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https://www.readbyqxmd.com/read/28431135/reconstitution-of-a-functional-7sk-snrnp
#1
John E Brogie, David H Price
The 7SK small nuclear ribonucleoprotein (snRNP) plays a central role in RNA polymerase II elongation control by regulating the availability of active P-TEFb. We optimized conditions for analyzing 7SK RNA by SHAPE and demonstrated a hysteretic effect of magnesium on 7SK folding dynamics including a 7SK GAUC motif switch. We also found evidence that the 5΄ end pairs alternatively with two different regions of 7SK giving rise to open and closed forms that dictate the state of the 7SK motif. We then used recombinant P-TEFb, HEXIM1, LARP7 and MEPCE to reconstruct a functional 7SK snRNP in vitro...
April 20, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28426094/sirt7-dependent-deacetylation-of-cdk9-activates-rna-polymerase-ii-transcription
#2
Maximilian F Blank, Sifan Chen, Fabian Poetz, Martina Schnölzer, Renate Voit, Ingrid Grummt
SIRT7 is an NAD+-dependent protein deacetylase that regulates cell growth and proliferation. Previous studies have shown that SIRT7 is required for RNA polymerase I (Pol I) transcription and pre-rRNA processing. Here, we took a proteomic approach to identify novel molecular targets and characterize the role of SIRT7 in non-nucleolar processes. We show that SIRT7 interacts with numerous proteins involved in transcriptional regulation and RNA metabolism, the majority of interactions requiring ongoing transcription...
March 17, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28392442/protein-arginine-methylation-of-npl3-promotes-splicing-of-the-sus1-intron-harboring-non-consensus-5-splice-site-and-branch-site
#3
Bhavana Muddukrishna, Christopher A Jackson, Michael C Yu
Protein arginine methylation occurs on spliceosomal components and spliceosome-associated proteins, but how this modification contributes to their function in pre-mRNA splicing remains sparse. Here we provide evidence that protein arginine methylation of the yeast SR-/hnRNP-like protein Npl3 plays a role in facilitating efficient splicing of the SUS1 intron that harbors a non-consensus 5' splice site and branch site. In yeast cells lacking the major protein arginine methyltransferase HMT1, we observed a change in the co-transcriptional recruitment of the U1 snRNP subunit Snp1 and Npl3 to pre-mRNAs harboring both consensus (ECM33 and ASC1) and non-consensus (SUS1) 5' splice site and branch site...
April 6, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28379520/sumo-conjugation-to-spliceosomal-proteins-is-required-for-efficient-pre-mrna-splicing
#4
Berta Pozzi, Laureano Bragado, Cindy L Will, Pablo Mammi, Guillermo Risso, Henning Urlaub, Reinhard Lührmann, Anabella Srebrow
Pre-mRNA splicing is catalyzed by the spliceosome, a multi-megadalton ribonucleoprotein machine. Previous work from our laboratory revealed the splicing factor SRSF1 as a regulator of the SUMO pathway, leading us to explore a connection between this pathway and the splicing machinery. We show here that addition of a recombinant SUMO-protease decreases the efficiency of pre-mRNA splicing in vitro. By mass spectrometry analysis of anti-SUMO immunoprecipitated proteins obtained from purified splicing complexes formed along the splicing reaction, we identified spliceosome-associated SUMO substrates...
March 30, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28379354/motor-neuronal-repletion-of-the-nmj-organizer-agrin-modulates-the-severity-of-the-spinal-muscular-atrophy-disease-phenotype-in-model-mice
#5
Jeong-Ki Kim, Charlotte Caine, Tomoyuki Awano, Ruth Herbst, Umrao R Monani
Spinal muscular atrophy (SMA) is a common and often fatal neuromuscular disorder caused by low levels of the Survival Motor Neuron (SMN) protein. Amongst the earliest detectable consequences of SMN deficiency are profound defects of the neuromuscular junctions (NMJs). In model mice these synapses appear disorganized, fail to mature and are characterized by poorly arborized nerve terminals. Given one role of the SMN protein in orchestrating the assembly of spliceosomal snRNP particles and subsequently regulating the alternative splicing of pre-mRNAs, a plausible link between SMN function and the distal neuromuscular SMA phenotype is an incorrectly spliced transcript or transcripts involved in establishing or maintaining NMJ structure...
