scholarly journals Secondary structure of pre-mRNA introns for genes in the 15q11-12 locus. Mapping of functionally significant motives for RNA-binding proteins and nucleosome positioning signals

2018 ◽  
Author(s):  
Viya B. Fedoseyeva ◽  
Irina A. Zharinova ◽  
Alexander A. Alexandrov

AbstractIn this study, we identified reproducible substructures in the folded structures of long intron RNAs for recursive spliced variants and annotated pre-mRNA for GABRB3 and GABRA5. We mapped the RNA motives recognized by RNA-binding proteins for the specified locus and characterized the area of preferred localization. A comparison of pre-mRNA variants revealed the dominant type of protein potential effects. We determined the structural specifics of RNA in the dense Alu cluster and clarified the analogy of apical substructure to the A-Xist fragment of transcriptional variant. Mapping of the nucleosome potential reveals alternation of strong and weak signals at the 3’-end portion of GABRB3 and clusters of nucleosome positioning signal in the vicinity of the Alu cluster. Distribution of simple oligonucleotides among reproducible substructures revealed an enrichment in Py-tracts; for some of them, this may be considered as a complementary supplement to the Pu-tract enrichment of ncRNA Malat1 as a component of nuclear speckles. The secondary structure elements of bidirectional transcripts are predisposed for somatic homolog pairing in this locus, as was previously shown experimentally.A model of potential intron RNA influence on splicing has been suggested based on its interaction with Py-tract-binding RNP, serine-arginine SRSF proteins, ncRNA Malat1, as well as the action of Alu cluster.

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1958
Author(s):  
Ella Alkalay ◽  
Chen Gam Ze Letova Refael ◽  
Irit Shoval ◽  
Noa Kinor ◽  
Ronit Sarid ◽  
...  

RNA-binding proteins, particularly splicing factors, localize to sub-nuclear domains termed nuclear speckles. During certain viral infections, as the nucleus fills up with replicating virus compartments, host cell chromatin distribution changes, ending up condensed at the nuclear periphery. In this study we wished to determine the fate of nucleoplasmic RNA-binding proteins and nuclear speckles during the lytic cycle of the Kaposi’s sarcoma associated herpesvirus (KSHV). We found that nuclear speckles became fewer and dramatically larger, localizing at the nuclear periphery, adjacent to the marginalized chromatin. Enlarged nuclear speckles contained splicing factors, whereas other proteins were nucleoplasmically dispersed. Polyadenylated RNA, typically found in nuclear speckles under regular conditions, was also found in foci separated from nuclear speckles in infected cells. Poly(A) foci did not contain lncRNAs known to colocalize with nuclear speckles but contained the poly(A)-binding protein PABPN1. Examination of the localization of spliced viral RNAs revealed that some spliced transcripts could be detected within the nuclear speckles. Since splicing is required for the maturation of certain KSHV transcripts, we suggest that the infected cell does not dismantle nuclear speckles but rearranges their components at the nuclear periphery to possibly serve in splicing and transport of viral RNAs into the cytoplasm.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Pamela J. McMillan ◽  
Timothy J. Strovas ◽  
Misa Baum ◽  
Brooke K. Mitchell ◽  
Randall J. Eck ◽  
...  

AbstractSeveral conserved nuclear RNA binding proteins (sut-1, sut-2, and parn-2) control tau aggregation and toxicity in C. elegans, mice, and human cells. MSUT2 protein normally resides in nuclear speckles, membraneless organelles composed of phase-separated RNAs and RNA-binding proteins that mediate critical steps in mRNA processing including mRNA splicing. We used human pathological tissue and transgenic mice to identify Alzheimer’s disease-specific cellular changes related to nuclear speckles. We observed that nuclear speckle constituent scaffold protein SRRM2 is mislocalized and accumulates in cytoplasmic lesions in AD brain tissue. Furthermore, progression of tauopathy in transgenic mice is accompanied by increasing mislocalization of SRRM2 from the neuronal nucleus to the soma. In AD brain tissue, SRRM2 mislocalization associates with increased severity of pathological tau deposition. These findings suggest potential mechanisms by which pathological tau impacts nuclear speckle function in diverse organisms ranging from C. elegans to mice to humans. Future translational studies aimed at restoring nuclear speckle homeostasis may provide novel candidate therapeutic targets for pharmacological intervention.


