1
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Chalivendra S, Shi S, Li X, Kuang Z, Giovinazzo J, Zhang L, Rossi J, Wang J, Saviola AJ, Welty R, Liu S, Vaeth KF, Zhou ZH, Hansen KC, Taliaferro JM, Zhao R. Selected humanization of yeast U1 snRNP leads to global suppression of pre-mRNA splicing and mitochondrial dysfunction in the budding yeast. RNA (NEW YORK, N.Y.) 2024; 30:1070-1088. [PMID: 38688558 PMCID: PMC11251525 DOI: 10.1261/rna.079917.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 04/16/2024] [Indexed: 05/02/2024]
Abstract
The recognition of the 5' splice site (5' ss) is one of the earliest steps of pre-mRNA splicing. To better understand, the mechanism and regulation of 5' ss recognition, we selectively humanized components of the yeast U1 (yU1) snRNP to reveal the function of these components in 5' ss recognition and splicing. We targeted U1C and Luc7, two proteins that interact with and stabilize the yU1 snRNA and the 5' ss RNA duplex. We replaced the zinc-finger (ZnF) domain of yeast U1C (yU1C) with its human counterpart, which resulted in a cold-sensitive growth phenotype and moderate splicing defects. We next added an auxin-inducible degron to yeast Luc7 (yLuc7) protein (to mimic the lack of Luc7Ls in human U1 snRNP). We found that Luc7-depleted yU1 snRNP resulted in the concomitant loss of Prp40 and Snu71 (two other essential yU1 snRNP proteins), and further biochemical analyses suggest a model of how these three proteins interact with each other in the U1 snRNP. The loss of these proteins resulted in a significant growth retardation accompanied by a global suppression of pre-mRNA splicing. The splicing suppression led to mitochondrial dysfunction as revealed by a release of Fe2+ into the growth medium and an induction of mitochondrial reactive oxygen species. Together, these observations indicate that the human U1C ZnF can substitute that of yeast, Luc7 is essential for the incorporation of the Luc7-Prp40-Snu71 trimer into yU1 snRNP, and splicing plays a major role in the regulation of mitochondrial function in yeast.
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Affiliation(s)
- Subbaiah Chalivendra
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Shasha Shi
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Xueni Li
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Zhiling Kuang
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Joseph Giovinazzo
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Lingdi Zhang
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - John Rossi
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Jingxin Wang
- Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66047, USA
| | - Anthony J Saviola
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Robb Welty
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Shiheng Liu
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095, USA
| | - Katherine F Vaeth
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Z Hong Zhou
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095, USA
| | - Kirk C Hansen
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - J Matthew Taliaferro
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | - Rui Zhao
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
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2
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Ottesen EW, Singh NN, Seo J, Singh RN. U1 snRNA interactions with deep intronic sequences regulate splicing of multiple exons of spinal muscular atrophy genes. Front Neurosci 2024; 18:1412893. [PMID: 39086841 PMCID: PMC11289892 DOI: 10.3389/fnins.2024.1412893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 07/02/2024] [Indexed: 08/02/2024] Open
Abstract
Introduction The U1 small nuclear RNA (snRNA) forms ribonucleoprotein particles (RNPs) such as U1 snRNP and U1-TAF15 snRNP. U1 snRNP is one of the most studied RNPs due to its critical role in pre-mRNA splicing in defining the 5' splice site (5'ss) of every exon through direct interactions with sequences at exon/intron junctions. Recent reports support the role of U1 snRNP in all steps of transcription, namely initiation, elongation, and termination. Functions of U1-TAF15 snRNP are less understood, though it associates with the transcription machinery and may modulate pre-mRNA splicing by interacting with the 5'ss and/or 5'ss-like sequences within the pre-mRNA. An anti-U1 antisense oligonucleotide (ASO) that sequesters the 5' end of U1 snRNA inhibits the functions of U1 snRNP, including transcription and splicing. However, it is not known if the inhibition of U1 snRNP influences post-transcriptional regulation of pre-mRNA splicing through deep intronic sequences. Methods We examined the effect of an anti-U1 ASO that sequesters the 5' end of U1 snRNA on transcription and splicing of all internal exons of the spinal muscular atrophy (SMA) genes, SMN1 and SMN2. Our study was enabled by the employment of a multi-exon-skipping detection assay (MESDA) that discriminates against prematurely terminated transcripts. We employed an SMN2 super minigene to determine if anti-U1 ASO differently affects splicing in the context of truncated introns. Results We observed substantial skipping of multiple internal exons of SMN1 and SMN2 triggered by anti-U1 treatment. Suggesting a role for U1 snRNP in interacting with deep intronic sequences, early exons of the SMN2 super minigene with truncated introns were resistant to anti-U1 induced skipping. Consistently, overexpression of engineered U1 snRNAs targeting the 5'ss of early SMN1 and SMN2 exons did not prevent exon skipping caused by anti-U1 treatment. Discussion Our results uncover a unique role of the U1 snRNA-associated RNPs in splicing regulation executed through deep intronic sequences. Findings are significant for developing novel therapies for SMA based on deep intronic targets.
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Affiliation(s)
| | | | | | - Ravindra N. Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, United States
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3
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Shanley HT, Taki AC, Nguyen N, Wang T, Byrne JJ, Ang CS, Leeming MG, Nie S, Williamson N, Zheng Y, Young ND, Korhonen PK, Hofmann A, Wells TNC, Jabbar A, Sleebs BE, Gasser RB. Structure activity relationship and target prediction for ABX464 analogues in Caenorhabditis elegans. Bioorg Med Chem 2024; 98:117540. [PMID: 38134663 DOI: 10.1016/j.bmc.2023.117540] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 11/20/2023] [Accepted: 12/02/2023] [Indexed: 12/24/2023]
Abstract
Global challenges with treatment failures and/or widespread resistance in parasitic worms against commercially available anthelmintics lend impetus to the development of new anthelmintics with novel mechanism(s) of action. The free-living nematode Caenorhabditis elegans is an important model organism used for drug discovery, including the screening and structure-activity investigation of new compounds, and target deconvolution. Previously, we conducted a whole-organism phenotypic screen of the 'Pandemic Response Box' (from Medicines for Malaria Venture, MMV) and identified a hit compound, called ABX464, with activity against C. elegans and a related, parasitic nematode, Haemonchus contortus. Here, we tested a series of 44 synthesized analogues to explore the pharmacophore of activity on C. elegans and revealed five compounds whose potency was similar or greater than that of ABX464, but which were not toxic to human hepatoma (HepG2) cells. Subsequently, we employed thermal proteome profiling (TPP), protein structure prediction and an in silico-docking algorithm to predict ABX464-target candidates. Taken together, the findings from this study contribute significantly to the early-stage drug discovery of a new nematocide based on ABX464. Future work is aimed at validating the ABX464-protein interactions identified here, and at assessing ABX464 and associated analogues against a panel of parasitic nematodes, towards developing a new anthelmintic with a mechanism of action that is distinct from any of the compounds currently-available commercially.
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Affiliation(s)
- Harrison T Shanley
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia; Chemical Biology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Aya C Taki
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Nghi Nguyen
- Chemical Biology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Tao Wang
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Joseph J Byrne
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ching-Seng Ang
- Melbourne Mass Spectrometry and Proteomics Facility, The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Michael G Leeming
- Melbourne Mass Spectrometry and Proteomics Facility, The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Shuai Nie
- Melbourne Mass Spectrometry and Proteomics Facility, The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Nicholas Williamson
- Melbourne Mass Spectrometry and Proteomics Facility, The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Yuanting Zheng
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Neil D Young
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Pasi K Korhonen
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Andreas Hofmann
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia; National Reference Centre for Authentic Food, Max Rubner-Institut, 95326 Kulmbach, Germany
| | - Tim N C Wells
- Medicines for Malaria Venture (MMV), 1215 Geneva, Switzerland
| | - Abdul Jabbar
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Brad E Sleebs
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia; Chemical Biology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia.
| | - Robin B Gasser
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia.
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4
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Chalivendra S, Shi S, Li X, Kuang Z, Giovinazzo J, Zhang L, Rossi J, Saviola AJ, Wang J, Welty R, Liu S, Vaeth K, Zhou ZH, Hansen KC, Taliaferro JM, Zhao R. Selected humanization of yeast U1 snRNP leads to global suppression of pre-mRNA splicing and mitochondrial dysfunction in the budding yeast. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.15.571893. [PMID: 38168357 PMCID: PMC10760170 DOI: 10.1101/2023.12.15.571893] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The recognition of 5' splice site (5' ss) is one of the earliest steps of pre-mRNA splicing. To better understand the mechanism and regulation of 5' ss recognition, we selectively humanized components of the yeast U1 snRNP to reveal the function of these components in 5' ss recognition and splicing. We targeted U1C and Luc7, two proteins that interact with and stabilize the yeast U1 (yU1) snRNA and the 5' ss RNA duplex. We replaced the Zinc-Finger (ZnF) domain of yU1C with its human counterpart, which resulted in cold-sensitive growth phenotype and moderate splicing defects. Next, we added an auxin-inducible degron to yLuc7 protein and found that Luc7-depleted yU1 snRNP resulted in the concomitant loss of PRP40 and Snu71 (two other essential yeast U1 snRNP proteins), and further biochemical analyses suggest a model of how these three proteins interact with each other in the U1 snRNP. The loss of these proteins resulted in a significant growth retardation accompanied by a global suppression of pre-mRNA splicing. The splicing suppression led to mitochondrial dysfunction as revealed by a release of Fe 2+ into the growth medium and an induction of mitochondrial reactive oxygen species. Together, these observations indicate that the human U1C ZnF can substitute that of yeast, Luc7 is essential for the incorporation of the Luc7-Prp40-Snu71 trimer into yeast U1 snRNP, and splicing plays a major role in the regulation of mitochondria function in yeast.
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5
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Cheng W, Hong C, Zeng F, Liu N, Gao H. Sequence variations affect the 5' splice site selection of plant introns. PLANT PHYSIOLOGY 2023; 193:1281-1296. [PMID: 37394939 DOI: 10.1093/plphys/kiad375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 05/31/2023] [Accepted: 06/04/2023] [Indexed: 07/04/2023]
Abstract
Introns are noncoding sequences spliced out of pre-mRNAs by the spliceosome to produce mature mRNAs. The 5' ends of introns mostly begin with GU and have a conserved sequence motif of AG/GUAAGU that could base-pair with the core sequence of U1 snRNA of the spliceosome. Intriguingly, ∼ 1% of introns in various eukaryotic species begin with GC. This occurrence could cause misannotation of genes; however, the underlying splicing mechanism is unclear. We analyzed the sequences around the intron 5' splice site (ss) in Arabidopsis (Arabidopsis thaliana) and found sequences at the GC intron ss are much more stringent than those of GT introns. Mutational analysis at various positions of the intron 5' ss revealed that although mutations impair base pairing, different mutations at the same site can have different effects, suggesting that steric hindrance also affects splicing. Moreover, mutations of 5' ss often activate a hidden ss nearby. Our data suggest that the 5' ss is selected via a competition between the major ss and the nearby minor ss. This work not only provides insights into the splicing mechanism of intron 5' ss but also improves the accuracy of gene annotation and the study of the evolution of intron 5' ss.
