1
|
Deepika, Madhu, Shekhawat J, Dixit S, Upadhyay SK. Pre-mRNA processing factor 4 kinases (PRP4Ks): Exploration of molecular features, interaction network and expression profiling in bread wheat. JOURNAL OF PLANT GROWTH REGULATION 2025; 44:806-820. [DOI: 10.1007/s00344-024-11489-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 09/06/2024] [Indexed: 10/09/2024]
|
2
|
Swale C, Bellini V, Bowler MW, Flore N, Brenier-Pinchart MP, Cannella D, Belmudes L, Mas C, Couté Y, Laurent F, Scherf A, Bougdour A, Hakimi MA. Altiratinib blocks Toxoplasma gondii and Plasmodium falciparum development by selectively targeting a spliceosome kinase. Sci Transl Med 2022; 14:eabn3231. [PMID: 35921477 DOI: 10.1126/scitranslmed.abn3231] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Apicomplexa comprise a large phylum of single-celled, obligate intracellular protozoa that include Toxoplasma gondii, Plasmodium, and Cryptosporidium spp., which infect humans and animals and cause severe parasitic diseases. Available therapeutics against these diseases are limited by suboptimal efficacy and frequent side effects, as well as the emergence and spread of resistance. We use a drug repurposing strategy and identify altiratinib, a compound originally developed to treat glioblastoma, as a promising drug candidate with broad spectrum activity against apicomplexans. Altiratinib is parasiticidal and blocks the development of intracellular zoites in the nanomolar range and with a high selectivity index when used against T. gondii. We have identified TgPRP4K of T. gondii as the primary target of altiratinib using genetic target deconvolution, which highlighted key residues within the kinase catalytic site that conferred drug resistance when mutated. We have further elucidated the molecular basis of the inhibitory mechanism and species selectivity of altiratinib for TgPRP4K and for its Plasmodium falciparum counterpart, PfCLK3. Our data identified structural features critical for binding of the other PfCLK3 inhibitor, TCMDC-135051. Consistent with the splicing control activity of this kinase family, we have shown that altiratinib can cause global disruption of splicing, primarily through intron retention in both T. gondii and P. falciparum. Thus, our data establish parasitic PRP4K/CLK3 as a potential pan-apicomplexan target whose repertoire of inhibitors can be expanded by the addition of altiratinib.
Collapse
Affiliation(s)
- Christopher Swale
- Institute for Advanced Biosciences (IAB), Team Host-Pathogen Interactions and Immunity to Infection, INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| | - Valeria Bellini
- Institute for Advanced Biosciences (IAB), Team Host-Pathogen Interactions and Immunity to Infection, INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| | - Matthew W Bowler
- European Molecular Biology Laboratory, Grenoble, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble, France
| | - Nardella Flore
- Institut Pasteur, Université de Paris, Unité de Biologie des Interactions Hôte-Parasite, CNRS ERL 9195, INSERM U1201, F-75015 Paris, France
| | - Marie-Pierre Brenier-Pinchart
- Institute for Advanced Biosciences (IAB), Team Host-Pathogen Interactions and Immunity to Infection, INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| | - Dominique Cannella
- Institute for Advanced Biosciences (IAB), Team Host-Pathogen Interactions and Immunity to Infection, INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| | - Lucid Belmudes
- Université Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000, Grenoble, France
| | - Caroline Mas
- Integrated Structural Biology Grenoble (ISBG) CNRS, CEA, Université Grenoble Alpes, EMBL, 71 avenue des Martyrs, F-38042, Grenoble, France
| | - Yohann Couté
- Université Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000, Grenoble, France
| | - Fabrice Laurent
- INRAE, Université François Rabelais de Tours, Centre Val de Loire, UMR1282 ISP, Laboratoire Apicomplexes et Immunité Mucosale, 37380 Nouzilly, France
| | - Artur Scherf
- Institut Pasteur, Université de Paris, Unité de Biologie des Interactions Hôte-Parasite, CNRS ERL 9195, INSERM U1201, F-75015 Paris, France
| | - Alexandre Bougdour
- Institute for Advanced Biosciences (IAB), Team Host-Pathogen Interactions and Immunity to Infection, INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| | - Mohamed-Ali Hakimi
- Institute for Advanced Biosciences (IAB), Team Host-Pathogen Interactions and Immunity to Infection, INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| |
Collapse
|
3
|
Habib EB, Mathavarajah S, Dellaire G. Tinker, Tailor, Tumour Suppressor: The Many Functions of PRP4K. Front Genet 2022; 13:839963. [PMID: 35281802 PMCID: PMC8912934 DOI: 10.3389/fgene.2022.839963] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 01/28/2022] [Indexed: 11/13/2022] Open
Abstract
Pre-mRNA processing factor 4 kinase (PRP4K, also known as PRPF4B) is an essential kinase first identified in the fission yeast Schizosaccharomyces pombe that is evolutionarily conserved from amoebae to animals. During spliceosomal assembly, PRP4K interacts with and phosphorylates PRPF6 and PRPF31 to facilitate the formation of the spliceosome B complex. However, over the past decade additional evidence has emerged that PRP4K has many diverse cellular roles beyond splicing that contribute to tumour suppression and chemotherapeutic responses in mammals. For example, PRP4K appears to play roles in regulating transcription and the spindle assembly checkpoint (SAC), a key pathway in maintaining chromosomes stability and the response of cancer cells to taxane-based chemotherapy. In addition, PRP4K has been revealed to be a haploinsufficient tumour suppressor that promotes aggressive cancer phenotypes when partially depleted. PRP4K is regulated by both the HER2 and estrogen receptor, and its partial loss increases resistance to the taxanes in multiple malignancies including cervical, breast and ovarian cancer. Moreover, ovarian and triple negative breast cancer patients harboring tumours with low PRP4K expression exhibit worse overall survival. The depletion of PRP4K also enhances both Yap and epidermal growth factor receptor (EGFR) signaling, the latter promoting anoikis resistance in breast and ovarian cancer. Finally, PRP4K is negatively regulated during epithelial-to-mesenchymal transition (EMT), a process that promotes increased cell motility, drug resistance and cancer metastasis. Thus, as we discuss in this review, PRP4K likely plays evolutionarily conserved roles not only in splicing but in a number of cellular pathways that together contribute to tumour suppression.
