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Jafari SH, Lajevardi ZS, Zamani Fard MM, Jafari A, Naghavi S, Ravaei F, Taghavi SP, Mosadeghi K, Zarepour F, Mahjoubin-Tehran M, Rahimian N, Mirzaei H. Imaging Techniques and Biochemical Biomarkers: New Insights into Diagnosis of Pancreatic Cancer. Cell Biochem Biophys 2024:10.1007/s12013-024-01437-z. [PMID: 39026059 DOI: 10.1007/s12013-024-01437-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2024] [Indexed: 07/20/2024]
Abstract
Pancreatic cancer (PaC) incidence is increasing, but our current screening and diagnostic strategies are not very effective. However, screening could be helpful in the case of PaC, as recent evidence shows that the disease progresses gradually. Unfortunately, there is no ideal screening method or program for detecting PaC in its early stages. Conventional imaging techniques, such as abdominal ultrasound, CT, MRI, and EUS, have not been successful in detecting early-stage PaC. On the other hand, biomarkers may be a more effective screening tool for PaC and have greater potential for further evaluation compared to imaging. Recent studies on biomarkers and artificial intelligence (AI)-enhanced imaging have shown promising results in the early diagnosis of PaC. In addition to proteins, non-coding RNAs are also being studied as potential biomarkers for PaC. This review consolidates the current literature on PaC screening modalities to provide an organized framework for future studies. While conventional imaging techniques have not been effective in detecting early-stage PaC, biomarkers and AI-enhanced imaging are promising avenues of research. Further studies on the use of biomarkers, particularly non-coding RNAs, in combination with imaging modalities may improve the accuracy of PaC screening and lead to earlier detection of this deadly disease.
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Affiliation(s)
- Seyed Hamed Jafari
- Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Radiology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zahra Sadat Lajevardi
- School of Medicine, Kashan University of Medical Sciences, Kashan, Iran
- Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | - Mohammad Masoud Zamani Fard
- School of Medicine, Kashan University of Medical Sciences, Kashan, Iran
- Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | - Ameneh Jafari
- Chronic Respiratory Diseases Research Center, NRITLD, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Soroush Naghavi
- Student Research Committee, Iran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Ravaei
- School of Medicine, Kashan University of Medical Sciences, Kashan, Iran
- Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | - Seyed Pouya Taghavi
- School of Medicine, Kashan University of Medical Sciences, Kashan, Iran
- Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | - Kimia Mosadeghi
- School of Medicine, Kashan University of Medical Sciences, Kashan, Iran
- Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | - Fatemeh Zarepour
- School of Medicine, Kashan University of Medical Sciences, Kashan, Iran
- Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran
| | | | - Neda Rahimian
- Endocrine Research Center, Institute of Endocrinology and Metabolism, Iran University of Medical Sciences (IUMS), Tehran, Iran; Department of Internal Medicine, School of Medicine, Firoozgar Hospital, Iran University of Medical Sciences, Tehran, Iran.
| | - Hamed Mirzaei
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Iran.
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2
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Veenstra BT, Veenstra TD. Proteomic applications in identifying protein-protein interactions. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 138:1-48. [PMID: 38220421 DOI: 10.1016/bs.apcsb.2023.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
There are many things that can be used to characterize a protein. Size, isoelectric point, hydrophobicity, structure (primary to quaternary), and subcellular location are just a few parameters that are used. The most important feature of a protein, however, is its function. While there are many experiments that can indicate a protein's role, identifying the molecules it interacts with is probably the most definitive way of determining its function. Owing to technology limitations, protein interactions have historically been identified on a one molecule per experiment basis. The advent of high throughput multiplexed proteomic technologies in the 1990s, however, made identifying hundreds and thousands of proteins interactions within single experiments feasible. These proteomic technologies have dramatically increased the rate at which protein-protein interactions (PPIs) are discovered. While the improvement in mass spectrometry technology was an early driving force in the rapid pace of identifying PPIs, advances in sample preparation and chromatography have recently been propelling the field. In this chapter, we will discuss the importance of identifying PPIs and describe current state-of-the-art technologies that demonstrate what is currently possible in this important area of biological research.
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Affiliation(s)
- Benjamin T Veenstra
- Department of Math and Sciences, Cedarville University, Cedarville, OH, United States
| | - Timothy D Veenstra
- School of Pharmacy, Cedarville University, Cedarville, OH, United States.
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3
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Díaz Casas A, Cordoba JJ, Ferrer BJ, Balakrishnan S, Wurm JE, Pastrana‐Ríos B, Chazin WJ. Binding by calmodulin is coupled to transient unfolding of the third FF domain of Prp40A. Protein Sci 2023; 32:e4606. [PMID: 36810829 PMCID: PMC10022492 DOI: 10.1002/pro.4606] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 02/16/2023] [Accepted: 02/18/2023] [Indexed: 02/24/2023]
Abstract
Human pre-mRNA processing protein 40 homolog A (hPrp40A) is a splicing factor that interacts with the Huntington's disease protein huntingtin (Htt). Evidence has accumulated that both Htt and hPrp40A are modulated by the intracellular Ca2+ sensor calmodulin (CaM). Here we report characterization of the interaction of human CM with the third FF domain (FF3 ) of hPrp40A using calorimetric, fluorescence and structural approaches. Homology modeling, differential scanning calorimetry and small angle X-ray scattering (SAXS) data show FF3 forms a folded globular domain. CaM was found to bind FF3 in a Ca2+ -dependent manner with a 1:1 stoichiometry and a dissociation constant (Kd ) of 25 ± 3 μM at 25°C. NMR studies showed that both domains of CaM are engaged in binding and SAXS analysis of the FF3 -CaM complex revealed CaM occupies an extended configuration. Analysis of the FF3 sequence showed that the anchors for CaM binding must be buried in its hydrophobic core, suggesting that binding to CaM requires unfolding of FF3 . Trp anchors were proposed based on sequence analysis and confirmed by intrinsic Trp fluorescence of FF3 upon binding of CaM and substantial reductions in affinity for Trp-Ala FF3 mutants. The consensus model of the complex showed that binding to CaM binding occurs to an extended, non-globular state of the FF3 , consistent with coupling to transient unfolding of the domain. The implications of these results are discussed in the context of the complex interplay of Ca2+ signaling and Ca2+ sensor proteins in modulating Prp40A-Htt function.
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Affiliation(s)
- A. Díaz Casas
- Department of BiochemistryVanderbilt UniversityNashvilleTennesseeUSA
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
- Present address:
Department of Natural SciencesPontifical Catholic University of Puerto RicoPoncePuerto RicoUSA
| | - J. J. Cordoba
- Department of BiochemistryVanderbilt UniversityNashvilleTennesseeUSA
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
- Chemical and Physical Biology Graduate ProgramVanderbilt UniversityNashvilleTennesseeUSA
| | - B. J. Ferrer
- Department of BiochemistryVanderbilt UniversityNashvilleTennesseeUSA
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
- Chemical and Physical Biology Graduate ProgramVanderbilt UniversityNashvilleTennesseeUSA
| | - S. Balakrishnan
- Department of BiochemistryVanderbilt UniversityNashvilleTennesseeUSA
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
| | - J. E. Wurm
- Chemical and Physical Biology Graduate ProgramVanderbilt UniversityNashvilleTennesseeUSA
| | - B. Pastrana‐Ríos
- Department of ChemistryUniversity of Puerto Rico, Mayagüez CampusMayagüezPuerto RicoUSA
| | - W. J. Chazin
- Department of BiochemistryVanderbilt UniversityNashvilleTennesseeUSA
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
- Chemical and Physical Biology Graduate ProgramVanderbilt UniversityNashvilleTennesseeUSA
- Department of ChemistryVanderbilt UniversityNashvilleTennesseeUSA
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4
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Stepien A, Dolata J, Gulanicz T, Bielewicz D, Bajczyk M, Smolinski DJ, Szweykowska-Kulinska Z, Jarmolowski A. Chromatin-associated microprocessor assembly is regulated by the U1 snRNP auxiliary protein PRP40. THE PLANT CELL 2022; 34:4920-4935. [PMID: 36087009 PMCID: PMC9709975 DOI: 10.1093/plcell/koac278] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 09/05/2022] [Indexed: 06/01/2023]
Abstract
In plants, microRNA (miRNA) biogenesis involves cotranscriptional processing of RNA polymerase II (RNAPII)-generated primary transcripts by a multi-protein complex termed the microprocessor. Here, we report that Arabidopsis (Arabidopsis thaliana) PRE-MRNA PROCESSING PROTEIN 40 (PRP40), the U1 snRNP auxiliary protein, positively regulates the recruitment of SERRATE, a core component of the plant microprocessor, to miRNA genes. The association of DICER-LIKE1 (DCL1), the microprocessor endoribonuclease, with chromatin was altered in prp40ab mutant plants. Impaired cotranscriptional microprocessor assembly was accompanied by RNAPII accumulation at miRNA genes and retention of miRNA precursors at their transcription sites in the prp40ab mutant plants. We show that cotranscriptional microprocessor assembly, regulated by AtPRP40, positively affects RNAPII transcription of miRNA genes and is important to reach the correct levels of produced miRNAs.
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Affiliation(s)
| | | | | | | | - Mateusz Bajczyk
- Department of Gene Expression, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan 61-614, Poland
| | - Dariusz J Smolinski
- Department of Cellular and Molecular Biology, Nicolaus Copernicus University, Torun 87-100, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Torun 87-100, Poland
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5
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Jamal QMS, Alharbi AH. Molecular docking and dynamics studies of cigarette smoke carcinogens interacting with acetylcholinesterase and butyrylcholinesterase enzymes of the central nervous system. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:61972-61992. [PMID: 34382170 DOI: 10.1007/s11356-021-15269-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
The free radicals produced by cigarette smoking are responsible for tissue damage, heart and lung diseases, and carcinogenesis. The effect of tobacco on the central nervous system (CNS) has received increased attention nowadays in research. Therefore, to explore the molecular interaction of cigarette smoke carcinogens (CSC) 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanol (NNAL), 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone (NNK), and N'-nitrosonornicotine (NNN) with well-known targets of CNS-related disorders, acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) enzymes, a cascade of the computational study was conducted including molecular docking and molecular dynamics simulations (MDS). The investigated results of NNAL+AChEcomplex, NNK+AChEcomplex, and NNK+BuChEcomplex based on intermolecular energies (∆G) were found to -8.57 kcal/mol, -8.21 kcal/mol, and -8.08 kcal/mol, respectively. MDS deviation and fluctuation plots of the NNAL and NNK interaction with AChE and BuChE have shown significant results. Further, Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) results shown the best total binding energy (Binding∆G) -87.381 (+/-13.119) kJ/mol during NNK interaction with AChE. Our study suggests that CSC is well capable of altering the normal biomolecular mechanism of CNS; thus, obtained data could be useful to design extensive wet laboratory experimentation to know the effects of CSC on human CNS.
