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https://www.readbyqxmd.com/read/28432478/the-arabidopsis-splicing-factors-atu2af65-atu2af35-and-atsf1-shuttle-between-nuclei-and-cytoplasms
#1
Hyo-Young Park, Keh Chien Lee, Yun Hee Jang, Soon-Kap Kim, May Phyo Thu, Jeong Hwan Lee, Jeong-Kook Kim
The Arabidopsis splicing factors, AtU2AF65, AtU2AF35, and AtSF1 shuttle between nuclei and cytoplasms. These proteins also move rapidly and continuously in the nuclei, and their movements are affected by ATP depletion. The U2AF65 proteins are splicing factors that interact with SF1 and U2AF35 proteins to promote U2snRNP for the recognition of the pre-mRNA 3' splice site during early spliceosome assembly. We have determined the subcellular localization and movement of these proteins' Arabidopsis homologs. It was found that Arabidopsis U2AF65 homologs, AtU2AF65a, and AtU2AF65b proteins interact with AtU2AF35a and AtU2AF35b, which are Arabidopsis U2AF35 homologs...
April 21, 2017: Plant Cell Reports
https://www.readbyqxmd.com/read/28432181/dual-nature-of-pseudouridylation-in-u2-snrna-pus1p-dependent-and-pus1p-independent-activities-in-yeasts-and-higher-eukaryotes
#2
Svetlana Deryusheva, Joseph G Gall
The pseudouridine at position 43 in vertebrate U2 snRNA is one of the most conserved posttranscriptional modifications of spliceosomal snRNAs; the equivalent position is pseudouridylated in U2 snRNAs in different phyla including fungi, insects, and worms. Pseudouridine synthase Pus1p acts alone on U2 snRNA to form this pseudouridine in yeast Saccharomyces cerevisiae and mouse. Furthermore, in S. cerevisiae Pus1p is the only pseudouridine synthase for this position. Using an in vivo yeast cell system we tested enzymatic activity of Pus1p from the fission yeast Schizosaccharomyces pombe, the worm Caenorhabditis elegans, the fruit fly Drosophila melanogaster and the frog Xenopus tropicalis...
April 21, 2017: RNA
https://www.readbyqxmd.com/read/28430982/evidence-of-nuclei-encoded-spliceosome-mediating-splicing-of-mitochondrial-rna
#3
Roberto H Herai, Priscilla D Negraes, Alysson R Muotri
Mitochondria are thought to have originated as free-living prokaryotes. Mitochondria organelles have small circular genomes with substantial structural (absence of histones and introns) and genetic similarity to bacteria. Contrary to the prevailing concept of intronless mitochondria, here we present evidences that mitochondrial RNA transcripts (mtRNA) are not limited to policystronic molecules, but also processed as nuclei-like transcripts that are differentially spliced and expressed in a cell-type specific manner...
April 19, 2017: Human Molecular Genetics
https://www.readbyqxmd.com/read/28424608/blood-transcriptomic-meta-analysis-identifies-dysregulation-of-hemoglobin-and-iron-metabolism-in-parkinson-disease
#4
Jose A Santiago, Judith A Potashkin
Disrupted iron metabolism has been implicated in the pathogenesis of Parkinson's disease (PD), a progressive neurodegenerative disorder that severely affects movement and coordination, yet the molecular mechanisms underlying this association remain unknown. To this end, we performed a transcriptomic meta-analysis of four blood microarrays in PD. We observed a significant downregulation of genes related to hemoglobin including, hemoglobin delta (HBD), alpha hemoglobin stabilizing protein (ASHP), genes implicated in iron metabolism including, solute carrier family 11 member 2 (SLC11A2), ferrochelatase (FECH), and erythrocyte-specific genes including erythrocyte membrane protein (EPB42), and 5'-aminolevulinate synthase 2 (ALAS2)...