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Affiliation(s)
- Wenzhen Cheng
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
| | - Conghao Hong
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
| | - Fang Zeng
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
| | - Nan Liu
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
| | - Hongbo Gao
- National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
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6
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Huang W, Zhang L, Zhu Y, Chen J, Zhu Y, Lin F, Chen X, Huang J. A genetic screen in Arabidopsis reveals the identical roles for RBP45d and PRP39a in 5' cryptic splice site selection. FRONTIERS IN PLANT SCIENCE 2022; 13:1086506. [PMID: 36618610 PMCID: PMC9813592 DOI: 10.3389/fpls.2022.1086506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 12/02/2022] [Indexed: 06/17/2023]
Abstract
Cryptic splice sites in eukaryotic genome are generally dormant unless activated by mutation of authentic splice sites or related splicing factors. How cryptic splice sites are used remains unclear in plants. Here, we identified two cryptic splicing regulators, RBP45d and PRP39a that are homologs of yeast U1 auxiliary protein Nam8 and Prp39, respectively, via genetic screening for suppressors of the virescent sot5 mutant, which results from a point mutation at the 5' splice site (5' ss) of SOT5 intron 7. Loss-of-function mutations in RBP45d and PRP39a significantly increase the level of a cryptically spliced variant that encodes a mutated but functional sot5 protein, rescuing sot5 to the WT phenotype. We furtherly demonstrated that RBP45d and PRP39a interact with each other and also with the U1C, a core subunit of U1 snRNP. We found that RBP45d directly binds to the uridine (U)-rich RNA sequence downstream the 5' ss of SOT5 intron 7. However, other RBP45/47 members do not function redundantly with RBP45d, at least in regulation of cryptic splicing. Taken together, RBP45d promotes U1 snRNP to recognize the specific 5' ss via binding to intronic U-rich elements in plants.
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Affiliation(s)
- Weihua Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Liqun Zhang
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Yajuan Zhu
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jingli Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Yawen Zhu
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Fengru Lin
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Xiaomei Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Jirong Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, Development Center of Plant Germplasm Resources, College of Life Sciences, Shanghai Normal University, Shanghai, China
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7
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Zhang T, Wang Z, Liu M, Liu L, Yang X, Zhang Y, Bie J, Li Y, Ren M, Song C, Wang W, Tan H, Luo J. Acetylation dependent translocation of EWSR1 regulates CHK2 alternative splicing in response to DNA damage. Oncogene 2022; 41:3694-3704. [PMID: 35732801 DOI: 10.1038/s41388-022-02383-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 11/09/2022]
Abstract
Ewing sarcoma breakpoint region 1 (EWSR1) is a member of FET (FUS/EWSR1/TAF15) RNA-binding family of proteins. The Ewing sarcoma oncoprotein EWS-FLI1 has been extensively studied, while much less is known about EWSR1 itself, especially the potential role of EWSR1 in response to DNA damage. Here, we found that UV irradiation induces acetylation of EWSR1, which is required for its nucleoli translocation. We identified K423, K432, K438, K640, and K643 as the major acetylation sites, p300/CBP and HDAC3/HDAC10 as the major acetyltransferases and deacetylases, respectively. Mechanically, UV-induced EWSR1 acetylation repressed its interaction with spliceosomal component U1C, which caused abnormal splicing of CHK2, suppressing the activity of CHK2 in response to UV irradiation. Taken together, our findings uncover acetylation as a novel regulatory modification of EWSR1, and is essential for its function in DNA damage response.
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Affiliation(s)
- Tianzhuo Zhang
- Department of Medical Genetics, Center for Medical Genetics, Peking University Health Science Center, Beijing, 100191, China.,Department of Biochemistry and Biophysics, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Peking University Health Science Center, Beijing, 100191, China
| | - Zhe Wang
- Department of Medical Genetics, Center for Medical Genetics, Peking University Health Science Center, Beijing, 100191, China
| | - Minghui Liu
- Department of Medical Genetics, Center for Medical Genetics, Peking University Health Science Center, Beijing, 100191, China
| | - Lu Liu
- Department of Medical Genetics, Center for Medical Genetics, Peking University Health Science Center, Beijing, 100191, China
| | - Xin Yang
- Department of Medical Genetics, Center for Medical Genetics, Peking University Health Science Center, Beijing, 100191, China
| | - Yu Zhang
- Department of Medical Genetics, Center for Medical Genetics, Peking University Health Science Center, Beijing, 100191, China
| | - Juntao Bie
- Department of Medical Genetics, Center for Medical Genetics, Peking University Health Science Center, Beijing, 100191, China
| | - Yutong Li
- Department of Medical Genetics, Center for Medical Genetics, Peking University Health Science Center, Beijing, 100191, China
| | - Mengmeng Ren
- Department of Medical Genetics, Center for Medical Genetics, Peking University Health Science Center, Beijing, 100191, China
| | - Chen Song
- Department of Medical Genetics, Center for Medical Genetics, Peking University Health Science Center, Beijing, 100191, China
| | - Wengong Wang
- Department of Biochemistry and Biophysics, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Peking University Health Science Center, Beijing, 100191, China
| | - Hongyu Tan
- Department of Anesthesiology, Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital & Institute, Beijing, 100142, China.
| | - Jianyuan Luo
- Department of Medical Genetics, Center for Medical Genetics, Peking University Health Science Center, Beijing, 100191, China. .,Department of Biochemistry and Biophysics, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Peking University Health Science Center, Beijing, 100191, China.
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8
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Kim D, Lee J, Cho CH, Kim EJ, Bhattacharya D, Yoon HS. Group II intron and repeat-rich red algal mitochondrial genomes demonstrate the dynamic recent history of autocatalytic RNAs. BMC Biol 2022; 20:2. [PMID: 34996446 PMCID: PMC8742464 DOI: 10.1186/s12915-021-01200-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 11/29/2021] [Indexed: 11/10/2022] Open
Abstract
Background Group II introns are mobile genetic elements that can insert at specific target sequences, however, their origins are often challenging to reconstruct because of rapid sequence decay following invasion and spread into different sites. To advance understanding of group II intron spread, we studied the intron-rich mitochondrial genome (mitogenome) in the unicellular red alga, Porphyridium. Results Analysis of mitogenomes in three closely related species in this genus revealed they were 3–6-fold larger in size (56–132 kbp) than in other red algae, that have genomes of size 21–43 kbp. This discrepancy is explained by two factors, group II intron invasion and expansion of repeated sequences in large intergenic regions. Phylogenetic analysis demonstrates that many mitogenome group II intron families are specific to Porphyridium, whereas others are closely related to sequences in fungi and in the red alga-derived plastids of stramenopiles. Network analysis of intron-encoded proteins (IEPs) shows a clear link between plastid and mitochondrial IEPs in distantly related species, with both groups associated with prokaryotic sequences. Conclusion Our analysis of group II introns in Porphyridium mitogenomes demonstrates the dynamic nature of group II intron evolution, strongly supports the lateral movement of group II introns among diverse eukaryotes, and reveals their ability to proliferate, once integrated in mitochondrial DNA. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01200-3.
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Affiliation(s)
- Dongseok Kim
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, South Korea
| | - JunMo Lee
- Department of Oceanography, Kyungpook National University, Daegu, 41566, South Korea
| | - Chung Hyun Cho
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Eun Jeung Kim
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, South Korea.
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9
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Zhang KL, Zhou JL, Yang JF, Zhao YZ, Das D, Hao GF, Wu C, Zhang J, Zhu FY, Chen MX, Zhou SM. Phylogenetic Comparison and Splicing Analysis of the U1 snRNP-specific Protein U1C in Eukaryotes. Front Mol Biosci 2021; 8:696319. [PMID: 34568424 PMCID: PMC8458698 DOI: 10.3389/fmolb.2021.696319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 08/26/2021] [Indexed: 11/13/2022] Open
Abstract
As a pivotal regulator of 5’ splice site recognition, U1 small nuclear ribonucleoprotein (U1 snRNP)-specific protein C (U1C) regulates pre-mRNA splicing by interacting with other components of the U1 snRNP complex. Previous studies have shown that U1 snRNP and its components are linked to a variety of diseases, including cancer. However, the phylogenetic relationships and expression profiles of U1C have not been studied systematically. To this end, we identified a total of 110 animal U1C genes and compared them to homologues from yeast and plants. Bioinformatics analysis shows that the structure and function of U1C proteins is relatively conserved and is found in multiple copies in a few members of the U1C gene family. Furthermore, the expression patterns reveal that U1Cs have potential roles in cancer progression and human development. In summary, our study presents a comprehensive overview of the animal U1C gene family, which can provide fundamental data and potential cues for further research in deciphering the molecular function of this splicing regulator.
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Affiliation(s)
- Kai-Lu Zhang
- Division of Gastroenterology, Shenzhen Children's Hospital, Shenzhen, China.,Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China.,State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Taian, China
| | - Jian-Li Zhou
- Division of Gastroenterology, Shenzhen Children's Hospital, Shenzhen, China
| | - Jing-Fang Yang
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China
| | - Yu-Zhen Zhao
- Division of Gastroenterology, Shenzhen Children's Hospital, Shenzhen, China
| | - Debatosh Das
- Department of Biology, Hong Kong Baptist University, and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, SAR China
| | - Ge-Fei Hao
- Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, China
| | - Caie Wu
- College of Light Industry and Food Engineering, Nanjing Forestry University, Jiangsu, China
| | - Jianhua Zhang
- Department of Biology, Hong Kong Baptist University, and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, SAR China
| | - Fu-Yuan Zhu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
| | - Mo-Xian Chen
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
| | - Shao-Ming Zhou
- Division of Gastroenterology, Shenzhen Children's Hospital, Shenzhen, China
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10
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Kumar Kulabhusan P, Hussain B, Yüce M. Current Perspectives on Aptamers as Diagnostic Tools and Therapeutic Agents. Pharmaceutics 2020; 12:E646. [PMID: 32659966 PMCID: PMC7407196 DOI: 10.3390/pharmaceutics12070646] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/05/2020] [Accepted: 07/06/2020] [Indexed: 12/12/2022] Open
Abstract
Aptamers are synthetic single-stranded DNA or RNA sequences selected from combinatorial oligonucleotide libraries through the well-known in vitro selection and iteration process, SELEX. The last three decades have witnessed a sudden boom in aptamer research, owing to their unique characteristics, like high specificity and binding affinity, low immunogenicity and toxicity, and ease in synthesis with negligible batch-to-batch variation. Aptamers can specifically bind to the targets ranging from small molecules to complex structures, making them suitable for a myriad of diagnostic and therapeutic applications. In analytical scenarios, aptamers are used as molecular probes instead of antibodies. They have the potential in the detection of biomarkers, microorganisms, viral agents, environmental pollutants, or pathogens. For therapeutic purposes, aptamers can be further engineered with chemical stabilization and modification techniques, thus expanding their serum half-life and shelf life. A vast number of antagonistic aptamers or aptamer-based conjugates have been discovered so far through the in vitro selection procedure. However, the aptamers face several challenges for its successful clinical translation, and only particular aptamers have reached the marketplace so far. Aptamer research is still in a growing stage, and a deeper understanding of nucleic acid chemistry, target interaction, tissue distribution, and pharmacokinetics is required. In this review, we discussed aptamers in the current diagnostics and theranostics applications, while addressing the challenges associated with them. The report also sheds light on the implementation of aptamer conjugates for diagnostic purposes and, finally, the therapeutic aptamers under clinical investigation, challenges therein, and their future directions.