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Affiliation(s)
- Qazi Mohammad Sajid Jamal
- Department of Health Informatics, College of Public Health and Health Informatics, Qassim University, Al Bukayriyah, Saudi Arabia.
| | - Ali H Alharbi
- Department of Health Informatics, College of Public Health and Health Informatics, Qassim University, Al Bukayriyah, Saudi Arabia
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6
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Rashmi R, Majumdar S. Pan-Cancer Analysis Reveals the Prognostic Potential of the THAP9/THAP9-AS1 Sense-Antisense Gene Pair in Human Cancers. Noncoding RNA 2022; 8:ncrna8040051. [PMID: 35893234 PMCID: PMC9326536 DOI: 10.3390/ncrna8040051] [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: 04/05/2022] [Revised: 06/11/2022] [Accepted: 06/13/2022] [Indexed: 11/18/2022] Open
Abstract
Human THAP9, which encodes a domesticated transposase of unknown function, and lncRNA THAP9-AS1 (THAP9-antisense1) are arranged head-to-head on opposite DNA strands, forming a sense and antisense gene pair. We predict that there is a bidirectional promoter that potentially regulates the expression of THAP9 and THAP9-AS1. Although both THAP9 and THAP9-AS1 are reported to be involved in various cancers, their correlative roles on each other’s expression has not been explored. We analyzed the expression levels, prognosis, and predicted biological functions of the two genes across different cancer datasets (TCGA, GTEx). We observed that although the expression levels of the two genes, THAP9 and THAP9-AS1, varied in different tumors, the expression of the gene pair was strongly correlated with patient prognosis; higher expression of the gene pair was usually linked to poor overall and disease-free survival. Thus, THAP9 and THAP9-AS1 may serve as potential clinical biomarkers of tumor prognosis. Further, we performed a gene co-expression analysis (using WGCNA) followed by a differential gene correlation analysis (DGCA) across 22 cancers to identify genes that share the expression pattern of THAP9 and THAP9-AS1. Interestingly, in both normal and cancer samples, THAP9 and THAP9-AS1 often co-express; moreover, their expression is positively correlated in each cancer type, suggesting the coordinated regulation of this H2H gene pair.
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7
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Borao S, Ayté J, Hümmer S. Evolution of the Early Spliceosomal Complex-From Constitutive to Regulated Splicing. Int J Mol Sci 2021; 22:ijms222212444. [PMID: 34830325 PMCID: PMC8624252 DOI: 10.3390/ijms222212444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/15/2021] [Accepted: 11/16/2021] [Indexed: 12/14/2022] Open
Abstract
Pre-mRNA splicing is a major process in the regulated expression of genes in eukaryotes, and alternative splicing is used to generate different proteins from the same coding gene. Splicing is a catalytic process that removes introns and ligates exons to create the RNA sequence that codifies the final protein. While this is achieved in an autocatalytic process in ancestral group II introns in prokaryotes, the spliceosome has evolved during eukaryogenesis to assist in this process and to finally provide the opportunity for intron-specific splicing. In the early stage of splicing, the RNA 5' and 3' splice sites must be brought within proximity to correctly assemble the active spliceosome and perform the excision and ligation reactions. The assembly of this first complex, termed E-complex, is currently the least understood process. We focused in this review on the formation of the E-complex and compared its composition and function in three different organisms. We highlight the common ancestral mechanisms in S. cerevisiae, S. pombe, and mammals and conclude with a unifying model for intron definition in constitutive and regulated co-transcriptional splicing.
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Affiliation(s)
- Sonia Borao
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain;
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain;
- Correspondence: (J.A.); (S.H.)
| | - Stefan Hümmer
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain;
- Translational Molecular Pathology, Vall d’Hebron Research Institute (VHIR), CIBERONC, 08035 Barcelona, Spain
- Correspondence: (J.A.); (S.H.)
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8
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Hümmer S, Borao S, Guerra-Moreno A, Cozzuto L, Hidalgo E, Ayté J. Cross talk between the upstream exon-intron junction and Prp2 facilitates splicing of non-consensus introns. Cell Rep 2021; 37:109893. [PMID: 34706246 DOI: 10.1016/j.celrep.2021.109893] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 04/27/2021] [Accepted: 10/06/2021] [Indexed: 10/20/2022] Open
Abstract
Splicing of mRNA precursors is essential in the regulation of gene expression. U2AF65 recognizes the poly-pyrimidine tract and helps in the recognition of the branch point. Inactivation of fission yeast U2AF65 (Prp2) blocks splicing of most, but not all, pre-mRNAs, for reasons that are not understood. Here, we have determined genome-wide the splicing efficiency of fission yeast cells as they progress into synchronous meiosis in the presence or absence of functional Prp2. Our data indicate that in addition to the splicing elements at the 3' end of any intron, the nucleotides immediately upstream the intron will determine whether Prp2 is required or dispensable for splicing. By changing those nucleotides in any given intron, we regulate its Prp2 dependency. Our results suggest a model in which Prp2 is required for the coordinated recognition of both intronic ends, placing Prp2 as a key regulatory element in the determination of the exon-intron boundaries.
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Affiliation(s)
- Stefan Hümmer
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain.
| | - Sonia Borao
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Angel Guerra-Moreno
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Luca Cozzuto
- CRG Bioinformatics Core, Centre de Regulació Genòmica (CRG), 08003 Barcelona, Spain
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain.
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9
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Wang Y, Zhang S, Sun Q, Yuan F, Zhao L, Ye Z, Li Y, Wang R, Jiang H, Hu P, Tian D, Liu B. WAC, a novel GBM tumor suppressor, induces GBM cell apoptosis and promotes autophagy. Med Oncol 2021; 38:132. [PMID: 34581882 DOI: 10.1007/s12032-021-01580-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 09/12/2021] [Indexed: 10/20/2022]
Abstract
WAC is closely related to the occurrence and development of tumors. However, its role in human glioblastoma (GBM) and its potential regulatory mechanisms have not been investigated. This study demonstrated that WAC is downregulated in GBM, and its low expression predicts a poor prognosis. We investigated the effect of WAC on the proliferation of glioma cells through a CCK-8 assay, EdU incorporation, and cell formation. The effects of WAC on apoptosis and autophagy in glioma were determined by flow cytometry, TUNEL detection, immunofluorescence, q-PCR, WB, and scanning electron microscopy. We found that overexpression of WAC inhibited the proliferation of glioma cells, promoted apoptosis, and induced autophagy. Therefore, WAC is likely to play a role as a new regulatory molecule in glioma.
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Affiliation(s)
- Yixuan Wang
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 238 Jiefang Street, Wuhan, 430060, Hubei, China.,Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China
| | - Si Zhang
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 238 Jiefang Street, Wuhan, 430060, Hubei, China.,Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China
| | - Qian Sun
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 238 Jiefang Street, Wuhan, 430060, Hubei, China.,Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China
| | - Fan'en Yuan
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 238 Jiefang Street, Wuhan, 430060, Hubei, China.,Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China
| | - Linyao Zhao
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 238 Jiefang Street, Wuhan, 430060, Hubei, China.,Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China
| | - Zhang Ye
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 238 Jiefang Street, Wuhan, 430060, Hubei, China.,Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China
| | - Yong Li
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 238 Jiefang Street, Wuhan, 430060, Hubei, China.,Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China
| | - Ronggui Wang
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 238 Jiefang Street, Wuhan, 430060, Hubei, China.,Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China
| | - Hongxiang Jiang
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 238 Jiefang Street, Wuhan, 430060, Hubei, China.,Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China
| | - Ping Hu
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 238 Jiefang Street, Wuhan, 430060, Hubei, China.,Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China
| | - Daofeng Tian
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 238 Jiefang Street, Wuhan, 430060, Hubei, China. .,Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China.
| | - Baohui Liu
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 238 Jiefang Street, Wuhan, 430060, Hubei, China. .,Central Laboratory, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China.
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10
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Choudhary B, Marx O, Norris AD. Spliceosomal component PRP-40 is a central regulator of microexon splicing. Cell Rep 2021; 36:109464. [PMID: 34348142 PMCID: PMC8378409 DOI: 10.1016/j.celrep.2021.109464] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/31/2021] [Accepted: 07/08/2021] [Indexed: 02/07/2023] Open
Abstract
Microexons (≤27 nt) play critical roles in nervous system development and function but create unique challenges for the splicing machinery. The mechanisms of microexon regulation are therefore of great interest. We performed a genetic screen for alternative splicing regulators in the C. elegans nervous system and identify PRP-40, a core component of the U1 snRNP. RNA-seq reveals that PRP-40 is required for inclusion of alternatively spliced, but not constitutively spliced, exons. PRP-40 is particularly required for inclusion of neuronal microexons, and our data indicate that PRP-40 is a central regulator of microexon splicing. Microexons can be relieved from PRP-40 dependence by artificially increasing exon size or reducing flanking intron size, indicating that PRP-40 is specifically required for microexons surrounded by conventionally sized introns. Knockdown of the orthologous PRPF40A in mouse neuroblastoma cells causes widespread dysregulation of microexons but not conventionally sized exons. PRP-40 regulation of neuronal microexons is therefore a widely conserved phenomenon.
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Affiliation(s)
- Bikash Choudhary
- Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA
| | - Olivia Marx
- Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA
| | - Adam D Norris
- Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA.