2017: Frontiers in Aging Neuroscience
https://www.readbyqxmd.com/read/28424163/clinical-significance-of-somatic-mutation-in-unexplained-blood-cytopenia
#5
Luca Malcovati, Anna Gallì, Erica Travaglino, Ilaria Ambaglio, Ettore Rizzo, Elisabetta Molteni, Chiara Elena, Virginia Valeria Ferretti, Silvia Catricalà, Elisa Bono, Gabriele Todisco, Antonio Bianchessi, Elisa Rumi, Silvia Zibellini, Daniela Pietra, Emanuela Boveri, Clara Camaschella, Daniela Toniolo, Elli Papaemmanuil, Seishi Ogawa, Mario Cazzola
Unexplained blood cytopenias, in particular anemia, are often found in older persons. The relationship between these cytopenias and myeloid neoplasms like myelodysplastic syndromes is currently poorly defined. We studied a prospective cohort of patients with unexplained cytopenia with the aim to estimate the predictive value of somatic mutations for identifying subjects with, or at risk of developing a myeloid neoplasm. The study included a learning cohort of 683 consecutive patients investigated for unexplained cytopenia, and a validation cohort of 190 patients referred for suspected myeloid neoplasm...
April 19, 2017: Blood
https://www.readbyqxmd.com/read/28420675/integrative-analysis-unveils-new-functions-for-the-drosophila-cutoff-protein-in-non-coding-rna-biogenesis-and-gene-regulation
#6
Yuri Pritykin, Tarcisio Brito, Trudi Schupbach, Mona Singh, Attilio Pane
Piwi-Interacting RNAs (piRNAs) are central components of the piRNA pathway, which directs transposon silencing and guarantees genome integrity in the germ cells of several metazoans. In Drosophila, piRNAs are produced from discrete regions of the genome termed piRNA clusters, whose expression relies on the RDC complex comprised of the core proteins Rhino, Deadlock and Cutoff. To date, the RDC complex has been exclusively implicated in the regulation of the piRNA loci. Here we further elucidate the function of Cutoff and the RDC complex by performing genome-wide ChIP-seq and RNA-seq assays in the Drosophila germline and analyzing these data together with other publicly available data sets...
April 18, 2017: RNA
https://www.readbyqxmd.com/read/28416821/pathogenic-variants-that-alter-protein-code-often-disrupt-splicing
#7
Rachel Soemedi, Kamil J Cygan, Christy L Rhine, Jing Wang, Charlston Bulacan, John Yang, Pinar Bayrak-Toydemir, Jamie McDonald, William G Fairbrother
The lack of tools to identify causative variants from sequencing data greatly limits the promise of precision medicine. Previous studies suggest that one-third of disease-associated alleles alter splicing. We discovered that the alleles causing splicing defects cluster in disease-associated genes (for example, haploinsufficient genes). We analyzed 4,964 published disease-causing exonic mutations using a massively parallel splicing assay (MaPSy), which showed an 81% concordance rate with splicing in patient tissue...
April 17, 2017: Nature Genetics
https://www.readbyqxmd.com/read/28416677/structural-toggle-in-the-rnaseh-domain-of-prp8-helps-balance-splicing-fidelity-and-catalytic-efficiency
#8
Megan Mayerle, Madhura Raghavan, Sarah Ledoux, Argenta Price, Nicholas Stepankiw, Haralambos Hadjivassiliou, Erica A Moehle, Senén D Mendoza, Jeffrey A Pleiss, Christine Guthrie, John Abelson
Pre-mRNA splicing is an essential step of eukaryotic gene expression that requires both high efficiency and high fidelity. Prp8 has long been considered the "master regulator" of the spliceosome, the molecular machine that executes pre-mRNA splicing. Cross-linking and structural studies place the RNaseH domain (RH) of Prp8 near the spliceosome's catalytic core and demonstrate that prp8 alleles that map to a 17-aa extension in RH stabilize it in one of two mutually exclusive structures, the biological relevance of which are unknown...
