A Potential Role for U2AF-SAP 155 Interactions in Recruiting U2 snRNP to the Branch Site

Gozani, Or; Potashkin, Judith A.; Reed, Robin

doi:10.1128/mcb.18.8.4752

Cited by 274 publications

(312 citation statements)

References 39 publications

(70 reference statements)

Supporting

Mentioning

290

Contrasting

Unclassified

Order By: Relevance

“…It is likely that stronger BP 0 (in terms of U2 snRNA complementarity) can compensate for lower AG affinity to U2AF, leading to the recognition of BP 0 in a U2AF-independent manner (or less dependent than in the case of canonical BP). This model is supported by our U2AF depletion experiments and is consistent with previous findings that BP recognition may depend or not on AG binding to U2AF35, according to BP and 3 0 ss sequence and organization 11,[16][17][18] . In contrast, SF3B1 WT may allow a more promiscuous binding of U2 snRNA to both canonical and alternative BPs, and in this case, the final choice of BP may be determined by context, especially 3 0 ss affinity for U2AF.…”

Section: Discussionsupporting

confidence: 80%

Cancer-associated SF3B1 mutations affect alternative splicing by promoting alternative branchpoint usage

Alsafadi¹,

Houy²,

Battistella³

et al. 2016

European Journal of Cancer

View full text Add to dashboard Cite

Hotspot mutations in the spliceosome gene SF3B1 are reported in B20% of uveal melanomas. SF3B1 is involved in 3 0 -splice site (3 0 ss) recognition during RNA splicing; however, the molecular mechanisms of its mutation have remained unclear. Here we show, using RNA-Seq analyses of uveal melanoma, that the SF3B1 R625/K666 mutation results in deregulated splicing at a subset of junctions, mostly by the use of alternative 3 0 ss. Modelling the differential junctions in SF3B1 WT and SF3B1 R625/K666 cell lines demonstrates that the deregulated splice pattern strictly depends on SF3B1 status and on the 3'ss-sequence context. SF3B1 WT knockdown or overexpression do not reproduce the SF3B1 R625/K666 splice pattern, qualifying SF3B1 R625/K666 as change-of-function mutants. Mutagenesis of predicted branchpoints reveals that the SF3B1 R625/K666 -promoted splice pattern is a direct result of alternative branchpoint usage. Altogether, this study provides a better understanding of the mechanisms underlying splicing alterations induced by mutant SF3B1 in cancer, and reveals a role for alternative branchpoints in disease.

show abstract

Section: Discussionsupporting

confidence: 80%

Cancer-associated SF3B1 mutations affect alternative splicing by promoting alternative branchpoint usage

Alsafadi¹,

Houy²,

Battistella³

et al. 2016

European Journal of Cancer

View full text Add to dashboard Cite

show abstract

“…2A). SF3B1, which was previously shown to directly bind substrate mRNAs and affect Bcl-x AS (Gozani et al 1998;Massiello et al 2006) and was herein identified in PQBP1 affinity purifications (Supplemental Table S1), constituted a prime candidate to work together with PQBP1. Consistent with this hypothesis, depletion of PQBP1 decreased SF3B1's association with Bcl-x mRNA (Fig.…”

Section: Pqbp1 Affects U2 Snrnp Component Sf3b1 Functionmentioning

confidence: 99%

PQBP1, a factor linked to intellectual disability, affects alternative splicing associated with neurite outgrowth

et al. 2013

View full text Add to dashboard Cite

Polyglutamine-binding protein 1 (PQBP1) is a highly conserved protein associated with neurodegenerative disorders. Here, we identify PQBP1 as an alternative messenger RNA (mRNA) splicing (AS) effector capable of influencing splicing of multiple mRNA targets. PQBP1 is associated with many splicing factors, including the key U2 small nuclear ribonucleoprotein (snRNP) component SF3B1 (subunit 1 of the splicing factor 3B [SF3B] protein complex). Loss of functional PQBP1 reduced SF3B1 substrate mRNA association and led to significant changes in AS patterns. Depletion of PQBP1 in primary mouse neurons reduced dendritic outgrowth and altered AS of mRNAs enriched for functions in neuron projection development. Disease-linked PQBP1 mutants were deficient in splicing factor associations and could not complement neurite outgrowth defects. Our results indicate that PQBP1 can affect the AS of multiple mRNAs and indicate specific affected targets whose splice site determination may contribute to the disease phenotype in PQBP1-linked neurological disorders.

