The Biflavonoid Isoginkgetin Is a General Inhibitor of Pre-mRNA Splicing

O'Brien, Kristine; Matlin, Arianne J.; Lowell, April M.; Moore, Melissa J.

doi:10.1074/jbc.m805556200

Cited by 183 publications

(218 citation statements)

References 39 publications

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“…3D). In further support of prespliced mRNAs as a source for antigenic peptide substrates, we observed an increase in antigen presentation when the splicing machinery was inhibited using the isoginkgetin compound (21,22) (Fig. 3E and Fig.…”

Section: Ribosomal Scanning Of Nonspliced Mrnas Gives Rise To Productmentioning

confidence: 52%

Translation of pre-spliced RNAs in the nuclear compartment generates peptides for the MHC class I pathway

Apcher

Millot

Daskalogianni

et al. 2013

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

100

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The scanning of maturing mRNAs by ribosomes plays a key role in the mRNA quality control process. When ribosomes first engage with the newly synthesized mRNA, and if peptides are produced, is unclear, however. Here we show that ribosomal scanning of prespliced mRNAs occurs in the nuclear compartment, and that this event produces peptide substrates for the MHC class I pathway. Inserting antigenic peptide sequences in introns that are spliced out before the mRNAs exit the nuclear compartment results in an equal amount of antigenic peptide products as when the peptides are encoded from the main open reading frame (ORF). Taken together with the detection of intron-encoded nascent peptides and RPS6/RPL7-carrying complexes in the perinucleolar compartment, these results show that peptides are produced by a translation event occurring before mRNA splicing. This suggests that ribosomes occupy and scan mRNAs early in the mRNA maturation process, and suggests a physiological role for nuclear mRNA translation, and also helps explain how the immune system tolerates peptides derived from tissue-specific mRNA splice variants.MHC class I restricted antigen presentation | mRNA maturation | nuclear translation R NAs carrying premature termination codons or are recognized as defective in other aspects are prevented from further translation and disposed of by the nonsense-mediated decay (NMD) pathway (1). The detection of premature stop codons is mediated by the scanning ribosome; however, when the ribosomes first engage with the newly synthesized mRNA, and if this event results in the production of peptides, is unclear. Two observations from the field of immunology and the presentation of peptides on MHC class I molecules have highlighted some aspects relevant to the role of the ribosomes in the mRNA maturation process. The first observation is related to the detection of antigenic peptides originating from intron sequences, and the second is related to the observation that the synthesis of antigenic peptide substrates and full-length proteins are two spatiotemporarily distinct events (2-5).The presentation of antigenic peptides on MHC class I molecules allows CD8 + T cells to detect and eliminate cells in which the repertoire of peptide substrates has been altered owing to the presence of viruses or to changes in the presentation of endogenous antigens (6, 7). However, despite the key role of antigen presentation on MHC class I molecules in immune surveillance, the source of peptides for the MHC class I pathway is not yet known. Accumulating evidence indicates that the processing of alternative peptide substrates plays a major role, and that degradation products derived from full-length proteins have limited access to the MHC class I pathway (8-10). We recently demonstrated that pioneer translation products (PTPs) that form antigenic peptide substrates for the MHC class I pathway are produced by a translation event that is distinct from the canonical event giving rise to full-length proteins and does not require the cap-binding ...

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Section: Ribosomal Scanning Of Nonspliced Mrnas Gives Rise To Productmentioning

confidence: 52%

Translation of pre-spliced RNAs in the nuclear compartment generates peptides for the MHC class I pathway

Apcher

Millot

Daskalogianni

et al. 2013

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

100

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“…Primer sequences are as follows: RBM5ex17: forward, 5Ј-CGGCTGTAGTGCCCAGAGT-3Ј, and reverse, 5Ј-TTGCG-AGTTGGGTCATAAT-3Ј, 58°C annealing temperature (13); CCNA2: forward, 5Ј-AACTTCAGCTTGTGGGCACT-3Ј, and reverse, 5Ј-AAAGGCAGCTCCAGCAATAA-3Ј, 60°C annealing temperature; SF3A1: forward, 5Ј-CCAAATTCCAGGAA-CGTG-3Ј, and reverse, 5Ј-AGCTCCTCTGGCGTGGTG-3Ј, 55°C annealing temperature (20); U6: forward, 5Ј-CGCTTCG-GCAGCACATATAC-3Ј, and reverse, 5Ј-GAATTTGCGTGT-CATCCTT-3Ј, 60°C annealing temperature (21).…”

Section: Methodsmentioning

confidence: 99%

Coherence between Cellular Responses and in Vitro Splicing Inhibition for the Anti-tumor Drug Pladienolide B and Its Analogs

Effenberger

Anderson

Bray

et al. 2014

Journal of Biological Chemistry

104

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Background: Pladienolide B is a complex natural product that potently inhibits pre-mRNA splicing. Results: The same molecular features of pladienolide B are required for the drug's effects on cell growth, morphology, and splicing. Conclusion: Simplified synthesis and modification of active pladienolide B is possible. Significance: Pladienolide B analogs can be used to study the relationship between splicing and cancer cell function.