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11
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Yeh FL, Chang SL, Ahmed GR, Liu HI, Tung L, Yeh CS, Lanier LS, Maeder C, Lin CM, Tsai SC, Hsiao WY, Chang WH, Chang TH. Activation of Prp28 ATPase by phosphorylated Npl3 at a critical step of spliceosome remodeling. Nat Commun 2021; 12:3082. [PMID: 34035302 PMCID: PMC8149812 DOI: 10.1038/s41467-021-23459-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 04/29/2021] [Indexed: 11/10/2022] Open
Abstract
Splicing, a key step in the eukaryotic gene-expression pathway, converts precursor messenger RNA (pre-mRNA) into mRNA by excising introns and ligating exons. This task is accomplished by the spliceosome, a macromolecular machine that must undergo sequential conformational changes to establish its active site. Each of these major changes requires a dedicated DExD/H-box ATPase, but how these enzymes are activated remain obscure. Here we show that Prp28, a yeast DEAD-box ATPase, transiently interacts with the conserved 5' splice-site (5'SS) GU dinucleotide and makes splicing-dependent contacts with the U1 snRNP protein U1C, and U4/U6.U5 tri-snRNP proteins, Prp8, Brr2, and Snu114. We further show that Prp28's ATPase activity is potentiated by the phosphorylated Npl3, but not the unphosphorylated Npl3, thus suggesting a strategy for regulating DExD/H-box ATPases. We propose that Npl3 is a functional counterpart of the metazoan-specific Prp28 N-terminal region, which can be phosphorylated and serves as an anchor to human spliceosome.
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Affiliation(s)
- Fu-Lung Yeh
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | | | | | - Hsin-I Liu
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Luh Tung
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Chung-Shu Yeh
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Leah Stands Lanier
- Department of Biology, Washington and Lee University, Lexington, VA, USA
| | - Corina Maeder
- Department of Chemistry, Trinity University, San Antonio, TX, USA
| | - Che-Min Lin
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Shu-Chun Tsai
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Wan-Yi Hsiao
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
- Institute of Biochemistry and Molecular Biology, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Wei-Hau Chang
- Institute of Chemistry, Academia Sinica, Taipei, Taiwan
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12
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Xiang X, Qiu R. Cargo-Mediated Activation of Cytoplasmic Dynein in vivo. Front Cell Dev Biol 2020; 8:598952. [PMID: 33195284 PMCID: PMC7649786 DOI: 10.3389/fcell.2020.598952] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/07/2020] [Indexed: 12/12/2022] Open
Abstract
Cytoplasmic dynein-1 is a minus-end-directed microtubule motor that transports a variety of cargoes including early endosomes, late endosomes and other organelles. In many cell types, dynein accumulates at the microtubule plus end, where it interacts with its cargo to be moved toward the minus end. Dynein binds to its various cargoes via the dynactin complex and specific cargo adapters. Dynactin and some of the coiled-coil-domain-containing cargo adapters not only link dynein to cargo but also activate dynein motility, which implies that dynein is activated by its cellular cargo. Structural studies indicate that a dynein dimer switches between the autoinhibited phi state and an open state; and the binding of dynactin and a cargo adapter to the dynein tails causes the dynein motor domains to have a parallel configuration, allowing dynein to walk processively along a microtubule. Recently, the dynein regulator LIS1 has been shown to be required for dynein activation in vivo, and its mechanism of action involves preventing dynein from switching back to the autoinhibited state. In this review, we will discuss our current understanding of dynein activation and point out the gaps of knowledge on the spatial regulation of dynein in live cells. In addition, we will emphasize the importance of studying a complete set of dynein regulators for a better understanding of dynein regulation in vivo.
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Affiliation(s)
- Xin Xiang
- Department of Biochemistry and Molecular Biology, The Uniformed Services University of the Health Sciences - F. Edward Hébert School of Medicine, Bethesda, MD, United States
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Qiu R, Zhang J, Xiang X. The splicing-factor Prp40 affects dynein-dynactin function in Aspergillus nidulans. Mol Biol Cell 2020; 31:1289-1301. [PMID: 32267207 PMCID: PMC7353152 DOI: 10.1091/mbc.e20-03-0166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The multi-component cytoplasmic dynein transports cellular cargoes with the help of another multi-component complex dynactin, but we do not know enough about factors that may affect the assembly and functions of these proteins. From a genetic screen for mutations affecting early-endosome distribution in Aspergillus nidulans, we identified the prp40AL438* mutation in Prp40A, a homologue of Prp40, an essential RNA-splicing factor in the budding yeast. Prp40A is not essential for splicing, although it associates with the nuclear splicing machinery. The prp40AL438* mutant is much healthier than the ∆prp40A mutant, but both mutants exhibit similar defects in dynein-mediated early-endosome transport and nuclear distribution. In the prp40AL438* mutant, the frequency but not the speed of dynein-mediated early-endosome transport is decreased, which correlates with a decrease in the microtubule plus-end accumulations of dynein and dynactin. Within the dynactin complex, the actin-related protein Arp1 forms a mini-filament. In a pull-down assay, the amount of Arp1 pulled down with its pointed-end protein Arp11 is lowered in the prp40AL438* mutant. In addition, we found from published interactome data that a mammalian Prp40 homologue PRPF40A interacts with Arp1. Thus, Prp40 homologues may regulate the assembly or function of dynein–dynactin and their mechanisms deserve to be further studied.
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Affiliation(s)
- Rongde Qiu
- Department of Biochemistry and Molecular Biology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Jun Zhang
- Department of Biochemistry and Molecular Biology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Xin Xiang
- Department of Biochemistry and Molecular Biology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
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Prieto-Sánchez S, Moreno-Castro C, Hernández-Munain C, Suñé C. Drosophila Prp40 localizes to the histone locus body and regulates gene transcription and development. J Cell Sci 2020; 133:jcs.239509. [PMID: 32094262 DOI: 10.1242/jcs.239509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 02/09/2020] [Indexed: 12/12/2022] Open
Abstract
In eukaryotes, a large amount of histones need to be synthesized during the S phase of the cell cycle to package newly synthesized DNA into chromatin. The transcription and 3' end processing of histone pre-mRNAs are controlled by the histone locus body (HLB), which is assembled on the shared promoter for H3 and H4 Here, we identified the Drosophila Prp40 pre-mRNA processing factor (dPrp40, annotated as CG3542) as a novel HLB component. We showed that dPrp40 is essential for Drosophila development, with functionally conserved activity in vertebrates and invertebrates. We observed that dPrp40 is fundamental in endocycling cells, highlighting a role for this factor in mediating replication efficiency in vivo The depletion of dPrp40 from fly cells inhibited the transcription, but not the 3' end processing, of histone mRNA in a H3- and H4-promoter-dependent manner. Our results establish that dPrp40 is an essential protein for Drosophila development that can localize to the HLB and might participate in histone mRNA biosynthesis.
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Affiliation(s)
- Silvia Prieto-Sánchez
- Department of Molecular Biology, Institute of Parasitology and Biomedicine "López-Neyra" (IPBLN-CSIC), PTS, 18016 Granada, Spain
| | - Cristina Moreno-Castro
- Department of Molecular Biology, Institute of Parasitology and Biomedicine "López-Neyra" (IPBLN-CSIC), PTS, 18016 Granada, Spain
| | - Cristina Hernández-Munain
- Department of Cell Biology and Immunology, Institute of Parasitology and Biomedicine "López-Neyra" (IPBLN-CSIC), PTS, 18016 Granada, Spain
| | - Carlos Suñé
- Department of Molecular Biology, Institute of Parasitology and Biomedicine "López-Neyra" (IPBLN-CSIC), PTS, 18016 Granada, Spain
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Wu F, Deng L, Zhai Q, Zhao J, Chen Q, Li C. Mediator Subunit MED25 Couples Alternative Splicing of JAZ Genes with Fine-Tuning of Jasmonate Signaling. THE PLANT CELL 2020; 32:429-448. [PMID: 31852773 PMCID: PMC7008490 DOI: 10.1105/tpc.19.00583] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 10/24/2019] [Accepted: 12/16/2019] [Indexed: 05/19/2023]
Abstract
JASMONATE ZIM-DOMAIN (JAZ) transcriptional repressors are key regulators of jasmonate (JA) signaling in plants. At the resting stage, the C-terminal Jas motifs of JAZ proteins bind the transcription factor MYC2 to repress JA signaling. Upon hormone elicitation, the Jas motif binds the hormone receptor CORONATINE INSENSITIVE1, which mediates proteasomal degradation of JAZs and thereby allowing the Mediator subunit MED25 to activate MYC2. Subsequently, plants desensitize JA signaling by feedback generation of dominant JAZ splice variants that repress MYC2. Here we report the mechanistic function of Arabidopsis (Arabidopsis thaliana) MED25 in regulating the alternative splicing of JAZ genes through recruiting the splicing factors PRE-mRNA-PROCESSING PROTEIN 39a (PRP39a) and PRP40a. We demonstrate that JA-induced generation of JAZ splice variants depends on MED25 and that MED25 recruits PRP39a and PRP40a to promote the full splicing of JAZ genes. Therefore, MED25 forms a module with PRP39a and PRP40a to prevent excessive desensitization of JA signaling mediated by JAZ splice variants.
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Affiliation(s)
- Fangming Wu
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Lei Deng
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Qingzhe Zhai
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
- Chinese Academy of Sciences Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiuhai Zhao
- State Key Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Shandong Province, Tai'an 271018, China
| | - Qian Chen
- State Key Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Shandong Province, Tai'an 271018, China
| | - Chuanyou Li
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
- Chinese Academy of Sciences Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
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Lorenzini PA, Chew RSE, Tan CW, Yong JY, Zhang F, Zheng J, Roca X. Human PRPF40B regulates hundreds of alternative splicing targets and represses a hypoxia expression signature. RNA (NEW YORK, N.Y.) 2019; 25:905-920. [PMID: 31088860 PMCID: PMC6633195 DOI: 10.1261/rna.069534.118] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 04/22/2019] [Indexed: 06/09/2023]
Abstract
Altered splicing contributes to the pathogenesis of human blood disorders including myelodysplastic syndromes (MDS) and leukemias. Here we characterize the transcriptomic regulation of PRPF40B, which is a splicing factor mutated in a small fraction of MDS patients. We generated a full PRPF40B knockout (KO) in the K562 cell line by CRISPR/Cas9 technology and rescued its levels by transient overexpression of wild-type (WT), P383L or P540S MDS alleles. Using RNA sequencing, we identified hundreds of differentially expressed genes and alternative splicing (AS) events in the KO that are rescued by WT PRPF40B, with a majority also rescued by MDS alleles, pointing to mild effects of these mutations. Among the PRPF40B-regulated AS events, we found a net increase in exon inclusion in the KO, suggesting that this splicing factor primarily acts as a repressor. PRPF40B-regulated splicing events are likely cotranscriptional, affecting exons with A-rich downstream intronic motifs and weak splice sites especially for 5' splice sites, consistent with its PRP40 yeast ortholog being part of the U1 small nuclear ribonucleoprotein. Loss of PRPF40B in K562 induces a KLF1 transcriptional signature, with genes involved in iron metabolism and mainly hypoxia, including related pathways like cholesterol biosynthesis and Akt/MAPK signaling. A cancer database analysis revealed that PRPF40B is lowly expressed in acute myeloid leukemia, whereas its paralog PRPF40A expression is high as opposed to solid tumors. Furthermore, these factors negatively or positively correlated with hypoxia regulator HIF1A, respectively. Our data suggest a PRPF40B role in repressing hypoxia in myeloid cells, and that its low expression might contribute to leukemogenesis.