show abstract

“…Previous studies in human and yeast extracts using hydroxy radical cleavage or protein-RNA crosslinking led to the hypothesis that the 5′SS and BS regions are closely positioned in early complexes containing only U1 and/or U2 (6)(7)(8)(9)(10)(11)(12). However, as both of these irreversible trapping methods can capture transient excursions that are not necessarily on the pathway for splicing, when during spliceosome assembly and activation the 5′SS and BS are stably juxtaposed has remained unclear.…”

mentioning

confidence: 99%

Single-molecule colocalization FRET evidence that spliceosome activation precedes stable approach of 5′ splice site and branch site

Crawford

Hoskins

Friedman

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Removal of introns from the precursors to messenger RNA (premRNAs) requires close apposition of intron ends by the spliceosome, but when and how apposition occurs is unclear. We investigated the process by which intron ends are brought together using single-molecule fluorescence resonance energy transfer together with colocalization single-molecule spectroscopy, a combination of methods that can directly reveal how conformational transitions in macromolecular machines are coupled to specific assembly and disassembly events. The FRET measurements suggest that the 5′ splice site and branch site remain physically separated throughout spliceosome assembly, and only approach one another after the spliceosome is activated for catalysis, at which time the pre-mRNA becomes highly dynamic. Separation of the sites of chemistry until very late in the splicing pathway may be crucial for preventing splicing at incorrect sites.splicing mechanism | single-molecule FRET | RNA dynamics I ntron excision from precursors to messenger RNAs (premRNAs) is carried out by the spliceosome, arguably the most complex macromolecular machine in the cell (1). One of the most important jobs of the spliceosome is to accurately and efficiently identify the ends of introns and bring them together to promote the chemistry of splicing. This chemistry occurs via two S N 2 transesterification reactions: (i) attack by the branch site (BS) adenosine on the phosphodiester bond at the beginning of the intron (the 5′ splice site; 5′SS) and (ii) attack of the released 5′ exon on the phosphodiester bond at the end of the intron (the 3′SS) (2). The BS adenosine is internal to the intron and usually located in the vicinity of the 3′SS.The spliceosome consists of four major subcomplexes that must assemble de novo on each new intron: the U1 and U2 small nuclear ribonucleoprotein particles (snRNPs), the U4/U6.U5 tri-snRNP, and the protein-only nineteen complex (NTC). The snRNPs each contain numerous proteins and one or more small nuclear RNAs (snRNAs). These subcomplexes assemble stepwise, with U1 and U2 recognition of the 5′SS and BS, respectively, preceding trisnRNP and NTC recruitment (3, 4). Throughout the assembly process, numerous large-scale conformational changes occur that involve making and breaking of pre-mRNA:snRNA and snRNA: snRNA base pairing interactions. These structural transitions are necessary for both recognition of the splice sites and creation of the catalytic core in which the splice sites are juxtaposed for chemistry. The two chemical steps occur within the activated spliceosome formed after ejection of the U1 and U4 snRNPs (5).When during spliceosome assembly are the splice sites brought into close proximity? Previous studies in human and yeast extracts using hydroxy radical cleavage or protein-RNA crosslinking led to the hypothesis that the 5′SS and BS regions are closely positioned in early complexes containing only U1 and/or U2 (6-12). However, as both of these irreversible trapping methods can capture transient excursions that are no...

show abstract

A Potential Role for U2AF-SAP 155 Interactions in Recruiting U2 snRNP to the Branch Site

Cited by 274 publications

References 39 publications

Cancer-associated SF3B1 mutations affect alternative splicing by promoting alternative branchpoint usage

Cancer-associated SF3B1 mutations affect alternative splicing by promoting alternative branchpoint usage

PQBP1, a factor linked to intellectual disability, affects alternative splicing associated with neurite outgrowth

Single-molecule colocalization FRET evidence that spliceosome activation precedes stable approach of 5′ splice site and branch site

Contact Info

Product

Resources

About