March 31, 2017: Human Molecular Genetics
https://www.readbyqxmd.com/read/28348170/crystal-structure-of-u2-snrnp-sf3b-components-hsh49p-in-complex-with-cus1p-binding-domain
#6
Anne-Marie A M van Roon, Chris Oubridge, Eiji Obayashi, Benedetta Sposito, Andrew James Newman, Bertrand Seraphin, Kiyoshi Nagai
Spliceosomal proteins Hsh49p and Cus1p are components of SF3b, which together with SF3a, Msl1p/Lea1p, Sm proteins and U2 snRNA, form U2 snRNP, which plays a crucial role in pre-mRNA splicing. Hsh49p, comprising two RRMs, forms a heterodimer with Cus1p. We determined the crystal structures of Saccharomyces cerevisiae full-length Hsh49p as well as its RRM1 in complex with a minimal binding region of Cus1p (residues 290-368). The structures show that the Cus1 fragment binds to the α-helical surface of Hsh49p RRM1, opposite the four-stranded β-sheet, leaving the canonical RNA binding surface available to bind RNA...
March 27, 2017: RNA
https://www.readbyqxmd.com/read/28335716/human-mfap1-is-a-cryptic-ortholog-of-the-saccharomyces-cerevisiae-spp381-splicing-factor
#7
Alexander K C Ulrich, Markus C Wahl
BACKGROUND: Pre-mRNA splicing involves the stepwise assembly of a pre-catalytic spliceosome, followed by its catalytic activation, splicing catalysis and disassembly. Formation of the pre-catalytic spliceosomal B complex involves the incorporation of the U4/U6.U5 tri-snRNP and of a group of non-snRNP B-specific proteins. While in Saccharomyces cerevisiae the Prp38 and Snu23 proteins are recruited as components of the tri-snRNP, metazoan orthologs of Prp38 and Snu23 associate independently of the tri-snRNP as members of the B-specific proteins...
March 24, 2017: BMC Evolutionary Biology
https://www.readbyqxmd.com/read/28302904/pharmacological-inhibition-of-the-spliceosome-subunit-sf3b-triggers-ejc-independent-nmd
#8
Teresa Carvalho, Sandra Martins, José Rino, Sérgio Marinho, Maria Carmo-Fonseca
Spliceostatin A, meayamycin, and pladienolide B are small molecules that target the SF3b subunit of spliceosomal U2 snRNP. These compounds are attracting much attention as tools to manipulate splicing and potential anti-cancer drugs. We investigated the effects of these inhibitors on mRNA transport and stability in human cells. Upon splicing inhibition unspliced pre-mRNAs accumulated in the nucleus, particularly within enlarged nuclear speckles. Yet, a small fraction of the pre-mRNA molecules were exported to the cytoplasm...
March 16, 2017: Journal of Cell Science
https://www.readbyqxmd.com/read/28300534/identification-of-a-small-molecule-inhibitor-that-stalls-splicing-at-an-early-step-of-spliceosome-activation
#9
Anzhalika Sidarovich, Cindy L Will, Maria M Anokhina, Javier Ceballos, Sonja Sievers, Dmitry E Agafonov, Timur Samatov, Penghui Bao, Berthold Kastner, Henning Urlaub, Herbert Waldmann, Reinhard Lührmann
Small molecule inhibitors of pre-mRNA splicing are important tools for identifying new spliceosome assembly intermediates, allowing a finer dissection of spliceosome dynamics and function. Here, we identified a small molecule that inhibits human pre-mRNA splicing at an intermediate stage during conversion of pre-catalytic spliceosomal B complexes into activated B(act) complexes. Characterization of the stalled complexes (designated B(028)) revealed that U4/U6 snRNP proteins are released during activation before the U6 Lsm and B-specific proteins, and before recruitment and/or stable incorporation of Prp19/CDC5L complex and other B(act) complex proteins...
March 16, 2017: ELife
https://www.readbyqxmd.com/read/28289156/u7-snrnp-is-recruited-to-histone-pre-mrna-in-a-flash-dependent-manner-by-two-separate-regions-of-the-stem-loop-binding-protein
#10
Aleksandra Skrajna, Xiao-Cui Yang, Katarzyna Bucholc, Jun Zhang, Traci M Hall, Michał Dadlez, William F Marzluff, Zbigniew Dominski
Cleavage of histone pre-mRNAs at the 3' end requires Stem-Loop Binding Protein (SLBP) and U7 snRNP that consists of U7 snRNA and a unique Sm ring containing two U7-specific proteins: Lsm10 and Lsm11. Lsm11 interacts with FLASH and together they bring a subset of polyadenylation factors to U7 snRNP, including the CPSF73 endonuclease that cleaves histone pre-mRNA. SLBP binds to a conserved stem-loop structure upstream of the cleavage site and acts by promoting an interaction between the U7 snRNP and a sequence element located downstream of the cleavage site...