RNA ◽  
2010 ◽  
Vol 16 (6) ◽  
pp. 1096-1107 ◽  
Author(s):  
X. Li ◽  
G. Quon ◽  
H. D. Lipshitz ◽  
Q. Morris

BMC Genomics ◽  
2020 ◽  
Vol 21 (S13) ◽  
Author(s):  
Lei Deng ◽  
Youzhi Liu ◽  
Yechuan Shi ◽  
Wenhao Zhang ◽  
Chun Yang ◽  
...  

Abstract Background RNA binding proteins (RBPs) play a vital role in post-transcriptional processes in all eukaryotes, such as splicing regulation, mRNA transport, and modulation of mRNA translation and decay. The identification of RBP binding sites is a crucial step in understanding the biological mechanism of post-transcriptional gene regulation. However, the determination of RBP binding sites on a large scale is a challenging task due to high cost of biochemical assays. Quite a number of studies have exploited machine learning methods to predict binding sites. Especially, deep learning is increasingly used in the bioinformatics field by virtue of its ability to learn generalized representations from DNA and protein sequences. Results In this paper, we implemented a novel deep neural network model, DeepRKE, which combines primary RNA sequence and secondary structure information to effectively predict RBP binding sites. Specifically, we used word embedding algorithm to extract features of RNA sequences and secondary structures, i.e., distributed representation of k-mers sequence rather than traditional one-hot encoding. The distributed representations are taken as input of convolutional neural networks (CNN) and bidirectional long-term short-term memory networks (BiLSTM) to identify RBP binding sites. Our results show that deepRKE outperforms existing counterpart methods on two large-scale benchmark datasets. Conclusions Our extensive experimental results show that DeepRKE is an efficacious tool for predicting RBP binding sites. The distributed representations of RNA sequences and secondary structures can effectively detect the latent relationship and similarity between k-mers, and thus improve the predictive performance. The source code of DeepRKE is available at https://github.com/youzhiliu/DeepRKE/.


2003 ◽  
Vol 23 (23) ◽  
pp. 8405-8415 ◽  
Author(s):  
Alexander N. Chkheidze ◽  
Stephen A. Liebhaber

ABSTRACT αCPs comprise a subfamily of KH-domain-containing RNA-binding proteins with specificity for C-rich pyrimidine tracts. These proteins play pivotal roles in a broad spectrum of posttranscriptional events. The five major αCP isoforms are encoded by four dispersed loci. Each isoform contains three repeats of the RNA-binding KH domain (KH1, KH2, and KH3) but lacks other identifiable motifs. To explore the complexity of their respective functions, we examined the subcellular localization of each αCP isoform. Immunofluorescence studies revealed three distinct distributions: αCP1 and αCP2 are predominantly nuclear with specific enrichment of αCP1 in nuclear speckles, αCP3 and αCP4 are restricted to the cytoplasm, and αCP2-KL, an αCP2 splice variant, is present at significant levels in both the nucleus and the cytoplasm. We mapped nuclear localization signals (NLSs) for αCP isoforms. αCP2 contains two functionally independent NLS. Both NLSs appear to be novel and were mapped to a 9-amino-acid segment between KH2 and KH3 (NLS I) and to a 12-amino-acid segment within KH3 (NLS II). NLS I is conserved in αCP1, whereas NLS II is inactivated by two amino acid substitutions. Neither NLS is present in αCP3 or αCP4. Consistent with mapping studies, deletion of NLS I from αCP1 blocks its nuclear accumulation, whereas NLS I and NLS II must both be inactivated to block nuclear accumulation of αCP2. These data demonstrate an unexpected complexity in the compartmentalization of αCP isoforms and identify two novel NLS that play roles in their respective distributions. This complexity of αCP distribution is likely to contribute to the diverse functions mediated by this group of abundant RNA-binding proteins.


2000 ◽  
Vol 113 (19) ◽  
pp. 3485-3497 ◽  
Author(s):  
K.V. Prasanth ◽  
T.K. Rajendra ◽  
A.K. Lal ◽  
S.C. Lakhotia

