scholarly journals CWC22-dependent pre-mRNA splicing and eIF4A3 binding enables global deposition of exon junction complexes

2015 ◽  
Vol 43 (9) ◽  
pp. 4687-4700 ◽  
Author(s):  
Anna-Lena Steckelberg ◽  
Janine Altmueller ◽  
Christoph Dieterich ◽  
Niels H. Gehring
Keyword(s):  
Mrna Splicing ◽  
Exon Junction ◽  
Global Deposition

scholarly journals The Splicing History of an mRNA Affects Its Level of Translation and Sensitivity to Cleavage by the Virion Host Shutoff Endonuclease during Herpes Simplex Virus Infections

2016 ◽  
Vol 90 (23) ◽  
pp. 10844-10856 ◽  
Author(s):  
Jouliana Sadek ◽  
G. Sullivan Read
Keyword(s):  
Gene Expression ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Mrna Splicing ◽  
Exon Junction ◽  
Virion Host Shutoff ◽  
History Of ◽  
Host Shutoff ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACTDuring lytic herpes simplex virus (HSV) infections, the virion host shutoff (Vhs) (UL41) endoribonuclease degrades many cellular and viral mRNAs. In uninfected cells, spliced mRNAs emerge into the cytoplasm bound by exon junction complexes (EJCs) and are translated several times more efficiently than unspliced mRNAs that have the same sequence but lack EJCs. Notably, most cellular mRNAs are spliced, whereas most HSV mRNAs are not. To examine the effect of splicing on gene expression during HSV infection, cells were transfected with plasmids harboring an unspliced renilla luciferase (RLuc) reporter mRNA or RLuc constructs with introns near the 5′ or 3′ end of the gene. After splicing of intron-containing transcripts, all three RLuc mRNAs had the same primary sequence. Upon infection in the presence of actinomycin D, spliced mRNAs were much less sensitive to degradation by copies of Vhs from infecting virions than were unspliced mRNAs. During productive infections (in the absence of drugs), RLuc was expressed at substantially higher levels from spliced than from unspliced mRNAs. Interestingly, the stimulatory effect of splicing on RLuc expression was significantly greater in infected than in uninfected cells. The translational stimulatory effect of an intron during HSV-1 infections could be replicated by artificially tethering various EJC components to an unspliced RLuc transcript. Thus, the splicing history of an mRNA, and the consequent presence or absence of EJCs, affects its level of translation and sensitivity to Vhs cleavage during lytic HSV infections.IMPORTANCEMost mammalian mRNAs are spliced. In contrast, of the more than 80 mRNAs harbored by herpes simplex virus 1 (HSV-1), only 5 are spliced. In addition, synthesis of the immediate early protein ICP27 causes partial inhibition of pre-mRNA splicing, with the resultant accumulation of both spliced and unspliced versions of some mRNAs in the cytoplasm. A common perception is that HSV-1 infection necessarily inhibits the expression of spliced mRNAs. In contrast, this study demonstrates two instances in which pre-mRNA splicing actually enhances the synthesis of proteins from mRNAs during HSV-1 infections. Specifically, splicing stabilized an mRNA against degradation by copies of the Vhs endoribonuclease from infecting virions and greatly enhanced the amount of protein synthesized from spliced mRNAs at late times after infection. The data suggest that splicing, and the resultant presence of exon junction complexes on an mRNA, may play an important role in gene expression during HSV-1 infections.

scholarly journals CWC22 Connects Pre-mRNA Splicing and Exon Junction Complex Assembly

Cell Reports ◽  
2012 ◽  
Vol 2 (3) ◽  
pp. 454-461 ◽  
Author(s):  
Anna-Lena Steckelberg ◽  
Volker Boehm ◽  
Agnieszka M. Gromadzka ◽  
Niels H. Gehring
Keyword(s):  
Mrna Splicing ◽  
Exon Junction Complex ◽  
Complex Assembly ◽  
Exon Junction

scholarly journals Activation of Pre-mRNA Splicing by Human RNPS1 Is Regulated by CK2 Phosphorylation