March 13, 2017: RNA
https://www.readbyqxmd.com/read/28263986/tdrd6-mediates-early-steps-of-spliceosome-maturation-in-primary-spermatocytes
#11
Müge Akpınar, Mathias Lesche, Grigorios Fanourgakis, Jun Fu, Konstantinos Anasstasiadis, Andreas Dahl, Rolf Jessberger
Tudor containing protein 6 (TDRD6) is a male germ line-specific protein essential for chromatoid body (ChB) structure, elongated spermatid development and male fertility. Here we show that in meiotic prophase I spermatocytes TDRD6 interacts with the key protein arginine methyl transferase PRMT5, which supports splicing. TDRD6 also associates with spliceosomal core protein SmB in the absence of RNA and in an arginine methylation dependent manner. In Tdrd6-/- diplotene spermatocytes PRMT5 association with SmB and arginine dimethylation of SmB are much reduced...
March 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28254838/the-7sk-snrnp-associates-with-the-little-elongation-complex-to-promote-snrna-gene-expression
#12
Sylvain Egloff, Patrice Vitali, Michael Tellier, Raoul Raffel, Shona Murphy, Tamás Kiss
The 7SK small nuclear RNP (snRNP), composed of the 7SK small nuclear RNA (snRNA), MePCE, and Larp7, regulates the mRNA elongation capacity of RNA polymerase II (RNAPII) through controlling the nuclear activity of positive transcription elongation factor b (P-TEFb). Here, we demonstrate that the human 7SK snRNP also functions as a canonical transcription factor that, in collaboration with the little elongation complex (LEC) comprising ELL, Ice1, Ice2, and ZC3H8, promotes transcription of RNAPII-specific spliceosomal snRNA and small nucleolar RNA (snoRNA) genes...
April 3, 2017: EMBO Journal
https://www.readbyqxmd.com/read/28248800/mixed-connective-tissue-disease-and-epitope-spreading-an-historical-cohort-study
#13
Laura Escolà-Vergé, Iago Pinal-Fernandez, Andreu Fernandez-Codina, Eduardo L Callejas-Moraga, Juan Espinosa, Ana Marin, Moises Labrador-Horrillo, Albert Selva-O'Callaghan
OBJECTIVES: Mixed connective tissue disease (MCTD) is characterized by the presence of anti-U1-snRNP autoantibodies and a variable set of associated clinical features. Some MCTD patients test positive over time to autoantibodies against Sm, proteins spatially related with U1-snRNP. This situation has been attributed to expanding of the autoimmune response by a phenomenon known as epitope spreading. Our aim was to study the frequency of this phenomenon in MCTD patients and the specific clinical features of those with epitope spreading...
April 2017: Journal of Clinical Rheumatology: Practical Reports on Rheumatic & Musculoskeletal Diseases
https://www.readbyqxmd.com/read/28223317/stabilized1-modulates-pre-mrna-splicing-for-thermotolerance
#14
Geun-Don Kim, Young-Hee Cho, Byeong-Ha Lee, Sang-Dong Yoo
High-temperature stress often leads to differential RNA splicing, thus accumulating different types and/or amounts of mature mRNAs in eukaryotic cells. However, regulatory mechanisms underlying plant precursor mRNA (pre-mRNA) splicing in the environmental stress conditions remain elusive. Herein, we describe that a U5-snRNP-interacting protein homolog STABILIZED1 (STA1) has pre-mRNA splicing activity for heat-inducible transcripts including HEAT STRESS TRANSCRIPTION FACTORs and various HEAT SHOCK PROTEINs for the establishment of heat stress tolerance in Arabidopsis (Arabidopsis thaliana)...
April 2017: Plant Physiology
https://www.readbyqxmd.com/read/28193846/protein-4-1r-exon-16-3-splice-site-activation-requires-coordination-among-tia1-pcbp1-and-rbm39-during-terminal-erythropoiesis
#15
Shu-Ching Huang, Henry S Zhang, Brian Yu, Ellen McMahon, Dan T Nguyen, Faye H Yu, Alexander C Ou, Jennie Park Ou, Edward J Benz
Exon 16 of protein 4.1R encodes a spectrin/actin-binding peptide critical for erythrocyte membrane stability. Its expression during erythroid differentiation is regulated by alternative pre-mRNA splicing. A UUUUCCCCCC-motif situated between the branch point and the 3' splice site is crucial for inclusion. We show that the "UUUU" region and the last 3 C's in this motif are necessary for the binding of splicing factors TIA1 and Pcbp1, and that these proteins appear to act in a collaborative manner to enhance exon 16 inclusion...