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Affiliation(s)
| | - Babar Hussain
- Faculty of Life Sciences, University of Central Punjab, Lahore 54000, Pakistan;
| | - Meral Yüce
- SUNUM Nanotechnology Research and Application Centre, Sabanci University, Istanbul 34956, Turkey
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11
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Lu L, Liu C, Miao W, Wang X, Guo G. Ultrasensitive detection of miRNA based on efficient immobilization of probe and electrochemiluminescent quenching of Ru(bpy) 32+ by methylene blue. Anal Chim Acta 2019; 1093:52-60. [PMID: 31735215 DOI: 10.1016/j.aca.2019.09.073] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 09/27/2019] [Indexed: 11/20/2022]
Abstract
A high performance miRNA biosensor based on effective click chemistry assembly of a Ru(bpy)32+ labeled DNA probe and efficient electrochemiluminescence (ECL) quenching of the Ru(bpy)32+/BDEA (BDEA = N-butyldiethanolamine) system by surface-confined electroactive methylene blue (MB) dye is reported. When the target miRNA was present, the ECL signal instantly changed from "light off" to "light on" status. Using the specific miRNA let-7d as the target analyte, this biosensor provided sensitive detection over approximately six orders of magnitude (10 fM-10 nM), with a limit of detection of 10 fM (S/N = 3). Detailed study of the ECL quenching behavior of the Ru(bpy)32+/BDEA system by MB in solution suggested that the ECL quenching involves a combination of photoluminescence dynamic quenching and quenching processes directly associated with the redox reactions, as well as resonance energy transfer. A large binding constant of 4.7 × 1011 M-1 between let-7d and the DNA hairpin was estimated using an ECL-based extended Langmuir isotherm model, suggesting remarkably strong binding of the target to the probe. Furthermore, our biosensor exhibited excellent specificity and reproducibility. Using the developed system, the concentration of the target miRNA extracted from the A549 cell line could be obtained, demonstrating the potential application of the developed biosensor to practical biological sample analysis.
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Affiliation(s)
- Liping Lu
- College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, 100124, China.
| | - Chang Liu
- College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, 100124, China
| | - Wujian Miao
- Department of Chemistry and Biochemistry, The University of Southern Mississippi, Hattiesburg, MS, 39406, USA.
| | - Xiayan Wang
- College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, 100124, China
| | - Guanghsheng Guo
- College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, 100124, China
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12
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Gu J, Xia Z, Luo Y, Jiang X, Qian B, Xie H, Zhu JK, Xiong L, Zhu J, Wang ZY. Spliceosomal protein U1A is involved in alternative splicing and salt stress tolerance in Arabidopsis thaliana. Nucleic Acids Res 2019; 46:1777-1792. [PMID: 29228330 PMCID: PMC5829640 DOI: 10.1093/nar/gkx1229] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/30/2017] [Indexed: 12/14/2022] Open
Abstract
Soil salinity is a significant threat to sustainable agricultural production worldwide. Plants must adjust their developmental and physiological processes to cope with salt stress. Although the capacity for adaptation ultimately depends on the genome, the exceptional versatility in gene regulation provided by the spliceosome-mediated alternative splicing (AS) is essential in these adaptive processes. However, the functions of the spliceosome in plant stress responses are poorly understood. Here, we report the in-depth characterization of a U1 spliceosomal protein, AtU1A, in controlling AS of pre-mRNAs under salt stress and salt stress tolerance in Arabidopsis thaliana. The atu1a mutant was hypersensitive to salt stress and accumulated more reactive oxygen species (ROS) than the wild-type under salt stress. RNA-seq analysis revealed that AtU1A regulates AS of many genes, presumably through modulating recognition of 5′ splice sites. We showed that AtU1A is associated with the pre-mRNA of the ROS detoxification-related gene ACO1 and is necessary for the regulation of ACO1 AS. ACO1 is important for salt tolerance because ectopic expression of ACO1 in the atu1a mutant can partially rescue its salt hypersensitive phenotype. Our findings highlight the critical role of AtU1A as a regulator of pre-mRNA processing and salt tolerance in plants.
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Affiliation(s)
- Jinbao Gu
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China
| | - Zhiqiang Xia
- Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan 571101, China
| | - Yuehua Luo
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China
| | - Xingyu Jiang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China
| | - Bilian Qian
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742, USA
| | - He Xie
- Tobacco Breeding and Biotechnology Research Center, Yunnan Academy of Tobacco Agricultural Sciences, Kunming 650021, China
| | - Jian-Kang Zhu
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47906, USA.,Shanghai Center for Plant Stress Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Liming Xiong
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences & Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Jianhua Zhu
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742, USA
| | - Zhen-Yu Wang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresource, Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China
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13
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Singh RN, Singh NN. A novel role of U1 snRNP: Splice site selection from a distance. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:634-642. [PMID: 31042550 DOI: 10.1016/j.bbagrm.2019.04.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 04/15/2019] [Accepted: 04/18/2019] [Indexed: 12/23/2022]
Abstract
Removal of introns by pre-mRNA splicing is fundamental to gene function in eukaryotes. However, understanding the mechanism by which exon-intron boundaries are defined remains a challenging endeavor. Published reports support that the recruitment of U1 snRNP at the 5'ss marked by GU dinucleotides defines the 5'ss as well as facilitates 3'ss recognition through cross-exon interactions. However, exceptions to this rule exist as U1 snRNP recruited away from the 5'ss retains the capability to define the splice site, where the cleavage takes place. Independent reports employing exon 7 of Survival Motor Neuron (SMN) genes suggest a long-distance effect of U1 snRNP on splice site selection upon U1 snRNP recruitment at target sequences with or without GU dinucleotides. These findings underscore that sequences distinct from the 5'ss may also impact exon definition if U1 snRNP is recruited to them through partial complementarity with the U1 snRNA. In this review we discuss the expanded role of U1 snRNP in splice-site selection due to U1 ability to be recruited at more sites than predicted solely based on GU dinucleotides.
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Affiliation(s)
- Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States of America.
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States of America
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14
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Peciuliene I, Vilys L, Jakubauskiene E, Zaliauskiene L, Kanopka A. Hypoxia alters splicing of the cancer associated Fas gene. Exp Cell Res 2019; 380:29-35. [PMID: 31002816 DOI: 10.1016/j.yexcr.2019.04.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/08/2019] [Accepted: 04/14/2019] [Indexed: 02/02/2023]
Abstract
The removal of introns from mRNA precursors (pre-mRNAs) is an essential step in eukaryotic gene expression. The splicing machinery heavily contributes to biological complexity and especially to the ability of cells to adapt to altered cellular conditions. Hypoxia also plays a key role in the pathophysiology of many disease states. Recent studies have revealed that tumorigenesis and hypoxia involve large-scale alterations in alternative pre-mRNA splicing. Cancer associated Fas protein plays a central role in the physiological regulation of programmed cell death and has been implicated in the pathogenesis of various malignancies and diseases of the immune system. Fas pre-mRNA is alternatively spliced by excluding exon 6 to produce soluble Fas (sFas) protein that lacks a transmembrane domain and acts by inhibiting Fas mediated apoptosis. Another cancer related protein Rac1 plays an important regulatory role specifically in cells' motility, growth and survival. Rac pre-mRNA is alternatively spliced to produce Rac1b protein, which is upregulated in metastatic diseases. In the present study we, for the first time, show that anti-apoptotic Fas mRNA isoform formation is regulated by cellular microenvironment - hypoxia. Hypoxic microenvironment, however, does not influence Rac1 pre-mRNAs alternative splicing. Also our presented results indicate that splicing factors hnRNP A1 and SPF45, previously shown to regulate Fas alternative splicing in normoxic cells, are not involved in hypoxia dependent alternative Fas pre-mRNA splicing regulation in an amount dependent manner. Our observations on hypoxia dependent alternative Fas pre-mRNA splicing regulation indicate a probable involvement of other, yet unidentified splicing factors. Presented data also shows the contribution of pre-mRNA splicing to cell survival under unfavorable conditions.
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Affiliation(s)
- Inga Peciuliene
- Department of Immunology and Cell Biology, Vilnius University, Institute of Biotechnology, Vilnius, Lithuania
| | - Laurynas Vilys
- Department of Immunology and Cell Biology, Vilnius University, Institute of Biotechnology, Vilnius, Lithuania
| | - Egle Jakubauskiene
- Department of Immunology and Cell Biology, Vilnius University, Institute of Biotechnology, Vilnius, Lithuania
| | | | - Arvydas Kanopka
- Department of Immunology and Cell Biology, Vilnius University, Institute of Biotechnology, Vilnius, Lithuania.
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15
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Xia X. RNA-Seq approach for accurate characterization of splicing efficiency of yeast introns. Methods 2019; 176:25-33. [PMID: 30926533 DOI: 10.1016/j.ymeth.2019.03.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 03/12/2019] [Accepted: 03/19/2019] [Indexed: 01/21/2023] Open
Abstract
Introns in different genes, or even different introns within the same gene, often have different splice sites and differ in splicing efficiency (SE). One expects mass-transcribed genes to have introns with higher SE than weakly transcribed genes. However, such a simple expectation cannot be tested directly because variable SE for these genes is often not measured. Mechanistically, SE should depend on signal strength at key splice sites (SS) such as 5'SS, 3'SS and branchpoint site (BPS), i.e., SE = F(5'SS, 3'SS, BPS). However, without SE, we again cannot model how these splice sites contribute to SE. Here I present an RNA-Seq approach to quantify SE for each of the 304 introns in yeast (Saccharomyces cerevisiae) genes, including 24 in the 5'UTR, by measuring 1) number of reads mapped to exon-exon junctions (NEE) as a proxy for the abundance of spliced form, and 2) number of reads mapped to exon-intron junction (NEI5 and NEI3 at 5' and 3' ends of intron) as a proxy for the abundance of unspliced form. The total mRNA is NTotal = NEE + p * NEI5 + (1-p) * NEI3, with the simplest p = 0.5 but statistical methods were presented to estimate p from data. An estimated p is needed because NEI5 is expected to be smaller than NEI3 due to 1) step 1 splicing occurs before step 2 so EI5 is broken before EI3, 2) enrichment of poly(A) mRNA by oligo-dT, and 3) 5' degradation. SE is defined as the proportion (NEE/NTotal). Application of the method shows that ribosomal protein messages are efficiently and mostly cotranscriptionally spliced. Yeast genes with long introns are also spliced efficiently. HAC1/YFL031W is poorly spliced partly because its splicing involves a nonspliceosome mechanism and partly because Ire1p, which participate in splicing HAC1, is hardly expressed. Many putative yeast genes have low SE, and some splice sites are incorrectly annotated.
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Affiliation(s)
- Xuhua Xia
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa K1N 6N5, Canada; Ottawa Institute of Systems Biology, Ottawa, Ontario K1H 8M5, Canada.
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16
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Bai R, Wan R, Yan C, Lei J, Shi Y. Structures of the fully assembled Saccharomyces cerevisiae spliceosome before activation. Science 2018; 360:1423-1429. [PMID: 29794219 DOI: 10.1126/science.aau0325] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 05/16/2018] [Indexed: 11/02/2022]
Abstract
The precatalytic spliceosome (B complex) is preceded by the pre-B complex. Here we report the cryo-electron microscopy structures of the Saccharomyces cerevisiae pre-B and B complexes at average resolutions of 3.3 to 4.6 and 3.9 angstroms, respectively. In the pre-B complex, the duplex between the 5' splice site (5'SS) and U1 small nuclear RNA (snRNA) is recognized by Yhc1, Luc7, and the Sm ring. In the B complex, U1 small nuclear ribonucleoprotein is dissociated, the 5'-exon-5'SS sequences are translocated near U6 snRNA, and three B-specific proteins may orient the precursor messenger RNA. In both complexes, U6 snRNA is anchored to loop I of U5 snRNA, and the duplex between the branch point sequence and U2 snRNA is recognized by the SF3b complex. Structural analysis reveals the mechanism of assembly and activation for the yeast spliceosome.