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Affiliation(s)
- Paolo Alberto Lorenzini
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore, Singapore
- Nanyang Institute of Technology in Health and Medicine, Interdisciplinary Graduate School (IGS), Nanyang Technological University, 637551 Singapore, Singapore
| | - Resilind Su Ern Chew
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore, Singapore
| | - Cheryl Weiqi Tan
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore, Singapore
| | - Jing Yen Yong
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore, Singapore
| | - Fan Zhang
- School of Computer Science and Engineering, Nanyang Technological University, 637551 Singapore, Singapore
| | - Jie Zheng
- School of Computer Science and Engineering, Nanyang Technological University, 637551 Singapore, Singapore
- School of Information Science and Technology, ShanghaiTech University, Pudong District, Shanghai 201210, China
| | - Xavier Roca
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore, Singapore
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Huo Z, Zhai S, Weng Y, Qian H, Tang X, Shi Y, Deng X, Wang Y, Shen B. PRPF40A as a potential diagnostic and prognostic marker is upregulated in pancreatic cancer tissues and cell lines: an integrated bioinformatics data analysis. Onco Targets Ther 2019; 12:5037-5051. [PMID: 31303762 PMCID: PMC6610298 DOI: 10.2147/ott.s206039] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 05/31/2019] [Indexed: 12/15/2022] Open
Abstract
Background Pre-mRNA processing factor 40 homolog A (PRPF40A) is an important protein involved in pre-mRNA splicing and is expressed in a variety of cell types. However, the function of PRPF40A in pancreatic cancer remains unclear. Therefore, our study is to investigate the role of PRPF40A in the pathogenesis of pancreatic cancer. Materials and methods We extracted expression data and clinical information of PRPF40A from different online databases, including the Cancer Genome Atlas (TCGA), Oncomine and the Gene Expression Omnibus (GEO). Subsequently, samples were collected from patients to validate gene expression using qPCR, Western blotting and immunohistochemical (IHC) analyses. Receiver operating characteristic (ROC) and Kaplan-Meier curve were used to evaluate the diagnostic and prognostic potential. Colony formation assays and CCK-8 assays were performed to measure the proliferative capacity of pancreatic cancer. Finally, gene ontology (GO) and pathway enrichment analyses of co-expressed genes of PRPF40A were conducted using the Database for Annotation, Visualization and Integrated Discovery (DAVID). Results We found that PRPF40A was upregulated based on data from both the online databases and our samples. PRPF40A possessed a significant diagnostic value, and its overexpression was associated with poor prognosis. PRPF40A knockdown inhibited cell proliferation in pancreatic cancer. GO and pathway analysis showed that the co-expressed genes were mainly involved in viral processing, mRNA splicing and the AMPK signaling pathway. Conclusion The results suggest that PRPF40A is an oncogene and can serve as a diagnostic and prognostic biomarker for pancreatic cancer. However, the underlying mechanisms remain to be elucidated.
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Affiliation(s)
- Zhen Huo
- Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China
| | - Shuyu Zhai
- Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China
| | - Yuanchi Weng
- Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China
| | - Hao Qian
- Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China
| | - Xiaomei Tang
- Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China
| | - Yusheng Shi
- Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China
| | - Xiaxing Deng
- Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China
| | - Yue Wang
- Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China
| | - Baiyong Shen
- Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, People's Republic of China
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Hernando CE, García Hourquet M, de Leone MJ, Careno D, Iserte J, Mora Garcia S, Yanovsky MJ. A Role for Pre-mRNA-PROCESSING PROTEIN 40C in the Control of Growth, Development, and Stress Tolerance in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2019; 10:1019. [PMID: 31456814 PMCID: PMC6700278 DOI: 10.3389/fpls.2019.01019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/22/2019] [Indexed: 05/08/2023]
Abstract
Because of their sessile nature, plants have adopted varied strategies for growing and reproducing in an ever-changing environment. Control of mRNA levels and pre-mRNA alternative splicing are key regulatory layers that contribute to adjust and synchronize plant growth and development with environmental changes. Transcription and alternative splicing are thought to be tightly linked and coordinated, at least in part, through a network of transcriptional and splicing regulatory factors that interact with the carboxyl-terminal domain (CTD) of the largest subunit of RNA polymerase II. One of the proteins that has been shown to play such a role in yeast and mammals is pre-mRNA-PROCESSING PROTEIN 40 (PRP40, also known as CA150, or TCERG1). In plants, members of the PRP40 family have been identified and shown to interact with the CTD of RNA Pol II, but their biological functions remain unknown. Here, we studied the role of AtPRP40C, in Arabidopsis thaliana growth, development and stress tolerance, as well as its impact on the global regulation of gene expression programs. We found that the prp40c knockout mutants display a late-flowering phenotype under long day conditions, associated with minor alterations in red light signaling. An RNA-seq based transcriptome analysis revealed differentially expressed genes related to biotic stress responses and also differentially expressed as well as differentially spliced genes associated with abiotic stress responses. Indeed, the characterization of stress responses in prp40c mutants revealed an increased sensitivity to salt stress and an enhanced tolerance to Pseudomonas syringae pv. maculicola (Psm) infections. This constitutes the most thorough analysis of the transcriptome of a prp40 mutant in any organism, as well as the first characterization of the molecular and physiological roles of a member of the PRP40 protein family in plants. Our results suggest that PRP40C is an important factor linking the regulation of gene expression programs to the modulation of plant growth, development, and stress responses.
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Díaz Casas A, Casanova Sepúlveda G, Sánchez Negrón O, Caro Muñiz AP, Malavé Ramos SR, Cebollero López AR, Pastrana-Ríos B. Molecular biophysical characterization of the third FF domain of Homo sapiens Prp40 homolog A. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.04.059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Pre-mRNA processing protein 40 (Prp40) is a nuclear protein that has a role in pre-mRNA splicing. Prp40 possesses two leucine-rich nuclear export signals, but little is known about the function of Prp40 in the export process. Another protein that has a role in protein export is centrin, a member of the EF-hand superfamily of Ca2+-binding proteins. Prp40 was found to be a centrin target by yeast-two-hybrid screening using both Homo sapiens centrin 2 (Hscen2) and Chlamydomonas reinhardtii centrin (Crcen). We identified a centrin-binding site within H. sapiens Prp40 homolog A (HsPrp40A), which contains a hydrophobic triad W1L4L8 that is known to be important in the interaction with centrin. This centrin-binding site is highly conserved within the first nuclear export signal consensus sequence identified in Saccharomyces cerevisiae Prp40. Here, we examine the interaction of HsPrp40A peptide (HsPrp40Ap) with both Hscen2 and Crcen by isothermal titration calorimetry. We employed the thermodynamic parameterization to estimate the polar and apolar surface area of the interface. In addition, we have defined the molecular mechanism of thermally induced unfolding and dissociation of the Crcen-HsPrp40Ap complex using two-dimensional infrared correlation spectroscopy. These complementary techniques showed for the first time, to our knowledge, that HsPrp40Ap interacts with centrin in vitro, supporting a coupled functional role for these proteins in pre-mRNA splicing.
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Workflow for Genome-Wide Determination of Pre-mRNA Splicing Efficiency from Yeast RNA-seq Data. BIOMED RESEARCH INTERNATIONAL 2016; 2016:4783841. [PMID: 28050562 PMCID: PMC5168555 DOI: 10.1155/2016/4783841] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/02/2016] [Indexed: 11/17/2022]
Abstract
Pre-mRNA splicing represents an important regulatory layer of eukaryotic gene expression. In the simple budding yeast Saccharomyces cerevisiae, about one-third of all mRNA molecules undergo splicing, and splicing efficiency is tightly regulated, for example, during meiotic differentiation. S. cerevisiae features a streamlined, evolutionarily highly conserved splicing machinery and serves as a favourite model for studies of various aspects of splicing. RNA-seq represents a robust, versatile, and affordable technique for transcriptome interrogation, which can also be used to study splicing efficiency. However, convenient bioinformatics tools for the analysis of splicing efficiency from yeast RNA-seq data are lacking. We present a complete workflow for the calculation of genome-wide splicing efficiency in S. cerevisiae using strand-specific RNA-seq data. Our pipeline takes sequencing reads in the FASTQ format and provides splicing efficiency values for the 5′ and 3′ splice junctions of each intron. The pipeline is based on up-to-date open-source software tools and requires very limited input from the user. We provide all relevant scripts in a ready-to-use form. We demonstrate the functionality of the workflow using RNA-seq datasets from three spliceosome mutants. The workflow should prove useful for studies of yeast splicing mutants or of regulated splicing, for example, under specific growth conditions.
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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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Meinel DM, Sträßer K. Co-transcriptional mRNP formation is coordinated within a molecular mRNP packaging station in S. cerevisiae. Bioessays 2015; 37:666-77. [PMID: 25801414 PMCID: PMC5054900 DOI: 10.1002/bies.201400220] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In eukaryotes, the messenger RNA (mRNA), the blueprint of a protein‐coding gene, is processed and packaged into a messenger ribonucleoprotein particle (mRNP) by mRNA‐binding proteins in the nucleus. The steps of mRNP formation – transcription, processing, packaging, and the orchestrated release of the export‐competent mRNP from the site of transcription for nuclear mRNA export – are tightly coupled to ensure a highly efficient and regulated process. The importance of highly accurate nuclear mRNP formation is illustrated by the fact that mutations in components of this pathway lead to cellular inviability or to severe diseases in metazoans. We hypothesize that efficient mRNP formation is realized by a molecular mRNP packaging station, which is built by several recruitment platforms and coordinates the individual steps of mRNP formation.
