Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Intron looping is mediated during transcription by U1 snRNP and RNA polymerase II [RIP-seq]

ABSTRACT: In the earliest step of spliceosome assembly, the two splice sites flanking an intron are brought into proximity by U1 snRNP and U2AF. The mechanism that facilitates this intron looping is poorly understood. Using a CRISPR interference-based approach to halt RNA polymerase II transcription in the middle of introns, we discovered that the 5 splice site base pairs with a U1 snRNA that is tethered to RNA polymerase II during intron synthesis. Correlation with splicing outcomes demonstrate that these associations are functional. The interactions between 5 splice sites, U1 snRNP, and elongating RNA polymerase II occurs genome-wide. Our findings reveal that during intron synthesis the upstream 5 splice site remains attached to the transcriptional machinery and is thus brought into proximity of the 3 splice site to enable rapid splicing.

ORGANISM(S): Homo sapiens

PROVIDER: GSE144905 | GEO | 2021/06/16

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Shared Molecules

Only show the datasets with similarity scores above: 0.5

Threshold

0.5

Similar Datasets

Intron looping is mediated by U1 snRNP and RNA polymerase II co-transcriptionally [ChIP-seq]

Project description:In the earliest step of spliceosome assembly, the two splice sites flanking an intron are brought into proximity by U1 snRNP and U2AF. The mechanism that facilitates this intron looping is poorly understood. Using a CRISPR interference-based approach to halt RNA polymerase II transcription in the middle of introns, we discovered that the 5 splice site base pairs with a U1 snRNA that is tethered to RNA polymerase II during intron synthesis. Correlation with splicing outcomes demonstrate that these associations are functional. The interactions between 5 splice sites, U1 snRNP, and elongating RNA polymerase II occurs genome-wide. Our findings reveal that during intron synthesis the upstream 5 splice site remains attached to the transcriptional machinery and is thus brought into proximity of the 3 splice site to enable rapid splicing.

2021-06-16 | GSE144874 | GEO

Intron looping is mediated during transcription by U1 snRNP and RNA polymerase II [RNA-Seq]

2021-06-16 | GSE144906 | GEO

LUC7 is an U1snRNP component that plays a role in alternative splicing and terminal introns removal in plants

Project description:Introns are removed by the spliceosome, a large complex composed of five ribonucleoprotein subcomplexes (U snRNP). In metazoans, the U1 snRNP, which binds to 5’ splice sites, also fulfills regulatory roles in splice site selection and possesses non-splicing related functions. Here, we show that an Arabidopsis U1 snRNP subunit, LUC7, affects constitutive and alternative splicing. Interestingly, LUC7 specifically promotes splicing of a subset of terminal introns. Splicing of LUC7-dependent terminal introns is a prerequisite for nuclear export and can be modulated by stress. Globally, intron retention under stress conditions occurs preferentially among first and terminal introns, uncovering an unknown bias for splicing regulation in Arabidopsis. Taken together, our study reveals that the Arabidopsis U1 snRNP is important for alternative splicing and removal of terminal introns and it suggests that Arabidopsis terminal introns fine-tune gene expression under stress conditions.

2017-05-24 | GSE98779 | GEO

Neuronal stimulation changes U1 snRNP binding and intronic polyadenylation

Project description:Synaptic activity induces well-known changes in enhancer-promoter driven gene expression but also induces changes in splicing and polyadenylation that are understudied. Here, we investigate the mechanism of expression for alternative polyadenylation isoform Homer1a, an immediate early gene essential to synaptic plasticity. We report that neuronal activation, in neuronal cultures and in adult mouse brain, depletes the splice factor U1 snRNP from Homer1 pre-mRNA and that this causes shifted utilization of a cryptic polyadenylation signal within intron 5 resulting in Homer1a expression. Because U1 snRNP is a ubiquitous splice factor, we tested the generality of activity-driven U1 snRNP depletion as a mechanism for gene expression using RNA immunoprecipitation sequencing. Analysis reveals that neuronal activity changes U1 snRNP binding to ~2000 transcripts and for a subset of transcripts, a reduction in U1 snRNP binding was accompanied by utilization of a cryptic intronic polyadenylation site. This subset is enriched for transcripts encoding synaptic proteins involved in excitability control. Genes demonstrating activity-dependent reduced U1 snRNP binding often encode a binding motif for Sam68, a neuronal alternative polyadenylation factor. Findings reveal that activity-driven changes in intron utilization for transcript termination serves an important role in synaptic plasticity.

2024-10-08 | GSE185662 | GEO

Novel RNA-binding Proteins Bind U1 snRNA to Promote Splicing of Weak 5' Splice Sites

Project description:Removal of introns during pre-mRNA splicing, which is central to gene expression, initiates by base pairing of U1 snRNA with a 5' splice site (5'SS). In mammals, many introns contain weak 5'SSs that are not efficiently recognized by the canonical U1 snRNP, suggesting alternative mechanisms exist. Here, we develop a cross-linking immunoprecipitation coupled to a high-throughput sequencing method, BCLIP-seq, to identify NRDE2 (Nuclear RNAi defective-2) and CCDC174 (Coiled-Coil Domain-Containing 174) as novel RNA-binding proteins in mouse ES cells that associate with U1 snRNA and unspliced 5'SSs. Both proteins bind directly to U1 snRNA independently of canonical U1 snRNP specific proteins, and they are required for the selection and effective processing of weak 5'SSs. Our results reveal that mammalian cells use non-canonical splicing factors bound directly to U1 snRNA to effectively select suboptimal 5'SS sequences in hundreds of genes, promoting proper splice site choice and accurate pre-mRNA splicing.