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Affiliation(s)
- Rui Bai
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Schools of Life Sciences and Medicine, Tsinghua University, Beijing 100084, China
| | - Ruixue Wan
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Schools of Life Sciences and Medicine, Tsinghua University, Beijing 100084, China
| | - Chuangye Yan
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Schools of Life Sciences and Medicine, Tsinghua University, Beijing 100084, China
| | - Jianlin Lei
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Schools of Life Sciences and Medicine, Tsinghua University, Beijing 100084, China.,Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, Schools of Life Sciences and Medicine, Tsinghua University, Beijing 100084, China. .,Institute of Biology, Westlake Institute for Advanced Study, Westlake University, 18 Shilongshan Road, Xihu District, Hangzhou 310064, Zhejiang Province, China
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17
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Nguyen H, Das U, Wang B, Xie J. The matrices and constraints of GT/AG splice sites of more than 1000 species/lineages. Gene 2018; 660:92-101. [PMID: 29588184 DOI: 10.1016/j.gene.2018.03.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 03/08/2018] [Accepted: 03/12/2018] [Indexed: 12/11/2022]
Abstract
To provide a resource for the splice sites (SS) of different species, we calculated the matrices of nucleotide compositions of about 38 million splice sites from >1000 species/lineages. The matrices are enriched of aGGTAAGT (5'SS) or (Y)6N(C/t)AG(g/a)t (3'SS) overall; however, they are quite diverse among hundreds of species. The diverse matrices remain prominent even under sequence selection pressures, suggesting the existence of diverse constraints as well as U snRNAs and other spliceosomal factors and/or their interactions with the splice sites. Using an algorithm to measure and compare the splice site constraints across all species, we demonstrate their distinct differences quantitatively. As an example of the resource's application to answering specific questions, we confirm that high constraints of particular positions are significantly associated with transcriptome-wide, increased occurrences of alternative splicing when uncommon nucleotides are present. More interestingly, the abundance of alternative splicing in 16 species correlates with the average constraint index of splice sites in a bell curve. This resource will allow users to assess specific sequences/splice sites against the consensus of every Ensembl-annotated species, and to explore the evolutionary changes or relationship to alternative splicing and transcriptome diversity. Web-search or update features are also included.
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Affiliation(s)
- Hai Nguyen
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 0J9, Canada; University of Winnipeg, Winnipeg, MB R3B 2E9, Canada
| | - Urmi Das
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Benjamin Wang
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 0J9, Canada; University of Illinois Urbana-Champaign, IL, USA
| | - Jiuyong Xie
- Department of Physiology & Pathophysiology, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 0J9, Canada.
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18
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Zhang Z, Liu C, Yang C, Wu Y, Yu F, Chen Y, Du J. Aptamer-Patterned Hydrogel Films for Spatiotemporally Programmable Capture and Release of Multiple Proteins. ACS APPLIED MATERIALS & INTERFACES 2018; 10:8546-8554. [PMID: 29465230 DOI: 10.1021/acsami.8b00191] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Various hydrogels have been used for protein delivery in the treatment of human diseases. Nevertheless, it is always difficult to control the capture and release of multiple proteins in different regions and periods. This research successfully proves that multiple proteins can be captured and released from the aptamer-patterned hydrogel films with an adjustable release rate at a prospective time and in specific regions utilizing the complementary DNA strand of aptamers via photoclick chemistry and DNA hybridization. The hydrogel film is successfully applied to complex matrixes such as human serum and has excellent cytocompatibility. Thus, the aptamer-patterned hydrogel film will be a good candidate for controlled delivery of multiple proteins.
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Affiliation(s)
- Zheng Zhang
- State Key Laboratory of Marine Resource Utilization in South China Sea, College of Materials and Chemical Engineering , Hainan University , Haikou 570228 , PR China
| | - Chen Liu
- State Key Laboratory of Marine Resource Utilization in South China Sea, College of Materials and Chemical Engineering , Hainan University , Haikou 570228 , PR China
| | - Chunzheng Yang
- State Key Laboratory of Marine Resource Utilization in South China Sea, College of Materials and Chemical Engineering , Hainan University , Haikou 570228 , PR China
| | - Yuyang Wu
- State Key Laboratory of Marine Resource Utilization in South China Sea, College of Materials and Chemical Engineering , Hainan University , Haikou 570228 , PR China
| | - Feng Yu
- State Key Laboratory of Marine Resource Utilization in South China Sea, College of Materials and Chemical Engineering , Hainan University , Haikou 570228 , PR China
| | - Yong Chen
- State Key Laboratory of Marine Resource Utilization in South China Sea, College of Materials and Chemical Engineering , Hainan University , Haikou 570228 , PR China
| | - Jie Du
- State Key Laboratory of Marine Resource Utilization in South China Sea, College of Materials and Chemical Engineering , Hainan University , Haikou 570228 , PR China
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19
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Feng C, Chan D, Joseph J, Muuronen M, Coldren WH, Dai N, Corrêa IR, Furche F, Hadad CM, Spitale RC. Light-activated chemical probing of nucleobase solvent accessibility inside cells. Nat Chem Biol 2018; 14:276-283. [PMID: 29334380 PMCID: PMC6203945 DOI: 10.1038/nchembio.2548] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 11/15/2017] [Indexed: 12/30/2022]
Abstract
The discovery of functional RNAs that are critical for normal and disease physiology continues to expand at a breakneck pace. Many RNA functions are controlled by the formation of specific structures, and an understanding of each structural component is necessary to elucidate its function. Measuring solvent accessibility intracellularly with experimental ease is an unmet need in the field. Here, we present a novel method for probing nucleobase solvent accessibility, Light Activated Structural Examination of RNA (LASER). LASER depends on light activation of a small molecule, nicotinoyl azide (NAz), to measure solvent accessibility of purine nucleobases. In vitro, this technique accurately monitors solvent accessibility and identifies rapid structural changes resulting from ligand binding in a metabolite-responsive RNA. LASER probing can further identify cellular RNA-protein interactions and unique intracellular RNA structures. Our photoactivation technique provides an adaptable framework to structurally characterize solvent accessibility of RNA in many environments.
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Affiliation(s)
- Chao Feng
- Department of Pharmaceutical Sciences, University of California, Irvine. Irvine, California 92697
| | - Dalen Chan
- Department of Pharmaceutical Sciences, University of California, Irvine. Irvine, California 92697
| | - Jojo Joseph
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18 Avenue, Columbus Ohio 43210
| | - Mikko Muuronen
- Department of Chemistry, University of California, Irvine. Irvine, California 92697
| | - William H. Coldren
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18 Avenue, Columbus Ohio 43210
| | - Nan Dai
- New England Biolabs, 240 County Road, Ipswich, Massachusetts 01938, USA
| | - Ivan R. Corrêa
- New England Biolabs, 240 County Road, Ipswich, Massachusetts 01938, USA
| | - Filipp Furche
- Department of Chemistry, University of California, Irvine. Irvine, California 92697
| | - Christopher M. Hadad
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18 Avenue, Columbus Ohio 43210
| | - Robert C. Spitale
- Department of Pharmaceutical Sciences, University of California, Irvine. Irvine, California 92697
- Department of Chemistry, University of California, Irvine. Irvine, California 92697
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20
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Zhai Q, Fu Z, Hong Y, Yu X, Han Q, Lu K, Li H, Dou X, Zhu C, Liu J, Lin J, Li G. iTRAQ-Based Comparative Proteomic Analysis of Adult Schistosoma japonicum from Water Buffalo and Yellow Cattle. Front Microbiol 2018; 9:99. [PMID: 29467732 PMCID: PMC5808103 DOI: 10.3389/fmicb.2018.00099] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 01/16/2018] [Indexed: 01/08/2023] Open
Abstract
Schistosomiasis japonicum is one of the most severe zoonotic diseases in China. Water buffalo and yellow cattle are important reservoir hosts and the main transmission sources of Schistosoma japonicum in endemic areas. The susceptibility of these two hosts to schistosome infection is different, as water buffaloes are less susceptible to S. japonicum than yellow cattle. In this study, iTRAQ-coupled LC-MS/MS was applied to compare the protein expression profiles of adult schistosomes recovered from water buffalo with those of yellow cattle. A total of 131 differentially expressed proteins (DEPs) were identified, including 46 upregulated proteins and 85 downregulated proteins. The iTRAQ results were confirmed by Western blotting and quantitative real-time PCR. Further analysis indicated that these DEPs were primarily involved in protein synthesis, transcriptional regulation, protein proteolysis, cytoskeletal structure and oxidative stress response processes. The results revealed that some of the differential expression molecules may affect the development and survival of schistosomes in these two natural hosts. Of note, this study provides useful information for understanding the interplay between schistosomes and their final hosts.
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Affiliation(s)
- Qi Zhai
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Zhiqiang Fu
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Yang Hong
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Xingang Yu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Qian Han
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Ke Lu
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Hao Li
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Xuefeng Dou
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Chuangang Zhu
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Jinming Liu
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Jiaojiao Lin
- Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Guoqing Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
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21
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Chen C, Zhou S, Cai Y, Tang F. Nucleic acid aptamer application in diagnosis and therapy of colorectal cancer based on cell-SELEX technology. NPJ Precis Oncol 2017; 1:37. [PMID: 29872716 PMCID: PMC5871892 DOI: 10.1038/s41698-017-0041-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 10/17/2017] [Accepted: 10/19/2017] [Indexed: 12/20/2022] Open
Abstract
Nucleic acid aptamers are a class of high-affinity nucleic acid ligands. They serve as “chemical antibodies” since their high affinity and specificity. Nucleic acid aptamers are generated from nucleic acid random-sequence using a systematic evolution of ligands by exponential enrichment (SELEX) technology. SELEX is a process of effectively selecting aptamers from different targets. A newly developed cell-based SELEX technique has been widely used in biomarker discovery, early diagnosis and targeted cancer therapy, particular at colorectal cancer (CRC). Combined with nanostructures, nano-aptamer-drug delivery system was constructed for drug delivery. Various nanostructures functionalized with aptamers are highly efficient and has been used in CRC therapeutic applications. In the present, we introduce a cell- SELEX technique, and summarize the potential application of aptamers as biomarkers in CRC diagnosis and therapy. And some characteristics of aptamer-targeted nanocarriers in CRC have been expatiated. The challenges and perspectives for cell-SELEX are also discussed.
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Affiliation(s)
- Chan Chen
- 1Clinical Laboratory and Medical Research Center, Zhuhai Hospital of Jinan University, Zhuhai People's Hospital, 519000 Zhuhai, Guangdong China
| | - Shan Zhou
- 1Clinical Laboratory and Medical Research Center, Zhuhai Hospital of Jinan University, Zhuhai People's Hospital, 519000 Zhuhai, Guangdong China
| | - Yongqiang Cai
- 1Clinical Laboratory and Medical Research Center, Zhuhai Hospital of Jinan University, Zhuhai People's Hospital, 519000 Zhuhai, Guangdong China
| | - Faqing Tang
- 1Clinical Laboratory and Medical Research Center, Zhuhai Hospital of Jinan University, Zhuhai People's Hospital, 519000 Zhuhai, Guangdong China.,2Clinical Laboratory, Hunan Cancer Hospital & The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, 410006 Changsha, China
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22
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Yeh CS, Chang SL, Chen JH, Wang HK, Chou YC, Wang CH, Huang SH, Larson A, Pleiss JA, Chang WH, Chang TH. The conserved AU dinucleotide at the 5' end of nascent U1 snRNA is optimized for the interaction with nuclear cap-binding-complex. Nucleic Acids Res 2017; 45:9679-9693. [PMID: 28934473 PMCID: PMC5766165 DOI: 10.1093/nar/gkx608] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/05/2017] [Indexed: 11/13/2022] Open
Abstract
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. This led to the unexpected findings that the AU dinucleotide dictates the optimal binding of cap-binding complex (CBC) to the 5' end of the nascent U1 snRNA, which ultimately influences the utilization of U1 snRNP in splicing. Our data also provide a structural interpretation as to why the AU dinucleotide is conserved during evolution.