April 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28412289/structural-studies-of-the-endogenous-spliceosome-the-supraspliceosome
#9
REVIEW
Joseph Sperling, Ruth Sperling
Pre-mRNA splicing is executed in mammalian cell nuclei within a huge (21 MDa) and highly dynamic molecular machine - the supraspliceosome - that individually package pre-mRNA transcripts of different sizes and number of introns into complexes of a unique structure, indicating their universal nature. Detailed structural analysis of this huge and complex structure requires a stepwise approach using hybrid methods. Structural studies of the supraspliceosome by room temperature electron tomography, cryo-electron tomography, and scanning transmission electron microscope mass measurements revealed that it is composed of four native spliceosomes, each resembling an in vitro assembled spliceosome, which are connected by the pre-mRNA...
April 12, 2017: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/28408981/rna-and-proteins-mutual-respect
#10
REVIEW
Kathleen B Hall
Proteins and RNA are often found in ribonucleoprotein particles (RNPs), where they function in cellular processes to synthesize proteins (the ribosome), chemically modify RNAs (small nucleolar RNPs), splice pre-mRNAs (the spliceosome), and, on a larger scale, sequester RNAs, degrade them, or process them (P bodies, Cajal bodies, and nucleoli). Each RNA-protein interaction is a story in itself, as both molecules can change conformation, compete for binding sites, and regulate cellular functions. Recent studies of Xist long non-coding RNP, the U4/5/6 tri-small nuclear RNP complex, and an activated state of a spliceosome reveal new features of RNA interactions with proteins, and, although their stories are incomplete, they are already fascinating...
2017: F1000Research
https://www.readbyqxmd.com/read/28408394/a-close-up-look-at-the-spliceosome-at-last
#11
John Abelson
Major developments in cryo-electron microscopy in the past three or four years have led to the solution of a number of spliceosome structures at high resolution, e.g., the fully assembled but not yet active spliceosome (Bact), the spliceosome just after the first step of splicing (C), and the spliceosome activated for the second step (C*). Therefore 30 years of genetics and biochemistry of the spliceosome can now be interpreted at the structural level. I have closely examined the RNase H domain of Prp8 in each of the structures...
April 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28403900/knockdown-of-ubiquitin-specific-peptidase-39-inhibited-the-growth-of-osteosarcoma-cells-and-induced-apoptosis-in-vitro
#12
Zhihua Gan, Kun Han, Shuchen Lin, Haiyan Hu, Zan Shen, Daliu Min
BACKGROUND: Ubiquitin specific peptidase 39 (USP39), an essential factor in the assembly of the mature spliceosome complex, has an aberrant expression in several cancer. However, its function and the corresponding mechanism on human osteosarcoma has not been fully explored yet. METHODS: The mRNA and DNA copies of USP39 were increased in osteosarcoma cancer tissues compared with the one in human normal tissues according to datasets from the publicly available Oncomine database...
April 12, 2017: Biological Research
https://www.readbyqxmd.com/read/28393272/heterozygous-hnrnpu-variants-cause-early-onset-epilepsy-and-severe-intellectual-disability
#13
Nuria C Bramswig, Hermann-Josef Lüdecke, Fadi F Hamdan, Janine Altmüller, Filippo Beleggia, Nursel H Elcioglu, Catharine Freyer, Erica H Gerkes, Yasemin Kendir Demirkol, Kelly G Knupp, Alma Kuechler, Yun Li, Daniel H Lowenstein, Jacques L Michaud, Kristen Park, Alexander P A Stegmann, Hermine E Veenstra-Knol, Thomas Wieland, Bernd Wollnik, Hartmut Engels, Tim M Strom, Tjitske Kleefstra, Dagmar Wieczorek
Pathogenic variants in genes encoding subunits of the spliceosome are the cause of several human diseases, such as neurodegenerative diseases. The RNA splicing process is facilitated by the spliceosome, a large RNA-protein complex consisting of small nuclear ribonucleoproteins (snRNPs), and many other proteins, such as heterogeneous nuclear ribonucleoproteins (hnRNPs). The HNRNPU gene (OMIM *602869) encodes the heterogeneous nuclear ribonucleoprotein U, which plays a crucial role in mammalian development. HNRNPU is expressed in the fetal brain and adult heart, kidney, liver, brain, and cerebellum...