Collapse
Affiliation(s)
- Elias B. Habib
- Dalhousie University, Department of Pathology, Halifax, NS, Canada
| | | | - Graham Dellaire
- Dalhousie University, Department of Pathology, Halifax, NS, Canada
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
- Beatrice Hunter Cancer Research Institute, Halifax, NS, Canada
- *Correspondence: Graham Dellaire,
| |
Collapse
|
4
|
Li X, Fan Z, Yan M, Qu J, Xu JR, Jin Q. Spontaneous mutations in FgSAD1 suppress the growth defect of the Fgprp4 mutant by affecting tri-snRNP stability and its docking in Fusarium graminearum. Environ Microbiol 2019; 21:4488-4503. [PMID: 31291045 DOI: 10.1111/1462-2920.14736] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/03/2019] [Accepted: 07/08/2019] [Indexed: 12/27/2022]
Abstract
FgPrp4, the only kinase in the spliceosome, is not essential for viability, but is important for splicing efficiency in Fusarium graminearum. The Fgprp4 deletion mutant had severe growth defects but often produced spontaneous suppressors with faster growth rate. To better understand the suppression mechanism, we identified and characterized spontaneous mutations in the tri-snRNP-specific protein, FgSad1, which suppressed the growth defects of Fgprp4. The L512P mutation was verified for its suppressive effects on Fgprp4, suggesting that mutations in FgSad1 may have effects involving FgPrp4 phosphorylation on FgSad1. Phosphoproteomics analysis showed that FgSad1 may not be the direct substrate of FgPrp4 kinase. Furthermore, truncation analysis showed that the N-terminal, extra RS-rich region of FgSad1 is critical for its function and is post-translationally modified. The P258S or S269P mutations in FgSad1 increased its interactions with the U5 protein FgPrp8 and the U4/U6 protein FgPrp31, which may result in tri-snRNP stabilization. Additionally, the D76N mutation increased the association of FgSad1 with the U2 snRNP. These data indicate that suppressor mutations in FgSad1 increase the stability of the tri-snRNP and/or the affinity of FgSad1 with U2 snRNP and therefore potentially facilitate the docking of tri-snRNP into the spliceosome.
Collapse
Affiliation(s)
- Xiaoping Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Zhili Fan
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Ming Yan
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Jia Qu
- Microbial Resource Center, Microbiology Institute of Shaanxi, Xi'an, Shaanxi, 710043, China
| | - Jin-Rong Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China.,Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Qiaojun Jin
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| |
Collapse
|
5
|
Bitencourt TA, Oliveira FB, Sanches PR, Rossi A, Martinez-Rossi NM. The prp4 kinase gene and related spliceosome factor genes in Trichophyton rubrum respond to nutrients and antifungals. J Med Microbiol 2019; 68:591-599. [PMID: 30900975 DOI: 10.1099/jmm.0.000967] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
PURPOSE Trichophyton rubrum is a dermatophyte that causes most human superficial mycoses worldwide. The spliceosome, a large ribonucleoprotein complex responsible for pre-mRNA processing, may confer adaptive advantages to deal with different stresses. Here, we assessed the structural aspects of the Prp4 kinase protein and other pre-mRNA-splicing factors (Prps) in T. rubrum grown in different protein sources and exposed to antifungal drugs. METHODOLOGY Quantitative Reverse Transcription PCR (RT-PCR) assessed the modulation of prp1, prp31, prp8 and prp4 kinase genes after exposure of T. rubrum to sub-lethal doses of amphotericin B, caspofungin and acriflavine, or after T. rubrum growth on keratin sources for 48 and 72 h. We also performed the in silico analysis of the domain organization of Prps orthologues from filamentous fungi and yeasts. RESULTS The prp4 gene was modulated in a time-dependent manner. Transcription levels were mostly up-regulated when T. rubrum was grown on keratin for 72 h, while exposure to amphotericin B promoted prp4 gene down-regulation at the same time point. We also observed co-expression of prp1 and prp31, and their down-regulation after amphotericin B exposure. In silico analysis revealed a conserved domain organization for most Prps orthologues with slight differences, which were mostly related to structural elements such as repetition domains in Prp1 and complexity in motif assembly for the Prp4 kinase. These differences were mainly observed in dermatophyte species and may alter protein interactions and substrate affinity. CONCLUSION Our results improve the understanding of spliceosome proteins in fungi as well as their roles in adaptation to different environmental situations.
Collapse
Affiliation(s)
- Tamires A Bitencourt
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Felipe B Oliveira
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Pablo R Sanches
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Nilce M Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| |
Collapse
|
6
|
Shakhmantsir I, Nayak S, Grant GR, Sehgal A. Spliceosome factors target timeless ( tim) mRNA to control clock protein accumulation and circadian behavior in Drosophila. eLife 2018; 7:39821. [PMID: 30516472 PMCID: PMC6281371 DOI: 10.7554/elife.39821] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 11/17/2018] [Indexed: 12/11/2022] Open
Abstract
Transcription-translation feedback loops that comprise eukaryotic circadian clocks rely upon temporal delays that separate the phase of active transcription of clock genes, such as Drosophila period (per) and timeless (tim), from negative feedback by the two proteins. However, our understanding of the mechanisms involved is incomplete. Through an RNA interference screen, we found that pre-mRNA processing 4 (PRP4) kinase, a component of the U4/U5.U6 triple small nuclear ribonucleoprotein (tri-snRNP) spliceosome, and other tri-snRNP components regulate cycling of the molecular clock as well as rest:activity rhythms. Unbiased RNA-Sequencing uncovered an alternatively spliced intron in tim whose increased retention upon prp4 downregulation leads to decreased TIM levels. We demonstrate that the splicing of tim is rhythmic with a phase that parallels delayed accumulation of the protein in a 24 hr cycle. We propose that alternative splicing constitutes an important clock mechanism for delaying the daily accumulation of clock proteins, and thereby negative feedback by them. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
Collapse
Affiliation(s)
- Iryna Shakhmantsir
- Chronobiology Program at Penn, Howard Hughes Medical Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
| | - Soumyashant Nayak
- The Institute for Translational Medicine and Therapeutics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
| | - Gregory R Grant
- The Institute for Translational Medicine and Therapeutics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
| | - Amita Sehgal
- Chronobiology Program at Penn, Howard Hughes Medical Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,The Institute for Translational Medicine and Therapeutics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States.,Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States
| |
Collapse
|
7
|
PRP4KA, a Putative Spliceosomal Protein Kinase, Is Important for Alternative Splicing and Development in Arabidopsis thaliana. Genetics 2018; 210:1267-1285. [PMID: 30297453 PMCID: PMC6283158 DOI: 10.1534/genetics.118.301515] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Accepted: 10/03/2018] [Indexed: 01/08/2023] Open
Abstract
Prp4 kinase (Prp4k) is the first spliceosome-associated kinase shown to regulate splicing in fungi and metazoans, but nothing is yet known about its functions in plants. Here, Kanno and Venhuizen et al. report... Splicing of precursor messenger RNAs (pre-mRNAs) is an essential step in the expression of most eukaryotic genes. Both constitutive splicing and alternative splicing, which produces multiple messenger RNA (mRNA) isoforms from a single primary transcript, are modulated by reversible protein phosphorylation. Although the plant splicing machinery is known to be a target for phosphorylation, the protein kinases involved remain to be fully defined. We report here the identification of pre-mRNA processing 4 (PRP4) KINASE A (PRP4KA) in a forward genetic screen based on an alternatively spliced GFP reporter gene in Arabidopsis thaliana (Arabidopsis). Prp4 kinase is the first spliceosome-associated kinase shown to regulate splicing in fungi and mammals but it has not yet been studied in plants. In the same screen we identified mutants defective in SAC3A, a putative mRNA export factor that is highly coexpressed with PRP4KA in Arabidopsis. Whereas the sac3a mutants appear normal, the prp4ka mutants display a pleiotropic phenotype featuring atypical rosettes, late flowering, tall final stature, reduced branching, and lowered seed set. Analysis of RNA-sequencing data from prp4ka and sac3a mutants identified widespread and partially overlapping perturbations in alternative splicing in the two mutants. Quantitative phosphoproteomic profiling of a prp4ka mutant detected phosphorylation changes in several serine/arginine-rich proteins, which regulate constitutive and alternative splicing, and other splicing-related factors. Tests of PRP4KB, the paralog of PRP4KA, indicated that the two genes are not functionally redundant. The results demonstrate the importance of PRP4KA for alternative splicing and plant phenotype, and suggest that PRP4KA may influence alternative splicing patterns by phosphorylating a subset of splicing regulators.