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Affiliation(s)
- Chung-Shu Yeh
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.,Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | | | - Jui-Hui Chen
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Hsuan-Kai Wang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan.,Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei, Taiwan
| | - Yue-Chang Chou
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | | | - Shih-Hsin Huang
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan.,Chemical Biology and Molecular Biophysics program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
| | - Amy Larson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Jeffrey A Pleiss
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Wei-Hau Chang
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan
| | - Tien-Hsien Chang
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.,Genomics Research Center, Academia Sinica, Taipei, Taiwan
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23
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Catania F. From intronization to intron loss: How the interplay between mRNA-associated processes can shape the architecture and the expression of eukaryotic genes. Int J Biochem Cell Biol 2017; 91:136-144. [PMID: 28673893 DOI: 10.1016/j.biocel.2017.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 06/25/2017] [Accepted: 06/30/2017] [Indexed: 12/29/2022]
Abstract
Transcription-coupled processes such as capping, splicing, and cleavage/polyadenylation participate in the journey from genes to proteins. Although they are traditionally thought to serve only as steps in the generation of mature mRNAs, a synthesis of available data indicates that these processes could also act as a driving force for the evolution of eukaryotic genes. A theoretical framework for how mRNA-associated processes may shape gene structure and expression has recently been proposed. Factors that promote splicing and cleavage/polyadenylation in this framework compete for access to overlapping or neighboring signals throughout the transcription cycle. These antagonistic interactions allow mechanisms for intron gain and splice site recognition as well as common trends in eukaryotic gene structure and expression to be coherently integrated. Here, I extend this framework further. Observations that largely (but not exclusively) revolve around the formation of DNA-RNA hybrid structures, called R loops, and promoter directionality are integrated. Additionally, the interplay between splicing factors and cleavage/polyadenylation factors is theorized to also affect the formation of intragenic DNA double-stranded breaks thereby contributing to intron loss. The most notable prediction in this proposition is that RNA molecules can mediate intron loss by serving as a template to repair DNA double-stranded breaks. The framework presented here leverages a vast body of empirical observations, logically extending previous suggestions, and generating verifiable predictions to further substantiate the view that the intracellular environment plays an active role in shaping the structure and the expression of eukaryotic genes.
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Affiliation(s)
- Francesco Catania
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstraße 1, 48149 Münster, Germany.
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24
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Abstract
More than 15% of all disease-causing mutations result in mRNA splicing defects. U1 snRNA binds to the 5' splice site (5'ss) through base pairing. Mutation-adapted U1 snRNA (with compensatory U1 snRNA changes) and exon-specific U1 snRNA (complementary to intronic sequences) have been shown to suppress 5'ss mutations in cellular and animal models. Areas covered: The history, mechanism of action, and efficacy of U1 snRNA-mediated gene therapy are covered. The clinical utility of this technology and its limitations will be discussed. Expert commentary: Recently, gene therapies with mutation-adapted U1 snRNAs have been conducted on animal models, including aromatic l-amino acid decarboxylase deficiency and spinal muscular atrophy. However, although U1-mediated therapy has the advantage of maintaining the regulated expression of defective genes, its accuracy and efficacy needs to be improved before clinical application of this technique is possible.
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Affiliation(s)
- Wuh-Liang Hwu
- a Department of Pediatrics and Medical Genetics , National Taiwan University Hospital and National Taiwan University College of Medicine , Taipei , Taiwan
| | - Yu-May Lee
- a Department of Pediatrics and Medical Genetics , National Taiwan University Hospital and National Taiwan University College of Medicine , Taipei , Taiwan
| | - Ni-Chung Lee
- a Department of Pediatrics and Medical Genetics , National Taiwan University Hospital and National Taiwan University College of Medicine , Taipei , Taiwan
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25
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mRNA-Associated Processes and Their Influence on Exon-Intron Structure in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2016; 6:1617-26. [PMID: 27172210 PMCID: PMC4889658 DOI: 10.1534/g3.116.029231] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
mRNA-associated processes and gene structure in eukaryotes are typically treated as separate research subjects. Here, we bridge this separation and leverage the extensive multidisciplinary work on Drosophila melanogaster to examine the roles that capping, splicing, cleavage/polyadenylation, and telescripting (i.e., the protection of nascent transcripts from premature cleavage/polyadenylation by the splicing factor U1) might play in shaping exon-intron architecture in protein-coding genes. Our findings suggest that the distance between subsequent internal 5′ splice sites (5′ss) in Drosophila genes is constrained such that telescripting effects are maximized, in theory, and thus nascent transcripts are less vulnerable to premature termination. Exceptionally weak 5′ss and constraints on intron-exon size at the gene 5′ end also indicate that capping might enhance the recruitment of U1 and, in turn, promote telescripting at this location. Finally, a positive correlation between last exon length and last 5′ss strength suggests that optimal donor splice sites in the proximity of the pre-mRNA tail may inhibit the processing of downstream polyadenylation signals more than weak donor splice sites do. These findings corroborate and build upon previous experimental and computational studies on Drosophila genes. They support the possibility, hitherto scantly explored, that mRNA-associated processes impose significant constraints on the evolution of eukaryotic gene structure.
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26
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Selection preserves Ubiquitin Specific Protease 4 alternative exon skipping in therian mammals. Sci Rep 2016; 6:20039. [PMID: 26833277 PMCID: PMC4735762 DOI: 10.1038/srep20039] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 12/23/2015] [Indexed: 01/03/2023] Open
Abstract
Ubiquitin specific protease 4 (USP4) is a highly networked deubiquitinating enzyme with reported roles in cancer, innate immunity and RNA splicing. In mammals it has two dominant isoforms arising from inclusion or skipping of exon 7 (E7). We evaluated two plausible mechanisms for the generation of these isoforms: (A) E7 skipping due to a long upstream intron and (B) E7 skipping due to inefficient 5′ splice sites (5′SS) and/or branchpoint sites (BPS). We then assessed whether E7 alternative splicing is maintained by selective pressure or arose from genetic drift. Both transcript variants were generated from a USP4-E7 minigene construct with short flanking introns, an observation consistent with the second mechanism whereby differential splice signal strengths are the basis of E7 skipping. Optimization of the downstream 5′SS eliminated E7 skipping. Experimental validation of the correlation between 5′SS identity and exon skipping in vertebrates pinpointed the +6 site as the key splicing determinant. Therian mammals invariably display a 5′SS configuration favouring alternative splicing and the resulting isoforms have distinct subcellular localizations. We conclude that alternative splicing of mammalian USP4 is under selective maintenance and that long and short USP4 isoforms may target substrates in various cellular compartments.
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27
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Becerra S, Andrés-León E, Prieto-Sánchez S, Hernández-Munain C, Suñé C. Prp40 and early events in splice site definition. WILEY INTERDISCIPLINARY REVIEWS-RNA 2015; 7:17-32. [PMID: 26494226 DOI: 10.1002/wrna.1312] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 09/18/2015] [Accepted: 09/22/2015] [Indexed: 12/14/2022]
Abstract
The alternative splicing (AS) of precursor messenger RNA (pre-mRNA) is a tightly regulated process through which introns are removed to leave the resulting exons in the mRNA appropriately aligned and ligated. The AS of pre-mRNA is a key mechanism for increasing the complexity of proteins encoded in the genome. In humans, more than 90% of genes undergo AS, underscoring the importance of this process in RNA biogenesis. As such, AS misregulation underlies multiple human diseases. The splicing reaction is catalyzed by the spliceosome, a highly dynamic complex that assembles at or near the intron/exon boundaries and undergoes sequential conformational and compositional changes during splicing. The initial recognition of splice sites defines the exons that are going to be removed, which is a critical step in the highly regulated splicing process. Although the available lines of evidence are increasing, the molecular mechanisms governing AS, including the initial interactions occurring at intron/exon boundaries, and the factors that modulate these critical connections by functioning as a scaffold for active-site RNAs or proteins, remain poorly understood. In this review, we summarize the major hallmarks of the initial steps in the splicing process and the role of auxiliary factors that contribute to the assembly of the spliceosomal complex. We also discuss the role of the essential yeast Prp40 protein and its mammalian homologs in the specificity of this pre-mRNA processing event. In addition, we provide the first exhaustive phylogenetic analysis of the molecular evolution of Prp40 family members. WIREs RNA 2016, 7:17-32. doi: 10.1002/wrna.1312 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Soraya Becerra
- Department of Molecular Biology, Instituto de Parasitología y Biomedicina "López Neyra", Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), PTS Granada 18016, Spain
| | - Eduardo Andrés-León
- Bioinformatics Unit, Instituto de Parasitología y Biomedicina "López Neyra", Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), PTS Granada 18016, Spain
| | - Silvia Prieto-Sánchez
- Department of Molecular Biology, Instituto de Parasitología y Biomedicina "López Neyra", Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), PTS Granada 18016, Spain
| | - Cristina Hernández-Munain
- Department of Cell Biology and Immunology, Instituto de Parasitología y Biomedicina "López Neyra", Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), PTS Granada 18016, Spain
| | - Carlos Suñé
- Department of Molecular Biology, Instituto de Parasitología y Biomedicina "López Neyra", Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), PTS Granada 18016, Spain
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28
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Abstract
Precursor messenger RNA (pre-mRNA) splicing is a critical step in the posttranscriptional regulation of gene expression, providing significant expansion of the functional proteome of eukaryotic organisms with limited gene numbers. Split eukaryotic genes contain intervening sequences or introns disrupting protein-coding exons, and intron removal occurs by repeated assembly of a large and highly dynamic ribonucleoprotein complex termed the spliceosome, which is composed of five small nuclear ribonucleoprotein particles, U1, U2, U4/U6, and U5. Biochemical studies over the past 10 years have allowed the isolation as well as compositional, functional, and structural analysis of splicing complexes at distinct stages along the spliceosome cycle. The average human gene contains eight exons and seven introns, producing an average of three or more alternatively spliced mRNA isoforms. Recent high-throughput sequencing studies indicate that 100% of human genes produce at least two alternative mRNA isoforms. Mechanisms of alternative splicing include RNA-protein interactions of splicing factors with regulatory sites termed silencers or enhancers, RNA-RNA base-pairing interactions, or chromatin-based effects that can change or determine splicing patterns. Disease-causing mutations can often occur in splice sites near intron borders or in exonic or intronic RNA regulatory silencer or enhancer elements, as well as in genes that encode splicing factors. Together, these studies provide mechanistic insights into how spliceosome assembly, dynamics, and catalysis occur; how alternative splicing is regulated and evolves; and how splicing can be disrupted by cis- and trans-acting mutations leading to disease states. These findings make the spliceosome an attractive new target for small-molecule, antisense, and genome-editing therapeutic interventions.
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Affiliation(s)
- Yeon Lee
- Center for RNA Systems Biology; Division of Biochemistry, Biophysics, and Structural Biology; Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3204;
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29
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Abstract
A high-resolution structure reveals how the ribonucleoprotein particle called U1 snRNP engages with 5′ splice sites.