2023-09-07 | PXD029392 | Pride

Novel RNA-binding Proteins Bind U1 snRNA to Promote Splicing of Weak 5' Splice Sites

2023-05-04 | GSE179744 | GEO

The competition between splicing and 3′ processing shapes the human transcriptome

Project description:Eukaryotic pre-mRNA processing steps, including splicing and 3′ processing, are tightly coordinated, but the underlying mechanisms remain poorly understood. Previous studies proposed that the splicing factor U1 snRNP inhibits 3′ processing at intronic polyadenylation (IPA) sites through a splicing-independent mechanism, called telescripting. However, we found that global or gene-specific perturbation of splicing by targeting multiple splicing factors, including U1 snRNP, U2 snRNP, U2AF, and SF3b led to activation of 3′ processing at IPA sites. Inhibiting different splicing factors activated overlapping and distinct IPA sites and such specificity was determined, at least in part, by alterations in RNA polymerase II elongation and termination. Conversely, we showed that blocking pre-mRNA 3′ processing promoted splicing globally. These results strongly suggest that splicing and 3′ processing are competing processes that shape the transcriptome. Finally, as splicing inhibition-induced shifts to IPA site usage can lead to gene inactivation, including tumor suppressor genes, the use of general splicing inhibitors to treat human diseases may pose a significant risk.

2024-10-28 | GSE275154 | GEO

Insights into transcriptome surveillance and alternative splicing regulation by the EJC-associated splicing factor RNPS1

Project description:Alternative splicing of pre-mRNAs increases the potential for regulation and complexity of gene expression. The exon junction complex (EJC) and its associated splicing factor RNPS1 were recently shown to suppress mis-splicing resulting from the usage of cryptic and reconstituted 5’ and 3’ splice sites in the vicinity of the EJC. Here, we aimed to further investigate the mechanisms underlying splicing regulation by RNPS1. A transcriptome-wide analysis identified hundreds of splice events affected by the knockdown (KD) of RNPS1 in HeLa cells. These included alternative splice site usage as well as intron retention, exon skipping and inclusion. However, only a fraction of these RNPS1-dependent splice events was fully or partially rescued by the expression of the RNPS1 RRM. These results indicated that another domain of RNPS1 is involved in the regulation of the majority of splicing events. Deletion experiments revealed that the N-terminus and S-domain, and in particular the C-terminus of RNPS1 strongly regulate these events. Several splicing factors, including SR proteins and U1 snRNP components, were strongly reduced in the interactome of RNPS1 lacking the C terminus. We conclude that RNPS1 interacts with many splicing factors to direct the assembly of EJC-dependent and-independent splicing complexes.

2022-05-31 | PXD027251 | Pride

Cooperative engagement and subsequent selective displacement of SR proteins define the pre-mRNA 3D structural scaffold for early spliceosome assembly

Project description:We recently reported that serine-arginine-rich (SR) protein-mediated pre-mRNA structural remodeling generates a pre-mRNA 3D structural scaffold that is stably recognized by the early spliceosomal components. However, the intermediate steps between the free pre-mRNA and the assembled early spliceosome are not yet characterized. By probing the early spliceosomal complexes in vitro and RNA-protein interactions in vivo, we show that the SR proteins bind the pre-mRNAs cooperatively generating a substrate that recruits U1 snRNP and U2AF65 in a splice signal-independent manner. Excess U1 snRNP selectively displaces some of the SR protein molecules from the pre-mRNA generating the substrate for splice signal-specific, sequential recognition by U1 snRNP, U2AF65, and U2AF35. Our work thus identifies a novel function of U1 snRNP in mammalian splicing substrate definition, explains the need for excess U1 snRNP compared to other U snRNPs in vivo, demonstrates how excess SR proteins could inhibit splicing, and provides a conceptual basis to examine if this mechanism of splicing substrate definition is employed by other splicing regulatory proteins.

2022-07-05 | GSE188652 | GEO

Discovery of pre-mRNA structural scaffold as a contributor to mammalian splicing code [In Vivo]

Project description:The specific recognition of splice signals at or near the exon-intron junctions is not explained by their weak conservation across the mammalian transcriptome and postulated to require a multitude of features embedded in the pre-mRNA strand. We explored the possibility of three-dimensional structural scaffold of a pre-mRNA guiding early spliceosomal components to the splice signal sequences. We find that mutation in non-cognate splice signal sequences of a model pre-mRNA substrate could impede recruitment of early spliceosomal components due to disruption of global structure of the pre-mRNA. We also find distribution of pre-mRNA segments potentially interacting with early spliceosomal component U1 snRNP across the intron, spatial proximity of 5′ and 3′ splice sites within the pre-mRNA scaffold, and an interplay between the structural scaffold and splicing regulatory elements in recruiting early spliceosomal components. These results suggest that early spliceosomal components could recognize a three-dimensional structural scaffold beyond the short splice signal sequences and that in our model pre-mRNA, this scaffold is formed across the intron involving the major splice signals. This work provides a conceptual base to extend our understanding of prevalence, distribution, and splicing regulatory potential of recognizable three-dimensional structural scaffolds across the mammalian transcriptome.

2021-06-23 | GSE173177 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data