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Luisa Vigevani, André Gohr, Thomas Webb, Manuel Irimia, Juan Valcárcel
Several splicing-modulating compounds, including Sudemycins and Spliceostatin A, display anti-tumor properties. Combining transcriptome, bioinformatic and mutagenesis analyses, we delineate sequence determinants of the differential sensitivity of 3' splice sites to these drugs. Sequences 5' from the branch point (BP) region strongly influence drug sensitivity, with additional functional BPs reducing, and BP-like sequences allowing, drug responses. Drug-induced retained introns are typically shorter, displaying higher GC content and weaker polypyrimidine-tracts and BPs...
December 13, 2017: Nature Communications
Lin Wang, Chenjun Hao, Yongqiu Deng, Yanbo Liu, Shiliang Hu, Yangang Peng, Manna He, Jinhu Fu, Ming Liu, Jia Chen, Xiaoming Chen
Systemic lupus erythematosus (SLE) is a common autoimmune disease. Many autoantibodies are closely associated with SLE. However, the specific epitopes recognized and bound by these autoantibodies are still unclear. This study screened the binding epitopes of SLE-related autoantibodies using a high-throughput screening method. Epitope prediction on 12 SLE-related autoantigens was performed using the Immune Epitope Database and Analysis Resource (IEDB) software. The predicted epitopes were synthesized into peptides and developed into a peptide array...
October 17, 2017: Oncotarget
Jia Wen, Jue Wang, Qing Zhang, Dianjing Guo
BACKGROUND: Pre-mRNA splicing is the removal of introns from precursor mRNAs (pre-mRNAs) and the concurrent ligation of the flanking exons to generate mature mRNA. This process is catalyzed by the spliceosome, where the splicing factor 1 (SF1) specifically recognizes the seven-nucleotide branch point sequence (BPS) and the U2 snRNP later displaces the SF1 and binds to the BPS. In mammals, the degeneracy of BPS motifs together with the lack of a large set of experimentally verified BPSs complicates the task of BPS prediction in silico...
October 24, 2017: BMC Bioinformatics
Xueni Li, Shiheng Liu, Jiansen Jiang, Lingdi Zhang, Sara Espinosa, Ryan C Hill, Kirk C Hansen, Z Hong Zhou, Rui Zhao
U1 snRNP plays a critical role in 5'-splice site recognition and is a frequent target of alternative splicing factors. These factors transiently associate with human U1 snRNP and are not amenable for structural studies, while their Saccharomyces cerevisiae (yeast) homologs are stable components of U1 snRNP. Here, we report the cryoEM structure of yeast U1 snRNP at 3.6 Å resolution with atomic models for ten core proteins, nearly all essential domains of its RNA, and five stably associated auxiliary proteins...
October 19, 2017: Nature Communications
Michaela Krausová, David Staněk
Split gene architecture of most human genes requires removal of intervening sequences by mRNA splicing that occurs on large multiprotein complexes called spliceosomes. Mutations compromising several spliceosomal components have been recorded in degenerative syndromes and haematological neoplasia, thereby highlighting the importance of accurate splicing execution in homeostasis of assorted adult tissues. Moreover, insufficient splicing underlies defective development of craniofacial skeleton and upper extremities...
October 19, 2017: Seminars in Cell & Developmental Biology
María Moriel-Carretero, Sara Ovejero, Marie Gérus-Durand, Dimos Vryzas, Angelos Constantinou
Proteins disabled in the cancer-prone disorder Fanconi anemia (FA) ensure the maintenance of chromosomal stability during DNA replication. FA proteins regulate replication dynamics, coordinate replication-coupled repair of interstrand DNA cross-links, and mitigate conflicts between replication and transcription. Here we show that FANCI and FANCD2 associate with splicing factor 3B1 (SF3B1), a key spliceosomal protein of the U2 small nuclear ribonucleoprotein (U2 snRNP). FANCI is in close proximity to SF3B1 in the nucleoplasm of interphase and mitotic cells...
October 13, 2017: Journal of Cell Biology
Wei Shen Aik, Min-Han Lin, Dazhi Tan, Ashutosh Tripathy, William F Marzluff, Zbigniew Dominski, Chi-Yuan Chou, Liang Tong
Unlike canonical pre-mRNAs, animal replication-dependent histone pre-mRNAs lack introns and are processed at the 3'-end by a mechanism distinct from cleavage and polyadenylation. They have a 3' stem loop and histone downstream element (HDE) that are recognized by stem-loop binding protein (SLBP) and U7 snRNP, respectively. The N-terminal domain (NTD) of Lsm11, a component of U7 snRNP, interacts with FLASH NTD and these two proteins recruit the histone cleavage complex containing the CPSF-73 endonuclease for the cleavage reaction...