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Affiliation(s)
- Timothy W Nilsen
- Center for RNA Molecular Biology, Case Western Reserve University, Cleveland, United States
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30
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Kondo Y, Oubridge C, van Roon AMM, Nagai K. Crystal structure of human U1 snRNP, a small nuclear ribonucleoprotein particle, reveals the mechanism of 5' splice site recognition. eLife 2015; 4. [PMID: 25555158 PMCID: PMC4383343 DOI: 10.7554/elife.04986] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/06/2014] [Indexed: 12/12/2022] Open
Abstract
U1 snRNP binds to the 5′ exon-intron junction of pre-mRNA and thus plays a
crucial role at an early stage of pre-mRNA splicing. We present two crystal
structures of engineered U1 sub-structures, which together reveal at atomic
resolution an almost complete network of protein–protein and RNA-protein
interactions within U1 snRNP, and show how the 5′ splice site of pre-mRNA is
recognised by U1 snRNP. The zinc-finger of U1-C interacts with the duplex between
pre-mRNA and the 5′-end of U1 snRNA. The binding of the RNA duplex is
stabilized by hydrogen bonds and electrostatic interactions between U1-C and the RNA
backbone around the splice junction but U1-C makes no base-specific contacts with
pre-mRNA. The structure, together with RNA binding assays, shows that the selection
of 5′-splice site nucleotides by U1 snRNP is achieved predominantly through
basepairing with U1 snRNA whilst U1-C fine-tunes relative affinities of mismatched
5′-splice sites. DOI:http://dx.doi.org/10.7554/eLife.04986.001 Genes are made up of long stretches of DNA. The regions of a gene that code for
proteins (known as exons) are interrupted by stretches of non-coding DNA called
introns. To produce proteins from a gene, the DNA is ‘transcribed’ to
form pre-mRNA molecules, from which the introns must be removed in a process called
splicing. The remaining exons are then joined together to form a mature mRNA molecule
that contains the instructions to build a protein. Errors in the splicing process can
lead to numerous diseases, such as cancer. A molecular machine known as a spliceosome is responsible for splicing the pre-mRNA
molecules. This consists of five different complexes called small nuclear
ribonucleoprotein particles (snRNPs), which are in turn made up from numerous
proteins and RNA molecules. The spliceosome assembles anew every time it splices, and
an early step in this assembly process involves the interaction of an snRNP called U1
with the start of an intron in the pre-mRNA. This interaction then stimulates the
assembly of the rest of the spliceosome. In 2009, researchers reported the structure
of the U1 snRNP, but the structure did not contain enough detail to reveal how the
snRNP recognizes the start of an intron. Kondo, Oubridge et al., including some of the researchers involved in the 2009 work,
now present the crystal structure of the human version of the U1 snRNP in more
detail. High-quality crystal structures of the complete U1 snRNP molecule could not
be obtained because the arrangement of the RNA molecules in the snRNP prevented a
regular crystal from forming. Kondo, Oubridge et al. instead engineered two
subcomponents of U1 snRNP that each crystallized well, and determined their
structures. This revealed that the interactions between the various parts of the U1
snRNP form a complex network. A protein present in the U1 snRNP, known as U1-C, had previously been reported to be
able to recognize introns on its own—without requiring the complete U1 snRNP.
Kondo, Oubridge et al. reveal that this is not the case and that U1-C does not read
the intron RNA sequence directly. Instead, U1 snRNP is able to find the start of the
intron because the U1 RNA can stably bind to this site. The U1-C protein can however
adjust the strength of this binding to ensure that the spliceosome can operate with a
variety of intron start sequences (or signals). DOI:http://dx.doi.org/10.7554/eLife.04986.002
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Affiliation(s)
- Yasushi Kondo
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Chris Oubridge
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Anne-Marie M van Roon
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Kiyoshi Nagai
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
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31
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Burroughs AM, Aravind L. Analysis of two domains with novel RNA-processing activities throws light on the complex evolution of ribosomal RNA biogenesis. Front Genet 2014; 5:424. [PMID: 25566315 PMCID: PMC4275035 DOI: 10.3389/fgene.2014.00424] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 11/19/2014] [Indexed: 11/13/2022] Open
Abstract
Ribosomal biogenesis has been extensively investigated, especially to identify the elusive nucleases and cofactors involved in the complex rRNA processing events in eukaryotes. Large-scale screens in yeast identified two biochemically uncharacterized proteins, TSR3 and TSR4, as being key players required for rRNA maturation. Using multiple computational approaches we identify the conserved domains comprising these proteins and establish sequence and structural features providing novel insights regarding their roles. TSR3 is unified with the DTW domain into a novel superfamily of predicted enzymatic domains, with the balance of the available evidence pointing toward an RNase role with the archaeo-eukaryotic TSR3 proteins processing rRNA and the bacterial versions potentially processing tRNA. TSR4, its other eukaryotic homologs PDCD2/rp-8, PDCD2L, Zfrp8, and trus, the predominantly bacterial DUF1963 proteins, and other uncharacterized proteins are unified into a new domain superfamily, which arose from an ancient duplication event of a strand-swapped, dimer-forming all-beta unit. We identify conserved features mediating protein-protein interactions (PPIs) and propose a potential chaperone-like function. While contextual evidence supports a conserved role in ribosome biogenesis for the eukaryotic TSR4-related proteins, there is no evidence for such a role for the bacterial versions. Whereas TSR3-related proteins can be traced to the last universal common ancestor (LUCA) with a well-supported archaeo-eukaryotic branch, TSR4-related proteins of eukaryotes are derived from within the bacterial radiation of this superfamily, with archaea entirely lacking them. This provides evidence for “systems admixture,” which followed the early endosymbiotic event, playing a key role in the emergence of the uniquely eukaryotic ribosome biogenesis process.
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Affiliation(s)
- A Maxwell Burroughs
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health Bethesda, MD, USA
| | - L Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health Bethesda, MD, USA
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32
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Meher PK, Sahu TK, Rao AR, Wahi SD. A statistical approach for 5' splice site prediction using short sequence motifs and without encoding sequence data. BMC Bioinformatics 2014; 15:362. [PMID: 25420551 PMCID: PMC4702320 DOI: 10.1186/s12859-014-0362-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Accepted: 10/24/2014] [Indexed: 11/17/2022] Open
Abstract
Background Most of the approaches for splice site prediction are based on machine learning techniques. Though, these approaches provide high prediction accuracy, the window lengths used are longer in size. Hence, these approaches may not be suitable to predict the novel splice variants using the short sequence reads generated from next generation sequencing technologies. Further, machine learning techniques require numerically encoded data and produce different accuracy with different encoding procedures. Therefore, splice site prediction with short sequence motifs and without encoding sequence data became a motivation for the present study. Results An approach for finding association among nucleotide bases in the splice site motifs is developed and used further to determine the appropriate window size. Besides, an approach for prediction of donor splice sites using sum of absolute error criterion has also been proposed. The proposed approach has been compared with commonly used approaches i.e., Maximum Entropy Modeling (MEM), Maximal Dependency Decomposition (MDD), Weighted Matrix Method (WMM) and Markov Model of first order (MM1) and was found to perform equally with MEM and MDD and better than WMM and MM1 in terms of prediction accuracy. Conclusions The proposed prediction approach can be used in the prediction of donor splice sites with higher accuracy using short sequence motifs and hence can be used as a complementary method to the existing approaches. Based on the proposed methodology, a web server was also developed for easy prediction of donor splice sites by users and is available at http://cabgrid.res.in:8080/sspred. Electronic supplementary material The online version of this article (doi:10.1186/s12859-014-0362-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Prabina Kumar Meher
- Division of Statistical Genetics, Indian Agricultural Statistics Research Institute, New Delhi, 110012, India.
| | - Tanmaya Kumar Sahu
- Centre for Agricultural Bioinformatics, Indian Agricultural Statistics Research Institute, New Delhi, 110012, India.
| | - Atmakuri Ramakrishna Rao
- Centre for Agricultural Bioinformatics, Indian Agricultural Statistics Research Institute, New Delhi, 110012, India.
| | - Sant Dass Wahi
- Division of Statistical Genetics, Indian Agricultural Statistics Research Institute, New Delhi, 110012, India.
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33
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Chan SL, Huppertz I, Yao C, Weng L, Moresco JJ, Yates JR, Ule J, Manley JL, Shi Y. CPSF30 and Wdr33 directly bind to AAUAAA in mammalian mRNA 3' processing. Genes Dev 2014; 28:2370-80. [PMID: 25301780 PMCID: PMC4215182 DOI: 10.1101/gad.250993.114] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
AAUAAA is the most highly conserved motif in eukaryotic mRNA polyadenylation sites and, in mammals, is specifically recognized by the multisubunit CPSF complex. Chan et al. found that CPSF subunits CPSF30 and Wdr33 directly contact AAUAAA. The CPSF30–RNA interaction is essential for mRNA 3′ processing and is primarily mediated by its zinc fingers 2 and 3, which are specifically targeted by the influenza protein NS1A to suppress host mRNA 3′ processing. AAUAAA is the most highly conserved motif in eukaryotic mRNA polyadenylation sites and, in mammals, is specifically recognized by the multisubunit CPSF (cleavage and polyadenylation specificity factor) complex. Despite its critical functions in mRNA 3′ end formation, the molecular basis for CPSF–AAUAAA interaction remains poorly defined. The CPSF subunit CPSF160 has been implicated in AAUAAA recognition, but direct evidence has been lacking. Using in vitro and in vivo assays, we unexpectedly found that CPSF subunits CPSF30 and Wdr33 directly contact AAUAAA. Importantly, the CPSF30–RNA interaction is essential for mRNA 3′ processing and is primarily mediated by its zinc fingers 2 and 3, which are specifically targeted by the influenza protein NS1A to suppress host mRNA 3′ processing. Our data suggest that AAUAAA recognition in mammalian mRNA 3′ processing is more complex than previously thought and involves multiple protein–RNA interactions.
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Affiliation(s)
- Serena L Chan
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California at Irvine, Irvine, California 92697, USA
| | - Ina Huppertz
- Department of Molecular Neuroscience, University College London Institute of Neurology, London WC1N 3BG, United Kingdom; Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Chengguo Yao
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California at Irvine, Irvine, California 92697, USA
| | - Lingjie Weng
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California at Irvine, Irvine, California 92697, USA; Institute for Genomics and Bioinformatics, Department of Computer Science, University of California at Irvine Irvine, California 92697, USA
| | - James J Moresco
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - John R Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Jernej Ule
- Department of Molecular Neuroscience, University College London Institute of Neurology, London WC1N 3BG, United Kingdom; Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Yongsheng Shi
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California at Irvine, Irvine, California 92697, USA
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34
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Guiro J, O'Reilly D. Insights into the U1 small nuclear ribonucleoprotein complex superfamily. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 6:79-92. [DOI: 10.1002/wrna.1257] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 06/17/2014] [Accepted: 07/14/2014] [Indexed: 12/12/2022]
Affiliation(s)
- J Guiro
- Institute of Biosciences; University of Sao Paulo; Sao Paulo Brazil
| | - D O'Reilly
- Sir William Dunn School of Pathology; Oxford United Kingdom
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35
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Li W, Kuzoff R, Wong CK, Tucker A, Lynch M. Characterization of newly gained introns in Daphnia populations. Genome Biol Evol 2014; 6:2218-34. [PMID: 25123113 PMCID: PMC4202315 DOI: 10.1093/gbe/evu174] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
As one of the few known species in an active phase of intron proliferation, the microcrustacean Daphnia pulex is an especially attractive system for interrogating the gain and loss of introns in natural populations. In this study, we used a comparative population-genomic approach to identify and characterize 90 recently gained introns in this species. Molecular clock analyses indicate that these introns arose between 3.9 × 10(5) and 1.45 × 10(4) years ago, with a spike in intron proliferation approximately 5.2 × 10(4) to 1.22 × 10(5) years ago. Parallel gains at homologous positions contribute to 47.8% (43/90) of discovered new introns. A disproportionally large number of new introns were found in historically isolated populations in Oregon. Nonetheless, derived, intron-bearing alleles were also identified in a wide range of geographic locations, suggesting intron gain and, to a lesser degree, intron loss are important sources of genetic variation in natural populations of Daphnia. A majority (55/90 or 61.1%) of the identified neointrons have associated internal direct repeats with lengths and compositions that are unlikely to occur by chance, suggesting repeated bouts of staggered double-strand breaks (DSBs) during their evolution. Accordingly, internal, staggered DSBs may contribute to a passive trend toward increased length and sequence diversity in nascent introns.
