Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

An extended U2AF(65)-RNA-binding domain recognizes the 3' splice site signal.

ABSTRACT: How the essential pre-mRNA splicing factor U2AF(65) recognizes the polypyrimidine (Py) signals of the major class of 3' splice sites in human gene transcripts remains incompletely understood. We determined four structures of an extended U2AF(65)-RNA-binding domain bound to Py-tract oligonucleotides at resolutions between 2.0 and 1.5 Å. These structures together with RNA binding and splicing assays reveal unforeseen roles for U2AF(65) inter-domain residues in recognizing a contiguous, nine-nucleotide Py tract. The U2AF(65) linker residues between the dual RNA recognition motifs (RRMs) recognize the central nucleotide, whereas the N- and C-terminal RRM extensions recognize the 3' terminus and third nucleotide. Single-molecule FRET experiments suggest that conformational selection and induced fit of the U2AF(65) RRMs are complementary mechanisms for Py-tract association. Altogether, these results advance the mechanistic understanding of molecular recognition for a major class of splice site signals.

SUBMITTER: Agrawal AA

PROVIDER: S-EPMC4786784 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

The human pseudouridine synthase PUS7 recognizes RNA with an extended multi-domain binding surface.

Project description:The human pseudouridine synthase PUS7 is a versatile RNA modification enzyme targeting many RNAs thereby playing a critical role in development and brain function. Whereas all target RNAs of PUS7 share a consensus sequence, additional recognition elements are likely required, and the structural basis for RNA binding by PUS7 is unknown. Here, we characterize the structure-function relationship of human PUS7 reporting its X-ray crystal structure at 2.26 Å resolution. Compared to its bacterial homolog, human PUS7 possesses two additional subdomains, and structural modeling studies suggest that these subdomains contribute to tRNA recognition through increased interactions along the tRNA substrate. Consistent with our modeling, we find that all structural elements of tRNA are required for productive interaction with PUS7 as the consensus sequence of target RNA alone is not sufficient for pseudouridylation by human PUS7. Moreover, PUS7 binds several, non-modifiable RNAs with medium affinity which likely enables PUS7 to screen for productive RNA substrates. Following tRNA modification, the product tRNA has a significantly lower affinity for PUS7 facilitating its dissociation. Taken together our studies suggest a combination of structure-specific and sequence-specific RNA recognition by PUS7 and provide mechanistic insight into its function.

| S-EPMC8599909 | biostudies-literature

Identification of U2AF(35)-dependent exons by RNA-Seq reveals a link between 3' splice-site organization and activity of U2AF-related proteins.

Project description:The auxiliary factor of U2 small nuclear RNA (U2AF) is a heterodimer consisting of 65- and 35-kD proteins that bind the polypyrimidine tract (PPT) and AG dinucleotides at the 3' splice site (3'ss). The gene encoding U2AF35 (U2AF1) is alternatively spliced, giving rise to two isoforms U2AF35a and U2AF35b. Here, we knocked down U2AF35 and each isoform and characterized transcriptomes of HEK293 cells with varying U2AF35/U2AF65 and U2AF35a/b ratios. Depletion of both isoforms preferentially modified alternative RNA processing events without widespread failure to recognize 3'ss or constitutive exons. Over a third of differentially used exons were terminal, resulting largely from the use of known alternative polyadenylation (APA) sites. Intronic APA sites activated in depleted cultures were mostly proximal whereas tandem 3'UTR APA was biased toward distal sites. Exons upregulated in depleted cells were preceded by longer AG exclusion zones and PPTs than downregulated or control exons and were largely activated by PUF60 and repressed by CAPERα. The U2AF(35) repression and activation was associated with a significant interchange in the average probabilities to form single-stranded RNA in the optimal PPT and branch site locations and sequences further upstream. Although most differentially used exons were responsive to both U2AF subunits and their inclusion correlated with U2AF levels, a small number of transcripts exhibited distinct responses to U2AF35a and U2AF35b, supporting the existence of isoform-specific interactions. These results provide new insights into function of U2AF and U2AF35 in alternative RNA processing.

| S-EPMC4402522 | biostudies-literature

Recognition of the 3' splice site RNA by the U2AF heterodimer involves a dynamic population shift.

