our transcriptome derives from integrated retroviral elements, termed endogenous retroviruses (ERVs), that comprise ∼8% of the human genome. Some ERVs have been shown to be transcribed under physiological and pathological conditions, suggesting that sophisticated regulatory mechanisms to coordinate and prevent their ectopic expression exist. However, it is unknown how broadly RBPs and ERV transcripts directly interact to provide a posttranscriptional layer of regulation. Here, we implemented a computational pipeline to determine the correlation of expression between individual RBPs and ERVs from single-cell or bulk RNA-sequencing data. One of our top candidates for an RBP negatively regulating ERV expression was RNA-binding motif protein 4 (RBM4). We used photoactivatable ribonucleoside-enhanced cross-linking and immunoprecipitation to demonstrate that RBM4 indeed bound ERV transcripts at CGG consensus elements. Loss of RBM4 resulted in an elevated transcript level of bound ERVs of the HERV-K and -H families, as well as increased expression of HERV-K envelope protein. We pinpointed RBM4 regulation of HERV-K to a CGG-containing element that is conserved in the LTRs of HERV-K-10, -K-11, and -K-20, and validated the functionality of this site using reporter assays. In summary, we systematically identified RBPs that may regulate ERV function and demonstrate a role for RBM4 in controlling ERV expression.

2020 ◽  
Author(s):  
Amir K. Foroushani ◽  
Bryan Chim ◽  
Madeline Wong ◽  
Andre Rastegar ◽  
Kent Barbian ◽  
...  

AbstractThe human genome encodes for over 1,500 RNA-binding proteins (RBPs), which coordinate regulatory events on RNA transcripts (Gerstberger et al., 2014). Most studies of RBPs concentrate on their action on mRNAs that encode protein, which constitute a minority of the transcriptome. A widely neglected subset of our transcriptome derives from integrated retroviral elements termed endogenous retroviruses (ERVs) that comprise ~8% of the human genome. Some ERVs have been shown to be transcribed under physiological and pathological conditions suggesting that sophisticated regulatory mechanisms to coordinate and prevent their ectopic expression exist. However, it is unknown whether RBPs and ERV transcripts directly interact to provide a post-transcriptional layer of regulation. Here, we implemented a computational pipeline to determine the correlation of expression between individual RBPs and ERVs from single-cell or bulk RNA sequencing data. One of our top candidates for an RBP negatively regulating ERV expression was RNA-Binding Motif Protein 4 (RBM4). We used PAR-CLIP to demonstrate that RBM4 indeed bound ERV transcripts at CGG consensus elements. Loss of RBM4 resulted in elevated transcript level of bound ERVs of the HERV-K and -H families, as well as increased expression of HERV-K envelope protein. We pinpointed RBM4 regulation of HERV-K to a CGG-containing element that is conserved in the long terminal repeats (LTRs) of HERV-K-10 and -K-11, and validated the functionality of this site using reporter assays. In summary, we identified RBPs as potential regulators of ERV function and demonstrate a new role for RBM4 in controlling ERV expression.Significance StatementThe expression of endogenous retroviruses (ERVs) appears to have broad impact on human biology. Nevertheless, only a handful of transcriptional regulators of ERV expression are known and to our knowledge no RNA-binding proteins (RBPs) were yet implicated in positive or negative post-transcriptional regulation of ERVs. We implemented a computational pipeline that allowed us to identify RBPs that modulate ERV expression levels. Experimental validation of one of the prime candidates we identified, RBM4, showed that it indeed bound RNAs made from ERVs and negatively regulated the levels of those RNAs. We hereby identify a new layer of ERV regulation by RBPs.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mariana G. Ferrarini ◽  
Avantika Lal ◽  
Rita Rebollo ◽  
Andreas J. Gruber ◽  
Andrea Guarracino ◽  
...  

AbstractThe novel betacoronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a worldwide pandemic (COVID-19) after emerging in Wuhan, China. Here we analyzed public host and viral RNA sequencing data to better understand how SARS-CoV-2 interacts with human respiratory cells. We identified genes, isoforms and transposable element families that are specifically altered in SARS-CoV-2-infected respiratory cells. Well-known immunoregulatory genes including CSF2, IL32, IL-6 and SERPINA3 were differentially expressed, while immunoregulatory transposable element families were upregulated. We predicted conserved interactions between the SARS-CoV-2 genome and human RNA-binding proteins such as the heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) and eukaryotic initiation factor 4 (eIF4b). We also identified a viral sequence variant with a statistically significant skew associated with age of infection, that may contribute to intracellular host–pathogen interactions. These findings can help identify host mechanisms that can be targeted by prophylactics and/or therapeutics to reduce the severity of COVID-19.