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Affiliation(s)
- Dominik M Meinel
- Bavarian Health and Food Safety Authority, Oberschleißheim, Germany
| | - Katja Sträßer
- Institute of Biochemistry, Justus Liebig University Giessen, Giessen, Germany
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Becerra S, Montes M, Hernández-Munain C, Suñé C. Prp40 pre-mRNA processing factor 40 homolog B (PRPF40B) associates with SF1 and U2AF65 and modulates alternative pre-mRNA splicing in vivo. RNA (NEW YORK, N.Y.) 2015; 21:438-57. [PMID: 25605964 PMCID: PMC4338339 DOI: 10.1261/rna.047258.114] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The first stable complex formed during the assembly of spliceosomes onto pre-mRNA substrates in mammals includes U1 snRNP, which recognizes the 5' splice site, and the splicing factors SF1 and U2AF, which bind the branch point sequence, polypyrimidine tract, and 3' splice site. The 5' and 3' splice site complexes are thought to be joined together by protein-protein interactions mediated by factors that ensure the fidelity of the initial splice site recognition. In this study, we identified and characterized PRPF40B, a putative mammalian ortholog of the U1 snRNP-associated yeast splicing factor Prp40. PRPF40B is highly enriched in speckles with a behavior similar to splicing factors. We demonstrated that PRPF40B interacts directly with SF1 and associates with U2AF(65). Accordingly, PRPF40B colocalizes with these splicing factors in the cell nucleus. Splicing assays with reporter minigenes revealed that PRPF40B modulates alternative splice site selection. In the case of Fas regulation of alternative splicing, weak 5' and 3' splice sites and exonic sequences are required for PRPF40B function. Placing our data in a functional context, we also show that PRPF40B depletion increased Fas/CD95 receptor number and cell apoptosis, which suggests the ability of PRPF40B to alter the alternative splicing of key apoptotic genes to regulate cell survival.
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Affiliation(s)
| | | | - Cristina Hernández-Munain
- Department of Cell Biology and Immunology, Instituto de Parasitología y Biomedicina "López Neyra" (IPBLN-CSIC), PTS, Granada 18016, Spain
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Das A, Bhattacharya S, Bagchi A, Dasgupta R. In-silico characterization of Formin Binding Protein 4 Family of proteins. Interdiscip Sci 2014; 7:43-64. [PMID: 25183348 DOI: 10.1007/s12539-013-0040-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 01/10/2014] [Accepted: 01/21/2014] [Indexed: 11/25/2022]
Abstract
Members of the Formin Binding Protein 4 Family or the FNBP4 were indirectly reported to be associated with many of the biological processes. These proteins possess two WW domains. So far there are practically no reports regarding the characterization and classification of the protein by any means. Keeping in mind the importance of the proteins from this FNBP4 family, we have tried an in silico approach to come up with a comprehensive analysis of the proteins. We have analyzed the proteins by considering their sequence conservation, their phylogenetic distributions among the different organisms. We have also investigated the functional properties of the WW domains in the proteins. Finally, we have made an attempt to elucidate the structural details of the domains and predicted the possible modes of their interactions. Our findings show that FNBP4 is eukaryotic in its distribution and follows a trend of evolution where animal and plant homologues have evolved in an independent manner. While the WW domain is the only common motif present across the FNBP4 family of proteins, there are different classes (mainly two) of WW domains that are found among different FNBP4 proteins. Structure function predictions indicate a possible role of FNBP4 in either protein stabilization control or transcript processing. Our study on FNBP4 may therefore open up new avenues to generate new interest in this highly important but largely unexplored class of proteins. Future studies with proteins from this family may answer many important questions of protein-protein interactions in different biologically important processes.
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Affiliation(s)
- Amit Das
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, Nadia, West Bengal, 741235, India
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26
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Nyambega B, Helbig C, Masiga DK, Clayton C, Levin MJ. Proteins associated with SF3a60 in T. brucei. PLoS One 2014; 9:e91956. [PMID: 24651488 PMCID: PMC3961280 DOI: 10.1371/journal.pone.0091956] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 02/18/2014] [Indexed: 12/29/2022] Open
Abstract
Trypanosoma brucei relies on Spliced leader trans splicing to generate functional messenger RNAs. Trans splicing joins the specialized SL exon from the SL RNA to pre-mRNAs and is mediated by the trans-spliceosome, which is made up of small nuclear ribonucleoprotein particles and non-snRNP factors. Although the trans spliceosome is essential for trypanosomatid gene expression, not all spliceosomal protein factors are known and of these, only a few are completely characterized. In this study, we have characterized the trypanosome Splicing Factor, SF3a60, the only currently annotated SF3a component. As expected, epitope-tagged SF3a60 localizes in the trypanosome nucleus. SF3a60 is essential for cell viability but its depletion seem to have no detectable effect on trans-splicing. In addition, we used SF3a60 as bait in a Yeast-2-hybrid system screen and identified its interacting protein factors. The interactions with SF3a120, SF3a66 and SAP130 were confirmed by tandem affinity purification and mass spectrometry.
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Affiliation(s)
- Benson Nyambega
- Laboratorio de Biología Molecular de la Enfermedad de Chagas, Instituto de Investigacíones en Ingeniería Genética y Biología Molecular (INGEBI), Buenos Aires, Argentina
- Molecular Biology and Biotechnology Department, International Center for Insect Physiology and Ecology (ICIPE), Nairobi, Kenya
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany
| | - Claudia Helbig
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany
| | - Daniel K. Masiga
- Molecular Biology and Biotechnology Department, International Center for Insect Physiology and Ecology (ICIPE), Nairobi, Kenya
| | - Christine Clayton
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Heidelberg, Germany
| | - Mariano J. Levin
- Laboratorio de Biología Molecular de la Enfermedad de Chagas, Instituto de Investigacíones en Ingeniería Genética y Biología Molecular (INGEBI), Buenos Aires, Argentina
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27
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Lee KM, Tarn WY. Coupling pre-mRNA processing to transcription on the RNA factory assembly line. RNA Biol 2013; 10:380-90. [PMID: 23392244 DOI: 10.4161/rna.23697] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
It has been well-documented that nuclear processing of primary transcripts of RNA polymerase II occurs co-transcriptionally and is functionally coupled to transcription. Moreover, increasing evidence indicates that transcription influences pre-mRNA splicing and even several post-splicing RNA processing events. In this review, we discuss the issues of how RNA polymerase II modulates co-transcriptional RNA processing events via its carboxyl terminal domain, and the protein domains involved in coupling of transcription and RNA processing events. In addition, we describe how transcription influences the expression or stability of mRNAs through the formation of distinct mRNP complexes. Finally, we delineate emerging findings that chromatin modifications function in the regulation of RNA processing steps, especially splicing, in addition to transcription. Overall, we provide a comprehensive view that transcription could integrate different control systems, from epigenetic to post-transcriptional control, for efficient gene expression.
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Affiliation(s)
- Kuo-Ming Lee
- Institute of Biomedical Sciences; Academia Sinica; Taipei, Taiwan
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28
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Montes M, Becerra S, Sánchez-Álvarez M, Suñé C. Functional coupling of transcription and splicing. Gene 2012; 501:104-17. [DOI: 10.1016/j.gene.2012.04.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 04/02/2012] [Accepted: 04/05/2012] [Indexed: 01/13/2023]
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29
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Makarov EM, Owen N, Bottrill A, Makarova OV. Functional mammalian spliceosomal complex E contains SMN complex proteins in addition to U1 and U2 snRNPs. Nucleic Acids Res 2011; 40:2639-52. [PMID: 22110043 PMCID: PMC3315330 DOI: 10.1093/nar/gkr1056] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spliceosomes remove introns from primary gene transcripts. They assemble de novo on each intron through a series of steps that involve the incorporation of five snRNP particles and multiple non-snRNP proteins. In mammals, all the intermediate complexes have been characterized on one transcript (MINX), with the exception of the very first, complex E. We have purified this complex by two independent procedures using antibodies to either U1-A or PRPF40A proteins, which are known to associate at an early stage of assembly. We demonstrate that the purified complexes are functional in splicing using commitment assays. These complexes contain components expected to be in the E complex and a number of previously unrecognized factors, including survival of motor neurons (SMN) and proteins of the SMN-associated complex. Depletion of the SMN complex proteins from nuclear extracts inhibits formation of the E complex and causes non-productive complexes to accumulate. This suggests that the SMN complex stabilizes the association of U1 and U2 snRNPs with pre-mRNA. In addition, the antibody to PRPF40A precipitated U2 snRNPs from nuclear extracts, indicating that PRPF40A associates with U2 snRNPs.
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Affiliation(s)
- Evgeny M Makarov
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, UK
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30
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Kidd BN, Cahill DM, Manners JM, Schenk PM, Kazan K. Diverse roles of the Mediator complex in plants. Semin Cell Dev Biol 2011; 22:741-8. [DOI: 10.1016/j.semcdb.2011.07.012] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 07/17/2011] [Indexed: 02/06/2023]
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31
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Spiluttini B, Gu B, Belagal P, Smirnova AS, Nguyen VT, Hébert C, Schmidt U, Bertrand E, Darzacq X, Bensaude O. Splicing-independent recruitment of U1 snRNP to a transcription unit in living cells. J Cell Sci 2010; 123:2085-93. [PMID: 20519584 DOI: 10.1242/jcs.061358] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Numerous non-coding RNAs are known to be involved in the regulation of gene expression. In this work, we analyzed RNAs that co-immunoprecipitated with human RNA polymerase II from mitotic cell extracts and identified U1 small nuclear RNA (snRNA) as a major species. To investigate a possible splicing-independent recruitment of U1 snRNA to transcription units, we established cell lines having integrated a reporter gene containing a functional intron or a splicing-deficient construction. Recruitment of U snRNAs and some splicing factors to transcription sites was evaluated using fluorescence in situ hybridization (FISH) and immunofluorescence. To analyze imaging data, we developed a quantitative procedure, 'radial analysis', based on averaging data from multiple fluorescence images. The major splicing snRNAs (U2, U4 and U6 snRNAs) as well as the U2AF65 and SC35 splicing factors were found to be recruited only to transcription units containing a functional intron. By contrast, U1 snRNA, the U1-70K (also known as snRNP70) U1-associated protein as well as the ASF/SF2 (also known as SFRS1) serine/arginine-rich (SR) protein were efficiently recruited both to normally spliced and splicing-deficient transcription units. The constitutive association of U1 small nuclear ribonucleoprotein (snRNP) with the transcription machinery might play a role in coupling transcription with pre-mRNA maturation.