2017: PloS One
Natalia N Singh, José Bruno Del Rio-Malewski, Diou Luo, Eric W Ottesen, Matthew D Howell, Ravindra N Singh
Spinal muscular atrophy (SMA) is caused by deletions or mutations of the Survival Motor Neuron 1 (SMN1) gene coupled with predominant skipping of SMN2 exon 7. The only approved SMA treatment is an antisense oligonucleotide that targets the intronic splicing silencer N1 (ISS-N1), located downstream of the 5' splice site (5'ss) of exon 7. Here, we describe a novel approach to exon 7 splicing modulation through activation of a cryptic 5'ss (Cr1). We discovered the activation of Cr1 in transcripts derived from SMN1 that carries a pathogenic G-to-C mutation at the first position (G1C) of intron 7...
September 15, 2017: Nucleic Acids Research
Tatsuo Kanno, Wen-Dar Lin, Jason L Fu, Chia-Liang Chang, Antonius J M Matzke, Marjori Matzke
In a genetic screen for mutants showing modified splicing of an alternatively-spliced GFP reporter gene in Arabidopsis thaliana, we identified mutations in genes encoding the putative U1 snRNP factors RBM25 and PRP39a. The latter has not yet been studied for its role in pre-mRNA splicing in plants. Both proteins contain predicted RNA-binding domains and have been implicated in 5' splice site selection in yeast and metazoan cells. In rbm25 mutants, splicing efficiency of GFP pre-mRNA was reduced and GFP protein levels lowered relative to wild-type plants...
September 29, 2017: Genetics
Jung-Min Oh, Chao Di, Christopher C Venters, Jiannan Guo, Chie Arai, Byung Ran So, Anna Maria Pinto, Zhenxi Zhang, Lili Wan, Ihab Younis, Gideon Dreyfuss
U1 snRNP (U1) functions in splicing introns and telescripting, which suppresses premature cleavage and polyadenylation (PCPA). Using U1 inhibition in human cells, we show that U1 telescripting is selectively required for sustaining long-distance transcription elongation in introns of large genes (median 39 kb). Evidence of widespread PCPA in the same locations in normal tissues reveals that large genes incur natural transcription attrition. Underscoring the importance of U1 telescripting as a gene-size-based mRNA-regulation mechanism, small genes were not sensitive to PCPA, and the spliced-mRNA productivity of ∼1,000 small genes (median 6...
November 2017: Nature Structural & Molecular Biology
Caroline Rajiv, S RaElle Jackson, Simon Cocklin, Elan Z Eisenmesser, Tara L Davis
Pre-mRNA splicing is a dynamic, multistep process that is catalyzed by the RNA (ribonucleic acid)-protein complex called the spliceosome. The spliceosome contains a core set of RNAs and proteins that are conserved in all organisms that perform splicing. In higher organisms, peptidyl-prolyl isomerase H (PPIH) directly interacts with the core protein pre-mRNA processing factor 4 (PRPF4) and both integrate into the pre-catalytic spliceosome as part of the tri-snRNP (small nuclear RNA-protein complex) subcomplex...
October 25, 2017: Biochemical Journal
Monika K Abramczuk, Thomas R Burkard, Vivien Rolland, Victoria Steinmann, Peter Duchek, Yanrui Jiang, Sebastian Wissel, Heinrich Reichert, Juergen A Knoblich
Stem cells need to balance self-renewal and differentiation for correct tissue development and homeostasis. Defects in this balance can lead to developmental defects or tumor formation. In recent years, mRNA splicing has emerged as one important mechanism regulating cell fate decisions. Here we address the role of the evolutionary conserved splicing co-factor Barricade (Barc)/Tat-SF1/CUS2 in Drosophila neural stem cell (neuroblast) lineage formation. We show that Barc is required for the generation of neurons during Drosophila brain development by ensuring correct neural progenitor proliferation and differentiation...
September 21, 2017: Development
Chung-Shu Yeh, Shang-Lin Chang, Jui-Hui Chen, Hsuan-Kai Wang, Yue-Chang Chou, Chun-Hsiung Wang, Shih-Hsin Huang, Amy Larson, Jeffrey A Pleiss, Wei-Hau Chang, Tien-Hsien Chang
Splicing is initiated by a productive interaction between the pre-mRNA and the U1 snRNP, in which a short RNA duplex is established between the 5' splice site of a pre-mRNA and the 5' end of the U1 snRNA. A long-standing puzzle has been why the AU dincucleotide at the 5'-end of the U1 snRNA is highly conserved, despite the absence of an apparent role in the formation of the duplex. To explore this conundrum, we varied this AU dinucleotide into all possible permutations and analyzed the resulting molecular consequences...
September 19, 2017: Nucleic Acids Research
Allison L Didychuk, Eric J Montemayor, Tucker J Carrocci, Andrew T DeLaitsch, Stefani E Lucarelli, William M Westler, David A Brow, Aaron A Hoskins, Samuel E Butcher
U6 small nuclear ribonucleoprotein (snRNP) biogenesis is essential for spliceosome assembly, but not well understood. Here, we report structures of the U6 RNA processing enzyme Usb1 from yeast and a substrate analog bound complex from humans. Unlike the human ortholog, we show that yeast Usb1 has cyclic phosphodiesterase activity that leaves a terminal 3' phosphate which prevents overprocessing. Usb1 processing of U6 RNA dramatically alters its affinity for cognate RNA-binding proteins. We reconstitute the post-transcriptional assembly of yeast U6 snRNP in vitro, which occurs through a complex series of handoffs involving 10 proteins (Lhp1, Prp24, Usb1 and Lsm2-8) and anti-cooperative interactions between Prp24 and Lhp1...