2018 ◽  
Vol 81 ◽  
pp. 129-140 ◽  
Author(s):  
Abhishek K. Singh ◽  
Binod Aryal ◽  
Xinbo Zhang ◽  
Yuhua Fan ◽  
Nathan L. Price ◽  
...  

2011 ◽  
Vol 22 (16) ◽  
pp. 2875-2885 ◽  
Author(s):  
Mai Nguyen Chi ◽  
Jacques Auriol ◽  
Bernard Jégou ◽  
Dimitris L. Kontoyiannis ◽  
James M.A. Turner ◽  
...  

Posttranscriptional mechanisms are crucial to regulate spermatogenesis. Accurate protein synthesis during germ cell development relies on RNA binding proteins that control the storage, stability, and translation of mRNAs in a tightly and temporally regulated manner. Here, we focused on the RNA binding protein Embryonic Lethal Abnormal Vision (ELAV) L1/Human antigen R (HuR) known to be a key regulator of posttranscriptional regulation in somatic cells but the function of which during gametogenesis has never been investigated. In this study, we have used conditional loss- and gain-of-function approaches to address this issue in mice. We show that targeted deletion of HuR specifically in germ cells leads to male but not female sterility. Mutant males are azoospermic because of the extensive death of spermatocytes at meiotic divisions and failure of spermatid elongation. The latter defect is also observed upon HuR overexpression. To elucidate further the molecular mechanisms underlying spermatogenesis defects in HuR-deleted and -overexpressing testes, we undertook a target gene approach and discovered that heat shock protein (HSP)A2/HSP70-2, a crucial regulator of spermatogenesis, was down-regulated in both situations. HuR specifically binds hspa2 mRNA and controls its expression at the translational level in germ cells. Our study provides the first genetic evidence of HuR involvement during spermatogenesis and reveals Hspa2 as a target for HuR.


2015 ◽  
Author(s):  
◽  
Erin C. Boone

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Meiotic silencing by unpaired DNA (MSUD) is an RNA interference (RNAi) pathway in Neurospora crassa that detects genes without a homologous partner and silences them for the duration of sexual development. In this study, we have further elucidated the function of known MSUD proteins, identified novel proteins that are required for MSUD, and demonstrated the conservation of RNAi-related processes at the nuclear periphery. We began by showing SAD-2 is crucial for the localization of other MSUD proteins in the perinuclear region. These data suggest that SAD-2 works as a scaffold protein and that proper function of MSUD, like other germline RNAi-like systems, is reliant on the presence of silencing proteins in the perinuclear region. An MSUD suppression assay identified two novel MSUD proteins, SAD-Y and SAD-B'. Even though SAD-Y and its homologs contain a conserved putative RNA- binding motif, they have yet to be assigned to a biochemical pathway. Our work here has linked silencing to SAD-Y-like proteins. SAD-Y has been shown to interact with other MSUD factors in both the nucleus and at the nuclear periphery. SAD-B's homolog has been found in the nuage, an epicenter for RNA-binding proteins involved in post-transcriptional regulation for Drosophila germline cells. SAD-B interacts with core MSUD proteins and has an especially intimate association with SMS-2, which requires it for localization. Furthermore, bimolecular fluorescence complementation (BiFC) revealed that SAD-B' interacts with a Golgi retrograde transport protein and an autophagy marker protein, suggesting the importance of the endomembrane system in this RNAi process.


2016 ◽  
Vol 23 (5) ◽  
pp. 466-477 ◽  
Author(s):  
Enrique Lara-Pezzi ◽  
Manuel Desco ◽  
Alberto Gatto ◽  
María Victoria Gómez-Gaviro

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.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Lulu Deng ◽  
Long Li ◽  
Cheng Zou ◽  
Chengchi Fang ◽  
Changchun Li

Many increasing documents have proved that alternative polyadenylation (APA) events with different polyadenylation sites (PAS) contribute to posttranscriptional regulation. However, little is known about the detailed molecular features of PASs and its role in porcine fast and slow skeletal muscles through microRNAs (miRNAs) and RNA binding proteins (RBPs). In this study, we combined single-molecule real-time sequencing and Illumina RNA-seq datasets to comprehensively analyze polyadenylation in pigs. We identified a total of 10,334 PASs, of which 8734 were characterized by reference genome annotation. 32.86% of PAS-associated genes were determined to have more than one PAS. Further analysis demonstrated that tissue-specific PASs between fast and slow muscles were enriched in skeletal muscle development pathways. In addition, we obtained 1407 target genes regulated by APA events through potential binding 69 miRNAs and 28 RBPs in variable 3′ UTR regions and some are involved in myofiber transformation. Furthermore, the de novo motif search confirmed that the most common usage of canonical motif AAUAAA and three types of PASs may be related to the strength of motifs. In summary, our results provide a useful annotation of PASs for pig transcriptome and suggest that APA may serve as a role in fast and slow muscle development under the regulation of miRNAs and RBPs.