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Affiliation(s)
- Béatrice Spiluttini
- Ecole Normale Supérieure, Institut de Biologie de l'ENS, IBENS, Paris, France
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32
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Sánchez-Álvarez M, Montes M, Sánchez-Hernández N, Hernández-Munain C, Suñé C. Differential effects of sumoylation on transcription and alternative splicing by transcription elongation regulator 1 (TCERG1). J Biol Chem 2010; 285:15220-15233. [PMID: 20215116 DOI: 10.1074/jbc.m109.063750] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Modification of proteins by small ubiquitin-like modifier (SUMO) is emerging as an important control of transcription and RNA processing. The human factor TCERG1 (also known as CA150) participates in transcriptional elongation and alternative splicing of pre-mRNAs. Here, we report that SUMO family proteins modify TCERG1. Furthermore, TCERG1 binds to the E2 SUMO-conjugating enzyme Ubc9. Two lysines (Lys-503 and Lys-608) of TCERG1 are the major sumoylation sites. Sumoylation does not affect localization of TCERG1 to the splicing factor-rich nuclear speckles or the alternative splicing function of TCERG1. However, mutation of the SUMO acceptor lysine residues enhanced TCERG1 transcriptional activity, indicating that SUMO modification negatively regulates TCERG1 transcriptional activity. These results reveal a regulatory role for sumoylation in controlling the activity of a transcription factor that modulates RNA polymerase II elongation and mRNA alternative processing, which are discriminated differently by this post-translational modification.
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Affiliation(s)
- Miguel Sánchez-Álvarez
- Departments of Molecular Biology, Consejo Superior de Investigaciones Científicas, Armilla, 18100 Granada, Spain; Departments of Cell Biology and Immunology, Instituto de Parasitología y Biomedicina "López Neyra," Consejo Superior de Investigaciones Científicas, Armilla, 18100 Granada, Spain
| | - Marta Montes
- Departments of Molecular Biology, Consejo Superior de Investigaciones Científicas, Armilla, 18100 Granada, Spain
| | - Noemí Sánchez-Hernández
- Departments of Molecular Biology, Consejo Superior de Investigaciones Científicas, Armilla, 18100 Granada, Spain
| | - Cristina Hernández-Munain
- Departments of Cell Biology and Immunology, Instituto de Parasitología y Biomedicina "López Neyra," Consejo Superior de Investigaciones Científicas, Armilla, 18100 Granada, Spain
| | - Carlos Suñé
- Departments of Molecular Biology, Consejo Superior de Investigaciones Científicas, Armilla, 18100 Granada, Spain.
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33
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Murphy JM, Hansen DF, Wiesner S, Muhandiram DR, Borg M, Smith MJ, Sicheri F, Kay LE, Forman-Kay JD, Pawson T. Structural Studies of FF Domains of the Transcription Factor CA150 Provide Insights into the Organization of FF Domain Tandem Arrays. J Mol Biol 2009; 393:409-24. [DOI: 10.1016/j.jmb.2009.08.049] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 08/06/2009] [Accepted: 08/20/2009] [Indexed: 11/26/2022]
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34
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Lu M, Yang J, Ren Z, Sabui S, Espejo A, Bedford MT, Jacobson RH, Jeruzalmi D, McMurray JS, Chen X. Crystal structure of the three tandem FF domains of the transcription elongation regulator CA150. J Mol Biol 2009; 393:397-408. [PMID: 19660470 DOI: 10.1016/j.jmb.2009.07.086] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 07/27/2009] [Accepted: 07/29/2009] [Indexed: 10/20/2022]
Abstract
FF domains are small protein-protein interaction modules that have two flanking conserved phenylalanine residues. They are present in proteins involved in transcription, RNA splicing, and signal transduction, and often exist in tandem arrays. Although several individual FF domain structures have been determined by NMR, the tandem nature of most FF domains has not been revealed. Here we report the 2.7-A-resolution crystal structure of the first three FF domains of the human transcription elongation factor CA150. Each FF domain is composed of three alpha-helices and a 3(10) helix between alpha-helix 2 and alpha-helix 3. The most striking feature of the structure is that an FF domain is connected to the next by an alpha-helix that continues from helix 3 to helix 1 of the next. The consequent elongated arrangement allows exposure of many charged residues within the region that can be engaged in interaction with other molecules. Binding studies using a peptide ligand suggest that a specific conformation of the FF domains might be required to achieve higher-affinity binding. Additionally, we explore potential DNA binding of the FF construct used in this study. Overall, we provide the first crystal structure of an FF domain and insights into the tandem nature of the FF domains and suggest that, in addition to protein binding, FF domains might be involved in DNA binding.
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Affiliation(s)
- Ming Lu
- Department of Biochemistry and Molecular Biology, University of Texas M. D. Anderson Cancer Center, Houston, 77030, USA
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35
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Bonet R, Ruiz L, Morales B, Macias MJ. Solution structure of the fourth FF domain of yeast Prp40 splicing factor. Proteins 2009; 77:1000-3. [DOI: 10.1002/prot.22547] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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36
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Kuhn AN, van Santen MA, Schwienhorst A, Urlaub H, Lührmann R. Stalling of spliceosome assembly at distinct stages by small-molecule inhibitors of protein acetylation and deacetylation. RNA (NEW YORK, N.Y.) 2009; 15:153-75. [PMID: 19029308 PMCID: PMC2612777 DOI: 10.1261/rna.1332609] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The removal of intervening sequences from a primary RNA transcript is catalyzed by the spliceosome, a large complex consisting of five small nuclear (sn) RNAs and more than 150 proteins. At the start of the splicing cycle, the spliceosome assembles anew onto each pre-mRNA intron in an ordered process. Here, we show that several small-molecule inhibitors of protein acetylation/deacetylation block the splicing cycle: by testing a small number of bioactive compounds, we found that three small-molecule inhibitors of histone acetyltransferases (HATs), as well as three small-molecule inhibitors of histone deacetylases (HDACs), block pre-mRNA splicing in vitro. By purifying and characterizing the stalled spliceosomes, we found that the splicing cycle is blocked at distinct stages by different inhibitors: two inhibitors allow only the formation of A-like spliceosomes (as determined by the size of the stalled complexes and their snRNA composition), while the other compounds inhibit activation for catalysis after incorporation of all U snRNPs into the spliceosome. Mass-spectrometric analysis of affinity-purified stalled spliceosomes indicated that the intermediates differ in protein composition both from each other and from previously characterized native A and B splicing complexes. This suggests that the stalled complexes represent hitherto unobserved intermediates of spliceosome assembly.
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Affiliation(s)
- Andreas N Kuhn
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
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37
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Chen YIG, Moore RE, Ge HY, Young MK, Lee TD, Stevens SW. Proteomic analysis of in vivo-assembled pre-mRNA splicing complexes expands the catalog of participating factors. Nucleic Acids Res 2007; 35:3928-44. [PMID: 17537823 PMCID: PMC1919476 DOI: 10.1093/nar/gkm347] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Previous compositional studies of pre-mRNA processing complexes have been performed in vitro on synthetic pre-mRNAs containing a single intron. To provide a more comprehensive list of polypeptides associated with the pre-mRNA splicing apparatus, we have determined the composition of the bulk pre-mRNA processing machinery in living cells. We purified endogenous nuclear pre-mRNA processing complexes from human and chicken cells comprising the massive (>200S) supraspliceosomes (a.k.a. polyspliceosomes). As expected, RNA components include a heterogeneous mixture of pre-mRNAs and the five spliceosomal snRNAs. In addition to known pre-mRNA splicing factors, 5′ end binding factors, 3′ end processing factors, mRNA export factors, hnRNPs and other RNA binding proteins, the protein components identified by mass spectrometry include RNA adenosine deaminases and several novel factors. Intriguingly, our purified supraspliceosomes also contain a number of structural proteins, nucleoporins, chromatin remodeling factors and several novel proteins that were absent from splicing complexes assembled in vitro. These in vivo analyses bring the total number of factors associated with pre-mRNA to well over 300, and represent the most comprehensive analysis of the pre-mRNA processing machinery to date.
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Affiliation(s)
- Yen-I G. Chen
- Graduate program in Microbiology, City of Hope Beckman Research Institute, Duarte, CA 91010, Section of Molecular Genetics and Microbiology, University of Texas at Austin, 1 University, Station #A4800, Austin, TX 78712 and Institute for Cellular and Molecular Biology, University of Texas at Austin, TX, USA
| | - Roger E. Moore
- Graduate program in Microbiology, City of Hope Beckman Research Institute, Duarte, CA 91010, Section of Molecular Genetics and Microbiology, University of Texas at Austin, 1 University, Station #A4800, Austin, TX 78712 and Institute for Cellular and Molecular Biology, University of Texas at Austin, TX, USA
| | - Helen Y. Ge
- Graduate program in Microbiology, City of Hope Beckman Research Institute, Duarte, CA 91010, Section of Molecular Genetics and Microbiology, University of Texas at Austin, 1 University, Station #A4800, Austin, TX 78712 and Institute for Cellular and Molecular Biology, University of Texas at Austin, TX, USA
| | - Mary K. Young
- Graduate program in Microbiology, City of Hope Beckman Research Institute, Duarte, CA 91010, Section of Molecular Genetics and Microbiology, University of Texas at Austin, 1 University, Station #A4800, Austin, TX 78712 and Institute for Cellular and Molecular Biology, University of Texas at Austin, TX, USA
| | - Terry D. Lee
- Graduate program in Microbiology, City of Hope Beckman Research Institute, Duarte, CA 91010, Section of Molecular Genetics and Microbiology, University of Texas at Austin, 1 University, Station #A4800, Austin, TX 78712 and Institute for Cellular and Molecular Biology, University of Texas at Austin, TX, USA
| | - Scott W. Stevens
- Graduate program in Microbiology, City of Hope Beckman Research Institute, Duarte, CA 91010, Section of Molecular Genetics and Microbiology, University of Texas at Austin, 1 University, Station #A4800, Austin, TX 78712 and Institute for Cellular and Molecular Biology, University of Texas at Austin, TX, USA
- *To whom correspondence should be addressed. +1-512-232-9303+1-512-232-3432
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Dönmez G, Hartmuth K, Kastner B, Will CL, Lührmann R. The 5′ End of U2 snRNA Is in Close Proximity to U1 and Functional Sites of the Pre-mRNA in Early Spliceosomal Complexes. Mol Cell 2007; 25:399-411. [PMID: 17289587 DOI: 10.1016/j.molcel.2006.12.019] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Revised: 12/06/2006] [Accepted: 12/20/2006] [Indexed: 10/23/2022]
Abstract
Recognition and pairing of the correct 5' and 3' splice sites (ss) of a pre-mRNA are critical events that occur early during spliceosome assembly. Little is known about the spatial organization in early spliceosomal complexes of the U1 and U2 snRNPs, which together with several non-snRNP proteins, are involved in juxtapositioning the functional sites of the pre-mRNA. To better understand the molecular mechanisms of splice-site recognition/pairing, we have examined the organization of U2 relative to U1 and pre-mRNA in spliceosomal complexes via hydroxyl-radical probing with Fe-BABE-tethered U2 snRNA. These studies reveal that functional sites of the pre-mRNA are located close to the 5' end of U2 both in E and A complexes. U2 is also positioned close to U1 in a defined orientation already in the E complex, and their relative spatial organization remains largely unchanged during the E to A transition.