September 8, 2017: Nature Communications
Andrea Pawellek, Ursula Ryder, Triin Tammsalu, Lewis J King, Helmi Kreinin, Tony Ly, Ronald T Hay, Richard C Hartley, Angus I Lamond
We have identified the plant biflavonoid hinokiflavone as an inhibitor of splicing in vitro and modulator of alternative splicing in cells. Chemical synthesis confirms hinokiflavone is the active molecule. Hinokiflavone inhibits splicing in vitro by blocking spliceosome assembly, preventing formation of the B complex. Cells treated with hinokiflavone show altered subnuclear organization specifically of splicing factors required for A complex formation, which relocalize together with SUMO1 and SUMO2 into enlarged nuclear speckles containing polyadenylated RNA...
September 8, 2017: ELife
Vanesa Lafarga, Olga Tapia, Sahil Sharma, Rocio Bengoechea, Georg Stoecklin, Miguel Lafarga, Maria T Berciano
The survival of motor neuron (SMN) protein plays an essential role in the biogenesis of spliceosomal snRNPs and the molecular assembly of Cajal bodies (CBs). Deletion of or mutations in the SMN1 gene cause spinal muscular atrophy (SMA) with degeneration and loss of motor neurons. Reduced SMN levels in SMA lead to deficient snRNP biogenesis with consequent splicing pathology. Here, we demonstrate that SMN is a novel and specific target of the acetyltransferase CBP (CREB-binding protein). Furthermore, we identify lysine (K) 119 as the main acetylation site in SMN...
September 6, 2017: Cellular and Molecular Life Sciences: CMLS
Jun Wu, Ming-Tao Ao, Rui Shao, Hui-Ru Wang, Diao Yu, Mei-Juan Fang, Xiang Gao, Zhen Wu, Qiang Zhou, Yu-Hua Xue
The principal barrier to the eradication of HIV/AIDS is the existence of latent viral reservoirs. One strategy to overcome this barrier is to use latency-reversing agents (LRAs) to reactivate the latent proviruses, which can then be eliminated by effective anti-retroviral therapy. Although a number of LRAs have been found to reactivate latent HIV, they have not been used clinically due to high toxicity and poor efficacy. In this study, we report the identification of a chalcone analogue called Amt-87 that can significantly reactivate the transcription of latent HIV provirses and act synergistically with known LRAs such as prostratin and JQ1 to reverse latency...
September 6, 2017: Scientific Reports
Stefanie Chan, Praveen Sridhar, Rory Kirchner, Ying Jie Lock, Zach Herbert, Silvia Buonamici, Peter Smith, Judy Lieberman, Fabio Petrocca
Prognosis of triple-negative breast cancer (TNBC) remains poor. To identify shared and selective vulnerabilities of basal-like TNBC, the most common TNBC subtype, a directed siRNA lethality screen was performed in 7 human breast cancer cell lines, focusing on 154 previously identified dependency genes of one TNBC line. Thirty common dependency genes were identified, including multiple proteasome and RNA splicing genes, especially those associated with the U4/U6.U5 tri-snRNP complex (e.g., PRPF8, PRPF38A). PRPF8 or PRPF38A knockdown or the splicing modulator E7107 led to widespread intronic retention and altered splicing of transcripts involved in multiple basal-like TNBC dependencies, including protein homeostasis, mitosis and apoptosis...
September 6, 2017: Molecular Cancer Therapeutics
Zhe Chen, Bin Gui, Yu Zhang, Guojia Xie, Wanjin Li, Shumeng Liu, Bosen Xu, Chongyang Wu, Lin He, Jianguo Yang, Xia Yi, Xiaohan Yang, Luyang Sun, Jing Liang, Yongfeng Shang
The de novo assembly and post-splicing reassembly of the U4/U6.U5 tri-snRNP remain to be investigated. We report here that ZIP, a protein containing a CCCH-type zinc finger and a G-patch domain, as characterized by us previously, regulates pre-mRNA splicing independent of RNA binding. We found that ZIP physically associates with the U4/U6.U5 tri-small nuclear ribonucleoprotein (tri-snRNP). Remarkably, the ZIP-containing tri-snRNP, which has a sedimentation coefficient of ∼35S, is a tri-snRNP that has not been described previously...
November 3, 2017: Journal of Biological Chemistry
Pilar Vazquez-Arango, Dawn O'Reilly
Much evidence is now accumulating that, in addition to their general role in splicing, the components of the core splicing machinery have extensive regulatory potential. In particular, recent evidence has demonstrated that de-regulation of these factors cause the highest extent of alternative splicing changes compared to de-regulation of the classical splicing regulators. This lack of a general inhibition of splicing resonates the differential splicing effects observed in different disease pathologies associated with specific mutations targeting core spliceosomal components...
September 6, 2017: RNA Biology
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