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Affiliation(s)
- Wenli Li
- Department of Pediatrics, Section of Genomic Pediatrics, Medical College of Wisconsin
| | - Robert Kuzoff
- Department of Biology, University of Wisconsin-Whitewater
| | - Chen Khuan Wong
- Genetics and Genomics Program, Department of Medicine, Boston University
| | | | - Michael Lynch
- Department of Biology, Indiana University, Bloomington
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Abstract
In this work we review the current knowledge on the prehistory, origins, and evolution of spliceosomal introns. First, we briefly outline the major features of the different types of introns, with particular emphasis on the nonspliceosomal self-splicing group II introns, which are widely thought to be the ancestors of spliceosomal introns. Next, we discuss the main scenarios proposed for the origin and proliferation of spliceosomal introns, an event intimately linked to eukaryogenesis. We then summarize the evidence that suggests that the last eukaryotic common ancestor (LECA) had remarkably high intron densities and many associated characteristics resembling modern intron-rich genomes. From this intron-rich LECA, the different eukaryotic lineages have taken very distinct evolutionary paths leading to profoundly diverged modern genome structures. Finally, we discuss the origins of alternative splicing and the qualitative differences in alternative splicing forms and functions across lineages.
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Affiliation(s)
- Manuel Irimia
- The Donnelly Centre, University of Toronto, Toronto, Ontario M5S3E1, Canada
| | - Scott William Roy
- Department of Biology, San Francisco State University, San Francisco, California 94132
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Paronetto M, Bernardis I, Volpe E, Bechara E, Sebestyén E, Eyras E, Valcárcel J. Regulation of FAS Exon Definition and Apoptosis by the Ewing Sarcoma Protein. Cell Rep 2014; 7:1211-26. [DOI: 10.1016/j.celrep.2014.03.077] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 02/16/2014] [Accepted: 03/31/2014] [Indexed: 12/18/2022] Open
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Preußer C, Rossbach O, Hung LH, Li D, Bindereif A. Genome-wide RNA-binding analysis of the trypanosome U1 snRNP proteins U1C and U1-70K reveals cis/trans-spliceosomal network. Nucleic Acids Res 2014; 42:6603-15. [PMID: 24748659 PMCID: PMC4041458 DOI: 10.1093/nar/gku286] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Trans-splicing in trypanosomes adds a 39-nucleotide mini-exon from the spliced leader (SL) RNA to the 5′ end of each protein-coding sequence. On the other hand, cis-splicing of the few intron-containing genes requires the U1 small nuclear ribonucleoprotein (snRNP) particle. To search for potential new functions of the U1 snRNP in Trypanosoma brucei, we applied genome-wide individual-nucleotide resolution crosslinking-immunoprecipitation (iCLIP), focusing on the U1 snRNP-specific proteins U1C and U1-70K. Surprisingly, U1C and U1-70K interact not only with the U1, but also with U6 and SL RNAs. In addition, mapping of crosslinks to the cis-spliced PAP [poly(A) polymerase] pre-mRNA indicate an active role of these proteins in 5′ splice site recognition. In sum, our results demonstrate that the iCLIP approach provides insight into stable and transient RNA–protein contacts within the spliceosomal network. We propose that the U1 snRNP may represent an evolutionary link between the cis- and trans-splicing machineries, playing a dual role in 5′ splice site recognition on the trans-spliceosomal SL RNP as well as on pre-mRNA cis-introns.
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Affiliation(s)
- Christian Preußer
- Institute of Biochemistry, Justus Liebig University of Giessen, D-35392 Giessen, Germany
| | - Oliver Rossbach
- Institute of Biochemistry, Justus Liebig University of Giessen, D-35392 Giessen, Germany
| | - Lee-Hsueh Hung
- Institute of Biochemistry, Justus Liebig University of Giessen, D-35392 Giessen, Germany
| | - Dan Li
- Institute of Biochemistry, Justus Liebig University of Giessen, D-35392 Giessen, Germany
| | - Albrecht Bindereif
- Institute of Biochemistry, Justus Liebig University of Giessen, D-35392 Giessen, Germany
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39
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Abstract
One of the most amazing findings in molecular biology was the discovery that eukaryotic genes are discontinuous, with coding DNA being interrupted by stretches of non-coding sequence. The subsequent realization that the intervening regions are removed from pre-mRNA transcripts via the activity of a common set of small nuclear RNAs (snRNAs), which assemble together with associated proteins into a complex known as the spliceosome, was equally surprising. How do cells coordinate the assembly of this molecular machine? And how does the spliceosome accurately recognize exons and introns to carry out the splicing reaction? Insights into these questions have been gained by studying the life cycle of spliceosomal snRNAs from their transcription, nuclear export and re-import to their dynamic assembly into the spliceosome. This assembly process can also affect the regulation of alternative splicing and has implications for human disease.
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Affiliation(s)
- A Gregory Matera
- Department of Biology, Department of Genetics and Integrative Program for Biological and Genome Sciences, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Zefeng Wang
- Department of Pharmacology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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40
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Schwer B, Shuman S. Structure-function analysis of the Yhc1 subunit of yeast U1 snRNP and genetic interactions of Yhc1 with Mud2, Nam8, Mud1, Tgs1, U1 snRNA, SmD3 and Prp28. Nucleic Acids Res 2014; 42:4697-711. [PMID: 24497193 PMCID: PMC3985668 DOI: 10.1093/nar/gku097] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Yhc1 and U1C are homologous essential subunits of the yeast and human U1 snRNP, respectively, that are implicated in the establishment and stability of the complex of U1 bound to the pre-mRNA 5′ splice site (5′SS). Here, we conducted a mutational analysis of Yhc1, guided by the U1C NMR structure and low-resolution crystal structure of human U1 snRNP. The N-terminal 170-amino acid segment of the 231-amino acid Yhc1 polypeptide sufficed for vegetative growth. Although changing the zinc-binding residue Cys6 to alanine was lethal, alanines at zinc-binding residues Cys9, His24 and His30 were not. Benign alanine substitutions at conserved surface residues elicited mutational synergies with other splicing components. YHC1-R21A was synthetically lethal in the absence of Mud2 and synthetically sick in the absence of Nam8, Mud1 and Tgs1 or in the presence of variant U1 snRNAs. YHC1 alleles K28A, Y12A, T14A, K22A and H15A displayed a progressively narrower range of synergies. R21A and K28A bypassed the essentiality of DEAD-box protein Prp28, suggesting that they affected U1•5′SS complex stability. Yhc1 Arg21 fortifies the U1•5′SS complex via contacts with SmD3 residues Glu37/Asp38, mutations of which synergized with mud2Δ and bypassed prp28Δ. YHC1-(1-170) was synthetically lethal with mutations of all components interrogated, with the exception of Nam8.
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Affiliation(s)
- Beate Schwer
- Microbiology and Immunology Department, Weill Cornell Medical College, New York, NY 10065, USA and Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
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Sad1 counteracts Brr2-mediated dissociation of U4/U6.U5 in tri-snRNP homeostasis. Mol Cell Biol 2013; 34:210-20. [PMID: 24190974 DOI: 10.1128/mcb.00837-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The yeast Sad1 protein was previously identified in a screen for factors involved in the assembly of the U4/U6 di-snRNP particle. Sad1 is required for pre-mRNA splicing both in vivo and in vitro, and its human orthologue has been shown to associate with U4/U6.U5 tri-snRNP. We show here that Sad1 plays a role in maintaining a functional form of the tri-snRNP by promoting the association of U5 snRNP with U4/U6 di-snRNP. In the absence of Sad1, the U4/U6.U5 tri-snRNP dissociates into U5 and U4/U6 upon ATP hydrolysis and cannot bind to the spliceosome. The separated U4/U6 and U5 can reassociate upon incubation more favorably in the absence of ATP and in the presence of Sad1. Brr2 is responsible for mediating ATP-dependent dissociation of the tri-snRNP. Our results demonstrate a role of Sad1 in maintaining the integrity of the tri-snRNP by counteracting Brr2-mediated dissociation of tri-snRNP and provide insights into homeostasis of the tri-snRNP.
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42
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Rösel-Hillgärtner TD, Hung LH, Khrameeva E, Le Querrec P, Gelfand MS, Bindereif A. A novel intra-U1 snRNP cross-regulation mechanism: alternative splicing switch links U1C and U1-70K expression. PLoS Genet 2013; 9:e1003856. [PMID: 24146627 PMCID: PMC3798272 DOI: 10.1371/journal.pgen.1003856] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 08/21/2013] [Indexed: 11/18/2022] Open
Abstract
The U1 small nuclear ribonucleoprotein (snRNP)-specific U1C protein participates in 5′ splice site recognition and regulation of pre-mRNA splicing. Based on an RNA-Seq analysis in HeLa cells after U1C knockdown, we found a conserved, intra-U1 snRNP cross-regulation that links U1C and U1-70K expression through alternative splicing and U1 snRNP assembly. To investigate the underlying regulatory mechanism, we combined mutational minigene analysis, in vivo splice-site blocking by antisense morpholinos, and in vitro binding experiments. Alternative splicing of U1-70K pre-mRNA creates the normal (exons 7–8) and a non-productive mRNA isoform, whose balance is determined by U1C protein levels. The non-productive isoform is generated through a U1C-dependent alternative 3′ splice site, which requires an adjacent cluster of regulatory 5′ splice sites and binding of intact U1 snRNPs. As a result of nonsense-mediated decay (NMD) of the non-productive isoform, U1-70K mRNA and protein levels are down-regulated, and U1C incorporation into the U1 snRNP is impaired. U1-70K/U1C-deficient particles are assembled, shifting the alternative splicing balance back towards productive U1-70K splicing, and restoring assembly of intact U1 snRNPs. Taken together, we established a novel feedback regulation that controls U1-70K/U1C homeostasis and ensures correct U1 snRNP assembly and function. The accurate removal of intervening sequences (introns) from precursor messenger RNAs (pre-mRNAs) represents an essential step in the expression of most eukaryotic protein-coding genes. Alternative splicing can create from a single primary transcript various mature mRNAs with diverse, sometimes even antagonistic, biological functions. Many human diseases are based on alternative-splicing defects, and most interestingly, certain defects are caused by mutations in general splicing factors that participate in each splicing event. To address the question of how a general splicing factor can regulate alternative splicing events, here we investigated the regulatory role of the U1C protein, a specific component of the U1 small nuclear ribonucleoprotein (snRNP) and important in initial 5′ splice site recognition. Our RNA-Seq analysis demonstrated that U1C affects more than 300 cases of alternative splicing in the human system. One U1C target, U1-70K, appeared to be particularly interesting, because both protein products are components of the U1 snRNP and functionally depend on each other. Analyzing the mechanistic basis of this intra-U1 snRNP cross-regulation, we discovered a U1C-dependent alternative splicing switch in the U1-70K pre-mRNA that regulates U1-70K expression. In sum, this feedback loop controls and links U1C and U1-70K homeostasis to guarantee correct U1 snRNP assembly and function.