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Affiliation(s)
- Gizem Dönmez
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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39
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Kato Y, Miyakawa T, Kurita JI, Tanokura M. Structure of FBP11 WW1-PL Ligand Complex Reveals the Mechanism of Proline-rich Ligand Recognition by Group II/III WW Domains. J Biol Chem 2006; 281:40321-9. [PMID: 17065151 DOI: 10.1074/jbc.m609321200] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
FBP11/HYPA is a mammalian homologue of yeast splicing factor Prp40. The first WW domain of FBP11/HYPA (FBP11 WW1) is essential for preventing severe neurological diseases such as Huntington disease and Rett syndrome and strongly resembles the WW domain of FCA, the essential regulator for flowering time control. We have solved the structure of FBP11 WW1 and a Pro-Pro-Leu-Pro ligand complex, and demonstrated the binding mechanism with mutational analysis using surface plasmon resonance. The overall structure of FBP11 WW1 in the complex form is quite similar to the structures of WW domains from Group I and IV in complexes. In addition, conformation of FBP11 WW1 does not change much upon ligand binding. The binding orientation of the ligand against FBP11 WW1 is the same as that of the Group IV WW domain-ligand complex, but opposite to that of the Group I complex. The ligand interacts with two grooves formed by surface aromatic residues. The Pro and Leu residues in the ligand interact with the grooves and the Loop I region of FBP11 WW1, respectively, which are necessary interactions for binding the ligand. Interestingly, the two aromatic grooves recognize the Pro residues in entirely different manners, which allows FBP11 WW1 to recognize shorter sequences than the SH3 domain. Combined with homology models of other WW domains, the present report shows the detailed mechanism of ligand binding by Group II/III WW domains, and provides information useful in designing drugs to treat neurodegenerative diseases.
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Affiliation(s)
- Yusuke Kato
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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40
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Gasch A, Wiesner S, Martin-Malpartida P, Ramirez-Espain X, Ruiz L, Macias MJ. The structure of Prp40 FF1 domain and its interaction with the crn-TPR1 motif of Clf1 gives a new insight into the binding mode of FF domains. J Biol Chem 2005; 281:356-64. [PMID: 16253993 DOI: 10.1074/jbc.m508047200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The yeast splicing factor Prp40 (pre-mRNA processing protein 40) consists of a pair of WW domains followed by several FF domains. The region comprising the FF domains has been shown to associate with the 5' end of U1 small nuclear RNA and to interact directly with two proteins, the Clf1 (Crooked neck-like factor 1) and the phosphorylated repeats of the C-terminal domain of RNA polymerase II (CTD-RNAPII). In this work we reported the solution structure of the first FF domain of Prp40 and the identification of a novel ligand-binding site in FF domains. By using chemical shift assays, we found a binding site for the N-terminal crooked neck tetratricopeptide repeat of Clf1 that is distinct and structurally separate from the previously identified CTD-RNAPII binding pocket of the FBP11 (formin-binding protein 11) FF1 domain. No interaction, however, was observed between the Prp40 FF1 domain and three different peptides derived from the CTD-RNAPII protein. Indeed, the equivalent CTD-RNAPII-binding site in the Prp40 FF1 domain is predominantly negatively charged and thus unfavorable for an interaction with phosphorylated peptide sequences. Sequence alignments and phylogenetic tree reconstructions using the FF domains of three functionally related proteins, Prp40, FBP11, and CA150, revealed that Prp40 and FBP11 are not orthologous proteins and supported the different ligand specificities shown by their respective FF1 domains. Our results also revealed that not all FF domains in Prp40 are functionally equivalent. We proposed that at least two different interaction surfaces exist in FF domains that have evolved to recognize distinct binding motifs.
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Affiliation(s)
- Alexander Gasch
- Structural Biology Program, EMBL Heidelberg, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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41
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Neubauer G. The Analysis of Multiprotein Complexes: The Yeast and the Human Spliceosome as Case Studies. Methods Enzymol 2005; 405:236-63. [PMID: 16413317 DOI: 10.1016/s0076-6879(05)05010-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
The yeast and human spliceosomes represent the first two multiprotein complexes of which protein components were identified solely by mass spectrometry (MS). In this chapter, the different approaches used for the purification of these protein complexes, the MS analysis of the components, and some functional characterization strategies adopted are discussed. Even though from the time of analysis up to 2005 much has been achieved in terms of purification techniques, MS protein analysis and sequence information in public databases, the key knowledge gained from the very early complex analyses still hold true today. The analysis of protein complexes is a powerful approach for understanding the organization of proteins and how they act in units to exert their biological effects. The analysis also creates hypotheses for the role of novel proteins in the context of the cellular function of the protein complex under study. However, the work on the spliceosomes described in this chapter also illustrates the relative ease of protein identification by MS and the difficulty to provide detailed functional information for the vast amount of data generated in such a study.
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Affiliation(s)
- Gitte Neubauer
- European Molecular Biology Laboratory, Meyerhofstrasse 1, Heidelberg, Germany
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42
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Smith MJ, Kulkarni S, Pawson T. FF domains of CA150 bind transcription and splicing factors through multiple weak interactions. Mol Cell Biol 2004; 24:9274-85. [PMID: 15485897 PMCID: PMC522232 DOI: 10.1128/mcb.24.21.9274-9285.2004] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human transcription factor CA150 modulates human immunodeficiency virus type 1 gene transcription and contains numerous signaling elements, including six FF domains. Repeated FF domains are present in several transcription and splicing factors and can recognize phosphoserine motifs in the C-terminal domain (CTD) of RNA polymerase II (RNAPII). Using mass spectrometry, we identify a number of nuclear binding partners for the CA150 FF domains and demonstrate a direct interaction between CA150 and Tat-SF1, a protein involved in the coupling of splicing and transcription. CA150 FF domains recognize multiple sites within the Tat-SF1 protein conforming to the consensus motif (D/E)(2/5)-F/W/Y-(D/E)(2/5). Individual FF domains are capable of interacting with Tat-SF1 peptide ligands in an equivalent and noncooperative manner, with affinities ranging from 150 to 500 microM. Repeated FF domains therefore appear to bind their targets through multiple weak interactions with motifs comprised of negatively charged residues flanking aromatic amino acids. The RNAPII CTD represents a consensus FF domain-binding site, contingent on generation of the requisite negative charges by phosphorylation of serines 2 and 5. We propose that CA150, through the dual recognition of acidic motifs in proteins such as Tat-SF1 and the phosphorylated CTD, could mediate the recruitment of transcription and splicing factors to actively transcribing RNAPII.
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Affiliation(s)
- Matthew J Smith
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Ave., Toronto, Ontario, Canada, M5G 1X5
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Murphy MW, Olson BL, Siliciano PG. The yeast splicing factor Prp40p contains functional leucine-rich nuclear export signals that are essential for splicing. Genetics 2004; 166:53-65. [PMID: 15020406 PMCID: PMC1470677 DOI: 10.1534/genetics.166.1.53] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To investigate the function of the essential U1 snRNP protein Prp40p, we performed a synthetic lethal screen in Saccharomyces cerevisiae. Using an allele of PRP40 that deletes 47 internal residues and causes only a slight growth defect, we identified aphenotypic mutations in three distinct complementation groups that conferred synthetic lethality. The synthetic phenotypes caused by these mutations were suppressed by wild-type copies of CRM1 (XPO1), YNL187w, and SME1, respectively. The strains whose synthetic phenotypes were suppressed by CRM1 contained no mutations in the CRM1 coding sequence or promoter. This indicates that overexpression of CRM1 confers dosage suppression of the synthetic lethality. Interestingly, PRP40 and YNL187w encode proteins with putative leucine-rich nuclear export signal (NES) sequences that fit the consensus sequence recognized by Crm1p. One of Prp40p's two NESs lies within the internal deletion. We demonstrate here that the NES sequences of Prp40p are functional for nuclear export in a leptomycin B-sensitive manner. Furthermore, mutation of these NES sequences confers temperature-sensitive growth and a pre-mRNA splicing defect. Although we do not expect that yeast snRNPs undergo compartmentalized biogenesis like their metazoan counterparts, our results suggest that Prp40p and Ynl187wp contain redundant NESs that aid in an important, Crm1p-mediated nuclear export event.