Collapse
|
8
|
Sun M, Zhang Y, Wang Q, Wu C, Jiang C, Xu JR. The tri-snRNP specific protein FgSnu66 is functionally related to FgPrp4 kinase in Fusarium graminearum. Mol Microbiol 2018; 109:494-508. [PMID: 29923654 DOI: 10.1111/mmi.14005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2018] [Indexed: 11/28/2022]
Abstract
Deletion of Prp4, the only kinase among spliceosome components, is not lethal in Fusarium graminearum but Fgprp4 mutants have severe growth defects and produced spontaneous suppressors. To identify novel suppressor mutations of Fgprp4, we sequenced the genome of suppressor S37 that was normal in growth but only partially recovered for intron splicing and identified a tandem duplication of 9-aa in the tri-snRNP component FgSNU66. Among the 19 additional suppressor strains found to have mutations in FgSNU66 (out of 260 screened), five had the same 9-aa duplication event with S37 and another five had the R477H/C mutation. The rest had nonsense or G-to-D mutations in the C-terminal 27-aa (CT27) region of FgSnu66, which is absent in its yeast ortholog. Truncation of this C-terminal region reduced the interaction of FgSnu66 with FgHub1 but increased its interaction with FgPrp8 and FgPrp6. Five phosphorylation sites were identified in FgSnu66 by phosphoproteomic analysis and the T418A-S420A-S422A mutation was shown to reduce virulence. Overall, our results showed that mutations in FgSNU66 can suppress deletion of Fgprp4, which has not been reported in other organisms, and the C-terminal tail of FgSnu66 plays a role in its interaction with key tri-snRNP components during spliceosome activation.
Collapse
Affiliation(s)
- Manli Sun
- State Key Laboratory of Crop Stress Biology for Arid Areas and NWAFU-Purdue Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yimei Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas and NWAFU-Purdue Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Qinhu Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and NWAFU-Purdue Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Chunlan Wu
- State Key Laboratory of Crop Stress Biology for Arid Areas and NWAFU-Purdue Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Cong Jiang
- State Key Laboratory of Crop Stress Biology for Arid Areas and NWAFU-Purdue Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Jin-Rong Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas and NWAFU-Purdue Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China.,Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| |
Collapse
|
9
|
Monedero Cobeta I, Stadler CB, Li J, Yu P, Thor S, Benito-Sipos J. Specification of Drosophila neuropeptidergic neurons by the splicing component brr2. PLoS Genet 2018; 14:e1007496. [PMID: 30133436 PMCID: PMC6122834 DOI: 10.1371/journal.pgen.1007496] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 09/04/2018] [Accepted: 06/18/2018] [Indexed: 02/07/2023] Open
Abstract
During embryonic development, a number of genetic cues act to generate neuronal diversity. While intrinsic transcriptional cascades are well-known to control neuronal sub-type cell fate, the target cells can also provide critical input to specific neuronal cell fates. Such signals, denoted retrograde signals, are known to provide critical survival cues for neurons, but have also been found to trigger terminal differentiation of neurons. One salient example of such target-derived instructive signals pertains to the specification of the Drosophila FMRFamide neuropeptide neurons, the Tv4 neurons of the ventral nerve cord. Tv4 neurons receive a BMP signal from their target cells, which acts as the final trigger to activate the FMRFa gene. A recent FMRFa-eGFP genetic screen identified several genes involved in Tv4 specification, two of which encode components of the U5 subunit of the spliceosome: brr2 (l(3)72Ab) and Prp8. In this study, we focus on the role of RNA processing during target-derived signaling. We found that brr2 and Prp8 play crucial roles in controlling the expression of the FMRFa neuropeptide specifically in six neurons of the VNC (Tv4 neurons). Detailed analysis of brr2 revealed that this control is executed by two independent mechanisms, both of which are required for the activation of the BMP retrograde signaling pathway in Tv4 neurons: (1) Proper axonal pathfinding to the target tissue in order to receive the BMP ligand. (2) Proper RNA splicing of two genes in the BMP pathway: the thickveins (tkv) gene, encoding a BMP receptor subunit, and the Medea gene, encoding a co-Smad. These results reveal involvement of specific RNA processing in diversifying neuronal identity within the central nervous system. The nervous system displays daunting cellular diversity, largely generated through complex regulatory input operating on stem cells and their neural lineages during development. Most of the reported mechanisms acting to generate neural diversity pertain to transcriptional regulation. In contrast, little is known regarding the post-transcriptional mechanisms involved. Here, we use a specific group of neurons, Apterous neurons, in the ventral nerve cord of Drosophila melanogaster as our model, to analyze the function of two essential components of the spliceosome; Brr2 and Prp8. Apterous neurons require a BMP retrograde signal for terminal differentiation, and we find that brr2 and Prp8 play crucial roles during this process. brr2 is critical for two independent events; axon pathfinding and BMP signaling, both of which are required for the activation of the retrograde signaling pathway necessary for Apterous neurons. These results identify a post-transcriptional mechanism as key for specifying neuronal identity, by ensuring the execution of a retrograde signal.
Collapse
Affiliation(s)
- Ignacio Monedero Cobeta
- Dept. of Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
- Dept. of Clinical and Experimental Medicine, Linkoping University, Linkoping, Sweden
| | | | - Jin Li
- Department of Electrical and Computer Engineering Texas A&M University, College Station, Texas, United States of America
- TEES-AgriLife Center for Bioinformatics and Genomic Systems Engineering, Texas A&M University, College Station, Texas, United States of America
| | - Peng Yu
- Department of Electrical and Computer Engineering Texas A&M University, College Station, Texas, United States of America
| | - Stefan Thor
- Dept. of Clinical and Experimental Medicine, Linkoping University, Linkoping, Sweden
| | - Jonathan Benito-Sipos
- Dept. of Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
- * E-mail:
| |
Collapse
|
10
|
Phosphorylation by Prp4 kinase releases the self-inhibition of FgPrp31 in Fusarium graminearum. Curr Genet 2018; 64:1261-1274. [PMID: 29671102 DOI: 10.1007/s00294-018-0838-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/04/2018] [Accepted: 04/11/2018] [Indexed: 02/06/2023]
Abstract
Prp31 is one of the key tri-snRNP components essential for pre-mRNA splicing although its exact molecular function is not well studied. In a previous study, suppressor mutations were identified in the PRP31 ortholog in two spontaneous suppressors of Fgprp4 mutant deleted of the only kinase of the spliceosome in Fusarium graminearum. To further characterize the function of FgPrp31 and its relationship with FgPrp4 kinase, in this study we identified additional suppressor mutations in FgPrp31 and determined the suppressive effects of selected mutations. In total, 28 of the 35 suppressors had missense or nonsense mutations in the C terminus 465-594 aa (CT130) region of FgPrp31. The other 7 had missense or deletion mutations in the 7-64 aa region. The nonsense mutation at R464 in FgPRP31 resulted in the truncation of CT130 that contains all the putative Prp4 kinase-phosphorylation sites reported in humans, and partially rescued intron splicing defects of Fgprp4. The CT130 of FgPrp31 displayed self-inhibitory interaction with the N-terminal 1-463 (N463) region, which was reduced or abolished by the L532P, D534G, or G529D mutation in yeast two-hybrid assays. The N463 region, but not full-length FgPrp31, interacted with the N-terminal region of FgBrr2, one main U5 snRNP protein. The L532P mutation in FgPrp31 increased its interaction with FgBrr2. In contrast, suppressor mutations in FgPrp31 reduced its interaction with FgPrp6, another key component of tri-snRNP. Furthermore, we showed that FgPrp31 was phosphorylated by FgPrp4 in vivo. Site-directed mutagenesis analysis showed that phosphorylation at multiple sites in FgPrp31 is necessary to suppress Fgprp4, and S520 and S521 are important FgPrp4-phosphorylation sites. Overall, these results indicated that phosphorylation by FgPrp4 at multiple sites may release the self-inhibitory binding of FgPrp31 and affect its interaction with other components of tri-snRNP during spliceosome activation.