Project description:An essential early step in the assembly of human spliceosomes onto pre-mRNA involves the recognition of regulatory RNA cis elements in the 3' splice site by the U2 auxiliary factor (U2AF). The large (U2AF65) and small (U2AF35) subunits of the U2AF heterodimer contact the polypyrimidine tract (Py-tract) and the AG-dinucleotide, respectively. The tandem RNA recognition motif domains (RRM1,2) of U2AF65 adopt closed/inactive and open/active conformations in the free form and when bound to bona fide Py-tract RNA ligands. To investigate the molecular mechanism and dynamics of 3' splice site recognition by U2AF65 and the role of U2AF35 in the U2AF heterodimer, we have combined single-pair FRET and NMR experiments. In the absence of RNA, the RRM1,2 domain arrangement is highly dynamic on a submillisecond time scale, switching between closed and open conformations. The addition of Py-tract RNA ligands with increasing binding affinity (strength) gradually shifts the equilibrium toward an open conformation. Notably, the protein-RNA complex is rigid in the presence of a strong Py-tract but exhibits internal motion with weak Py-tracts. Surprisingly, the presence of U2AF35, whose UHM domain interacts with U2AF65 RRM1, increases the population of the open arrangement of U2AF65 RRM1,2 in the absence and presence of a weak Py-tract. These data indicate that the U2AF heterodimer promotes spliceosome assembly by a dynamic population shift toward the open conformation of U2AF65 to facilitate the recognition of weak Py-tracts at the 3' splice site. The structure and RNA binding of the heterodimer was unaffected by cancer-linked myelodysplastic syndrome mutants.

| S-EPMC5135374 | biostudies-literature

Polypyrimidine tract binding protein blocks the 5' splice site-dependent assembly of U2AF and the prespliceosomal E complex.

Project description:Polypyrimidine tract binding protein (PTB) represses some alternatively spliced exons by direct occlusion of splice sites. In repressing the splicing of the c-src N1 exon, we find that PTB acts by a different mechanism. PTB does not interfere with U1 snRNP binding to the N1 5' splice site. Instead, PTB prevents formation of the prespliceosomal early (E) complex across the intervening intron by preventing the assembly of the splicing factor U2AF on the 3' splice site of exon 4. When the unregulated 5' splice site of the upstream exon 3 is present, U2AF binding is restored and splicing between exons 3 and 4 proceeds in spite of the N1 exon bound PTB. Thus, rather than directly blocking the N1 splice sites, PTB prevents the 5' splice site-dependent assembly of U2AF into the E complex. This mechanism likely occurs in many other alternative exons.

| S-EPMC1635971 | biostudies-literature

A bimodular nuclear localization signal assembled via an extended double-stranded RNA-binding domain acts as an RNA-sensing signal for transportin 1.

Project description:The human RNA-editing enzyme adenosine deaminase acting on RNA (ADAR1) carries a unique nuclear localization signal (NLS) that overlaps one of its double-stranded RNA-binding domains (dsRBDs). This dsRBD-NLS is recognized by the nuclear import receptor transportin 1 (Trn1; also called karyopherin-β2) in an RNA-sensitive manner. Most Trn1 cargos bear a well-characterized proline-tyrosine-NLS, which is missing from the dsRBD-NLS. Here, we report the structure of the dsRBD-NLS, which reveals an unusual dsRBD fold extended by an additional N-terminal α-helix that brings the N- and C-terminal flanking regions in close proximity. We demonstrate experimentally that the atypical ADAR1-NLS is bimodular and is formed by the combination of the two flexible fragments flanking the folded domain. The intervening dsRBD acts only as an RNA-sensing scaffold, allowing the two NLS modules to be properly positioned for interacting with Trn1. We also provide a structural model showing how Trn1 can recognize the dsRBD-NLS and how dsRNA binding can interfere with Trn1 binding.

| S-EPMC4020056 | biostudies-literature

Pre-mRNA splicing factor U2AF2 recognizes distinct conformations of nucleotide variants at the center of the pre-mRNA splice site signal.

Project description:The essential pre-mRNA splicing factor U2AF2 (also called U2AF65) identifies polypyrimidine (Py) tract signals of nascent transcripts, despite length and sequence variations. Previous studies have shown that the U2AF2 RNA recognition motifs (RRM1 and RRM2) preferentially bind uridine-rich RNAs. Nonetheless, the specificity of the RRM1/RRM2 interface for the central Py tract nucleotide has yet to be investigated. We addressed this question by determining crystal structures of U2AF2 bound to a cytidine, guanosine, or adenosine at the central position of the Py tract, and compared U2AF2-bound uridine structures. Local movements of the RNA site accommodated the different nucleotides, whereas the polypeptide backbone remained similar among the structures. Accordingly, molecular dynamics simulations revealed flexible conformations of the central, U2AF2-bound nucleotide. The RNA binding affinities and splicing efficiencies of structure-guided mutants demonstrated that U2AF2 tolerates nucleotide substitutions at the central position of the Py tract. Moreover, enhanced UV-crosslinking and immunoprecipitation of endogenous U2AF2 in human erythroleukemia cells showed uridine-sensitive binding sites, with lower sequence conservation at the central nucleotide positions of otherwise uridine-rich, U2AF2-bound splice sites. Altogether, these results highlight the importance of RNA flexibility for protein recognition and take a step towards relating splice site motifs to pre-mRNA splicing efficiencies.

| S-EPMC9128377 | biostudies-literature

The glucocorticoid receptor DNA-binding domain recognizes RNA hairpin structures with high affinity.