Fluorescence RNA:RNA in situ hybridization studies in various larval and adult cell types of Drosophila melanogaster showed that the noncoding hsr-omega nuclear (hsromega-n) transcripts were present in the form of many small speckles. These speckles, which we name ‘omega speckles’, were distributed in the interchromatin space in close proximity to the chromatin. The only chromosomal site where hsromega-n transcripts localized was the 93D locus or the hsromega gene itself. The number of nucleoplasmic speckles varied in different cell types. Heat shock, which inhibits general chromosomal transcription, caused the individual speckles to coalesce into larger but fewer clusters. In extreme cases, only a single large cluster of hsromega-n transcripts localizing to the hsromega locus was seen in each nucleus. In situ immunocytochemical staining using antibodies against heterogenous nuclear RNA binding proteins (hnRNPs) like HRB87F, Hrp40, Hrb57A and S5 revealed that, in all cell types, all the hnRNPs gave a diffuse staining of chromatin areas and in addition, were present as large numbers of speckles. Colocalization studies revealed an absolute colocalization of the hnRNPs and the omegaspeckles. Heat shock caused all the hnRNPs to cluster together exactly, following the hsromega-n transcripts. Immunoprecipitation studies using the hnRNP antibodies further demonstrated a physical association of hnRNPs and hsromega transcripts. The omegaspeckles are distinct from interchromatin granules since nuclear speckles containing serine/arginine-rich SR-proteins like SC35 and SRp55 did not colocalize with the ω speckles. The speckled distribution of hnRNPs was completely disrupted in hsromega nullosomics. We conclude that the hsromega-n transcripts play essential structural and functional roles in organizing and establishing the hnRNP-containing omega speckles and thus regulate the trafficking and availability of hnRNPs and other related RNA binding proteins in the cell nucleus.


2021 ◽  
Vol 14 ◽  
Author(s):  
Qi Guo ◽  
Eric B. Dammer ◽  
Maotian Zhou ◽  
Sean R. Kundinger ◽  
Marla Gearing ◽  
...  

Core spliceosome and related RNA-binding proteins aggregate in Alzheimer’s disease (AD) brain even in early asymptomatic stages (AsymAD) of disease. To assess the specificity of RNA-binding protein aggregation in AD, we developed a targeted mass spectrometry approach to quantify broad classes of RNA-binding proteins with other pathological proteins including tau and amyloid beta (Aβ) in detergent insoluble fractions from control, AsymAD, AD and Parkinson’s disease (PD) brain. Relative levels of specific insoluble RNA-binding proteins across different disease groups correlated with accumulation of Aβ and tau aggregates. RNA-binding proteins, including splicing factors with homology to the basic-acidic dipeptide repeats of U1-70K, preferentially aggregated in AsymAD and AD. In contrast, PD brain aggregates were relatively depleted of many RNA-binding proteins compared to AsymAD and AD groups. Correlation network analyses resolved 29 distinct modules of co-aggregating proteins including modules linked to spliceosome assembly, nuclear speckles and RNA splicing. Modules related to spliceosome assembly and nuclear speckles showed stage-specific enrichment of insoluble RBPs from AsymAD and AD brains, whereas the RNA splicing module was reduced specifically in PD. Collectively, this work identifies classes of RNA-binding proteins that distinctly co-aggregate in detergent-insoluble fractions across the specific neurodegenerative diseases we examined.


2013 ◽  
Vol 42 (5) ◽  
pp. 3177-3193 ◽  
Author(s):  
Bhagyashri D. Burgute ◽  
Vivek S. Peche ◽  
Anna-Lena Steckelberg ◽  
Gernot Glöckner ◽  
Berthold Gaßen ◽  
...  

Abstract NKAP is a highly conserved protein with roles in transcriptional repression, T-cell development, maturation and acquisition of functional competency and maintenance and survival of adult hematopoietic stem cells. Here we report the novel role of NKAP in splicing. With NKAP-specific antibodies we found that NKAP localizes to nuclear speckles. NKAP has an RS motif at the N-terminus followed by a highly basic domain and a DUF 926 domain at the C-terminal region. Deletion analysis showed that the basic domain is important for speckle localization. In pull-down experiments, we identified RNA-binding proteins, RNA helicases and splicing factors as interaction partners of NKAP, among them FUS/TLS. The FUS/TLS–NKAP interaction takes place through the RS domain of NKAP and the RGG1 and RGG3 domains of FUS/TLS. We analyzed the ability of NKAP to interact with RNA using in vitro splicing assays and found that NKAP bound both spliced messenger RNA (mRNA) and unspliced pre-mRNA. Genome-wide analysis using crosslinking and immunoprecipitation-seq revealed NKAP association with U1, U4 and U5 small nuclear RNA, and we also demonstrated that knockdown of NKAP led to an increase in pre-mRNA percentage. Our results reveal NKAP as nuclear speckle protein with roles in RNA splicing and processing.


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