Collapse
|
11
|
Effenberger KA, Urabe VK, Jurica MS. Modulating splicing with small molecular inhibitors of the spliceosome. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 8. [PMID: 27440103 DOI: 10.1002/wrna.1381] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 06/06/2016] [Accepted: 06/28/2016] [Indexed: 12/23/2022]
Abstract
Small molecule inhibitors that target components of the spliceosome have great potential as tools to probe splicing mechanism and dissect splicing regulatory networks in cells. These compounds also hold promise as drug leads for diseases in which splicing regulation plays a critical role, including many cancers. Because the spliceosome is a complicated and dynamic macromolecular machine comprised of many RNA and protein components, a variety of compounds that interfere with different aspects of spliceosome assembly is needed to probe its function. By screening chemical libraries with high-throughput splicing assays, several labs have added to the collection of splicing inhibitors, although the mechanistic insight into splicing yielded from the initial compound hits is somewhat limited so far. In contrast, SF3B1 inhibitors stand out as a great example of what can be accomplished with small molecule tools. This group of compounds were first discovered as natural products that are cytotoxic to cancer cells, and then later shown to target the core spliceosome protein SF3B1. The inhibitors have since been used to uncover details of SF3B1 mechanism in the spliceosome and its impact on gene expression in cells. Continuing structure activity relationship analysis of the compounds is also making progress in identifying chemical features key to their function, which is critical in understanding the mechanism of SF3B1 inhibition. The knowledge is also important for the design of analogs with new and useful features for both splicing researchers and clinicians hoping to exploit splicing as pressure point to target in cancer therapy. WIREs RNA 2017, 8:e1381. doi: 10.1002/wrna.1381 For further resources related to this article, please visit the WIREs website.
Collapse
Affiliation(s)
- Kerstin A Effenberger
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, CA, USA.,Center for Molecular Biology of RNA, University of California, Santa Cruz, CA, USA
| | - Veronica K Urabe
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, CA, USA.,Center for Molecular Biology of RNA, University of California, Santa Cruz, CA, USA
| | - Melissa S Jurica
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, CA, USA.,Center for Molecular Biology of RNA, University of California, Santa Cruz, CA, USA
| |
Collapse
|
12
|
Yadav S, Sonkar A, Ahamad N, Ahmed S. Mutant allele of rna14 in fission yeast affects pre-mRNA splicing. J Genet 2016; 95:389-97. [PMID: 27350684 DOI: 10.1007/s12041-016-0652-z] [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: 11/25/2022]
Abstract
Spliceosome and 3'-end processing complexes are necessary for the precursor mRNA (pre-mRNA) maturation. Spliceosome complex removes noncoding introns, while 3'-end processing involves in cleavage and addition of poly(A) tails to the nascent transcript. Rna14 protein in budding yeast has been implicated in cleavage and polyadenylation of mRNA in the nucleus but their role in the pre-mRNA splicing has not been studied. Here, we report the isolation of a mutant allele of rna14 in fission yeast, Schizosaccharomyces pombe that exhibits reduction in protein level of Chk1 at the nonpermissive temperature, primarily due to the defects in posttranscriptional processing. Reverse transcriptase-polymerase chain reaction analysis reveals defective splicing of the chk1(+) transcript at the nonpermissive temperature. Apart from chk1(+), the splicing of some other genes were also found to be defective at the nonpermissive temperature suggesting that Rna14 might be involved in pre-mRNA splicing. Subsequently, genetic interaction of Rna14 with prp1 and physical interactions with Prp28 suggest that the Rna14 might be part of a larger protein complex responsible for the pre-mRNA maturation.
Collapse
Affiliation(s)
- Sudhanshu Yadav
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226 031,
| | | | | | | |
Collapse
|
13
|
Mayerle M, Guthrie C. Prp8 retinitis pigmentosa mutants cause defects in the transition between the catalytic steps of splicing. RNA (NEW YORK, N.Y.) 2016; 22:793-809. [PMID: 26968627 PMCID: PMC4836653 DOI: 10.1261/rna.055459.115] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/11/2016] [Indexed: 05/14/2023]
Abstract
Pre-mRNA splicing must occur with high fidelity and efficiency for proper gene expression. The spliceosome uses DExD/H box helicases to promote on-pathway interactions while simultaneously minimizing errors. Prp8 and Snu114, an EF2-like GTPase, regulate the activity of the Brr2 helicase, promoting RNA unwinding by Brr2 at appropriate points in the splicing cycle and repressing it at others. Mutations linked to retinitis pigmentosa (RP), a disease that causes blindness in humans, map to the Brr2 regulatory region of Prp8. Previous in vitro studies of homologous mutations in Saccharomyces cerevisiaes how that Prp8-RP mutants cause defects in spliceosome activation. Here we show that a subset of RP mutations in Prp8 also causes defects in the transition between the first and second catalytic steps of splicing. Though Prp8-RP mutants do not cause defects in splicing fidelity, they result in an overall decrease in splicing efficiency. Furthermore, genetic analyses link Snu114 GTP/GDP occupancy to Prp8-dependent regulation of Brr2. Our results implicate the transition between the first and second catalytic steps as a critical place in the splicing cycle where Prp8-RP mutants influence splicing efficiency. The location of the Prp8-RP mutants, at the "hinge" that links the Prp8 Jab1-MPN regulatory "tail" to the globular portion of the domain, suggests that these Prp8-RP mutants inhibit regulated movement of the Prp8 Jab1/MPN domain into the Brr2 RNA binding channel to transiently inhibit Brr2. Therefore, in Prp8-linked RP, disease likely results not only from defects in spliceosome assembly and activation, but also because of defects in splicing catalysis.