February 13, 2017: Molecular and Cellular Biology
https://www.readbyqxmd.com/read/28157704/overlooked-fancd2-variant-encodes-a-promising-portent-tumor-suppressor-and-alternative-polyadenylation-contributes-to-its-expression
#16
Bing Han, Yihang Shen, Piyan Zhang, Panneerselvam Jayabal, Raymond Che, Jun Zhang, Herbert Yu, Peiwen Fei
Fanconi Anemia (FA) complementation group D2 protein (FANCD2) is the center of the FA tumor suppressor pathway, which has become an important field of investigation in human aging and cancer. Here we report an overlooked central player in the FA pathway, FANCD2 variant 2 (FANCD2-V2), which appears to perform more potent tumor suppressor-function compared to the known variant of FANCD2, namely, FANCD2-V1. Detailed analysis of the FANCD2 gene structure indicated a proximal and distal polyadenylation site (PAS), associated with V2 and V1 transcripts accordingly...
April 4, 2017: Oncotarget
https://www.readbyqxmd.com/read/28103691/sudemycin-k-a-synthetic-antitumor-splicing-inhibitor-variant-with-improved-activity-and-versatile-chemistry
#17
Kamil Makowski, Luisa Vigevani, Fernando Albericio, Juan Valcárcel, Mercedes Álvarez
Important links exist between the process of pre-mRNA splicing and cancer, as illustrated by the frequent mutation of splicing factors in tumors and the emergence of various families of antitumor drugs that target components of the splicing machinery, notably SF3B1, a protein subunit of spliceosomal U2 small nuclear ribonucleoprotein particle (snRNP). Sudemycins are synthetic compounds that harbor a pharmacophore common to various classes of splicing inhibitors. Here, we describe the synthesis and functional characterization of novel sudemycin analogues that functionally probe key chemical groups within this pharmacophore...
January 20, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28102758/p-tefb-finding-its-ways-to-release-promoter-proximally-paused-rna-polymerase-ii
#18
You Li, Min Liu, Lin-Feng Chen, Ruichuan Chen
The release of a paused Pol II depends on the recruitment of P-TEFb. Recent studies showed that both active P-TEFb and inactive P-TEFb (7SK snRNP) can be recruited to the promoter regions of global genes by different mechanisms. Here, we summarize the recent advances on these distinct recruitment mechanisms.
January 19, 2017: Transcription
https://www.readbyqxmd.com/read/28088760/usp15-regulates-dynamic-protein-protein-interactions-of-the-spliceosome-through-deubiquitination-of-prp31
#19
Tanuza Das, Joon Kyu Park, Jinyoung Park, Eunji Kim, Michael Rape, Eunice EunKyeong Kim, Eun Joo Song
Post-translational modifications contribute to the spliceosome dynamics by facilitating the physical rearrangements of the spliceosome. Here, we report USP15, a deubiquitinating enzyme, as a regulator of protein-protein interactions for the spliceosome dynamics. We show that PRP31, a component of U4 snRNP, is modified with K63-linked ubiquitin chains by the PRP19 complex and deubiquitinated by USP15 and its substrate targeting factor SART3. USP15(SART3) makes a complex with USP4 and this ternary complex serves as a platform to deubiquitinate PRP31 and PRP3...
January 13, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28087715/sf3b1-hsh155-heat-motif-mutations-affect-interaction-with-the-spliceosomal-atpase-prp5-resulting-in-altered-branch-site-selectivity-in-pre-mrna-splicing
#20
Qing Tang, Susana Rodriguez-Santiago, Jing Wang, Jia Pu, Andrea Yuste, Varun Gupta, Alberto Moldón, Yong-Zhen Xu, Charles C Query
Mutations in the U2 snRNP component SF3B1 are prominent in myelodysplastic syndromes (MDSs) and other cancers and have been shown recently to alter branch site (BS) or 3' splice site selection in splicing. However, the molecular mechanism of altered splicing is not known. We show here that hsh155 mutant alleles in Saccharomyces cerevisiae, counterparts of SF3B1 mutations frequently found in cancers, specifically change splicing of suboptimal BS pre-mRNA substrates. We found that Hsh155p interacts directly with Prp5p, the first ATPase that acts during spliceosome assembly, and localized the interacting regions to HEAT (Huntingtin, EF3, PP2A, and TOR1) motifs in SF3B1 associated with disease mutations...
December 15, 2016: Genes & Development
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