April 9, 2017: Human Genetics
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
#14
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/28391323/genomic-and-transcriptomic-analysis-reveals-spliced-leader-trans-splicing-in-cryptomonads
#15
Scott William Roy
Spliced leader trans-splicing (SLTS) is a poorly understood mechanism that is found in a diversity of eukaryotic lineages. In SLTS, a short RNA sequence is added near the 5' ends of the transcripts of protein-coding genes by a modified spliceosomal reaction. Available data suggest that SLTS has evolved many times, and might be more likely to evolve in animals. That SLTS might be more likely to evolve in the context of the generally complex transcriptomes characteristic of animals suggests the possibility that SLTS functions in gene regulation or transcriptome diversification, however no general novel function for SLTS is known...
March 1, 2017: Genome Biology and Evolution
https://www.readbyqxmd.com/read/28379520/sumo-conjugation-to-spliceosomal-proteins-is-required-for-efficient-pre-mrna-splicing
#16
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
#17
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/28374749/pkr-activation-and-eif2%C3%AE-phosphorylation-mediate-human-globin-mrna-splicing-at-spliceosome-assembly
#18
Lena Ilan, Farhat Osman, Lise Sarah Namer, Einav Eliahu, Smadar Cohen-Chalamish, Yitzhak Ben-Asouli, Yona Banai, Raymond Kaempfer
Short elements in mammalian mRNA can control gene expression by activating the RNA-dependent protein kinase PKR that attenuates translation by phosphorylating cytoplasmic eukaryotic initiation factor 2α (eIF2α). We demonstrate a novel, positive role for PKR activation and eIF2α phosphorylation in human globin mRNA splicing. PKR localizes in splicing complexes and associates with splicing factor SC35. Splicing and early-stage spliceosome assembly on β-globin pre-mRNA depend strictly on activation of PKR by a codon-containing RNA fragment within exon 1 and on phosphorylation of nuclear eIF2α on Serine 51...
April 4, 2017: Cell Research
https://www.readbyqxmd.com/read/28374191/alternative-splicing-the-pledge-the-turn-and-the-prestige-the-key-role-of-alternative-splicing-in-human-biological-systems
#19
REVIEW
L M Gallego-Paez, M C Bordone, A C Leote, N Saraiva-Agostinho, M Ascensão-Ferreira, N L Barbosa-Morais
Alternative pre-mRNA splicing is a tightly controlled process conducted by the spliceosome, with the assistance of several regulators, resulting in the expression of different transcript isoforms from the same gene and increasing both transcriptome and proteome complexity. The differences between alternative isoforms may be subtle but enough to change the function or localization of the translated proteins. A fine control of the isoform balance is, therefore, needed throughout developmental stages and adult tissues or physiological conditions and it does not come as a surprise that several diseases are caused by its deregulation...
April 3, 2017: Human Genetics
https://www.readbyqxmd.com/read/28373290/a-genetic-screen-implicates-a-cwc16-yju2-ccdc130-protein-and-smu1-in-alternative-splicing-in-arabidopsis-thaliana
#20
Tatsuo Kanno, Wen-Dar Lin, Jason Fu, Antonius Matzke, Marjori Matzke
To identify regulators of pre-mRNA splicing in plants, we developed a forward genetic screen based on an alternatively-spliced GFP reporter gene in Arabidopsis thaliana. In wild-type plants, three major splice variants issue from the GFP gene but only one represents a translatable GFP mRNA. Compared to wild-type seedlings, which exhibit an intermediate level of GFP expression, mutants identified in the screen feature either a 'GFP-weak' or 'Hyper-GFP' phenotype depending on the ratio of the three splice variants...
April 3, 2017: RNA
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