Collapse
Affiliation(s)
- Megan Mayerle
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California 94143, USA
| | - Christine Guthrie
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California 94143, USA
| |
Collapse
|
14
|
Abstract
Several pathways control time to flowering in Arabidopsis thaliana through transcriptional and posttranscriptional gene regulation. In recent years, mRNA processing has gained interest as a critical regulator of flowering time control in plants. However, the molecular mechanisms linking RNA splicing to flowering time are not well understood. In a screen for Arabidopsis early flowering mutants we identified an allele of BRR2a. BRR2 proteins are components of the spliceosome and highly conserved in eukaryotes. Arabidopsis BRR2a is ubiquitously expressed in all analyzed tissues and involved in the processing of flowering time gene transcripts, most notably FLC. A missense mutation of threonine 895 in BRR2a caused defects in FLC splicing and greatly reduced FLC transcript levels. Reduced FLC expression increased transcription of FT and SOC1 leading to early flowering in both short and long days. Genome-wide experiments established that only a small set of introns was not correctly spliced in the brr2a mutant. Compared to control introns, retained introns were often shorter and GC-poor, had low H3K4me1 and CG methylation levels, and were often derived from genes with a high-H3K27me3-low-H3K36me3 signature. We propose that BRR2a is specifically needed for efficient splicing of a subset of introns characterized by a combination of factors including intron size, sequence and chromatin, and that FLC is most sensitive to splicing defects. Timing of flowering has a great effect on reproductive success and fitness. It is controlled by many external signals and internal states involving a large set of genes. Here we report that the Arabidopsis thaliana BRR2a gene is needed for normal flowering. BRR2 proteins are components of the spliceosome and highly conserved in eukaryotes. BRR2a is needed for splicing of a subset of introns, most noticeably in the transcript of the flowering repressor FLC. Reduced FLC expression increased transcription of key floral activators, leading to early flowering in both short and long days. Genome-wide experiments established that full BRR2a activity was required only for a small group of introns. We propose that uncompromised BRR2a activity is most important for efficient splicing of a subset of introns of particular size, sequence and chromatin composition, and that FLC is most sensitive to splicing defects.
Collapse
|
15
|
Gao X, Jin Q, Jiang C, Li Y, Li C, Liu H, Kang Z, Xu JR. FgPrp4 Kinase Is Important for Spliceosome B-Complex Activation and Splicing Efficiency in Fusarium graminearum. PLoS Genet 2016; 12:e1005973. [PMID: 27058959 PMCID: PMC4825928 DOI: 10.1371/journal.pgen.1005973] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 03/11/2016] [Indexed: 12/23/2022] Open
Abstract
PRP4 encodes the only kinase among the spliceosome components. Although it is an essential gene in the fission yeast and other eukaryotic organisms, the Fgprp4 mutant was viable in the wheat scab fungus Fusarium graminearum. Deletion of FgPRP4 did not block intron splicing but affected intron splicing efficiency in over 60% of the F. graminearum genes. The Fgprp4 mutant had severe growth defects and produced spontaneous suppressors that were recovered in growth rate. Suppressor mutations were identified in the PRP6, PRP31, BRR2, and PRP8 orthologs in nine suppressor strains by sequencing analysis with candidate tri-snRNP component genes. The Q86K mutation in FgMSL1 was identified by whole genome sequencing in suppressor mutant S3. Whereas two of the suppressor mutations in FgBrr2 and FgPrp8 were similar to those characterized in their orthologs in yeasts, suppressor mutations in Prp6 and Prp31 orthologs or FgMSL1 have not been reported. Interestingly, four and two suppressor mutations identified in FgPrp6 and FgPrp31, respectively, all are near the conserved Prp4-phosphorylation sites, suggesting that these mutations may have similar effects with phosphorylation by Prp4 kinase. In FgPrp31, the non-sense mutation at R464 resulted in the truncation of the C-terminal 130 aa region that contains all the conserved Prp4-phosphorylation sites. Deletion analysis showed that the N-terminal 310-aa rich in SR residues plays a critical role in the localization and functions of FgPrp4. We also conducted phosphoproteomics analysis with FgPrp4 and identified S289 as the phosphorylation site that is essential for its functions. These results indicated that FgPrp4 is critical for splicing efficiency but not essential for intron splicing, and FgPrp4 may regulate pre-mRNA splicing by phosphorylation of other components of the tri-snRNP although itself may be activated by phosphorylation at S289.
Collapse
Affiliation(s)
- Xuli Gao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Qiaojun Jin
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Cong Jiang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- Dept. of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, United States of America
| | - Yang Li
- Dept. of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, United States of America
| | - Chaohui Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Huiquan Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Zhensheng Kang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Jin-Rong Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- Dept. of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail:
| |
Collapse
|
16
|
Schmoll M, Dattenböck C, Carreras-Villaseñor N, Mendoza-Mendoza A, Tisch D, Alemán MI, Baker SE, Brown C, Cervantes-Badillo MG, Cetz-Chel J, Cristobal-Mondragon GR, Delaye L, Esquivel-Naranjo EU, Frischmann A, Gallardo-Negrete JDJ, García-Esquivel M, Gomez-Rodriguez EY, Greenwood DR, Hernández-Oñate M, Kruszewska JS, Lawry R, Mora-Montes HM, Muñoz-Centeno T, Nieto-Jacobo MF, Nogueira Lopez G, Olmedo-Monfil V, Osorio-Concepcion M, Piłsyk S, Pomraning KR, Rodriguez-Iglesias A, Rosales-Saavedra MT, Sánchez-Arreguín JA, Seidl-Seiboth V, Stewart A, Uresti-Rivera EE, Wang CL, Wang TF, Zeilinger S, Casas-Flores S, Herrera-Estrella A. The Genomes of Three Uneven Siblings: Footprints of the Lifestyles of Three Trichoderma Species. Microbiol Mol Biol Rev 2016; 80:205-327. [PMID: 26864432 PMCID: PMC4771370 DOI: 10.1128/mmbr.00040-15] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The genus Trichoderma contains fungi with high relevance for humans, with applications in enzyme production for plant cell wall degradation and use in biocontrol. Here, we provide a broad, comprehensive overview of the genomic content of these species for "hot topic" research aspects, including CAZymes, transport, transcription factors, and development, along with a detailed analysis and annotation of less-studied topics, such as signal transduction, genome integrity, chromatin, photobiology, or lipid, sulfur, and nitrogen metabolism in T. reesei, T. atroviride, and T. virens, and we open up new perspectives to those topics discussed previously. In total, we covered more than 2,000 of the predicted 9,000 to 11,000 genes of each Trichoderma species discussed, which is >20% of the respective gene content. Additionally, we considered available transcriptome data for the annotated genes. Highlights of our analyses include overall carbohydrate cleavage preferences due to the different genomic contents and regulation of the respective genes. We found light regulation of many sulfur metabolic genes. Additionally, a new Golgi 1,2-mannosidase likely involved in N-linked glycosylation was detected, as were indications for the ability of Trichoderma spp. to generate hybrid galactose-containing N-linked glycans. The genomic inventory of effector proteins revealed numerous compounds unique to Trichoderma, and these warrant further investigation. We found interesting expansions in the Trichoderma genus in several signaling pathways, such as G-protein-coupled receptors, RAS GTPases, and casein kinases. A particularly interesting feature absolutely unique to T. atroviride is the duplication of the alternative sulfur amino acid synthesis pathway.