2020 ◽  
Vol 48 (7) ◽  
pp. 3869-3887 ◽  
Author(s):  
Linlin Hou ◽  
Yuanjie Wei ◽  
Yingying Lin ◽  
Xiwei Wang ◽  
Yiwei Lai ◽  
...  

Abstract Some transcription factors that specifically bind double-stranded DNA appear to also function as RNA-binding proteins. Here, we demonstrate that the transcription factor Sox2 is able to directly bind RNA in vitro as well as in mouse and human cells. Sox2 targets RNA via a 60-amino-acid RNA binding motif (RBM) positioned C-terminally of the DNA binding high mobility group (HMG) box. Sox2 can associate with RNA and DNA simultaneously to form ternary RNA/Sox2/DNA complexes. Deletion of the RBM does not affect selection of target genes but mitigates binding to pluripotency related transcripts, switches exon usage and impairs the reprogramming of somatic cells to a pluripotent state. Our findings designate Sox2 as a multi-functional factor that associates with RNA whilst binding to cognate DNA sequences, suggesting that it may co-transcriptionally regulate RNA metabolism during somatic cell reprogramming.


2020 ◽  
Vol 21 (12) ◽  
pp. 4302 ◽  
Author(s):  
Debojyoti Das ◽  
Aniruddha Das ◽  
Mousumi Sahu ◽  
Smruti Sambhav Mishra ◽  
Shaheerah Khan ◽  
...  

Circular RNAs (circRNAs) are a large family of noncoding RNAs that have emerged as novel regulators of gene expression. However, little is known about the function of circRNAs in pancreatic β-cells. Here, transcriptomic analysis of mice pancreatic islet RNA-sequencing data identified 77 differentially expressed circRNAs between mice fed with a normal diet and a high-fat diet. Surprisingly, multiple circRNAs were derived from the intron 2 of the preproinsulin 2 (Ins2) gene and are termed as circular intronic (ci)-Ins2. The expression of ci-Ins2 transcripts in mouse pancreatic islets, and βTC6 cells were confirmed by reverse transcription PCR, DNA sequencing, and RNase R treatment experiments. The level of ci-Ins2 was altered in βTC6 cells upon exposure to elevated levels of palmitate and glucose. Computational analysis predicted the interaction of several RNA-binding proteins with ci-Ins2 and their flanking region, suggesting their role in the ci-Ins2 function or biogenesis. Additionally, bioinformatics analysis predicted the association of several microRNAs with ci-Ins2. Gene ontology and pathway analysis of genes targeted by miRNAs associated with ci-Ins2 suggested the regulation of several key biological processes. Together, our findings indicate that differential expression of circRNAs, especially ci-Ins2 transcripts, may regulate β-cell function and may play a critical role in the development of diabetes.


1995 ◽  
Vol 129 (3) ◽  
pp. 551-560 ◽  
Author(s):  
H Siomi ◽  
G Dreyfuss

The heterogeneous nuclear RNP (hnRNP) A1 protein is one of the major pre-mRNA/mRNA binding proteins in eukaryotic cells and one of the most abundant proteins in the nucleus. It is localized to the nucleoplasm and it also shuttles between the nucleus and the cytoplasm. The amino acid sequence of A1 contains two RNP motif RNA-binding domains (RBDs) at the amino terminus and a glycine-rich domain at the carboxyl terminus. This configuration, designated 2x RBD-Gly, is representative of perhaps the largest family of hnRNP proteins. Unlike most nuclear proteins characterized so far, A1 (and most 2x RBD-Gly proteins) does not contain a recognizable nuclear localization signal (NLS). We have found that a segment of ca. 40 amino acids near the carboxyl end of the protein (designated M9) is necessary and sufficient for nuclear localization; attaching this segment to the bacterial protein beta-galactosidase or to pyruvate kinase completely localized these otherwise cytoplasmic proteins to the nucleus. The RBDs and another RNA binding motif found in the glycine-rich domain, the RGG box, are not required for A1 nuclear localization. M9 is a novel type of nuclear localization domain as it does not contain sequences similar to classical basic-type NLS. Interestingly, sequences similar to M9 are found in other nuclear RNA-binding proteins including hnRNP A2.


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