2005 ◽  
Vol 25 (4) ◽  
pp. 1446-1457 ◽  
Author(s):  
Janeen H. Trembley ◽  
Sawako Tatsumi ◽  
Eiji Sakashita ◽  
Pascal Loyer ◽  
Clive A. Slaughter ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Phosphorylation Site ◽  
Mrna Splicing ◽  
Exon Junction Complex ◽  
Exon Junction ◽  
In Vivo Experiments ◽  
Splicing Regulator ◽  
Major Phosphorylation Site

ABSTRACT Human RNPS1 was originally characterized as a pre-mRNA splicing activator in vitro and was shown to regulate alternative splicing in vivo. RNPS1 was also identified as a protein component of the splicing-dependent mRNP complex, or exon-exon junction complex (EJC), and a role for RNPS1 in postsplicing processes has been proposed. Here we demonstrate that RNPS1 incorporates into active spliceosomes, enhances the formation of the ATP-dependent A complex, and promotes the generation of both intermediate and final spliced products. RNPS1 is phosphorylated in vivo and interacts with the CK2 (casein kinase II) protein kinase. Serine 53 (Ser-53) of RNPS1 was identified as the major phosphorylation site for CK2 in vitro, and the same site is also phosphorylated in vivo. The phosphorylation status of Ser-53 significantly affects splicing activation in vitro, but it does not perturb the nuclear localization of RNPS1. In vivo experiments indicated that the phosphorylation of RNPS1 at Ser-53 influences the efficiencies of both splicing and translation. We propose that RNPS1 is a splicing regulator whose activator function is controlled in part by CK2 phosphorylation.

scholarly journals A Day in the Life of the Exon Junction Complex

Biomolecules ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 866 ◽  
Author(s):  
Lena P. Schlautmann ◽  
Niels H. Gehring
Keyword(s):  
Mrna Export ◽  
Mrna Splicing ◽  
Exon Junction Complex ◽  
Chronological Order ◽  
Exon Junction ◽  
Messenger Ribonucleoprotein ◽  
Associated Proteins ◽  
Core Components ◽  
Nonsense Mediated Mrna Decay ◽  
Exon Junctions

The exon junction complex (EJC) is an abundant messenger ribonucleoprotein (mRNP) component that is assembled during splicing and binds to mRNAs upstream of exon-exon junctions. EJCs accompany the mRNA during its entire life in the nucleus and the cytoplasm and communicate the information about the splicing process and the position of introns. Specifically, the EJC’s core components and its associated proteins regulate different steps of gene expression, including pre-mRNA splicing, mRNA export, translation, and nonsense-mediated mRNA decay (NMD). This review summarizes the most important functions and main protagonists in the life of the EJC. It also provides an overview of the latest findings on the assembly, composition and molecular activities of the EJC and presents them in the chronological order, in which they play a role in the EJC’s life cycle.

scholarly journals PsiCLIP reveals dynamic RNA binding by DEAH-box helicases before and after exon ligation

2020 ◽  
Author(s):  
Lisa M. Strittmatter ◽  
Charlotte Capitanchik ◽  
Andrew J. Newman ◽  
Martina Hallegger ◽  
Christine M. Norman ◽  
...  
Keyword(s):  
Rna Binding ◽  
Positional Information ◽  
Mrna Splicing ◽  
Splicing Factors ◽  
Imaging Studies ◽  
Rna Helicases ◽  
Binding Profile ◽  
Exon Junction ◽  
Exon Ligation ◽  
Before And After

AbstractEight RNA helicases remodel the spliceosome to effect pre-mRNA splicing but their mechanism of action remains poorly understood. We have developed “purified spliceosome iCLIP” (psiCLIP) to define helicase-RNA contacts in specific spliceosomal states. psiCLIP reveals previously unappreciated dynamics of spliceosomal helicases. The binding profile of the helicase Prp16 is influenced by the distance between the branch-point and 3’ splice site, while Prp22 binds diffusely on the intron before exon ligation but switches to more narrow binding downstream of the exon junction after exon ligation. Notably, depletion of the exon-ligation factor Prp18 destabilizes Prp22 binding to the pre-mRNA, demonstrating that psiCLIP can be used to study the relationships between helicases and auxiliary splicing factors. Thus, psiCLIP is sensitive to spliceosome dynamics and complements the insights from structural and imaging studies by providing crucial positional information on helicase-RNA contacts during spliceosomal remodeling.

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