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“…The identification of specific roles for SF3b via the use of E7 and spliceostatin A, as well as other recent work using small molecules to examine splicing, underscores the utility of these compounds for elucidating specific functions of the highly complex, dynamic factors in the spliceosome (Pilch et al 2001;Muraki et al 2004;Kaida et al 2007;Kotake et al2007;O'Brien et al 2008;Stoilov et al 2008;Sumanasekera et al 2008;Kuhn et al2009;Younis et al 2010). Although the binding affinity of SF3b to E7 is highly correlated with its cell growth inhibition activity (Kotake et al 2007), the mechanistic basis for the anti-tumor effect of E7 is not known.…”

Section: E7 Blocks Atp-dependent Remodeling Of U2 Snrnp That Exposes mentioning

confidence: 99%

The anti-tumor drug E7107 reveals an essential role for SF3b in remodeling U2 snRNP to expose the branch point-binding region

Folco¹,

Coil²,

Reed³

2011

Genes Dev.

151

139

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Duplex formation between the branch point-binding region (BBR) of U2 snRNA and the branch point sequence (BPS) in the intron is essential for splicing. Both the BBR and BPS interact with the U2 small nuclear ribonucleoprotein (snRNP)-associated SF3b complex, which is the target of the anti-tumor drug E7107. We show that E7107 blocks spliceosome assembly by preventing tight binding of U2 snRNP to pre-mRNA. E7107 has no apparent effect on U2 snRNP integrity. Instead, E7107 abolishes an ATPdependent conformational change in U2 snRNP that exposes the BBR. We conclude that SF3b is required for this remodeling, which exposes the BBR for tight U2 snRNP binding to pre-mRNA.Supplemental material is available for this article.Received November 3, 2010; revised version accepted January 18, 2011.Most pre-mRNAs in higher eukaryotes contain multiple introns that are excised by the spliceosome to generate mature mRNA (Konarska and Query 2005;Smith et al. 2008;Wahl et al. 2009). The spliceosome, composed of five snRNAs (U1, U2, U4, U5, and U6) and many proteins, undergoes a series of dynamic changes during the splicing pathway (Staley and Guthrie 1998;Smith et al. 2008;Wahl et al. 2009). In the early steps, U1 small nuclear ribonucleoprotein (snRNP) binds to the pre-mRNA, and U1 snRNA base-pairs to the 59 splice site to form the ATP-independent early (E) complex (Reed 1996;Smith et al. 2008;Wahl et al. 2009). U2 snRNP is also recruited to the E complex, but is not tightly bound (Das et al. 2000;Donmez et al. 2004Donmez et al. , 2007. Subsequently, in an ATPdependent step, the A complex is assembled, in which U2 snRNP binds tightly. At this time, a duplex is formed between the branch point sequence (BPS) in the intron and the branch point-binding region (BBR) located near the 59 end of U2 snRNA (Konarska and Query 2005;Smith et al. 2008;Wahl et al. 2009). This tight binding of U2 snRNP to the pre-mRNA and formation of the BBR-BPS duplex are critical early steps in establishing the catalytic center of the spliceosome. In later steps, multiple complex rearrangements occur, resulting in binding of U4/U5/U6 snRNPs to form the B complex, and finally the catalytically active C complex.Although a great deal has been learned about spliceosome assembly and splicing, it has been difficult to achieve a detailed understanding of the numerous steps in this pathway without the aid of small molecule inhibitors. Recently, an anti-tumor drug, E7107 (E7), was identified that blocks splicing by targeting the U2 snRNP-associated complex SF3b (Kotake et al. 2007). SF3b associates with both the 59 end of U2 snRNA and the BPS region of the intron (Gozani et al. 1996;Kramer et al. 1999;Will et al. 2001;Dybkov et al. 2006). Thus, SF3b is positioned at the critical site of the spliceosome, where the BBR-BPS duplex forms during establishment of the catalytic center of the spliceosome. However, the precise function of SF3b is not known. Here, we show that E7 results in formation of a defective spliceosome in which U2 snRNP fails to bind tightly to pre-mRNA...

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The Biflavonoid Isoginkgetin Is a General Inhibitor of Pre-mRNA Splicing

Cited by 183 publications

References 39 publications

Translation of pre-spliced RNAs in the nuclear compartment generates peptides for the MHC class I pathway

Translation of pre-spliced RNAs in the nuclear compartment generates peptides for the MHC class I pathway

Coherence between Cellular Responses and in Vitro Splicing Inhibition for the Anti-tumor Drug Pladienolide B and Its Analogs

The anti-tumor drug E7107 reveals an essential role for SF3b in remodeling U2 snRNP to expose the branch point-binding region

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