Collapse
Affiliation(s)
- Monika Schmoll
- Austrian Institute of Technology, Department Health and Environment, Bioresources Unit, Tulln, Austria
| | - Christoph Dattenböck
- Austrian Institute of Technology, Department Health and Environment, Bioresources Unit, Tulln, Austria
| | | | | | - Doris Tisch
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | - Mario Ivan Alemán
- Cinvestav, Department of Genetic Engineering, Irapuato, Guanajuato, Mexico
| | - Scott E Baker
- Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Christopher Brown
- University of Otago, Department of Biochemistry and Genetics, Dunedin, New Zealand
| | | | - José Cetz-Chel
- LANGEBIO, National Laboratory of Genomics for Biodiversity, Cinvestav-Irapuato, Guanajuato, Mexico
| | | | - Luis Delaye
- Cinvestav, Department of Genetic Engineering, Irapuato, Guanajuato, Mexico
| | | | - Alexa Frischmann
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | | | - Monica García-Esquivel
- LANGEBIO, National Laboratory of Genomics for Biodiversity, Cinvestav-Irapuato, Guanajuato, Mexico
| | | | - David R Greenwood
- The University of Auckland, School of Biological Sciences, Auckland, New Zealand
| | - Miguel Hernández-Oñate
- LANGEBIO, National Laboratory of Genomics for Biodiversity, Cinvestav-Irapuato, Guanajuato, Mexico
| | - Joanna S Kruszewska
- Polish Academy of Sciences, Institute of Biochemistry and Biophysics, Laboratory of Fungal Glycobiology, Warsaw, Poland
| | - Robert Lawry
- Lincoln University, Bio-Protection Research Centre, Lincoln, Canterbury, New Zealand
| | | | | | | | | | | | | | - Sebastian Piłsyk
- Polish Academy of Sciences, Institute of Biochemistry and Biophysics, Laboratory of Fungal Glycobiology, Warsaw, Poland
| | - Kyle R Pomraning
- Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Aroa Rodriguez-Iglesias
- Austrian Institute of Technology, Department Health and Environment, Bioresources Unit, Tulln, Austria
| | | | | | - Verena Seidl-Seiboth
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria
| | | | | | - Chih-Li Wang
- National Chung-Hsing University, Department of Plant Pathology, Taichung, Taiwan
| | - Ting-Fang Wang
- Academia Sinica, Institute of Molecular Biology, Taipei, Taiwan
| | - Susanne Zeilinger
- Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, Vienna, Austria University of Innsbruck, Institute of Microbiology, Innsbruck, Austria
| | | | - Alfredo Herrera-Estrella
- LANGEBIO, National Laboratory of Genomics for Biodiversity, Cinvestav-Irapuato, Guanajuato, Mexico
| |
Collapse
|
17
|
Functional Splicing Network Reveals Extensive Regulatory Potential of the Core Spliceosomal Machinery. Mol Cell 2015; 57:7-22. [DOI: 10.1016/j.molcel.2014.10.030] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 09/24/2014] [Accepted: 10/31/2014] [Indexed: 12/12/2022]
|
18
|
Wang J, Tadeo X, Hou H, Andrews S, Moresco JJ, Yates JR, Nagy PL, Jia S. Tls1 regulates splicing of shelterin components to control telomeric heterochromatin assembly and telomere length. Nucleic Acids Res 2014; 42:11419-32. [PMID: 25245948 PMCID: PMC4191416 DOI: 10.1093/nar/gku842] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Heterochromatin preferentially forms at repetitive DNA elements through RNAi-mediated targeting of histone-modifying enzymes. It was proposed that splicing factors interact with the RNAi machinery or regulate the splicing of repeat transcripts to directly participate in heterochromatin assembly. Here, by screening the fission yeast deletion library, we comprehensively identified factors required for telomeric heterochromatin assembly, including a novel gene tls1+. Purification of Tls1 and mass spectrometry analysis of its interacting proteins show that Tls1 associates with the spliceosome subunit Brr2. RNA sequencing analysis shows that the splicing of a subset of mRNAs are affected in tls1Δ cells, including mRNAs of shelterin components rap1+ and poz1+. Importantly, replacing rap1+ and poz1+ with their cDNAs significantly alleviated heterochromatin defects of tls1Δ cells, suggesting that the missplicing of shelterin components is the cause of such defects, and that splicing factors regulate telomeric heterochromatin through the proper splicing of heterochromatin factors. In addition to its role in telomeric heterochromatin assembly, Tls1-mediated splicing of shelterin mRNAs also regulates telomere length. Given that its human homologue C9ORF78 also associates with the spliceosome and is overexpressed in multiple cancer cell lines, our results suggest that C9ORF78 overexpression might alter the proper splicing of genes during cancer progression.
Collapse
Affiliation(s)
- Jiyong Wang
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Xavier Tadeo
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Haitong Hou
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Stuart Andrews
- Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - James J Moresco
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA
| | - John R Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Peter L Nagy
- Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Songtao Jia
- Department of Biological Sciences, Columbia University, New York, NY, USA
| |
Collapse
|
19
|
Splicing functions and global dependency on fission yeast slu7 reveal diversity in spliceosome assembly. Mol Cell Biol 2013; 33:3125-36. [PMID: 23754748 DOI: 10.1128/mcb.00007-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The multiple short introns in Schizosaccharomyces pombe genes with degenerate cis sequences and atypically positioned polypyrimidine tracts make an interesting model to investigate canonical and alternative roles for conserved splicing factors. Here we report functions and interactions of the S. pombe slu7(+) (spslu7(+)) gene product, known from Saccharomyces cerevisiae and human in vitro reactions to assemble into spliceosomes after the first catalytic reaction and to dictate 3' splice site choice during the second reaction. By using a missense mutant of this essential S. pombe factor, we detected a range of global splicing derangements that were validated in assays for the splicing status of diverse candidate introns. We ascribe widespread, intron-specific SpSlu7 functions and have deduced several features, including the branch nucleotide-to-3' splice site distance, intron length, and the impact of its A/U content at the 5' end on the intron's dependence on SpSlu7. The data imply dynamic substrate-splicing factor relationships in multiintron transcripts. Interestingly, the unexpected early splicing arrest in spslu7-2 revealed a role before catalysis. We detected a salt-stable association with U5 snRNP and observed genetic interactions with spprp1(+), a homolog of human U5-102k factor. These observations together point to an altered recruitment and dependence on SpSlu7, suggesting its role in facilitating transitions that promote catalysis, and highlight the diversity in spliceosome assembly.
Collapse
|
20
|
A quantitative high-throughput in vitro splicing assay identifies inhibitors of spliceosome catalysis. Mol Cell Biol 2012; 32:1271-83. [PMID: 22252314 DOI: 10.1128/mcb.05788-11] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Despite intensive research, there are very few reagents with which to modulate and dissect the mRNA splicing pathway. Here, we describe a novel approach to identify such tools, based on detection of the exon junction complex (EJC), a unique molecular signature that splicing leaves on mRNAs. We developed a high-throughput, splicing-dependent EJC immunoprecipitation (EJIPT) assay to quantitate mRNAs spliced from biotin-tagged pre-mRNAs in cell extracts, using antibodies to EJC components Y14 and eukaryotic translation initiation factor 4aIII (eIF4AIII). Deploying EJIPT we performed high-throughput screening (HTS) in conjunction with secondary assays to identify splicing inhibitors. We describe the identification of 1,4-naphthoquinones and 1,4-heterocyclic quinones with known anticancer activity as potent and selective splicing inhibitors. Interestingly, and unlike previously described small molecules, most of which target early steps, our inhibitors represented by the benzothiazole-4,7-dione, BN82685, block the second of two trans-esterification reactions in splicing, preventing the release of intron lariat and ligation of exons. We show that BN82685 inhibits activated spliceosomes' elaborate structural rearrangements that are required for second-step catalysis, allowing definition of spliceosomes stalled in midcatalysis. EJIPT provides a platform for characterization and discovery of splicing and EJC modulators.