Project description:The glucocorticoid receptor (GR) binds the noncoding RNA Gas5 via its DNA-binding domain (DBD) with functional implications in pro-apoptosis signaling. Here, we report a comprehensive in vitro binding study where we have determined that GR-DBD is a robust structure-specific RNA-binding domain. GR-DBD binds to a diverse range of RNA hairpin motifs, both synthetic and biologically derived, with apparent mid-nanomolar affinity while discriminating against uniform dsRNA. As opposed to dimeric recognition of dsDNA, GR-DBD binds to RNA as a monomer and confers high affinity primarily through electrostatic contacts. GR-DBD adopts a discrete RNA-bound state, as assessed by NMR, distinct from both free and DNA-bound. NMR and alanine mutagenesis suggest a heightened involvement of the C-terminal α-helix of the GR-DBD in RNA-binding. RNA competes for binding with dsDNA and occurs in a similar affinity range as dimer binding to the canonical DNA element. Given the prevalence of RNA hairpins within the transcriptome, our findings strongly suggest that many RNAs have potential to impact GR biology.

| S-EPMC6735959 | biostudies-literature

The DGCR8 RNA-binding heme domain recognizes primary microRNAs by clamping the hairpin.

Project description:Canonical primary microRNA transcripts (pri-miRNAs) are characterized by a ∼30 bp hairpin flanked by single-stranded regions. These pri-miRNAs are recognized and cleaved by the Microprocessor complex consisting of the Drosha nuclease and its obligate RNA-binding partner DGCR8. It is not well understood how the Microprocessor specifically recognizes pri-miRNA substrates. Here, we show that in addition to the well-known double-stranded RNA-binding domains, DGCR8 uses a dimeric heme-binding domain to directly contact pri-miRNAs. This RNA-binding heme domain (Rhed) directs two DGCR8 dimers to bind each pri-miRNA hairpin. The two Rhed-binding sites are located at both ends of the hairpin. The Rhed and its RNA-binding surface are important for pri-miRNA processing activity. Additionally, the heme cofactor is required for formation of processing-competent DGCR8-pri-miRNA complexes. Our study reveals a unique protein-RNA interaction central to pri-miRNA recognition. We propose a unifying model in which two DGCR8 dimers clamp a pri-miRNA hairpin using their Rheds.

| S-EPMC4133150 | biostudies-literature

A novel 3' splice site recognition by the two zinc fingers in the U2AF small subunit.

Project description:The pre-mRNA splicing reaction of eukaryotic cells has to be carried out extremely accurately, as failure to recognize the splice sites correctly causes serious disease. The small subunit of the U2AF heterodimer is essential for the determination of 3' splice sites in pre-mRNA splicing, and several single-residue mutations of the U2AF small subunit cause severe disorders such as myelodysplastic syndromes. However, the mechanism of RNA recognition is poorly understood. Here we solved the crystal structure of the U2AF small subunit (U2AF23) from fission yeast, consisting of an RNA recognition motif (RRM) domain flanked by two conserved CCCH-type zinc fingers (ZFs). The two ZFs are positioned side by side on the β sheet of the RRM domain. Further mutational analysis revealed that the ZFs bind cooperatively to the target RNA sequence, but the RRM domain acts simply as a scaffold to organize the ZFs and does not itself contact the RNA directly. This completely novel and unexpected mode of RNA-binding mechanism by the U2AF small subunit sheds light on splicing errors caused by mutations of this highly conserved protein.

| S-EPMC4536312 | biostudies-literature

Interactome for auxiliary splicing factor U2AF(65) suggests diverse roles.

Project description:U2 small nuclear ribonucleoprotein auxiliary factor (U2AF) is an essential component of the splicing machinery that is composed of two protein subunits, the 35 kDa U2AF(35) (U2AF1) and the 65 kDa U2AF(65) (U2AF2). U2AF interacts with various splicing factors within this machinery. Here we expand the list of mammalian splicing factors that are known to interact with U2AF(65) as well as the list of nuclear proteins not known to participate in splicing that interact with U2AF(65). Using a yeast two-hybrid system, we found fourteen U2AF(65)-interacting proteins. The validity of the screen was confirmed by identification of five known U2AF(65)-interacting proteins, including its heterodimeric partner, U2AF(35). In addition to binding these known partners, we found previously unrecognized U2AF(65) interactions with four splicing-related proteins (DDX39, SFRS3, SFRS18, SNRPA), two zinc finger proteins (ZFP809 and ZC3H11A), a U2AF(65) homolog (RBM39), and two other regulatory proteins (DAXX and SERBP1). We report which regions of U2AF(65) each of these proteins interacts with and we discuss their potential roles in regulation of pre-mRNA splicing, 3'-end mRNA processing, and U2AF(65) sub-nuclear localization. These findings suggest expanded roles for U2AF(65) in both splicing and non-splicing functions.

| S-EPMC2748126 | biostudies-literature

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