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Affiliation(s)
- Mark W Murphy
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
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Sun X, Zhao J, Kylberg K, Soop T, Palka K, Sonnhammer E, Visa N, Alzhanova-Ericsson AT, Daneholt B. Conspicuous accumulation of transcription elongation repressor hrp130/CA150 on the intron-rich Balbiani ring 3 gene. Chromosoma 2004; 113:244-57. [PMID: 15480727 DOI: 10.1007/s00412-004-0314-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Revised: 08/19/2004] [Accepted: 08/19/2004] [Indexed: 11/28/2022]
Abstract
Chromosomal puffs on the polytene chromosomes in the dipteran Chironomus tentans offer the possibility of comparing the appearance of RNA-binding proteins at different transcription sites. We raised a monoclonal antibody that recognized a 130 kDa protein, designated hrp130. Immunocytological analysis of isolated chromosomes showed that hrp130 is heavily accumulated in a specific puff, called Balbiani ring 3; only occasionally is hrp130 abundant in one or two additional puffs on other chromosomes. The immunolabeling was sensitive to RNase treatment, suggesting that hrp130 is associated with nascent ribonucleoproteins. As shown by immunoelectron microscopy hrp130 is distributed along the active BR3 genes. The full sequence of hrp130 was determined by cDNA cloning. The protein comprises 1028 amino acids and contains three WW domains in the N-terminal half and six FF domains in the C-terminal half of the molecule. The protein is conserved from Caenorhabditis elegans to mammals; the human homolog is known as the transcription elongation repressor CA150. We propose that the abundance of hrp130/CA150 in BR3 is connected with the exceptionally high level of splicing in this locus and that hrp130/CA150 adjusts the transcription rate to the numerous splicing events taking place along the gene to ensure proper splicing.
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Affiliation(s)
- Xin Sun
- Department of Cell and Molecular Biology, Medical Nobel Institute, Karolinska Institutet, 17177 Stockholm, Sweden
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45
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Buschdorf JP, Strätling WH. A WW domain binding region in methyl-CpG-binding protein MeCP2: impact on Rett syndrome. J Mol Med (Berl) 2004; 82:135-43. [PMID: 14618241 DOI: 10.1007/s00109-003-0497-9] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2003] [Accepted: 09/09/2003] [Indexed: 11/25/2022]
Abstract
Rett syndrome is a dominant neurological disorder caused by loss-of-function mutations of methyl-CpG-binding protein 2 (MeCP2). MeCP2 is an abundant chromatin-associated protein that contains two well characterized domains. Through an N-terminal domain it recognizes methyl-CpGs and binds to nonmethylated DNA. A domain in the middle of the protein can act as a transcriptional repressor in transient transfection studies. The C-terminal region of the protein is equally essential for the function of MeCP2, as documented by recurrently found frameshift mutations. However, little is known about its functional role. Here we mapped a domain within MeCP2 capable of binding specifically to Group II WW domains of splicing factors formin-binding protein (FBP) 11 and HYPC. Binding was assessed by glutathione S-transferase pull-down assays and coimmunoprecipitation assays. The Group II WW domain binding region was localized from residue 325 to the C-terminus, with the interacting proline-rich sequence at its center. We then used comparison with genotype-phenotype studies in Rett syndrome patients to evaluate the relevance of Group II WW domain interactions of MeCP2 for pathogenesis. Truncation of the WW domain binding region by 48 C-terminal amino acids (to residue 438), causing Rett syndrome, resulted in reduced or loss of WW domain binding activity. Truncation to residue 400, representing a large group of frameshift mutations accounting for approx. 10% of Rett syndrome cases, abolished WW domain binding activity completely. On the other hand, two benign missense mutations did not affect binding. Furthermore, a short C-terminal truncation and an internal deletion, both causing mild to moderate mental retardation in males, were associated with weak or loss of WW domain binding activity.
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Affiliation(s)
- Jan P Buschdorf
- Institut für Biochemie und Molekularbiologie I, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
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Xu YX, Hirose Y, Zhou XZ, Lu KP, Manley JL. Pin1 modulates the structure and function of human RNA polymerase II. Genes Dev 2003; 17:2765-76. [PMID: 14600023 PMCID: PMC280625 DOI: 10.1101/gad.1135503] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2003] [Accepted: 09/17/2003] [Indexed: 01/01/2023]
Abstract
The C-terminal domain of the RNA polymerase (RNAP) II largest subunit (CTD) plays critical roles both in transcription of mRNA precursors and in the processing reactions needed to form mature mRNAs. The CTD undergoes dynamic changes in phosphorylation during the transcription cycle, and this plays a significant role in coordinating its multiple activities. But how these changes themselves are regulated is not well understood. Here we show that the peptidyl-prolyl isomerase Pin1 influences the phosphorylation status of the CTD in vitro by inhibiting the CTD phosphatase FCP1 and stimulating CTD phosphorylation by cdc2/cyclin B. This is reflected in vivo by accumulation of hypophosphorylated RNAP II in pin1-/- cells, and of a novel hyper-hyperphosphorylated form in cells induced to overexpress Pin1. This hyper-hyperphosphorylated form of RNAP II also accumulates in M-phase cells, in a Pin1-dependent manner, and associates specifically with Pin1. Functionally, we find that Pin1 overexpression specifically inhibits ongoing transcription of mRNA precursors in vivo and both transcription and RNAP II-stimulated pre-mRNA splicing in cell extracts. Pin1 thus plays a significant role in regulating RNAP II CTD structure and function.
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Affiliation(s)
- Yu-Xin Xu
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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Olson BL, Siliciano PG. A diverse set of nuclear RNAs transfer between nuclei of yeast heterokaryons. Yeast 2003; 20:893-903. [PMID: 12868058 DOI: 10.1002/yea.1015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Small nuclear RNAs and small nucleolar RNAs function in the nucleus of eukaryotic cells during pre-mRNA splicing and ribosomal RNA processing, respectively. In metazoan cells, the small nuclear RNAs shuttle between the nucleus and the cytoplasm during ribonucleoprotein particle assembly. Nuclear export of these small RNAs in yeast, however, has not been demonstrated. Therefore, we have attempted to visualize internuclear RNA movements by in situ hybridization in heterokaryon yeast cells. Using the kar1Delta15 mutation to block karyogamy, we mated two strains, each expressing a unique allele of U1 snRNA. In these heterokaryons, we observed a time-dependent transfer of U1 snRNA from one nucleus to the other. This transfer was reduced two-fold by the addition of the Crm1p-inhibitor leptomycin B. Interestingly, however, we observed identical transfer of the U2 and U6 snRNAs and SNR4, SNR8, SNR9 and SNR11 snoRNAs. Remarkably, when the U2, U6 or SNR4 RNAs were observed in the same heterokaryon as the U1 snRNA, both RNAs always transferred simultaneously. These data suggest a global leaking or transport of material between nuclei of yeast heterokaryons. Our results suggest that caution must be taken when testing nuclear envelope shuttling in yeast heterokaryons.
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MESH Headings
- Active Transport, Cell Nucleus/genetics
- Active Transport, Cell Nucleus/physiology
- Antifungal Agents/pharmacology
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- DNA, Fungal/genetics
- DNA, Fungal/metabolism
- Fatty Acids, Unsaturated/pharmacology
- Genes, Fungal/genetics
- Genes, Fungal/physiology
- In Situ Hybridization, Fluorescence
- RNA, Small Nuclear/genetics
- RNA, Small Nuclear/metabolism
- RNA, Small Nucleolar/genetics
- RNA, Small Nucleolar/metabolism
- Yeasts/genetics
- Yeasts/metabolism
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Affiliation(s)
- Brian L Olson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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Abstract
Introns are removed from precursor messenger RNAs in the cell nucleus by a large ribonucleoprotein complex called the spliceosome. The spliceosome contains five subcomplexes called snRNPs, each with one RNA and several protein components. Interactions of the snRNPs with each other and the intron are highly dynamic, changing in an ordered progression throughout the splicing process. This allosteric cascade of interactions is programmed into the RNA and protein components of the spliceosome, and is driven by a family of DExD/H-box RNA-dependent ATPases. The dependence of cascade progression on multiple intron-recognition events likely serves to enforce the accuracy of splicing. Here, the progression of the allosteric cascade from the first recognition event to the first catalytic step of splicing is reviewed.
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Affiliation(s)
- David A Brow
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706-1532, USA.
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Libri D, Duconge F, Levy L, Vinauger M. A role for the Psi-U mismatch in the recognition of the 5' splice site of yeast introns by the U1 small nuclear ribonucleoprotein particle. J Biol Chem 2002; 277:18173-81. [PMID: 11877437 DOI: 10.1074/jbc.m112460200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The U1 small nuclear ribonucleoprotein particle (snRNP)/5' splice site (5'SS) interaction in yeast is essential for the splicing process and depends on the formation of a short RNA duplex between the 5' arm of U1 snRNA and the 1st intronic nucleotides. This RNA/RNA interaction is characterized by the presence of a mismatch that occurs with almost all yeast introns and concerns nucleotides 4 on the pre-mRNA (a U) and 5 on U1 snRNA (a Psi). The latter nucleotide is well conserved from yeast to vertebrates, but its role in yeast and the significance of the associated mismatch in the U1 snRNA/5'SS interaction have never been fully explained. We report here that the presence of this mismatch is a determinant of stability that mainly affects the off rate of the interaction. To our knowledge this is the first report assigning a function to this noncanonical interaction. We also performed SELEX (systematic evolution of ligands by exponential enrichment) experiments by immunoprecipitating U1 snRNP and the associated RNA. The artificial phylogeny derived from these experiments allows the isolation of the selective pressure due to U1 snRNP binding on the 5'SS of yeast introns.
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Affiliation(s)
- Domenico Libri
- Centre de Génétique Moléculaire, CNRS, 91190 Gif sur Yvette, France.
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Xu GM, Arnaout MA. WAC, a novel WW domain-containing adapter with a coiled-coil region, is colocalized with splicing factor SC35. Genomics 2002; 79:87-94. [PMID: 11827461 DOI: 10.1006/geno.2001.6684] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
WW domains mediate protein-protein interactions in many intracellular processes. In pre-mRNA splicing, WW domains participate in cross-intron bridging. These WW domains are characterized by a central aromatic block of three tyrosine residues. We identified a novel protein containing the same type of WW domain. The gene encoding the protein, named WAC, is located in human chromosome 10p11.2-10p12.1. A Drosophila melanogaster WAC homolog (CG8949) was identified as a Rosetta stone protein. Domain fusion analysis of the Rosetta stone protein linked WAC to splicing factor SNRP70. WAC existed mainly in a tyrosine-phosphorylated form. Immunofluorescence analysis colocalized WAC with SC35, the marker for pre-mRNA splicing machinery. Our analysis suggests that WAC represents a novel member of WW-domain-containing proteins for RNA processing.
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Affiliation(s)
- G Mark Xu
- Polycystic Kidney Disease Program, Renal Unit, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA.
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