Collapse
|
21
|
Abstract
The U5 snRNP (small ribonucleoprotein) contains several functionally crucial splicing factors that form an extensive interaction network both in the snRNP and within the spliceosome. In this issue of Genes & Development, Weber and colleagues (pp. 1601-1612) shed light on the dynamic assembly of this critical spliceosomal component and elucidate the molecular interactions underlying the ordered addition of Brr2, a pivotal spliceosomal helicase, to the U5 snRNP.
Collapse
Affiliation(s)
- Saba Valadkhan
- Center for RNA Molecular Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA.
| |
Collapse
|
22
|
Valadkhan S, Jaladat Y. The spliceosomal proteome: at the heart of the largest cellular ribonucleoprotein machine. Proteomics 2010; 10:4128-41. [PMID: 21080498 DOI: 10.1002/pmic.201000354] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Almost all primary transcripts in higher eukaryotes undergo several splicing events and alternative splicing is a major factor in generating proteomic diversity. Thus, the spliceosome, the ribonucleoprotein assembly that performs splicing, is a highly critical cellular machine and as expected, a very complex one. Indeed, the spliceosome is one of the largest, if not the largest, molecular machine in the cell with over 150 different components in human. A large fraction of the spliceosomal proteome is organized into small nuclear ribonucleoprotein particles by associating with one of the small nuclear RNAs, and the function of many spliceosomal proteins revolve around their association or interaction with the spliceosomal RNAs or the substrate pre-messenger RNAs. In addition to the complex web of protein-RNA interactions, an equally complex network of protein-protein interactions exists in the spliceosome, which includes a number of large, conserved proteins with critical functions in the spliceosomal catalytic core. These include the largest conserved nuclear protein, Prp8, which plays a critical role in spliceosomal function in a hitherto unknown manner. Taken together, the large spliceosomal proteome and its dynamic nature has made it a highly challenging system to study, and at the same time, provides an exciting example of the evolution of a proteome around a backbone of primordial RNAs likely dating from the RNA World.
Collapse
Affiliation(s)
- Saba Valadkhan
- Center for RNA Molecular Biology, Case Western Reserve University, Cleveland, OH 44113, USA.
| | | |
Collapse
|
23
|
Schneider M, Hsiao HH, Will CL, Giet R, Urlaub H, Lührmann R. Human PRP4 kinase is required for stable tri-snRNP association during spliceosomal B complex formation. Nat Struct Mol Biol 2010; 17:216-21. [PMID: 20118938 DOI: 10.1038/nsmb.1718] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 10/09/2009] [Indexed: 11/09/2022]
Abstract
Reversible protein phosphorylation has an essential role during pre-mRNA splicing. Here we identify two previously unidentified phosphoproteins in the human spliceosomal B complex, namely the pre-mRNA processing factors PRP6 and PRP31, both components of the U4/U6-U5 tri-small nuclear ribonucleoprotein (snRNP). We provide evidence that PRP6 and PRP31 are directly phosphorylated by human PRP4 kinase (PRP4K) concomitant with their incorporation into B complexes. Immunodepletion and complementation studies with HeLa splicing extracts revealed that active human PRP4K is required for the phosphorylation of PRP6 and PRP31 and for the assembly of stable, functional B complexes. Thus, the phosphorylation of PRP6 and PRP31 is likely to have a key role during spliceosome assembly. Our data provide new insights into the molecular mechanism by which PRP4K contributes to splicing. They further indicate that numerous phosphorylation events contribute to spliceosome assembly and, thus, that splicing can potentially be modulated at multiple regulatory checkpoints.
Collapse
Affiliation(s)
- Marc Schneider
- Department of Cellular Biochemistry, Max Planck Institute of Biophysical Chemistry, Göttingen, Germany
| | | | | | | | | | | |
Collapse
|
24
|
Lützelberger M, Bottner CA, Schwelnus W, Zock-Emmenthal S, Razanau A, Käufer NF. The N-terminus of Prp1 (Prp6/U5-102 K) is essential for spliceosome activation in vivo. Nucleic Acids Res 2009; 38:1610-22. [PMID: 20007600 PMCID: PMC2836577 DOI: 10.1093/nar/gkp1155] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The spliceosomal protein Prp1 (Prp6/U5-102 K) is necessary for the integrity of pre-catalytic spliceosomal complexes. We have identified a novel regulatory function for Prp1. Expression of mutations in the N-terminus of Prp1 leads to the accumulation of pre-catalytic spliceosomal complexes containing the five snRNAs U1, U2, U5 and U4/U6 and pre-mRNAs. The mutations in the N-terminus, which prevent splicing to occur, include in vitro and in vivo identified phosphorylation sites of Prp4 kinase. These sites are highly conserved in the human ortholog U5-102 K. The results presented here demonstrate that structural integrity of the N-terminus is required to mediate a splicing event, but is not necessary for the assembly of spliceosomes.
Collapse
Affiliation(s)
- Martin Lützelberger
- Institute of Genetics, University of Braunschweig TU, Spielmannstr. 7, 38106 Braunschweig, Germany
| | | | | | | | | | | |
Collapse
|
25
|
Haudek KC, Voss PG, Locascio LE, Wang JL, Patterson RJ. A mechanism for incorporation of galectin-3 into the spliceosome through its association with U1 snRNP. Biochemistry 2009; 48:7705-12. [PMID: 19603745 PMCID: PMC2760976 DOI: 10.1021/bi900071b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previously, we showed that galectin-1 and galectin-3 are redundant pre-mRNA splicing factors associated with the spliceosome throughout the splicing pathway. Here we present evidence for the association of galectin-3 with snRNPs outside of the spliceosome (i.e., in the absence of pre-mRNA splicing substrate). Immunoprecipitation of HeLa nuclear extract with anti-galectin-3 resulted in the coprecipitation of the five spliceosomal snRNAs, core Sm polypeptides, and the U1-specific protein, U1 70K. When nuclear extract was fractionated on glycerol gradients, some galectin-3 molecules cosedimented with snRNP complexes. This cosedimentation represents bona fide galectin-3--snRNP complexes as (i) immunoprecipitation of gradient fractions with anti-galectin-3 yielded several complexes with varying ratios of snRNAs and associated proteins and (ii) the distribution of galectin-3--snRNP complexes was altered when the glycerol gradient was sedimented in the presence of lactose, a galectin ligand. A complex at approximately 10S showed an association of galectin-3 with U1 snRNP that was sensitive to treatment with ribonuclease A. We tested the ability of this U1 snRNP to recognize an exogenous pre-mRNA substrate. Under conditions that assemble early splicing complexes, we found this isolated galectin-3--U1 snRNP particle was sufficient to load galectin-3 onto a pre-mRNA substrate, but not onto a control RNA lacking splice sites. Pretreatment of the U1 snRNP with micrococcal nuclease abolished the assembly of galectin-3 onto this early complex. These data identify galectin-3 as a polypeptide associated with snRNPs in the absence of splicing substrate and describe a mechanism for the assembly of galectin-3 onto the forming spliceosome.