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Affiliation(s)
| | - Lee-Hsueh Hung
- Institute of Biochemistry, Justus Liebig University of Giessen, Giessen, Germany
| | - Ekaterina Khrameeva
- Kharkevich Institute for Information Transmission Problems, RAS, Moscow, Russia
- Lomonosov Moscow State University, Department of Bioengineering and Bioinformatics, Moscow, Russia
| | - Patrick Le Querrec
- Institute of Biochemistry, Justus Liebig University of Giessen, Giessen, Germany
| | - Mikhail S. Gelfand
- Kharkevich Institute for Information Transmission Problems, RAS, Moscow, Russia
- Lomonosov Moscow State University, Department of Bioengineering and Bioinformatics, Moscow, Russia
| | - Albrecht Bindereif
- Institute of Biochemistry, Justus Liebig University of Giessen, Giessen, Germany
- * E-mail:
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43
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Roca X, Krainer AR, Eperon IC. Pick one, but be quick: 5' splice sites and the problems of too many choices. Genes Dev 2013; 27:129-44. [PMID: 23348838 DOI: 10.1101/gad.209759.112] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Splice site selection is fundamental to pre-mRNA splicing and the expansion of genomic coding potential. 5' Splice sites (5'ss) are the critical elements at the 5' end of introns and are extremely diverse, as thousands of different sequences act as bona fide 5'ss in the human transcriptome. Most 5'ss are recognized by base-pairing with the 5' end of the U1 small nuclear RNA (snRNA). Here we review the history of research on 5'ss selection, highlighting the difficulties of establishing how base-pairing strength determines splicing outcomes. We also discuss recent work demonstrating that U1 snRNA:5'ss helices can accommodate noncanonical registers such as bulged duplexes. In addition, we describe the mechanisms by which other snRNAs, regulatory proteins, splicing enhancers, and the relative positions of alternative 5'ss contribute to selection. Moreover, we discuss mechanisms by which the recognition of numerous candidate 5'ss might lead to selection of a single 5'ss and propose that protein complexes propagate along the exon, thereby changing its physical behavior so as to affect 5'ss selection.
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Affiliation(s)
- Xavier Roca
- School of Biological Sciences, Division of Molecular Genetics and Cell Biology, Nanyang Technological University, Singapore.
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44
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Yang F, Wang XY, Zhang ZM, Pu J, Fan YJ, Zhou J, Query CC, Xu YZ. Splicing proofreading at 5' splice sites by ATPase Prp28p. Nucleic Acids Res 2013; 41:4660-70. [PMID: 23462954 PMCID: PMC3632134 DOI: 10.1093/nar/gkt149] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Fidelity and efficiency of pre-mRNA splicing are critical for generating functional mRNAs, but how such accuracy in 5′ splice site (SS) selection is attained is not fully clear. Through a series of yeast genetic screens, we isolated alleles of prp28 that improve splicing of suboptimal 5′SS substrates, demonstrating that WT-Prp28p proofreads, and consequently rejects, poor 5′SS. Prp28p is thought to facilitate the disruption of 5′SS–U1 snRNA pairing to allow for 5′SS–U6 snRNA pairing in the catalytic spliceosome; unexpectedly, 5′SS proofreading by Prp28p is dependent on competition with the stability of the 5′SS:U6 duplex, but not the 5′SS:U1 duplex. E404K, the strongest prp28 allele containing a mutation located in the linker region between adenosine triphosphatase (ATPase) subdomains, exhibited lower RNA-binding activity and enhanced splicing of suboptimal substrates before first-step catalysis, suggesting that decreased Prp28p activity allows longer time for suboptimal 5′SS substrates to pair with U6 snRNA and thereby reduces splicing fidelity. Residue E404 is critical for providing high splicing activity, demonstrated here in both yeast and Drosophila cells. Thus, the subdomain linker in Prp28p plays important roles both in splicing efficiency across species and in proofreading of 5′SS.
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Affiliation(s)
- Fei Yang
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
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45
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Coelho Ribeiro MDL, Espinosa J, Islam S, Martinez O, Thanki JJ, Mazariegos S, Nguyen T, Larina M, Xue B, Uversky VN. Malleable ribonucleoprotein machine: protein intrinsic disorder in the Saccharomyces cerevisiae spliceosome. PeerJ 2013; 1:e2. [PMID: 23638354 PMCID: PMC3628832 DOI: 10.7717/peerj.2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 12/01/2012] [Indexed: 12/29/2022] Open
Abstract
Recent studies revealed that a significant fraction of any given proteome is presented by proteins that do not have unique 3D structures as a whole or in significant parts. These intrinsically disordered proteins possess dramatic structural and functional variability, being especially enriched in signaling and regulatory functions since their lack of fixed structure defines their ability to be involved in interaction with several proteins and allows them to be re-used in multiple pathways. Among recognized disorder-based protein functions are interactions with nucleic acids and multi-target binding; i.e., the functions ascribed to many spliceosomal proteins. Therefore, the spliceosome, a multimegadalton ribonucleoprotein machine catalyzing the excision of introns from eukaryotic pre-mRNAs, represents an attractive target for the focused analysis of the abundance and functionality of intrinsic disorder in its proteinaceous components. In yeast cells, spliceosome consists of five small nuclear RNAs (U1, U2, U4, U5, and U6) and a range of associated proteins. Some of these proteins constitute cores of the corresponding snRNA-protein complexes known as small nuclear ribonucleoproteins (snRNPs). Other spliceosomal proteins have various auxiliary functions. To gain better understanding of the functional roles of intrinsic disorder, we have studied the prevalence of intrinsically disordered proteins in the yeast spliceosome using a wide array of bioinformatics methods. Our study revealed that similar to the proteins associated with human spliceosomes (Korneta & Bujnicki, 2012), proteins found in the yeast spliceosome are enriched in intrinsic disorder.
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Affiliation(s)
- Maria de Lourdes Coelho Ribeiro
- Cancer Imaging Metabolism, H. Lee Moffitt Cancer Center & Research Institute , United States ; Department of Molecular Medicine, University of South Florida , Tampa, Florida , United States
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46
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Koonin EV, Csuros M, Rogozin IB. Whence genes in pieces: reconstruction of the exon-intron gene structures of the last eukaryotic common ancestor and other ancestral eukaryotes. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 4:93-105. [PMID: 23139082 DOI: 10.1002/wrna.1143] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In eukaryotes, protein-coding sequences are interrupted by non-coding sequences known as introns. During mRNA maturation, introns are excised by the spliceosome and the coding regions, exons, are spliced to form the mature coding region. The intron densities widely differ between eukaryotic lineages, from 6 to 7 introns per kb of coding sequence in vertebrates, some invertebrates and green plants, to only a few introns across the entire genome in many unicellular eukaryotes. Evolutionary reconstructions using maximum likelihood methods suggest intron-rich ancestors for each major group of eukaryotes. For the last common ancestor of animals, the highest intron density of all extant and extinct eukaryotes was inferred, at 120-130% of the human intron density. Furthermore, an intron density within 53-74% of the human values was inferred for the last eukaryotic common ancestor. Accordingly, evolution of eukaryotic genes in all lines of descent involved primarily intron loss, with substantial gain only at the bases of several branches including plants and animals. These conclusions have substantial biological implications indicating that the common ancestor of all modern eukaryotes was a complex organism with a gene architecture resembling those in multicellular organisms. Alternative splicing most likely initially appeared as an inevitable result of splicing errors and only later was employed to generate structural and functional diversification of proteins.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information NLM/NIH, Bethesda, MD, USA.
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47
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Abstract
RNA splicing is one of the fundamental processes in gene expression in eukaryotes. Splicing of pre-mRNA is catalysed by a large ribonucleoprotein complex called the spliceosome, which consists of five small nuclear RNAs and numerous protein factors. The spliceosome is a highly dynamic structure, assembled by sequential binding and release of the small nuclear RNAs and protein factors. DExD/H-box RNA helicases are required to mediate structural changes in the spliceosome at various steps in the assembly pathway and have also been implicated in the fidelity control of the splicing reaction. Other proteins also play key roles in mediating the progression of the spliceosome pathway. In this review, we discuss the functional roles of the protein factors involved in the spliceosome pathway primarily from studies in the yeast system.
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48
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O'Reilly D, Dienstbier M, Cowley SA, Vazquez P, Drozdz M, Taylor S, James WS, Murphy S. Differentially expressed, variant U1 snRNAs regulate gene expression in human cells. Genome Res 2012; 23:281-91. [PMID: 23070852 PMCID: PMC3561869 DOI: 10.1101/gr.142968.112] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Human U1 small nuclear (sn)RNA, required for splicing of pre-mRNA, is encoded by genes on chromosome 1 (1p36). Imperfect copies of these U1 snRNA genes, also located on chromosome 1 (1q12-21), were thought to be pseudogenes. However, many of these "variant" (v)U1 snRNA genes produce fully processed transcripts. Using antisense oligonucleotides to block the activity of a specific vU1 snRNA in HeLa cells, we have identified global transcriptome changes following interrogation of the Affymetrix Human Exon ST 1.0 array. Our results indicate that this vU1 snRNA regulates expression of a subset of target genes at the level of pre-mRNA processing. This is the first indication that variant U1 snRNAs have a biological function in vivo. Furthermore, some vU1 snRNAs are packaged into unique ribonucleoproteins (RNPs), and many vU1 snRNA genes are differentially expressed in human embryonic stem cells (hESCs) and HeLa cells, suggesting developmental control of RNA processing through expression of different sets of vU1 snRNPs.
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Affiliation(s)
- Dawn O'Reilly
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
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49
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Roca X, Akerman M, Gaus H, Berdeja A, Bennett CF, Krainer AR. Widespread recognition of 5' splice sites by noncanonical base-pairing to U1 snRNA involving bulged nucleotides. Genes Dev 2012; 26:1098-109. [PMID: 22588721 DOI: 10.1101/gad.190173.112] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
An established paradigm in pre-mRNA splicing is the recognition of the 5' splice site (5'ss) by canonical base-pairing to the 5' end of U1 small nuclear RNA (snRNA). We recently reported that a small subset of 5'ss base-pair to U1 in an alternate register that is shifted by 1 nucleotide. Using genetic suppression experiments in human cells, we now demonstrate that many other 5'ss are recognized via noncanonical base-pairing registers involving bulged nucleotides on either the 5'ss or U1 RNA strand, which we term "bulge registers." By combining experimental evidence with transcriptome-wide free-energy calculations of 5'ss/U1 base-pairing, we estimate that 10,248 5'ss (∼5% of human 5'ss) in 6577 genes use bulge registers. Several of these 5'ss occur in genes with mutations causing genetic diseases and are often associated with alternative splicing. These results call for a redefinition of an essential element for gene expression that incorporates these registers, with important implications for the molecular classification of splicing mutations and for alternative splicing.
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Affiliation(s)
- Xavier Roca
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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50
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De Conti L, Skoko N, Buratti E, Baralle M. Complexities of 5'splice site definition: implications in clinical analyses. RNA Biol 2012; 9:911-23. [PMID: 22617876 DOI: 10.4161/rna.20386] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
In higher eukaryotes, the 5' splice site (5'ss) is initially recognized through an RNA-RNA interaction by U1 small nuclear ribonucleoprotein (U1 snRNP). This event represents one of the key steps in initial spliceosomal assembly and many disease-associated mutations in humans often disrupt this process. Beside base pair complementarity, 5'ss recognition can also be modified by additional factors such as RNA secondary structures or the specific binding of other nuclear proteins. In this work, we have focused on investigating a few examples of changes detected within the 5'ss in patients, that would not be immediately considered "disease causing mutations". We show that the splicing outcome of very similar mutations can be very different due to variations in trans-acting factor(s) interactions and specific context influences. Using several NF1 donor sites and SELEX approaches as experimental models, we have examined the binding properties of particular sequence motifs such as GGGU found in donor sites, and how the sequence context can change their interaction with hnRNPs such as H/F and A1/A2. Our results clearly show that even minor differences in local nucleotide context can differentially affect the binding ability of these factors to the GGGU core. Finally, using a previously identified mutation in KCNH2 that resulted in intron retention we show how very similar 5'ss mutations found in patients can have a very different splicing outcome due to the neighbouring sequence context, thus highlighting the general need to approach splicing problems with suitable experimental approaches.
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Affiliation(s)
- Laura De Conti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
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