Collapse
Affiliation(s)
- Kevin C. Haudek
- Department of Biochemistry and Molecular Biology, 4198 BPS, Michigan State University, East Lansing, MI 48824
| | - Patricia G. Voss
- Department of Biochemistry and Molecular Biology, 4198 BPS, Michigan State University, East Lansing, MI 48824
| | - Lauren E. Locascio
- Department of Biochemistry and Molecular Biology, 4198 BPS, Michigan State University, East Lansing, MI 48824
| | - John L. Wang
- Department of Biochemistry and Molecular Biology, 4198 BPS, Michigan State University, East Lansing, MI 48824
| | - Ronald J. Patterson
- Department of Microbiology and Molecular Genetics, 4198 BPS, Michigan State University, East Lansing, MI 48824
| |
Collapse
|
26
|
Venancio TM, Balaji S, Iyer LM, Aravind L. Reconstructing the ubiquitin network: cross-talk with other systems and identification of novel functions. Genome Biol 2009; 10:R33. [PMID: 19331687 PMCID: PMC2691004 DOI: 10.1186/gb-2009-10-3-r33] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 02/11/2009] [Accepted: 03/30/2009] [Indexed: 12/31/2022] Open
Abstract
A computational model of the yeast Ubiquitin system highlights interesting biological features including functional interactions between components and interplay with other regulatory mechanisms. Background The ubiquitin system (Ub-system) can be defined as the ensemble of components including Ub/ubiquitin-like proteins, their conjugation and deconjugation apparatus, binding partners and the proteasomal system. While several studies have concentrated on structure-function relationships and evolution of individual components of the Ub-system, a study of the system as a whole is largely lacking. Results Using numerous genome-scale datasets, we assemble for the first time a comprehensive reconstruction of the budding yeast Ub-system, revealing static and dynamic properties. We devised two novel representations, the rank plot to understand the functional diversification of different components and the clique-specific point-wise mutual-information network to identify significant interactions in the Ub-system. Conclusions Using these representations, evidence is provided for the functional diversification of components such as SUMO-dependent Ub-ligases. We also identify novel components of SCF (Skp1-cullin-F-box)-dependent complexes, receptors in the ERAD (endoplasmic reticulum associated degradation) system and a key role for Sus1 in coordinating multiple Ub-related processes in chromatin dynamics. We present evidence for a major impact of the Ub-system on large parts of the proteome via its interaction with the transcription regulatory network. Furthermore, the dynamics of the Ub-network suggests that Ub and SUMO modifications might function cooperatively with transcription control in regulating cell-cycle-stage-specific complexes and in reinforcing periodicities in gene expression. Combined with evolutionary information, the structure of this network helps in understanding the lineage-specific expansion of SCF complexes with a potential role in pathogen response and the origin of the ERAD and ESCRT systems.
Collapse
Affiliation(s)
- Thiago M Venancio
- National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, MD 20894, USA.
| | | | | | | |
Collapse
|
27
|
Valadkhan S. The spliceosome: caught in a web of shifting interactions. Curr Opin Struct Biol 2007; 17:310-5. [PMID: 17574835 DOI: 10.1016/j.sbi.2007.05.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Revised: 03/27/2007] [Accepted: 05/25/2007] [Indexed: 11/23/2022]
Abstract
Splicing is a crucial, ubiquitous and highly complex step in eukaryotic gene expression. The daunting complexity of the splicing reaction, although fascinating, has severely limited our understanding of its mechanistic details. Recent advances have begun to provide exciting new insights into the dynamic interactions that govern the function of the spliceosome, the multi-megadalton complex that performs splicing. An emerging paradigm is the presence of a succession of distinct conformational states, which are stabilized by an intricate network of interactions. Recent data suggest that even subtle changes in the composition of the interaction network can result in interconversion of the different conformational states, providing opportunities for regulation and proofreading of spliceosome function. Significant progress in proteomics has elucidated the protein composition of the spliceosome at different stages of assembly. Also, the increased sophistication and resolution of cryo-electron microscopy techniques, combined with high-resolution structural studies on a smaller scale, promise to create detailed images of the global structure of the spliceosome and its main components, which in turn will provide a plethora of mechanistic insights. Overall, the past two years have seen a convergence of data from different lines of research into what promises to become a holistic picture of spliceosome function.
Collapse
Affiliation(s)
- Saba Valadkhan
- Center for RNA Molecular Biology, Case Western Reserve University, 10900 Euclid Avenue, Wood RT 100-8, Cleveland, OH 44106, USA.
| |
Collapse
|
28
|
Newo ANS, Lützelberger M, Bottner CA, Wehland J, Wissing J, Jänsch L, Käufer NF. Proteomic analysis of the U1 snRNP of Schizosaccharomyces pombe reveals three essential organism-specific proteins. Nucleic Acids Res 2007; 35:1391-401. [PMID: 17264129 PMCID: PMC1865046 DOI: 10.1093/nar/gkl1144] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Characterization of spliceosomal complexes in the fission yeast Schizosaccharomyces pombe revealed particles sedimenting in the range of 30-60S, exclusively containing U1 snRNA. Here, we report the tandem affinity purification (TAP) of U1-specific protein complexes. The components of the complexes were identified using (LC-MS/MS) mass spectrometry. The fission yeast U1 snRNP contains 16 proteins, including the 7 Sm snRNP core proteins. In both fission and budding yeast, the U1 snRNP contains 9 and 10 U1 specific proteins, respectively, whereas the U1 particle found in mammalian cells contains only 3. Among the U1-specific proteins in S. pombe, three are homolog to the mammalian and six to the budding yeast Saccharomyces cerevisiae U1-specific proteins, whereas three, called U1H, U1J and U1L, are proteins specific to S. pombe. Furthermore, we demonstrate that the homolog of U1-70K and the three proteins specific to S. pombe are essential for growth. We will discuss the differences between the U1 snRNPs with respect to the organism-specific proteins found in the two yeasts and the resulting effect it has on pre-mRNA splicing.
Collapse
Affiliation(s)
- Alain N. S. Newo
- Institute of Genetics, Technical University of Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany and Helmholtz Center for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany
| | - Martin Lützelberger
- Institute of Genetics, Technical University of Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany and Helmholtz Center for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany
| | - Claudia A. Bottner
- Institute of Genetics, Technical University of Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany and Helmholtz Center for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany
| | - Jürgen Wehland
- Institute of Genetics, Technical University of Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany and Helmholtz Center for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany
| | - Josef Wissing
- Institute of Genetics, Technical University of Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany and Helmholtz Center for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany
| | - Lothar Jänsch
- Institute of Genetics, Technical University of Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany and Helmholtz Center for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany
| | - Norbert F. Käufer
- Institute of Genetics, Technical University of Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany and Helmholtz Center for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany
- *To whom correspondence should be addressed. +49 531 391 5774+49 531 391 5765
| |
Collapse
|
29
|
John Wiley & Sons, Ltd.. Current awareness on yeast. Yeast 2006. [DOI: 10.1002/yea.1314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|