1
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Ngo LH, Bert AG, Dredge BK, Williams T, Murphy V, Li W, Hamilton WB, Carey KT, Toubia J, Pillman KA, Liu D, Desogus J, Chao JA, Deans AJ, Goodall GJ, Wickramasinghe VO. Nuclear export of circular RNA. Nature 2024; 627:212-220. [PMID: 38355801 DOI: 10.1038/s41586-024-07060-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 01/12/2024] [Indexed: 02/16/2024]
Abstract
Circular RNAs (circRNAs), which are increasingly being implicated in a variety of functions in normal and cancerous cells1-5, are formed by back-splicing of precursor mRNAs in the nucleus6-10. circRNAs are predominantly localized in the cytoplasm, indicating that they must be exported from the nucleus. Here we identify a pathway that is specific for the nuclear export of circular RNA. This pathway requires Ran-GTP, exportin-2 and IGF2BP1. Enhancing the nuclear Ran-GTP gradient by depletion or chemical inhibition of the major protein exporter CRM1 selectively increases the nuclear export of circRNAs, while reducing the nuclear Ran-GTP gradient selectively blocks circRNA export. Depletion or knockout of exportin-2 specifically inhibits nuclear export of circRNA. Analysis of nuclear circRNA-binding proteins reveals that interaction between IGF2BP1 and circRNA is enhanced by Ran-GTP. The formation of circRNA export complexes in the nucleus is promoted by Ran-GTP through its interactions with exportin-2, circRNA and IGF2BP1. Our findings demonstrate that adaptors such as IGF2BP1 that bind directly to circular RNAs recruit Ran-GTP and exportin-2 to export circRNAs in a mechanism that is analogous to protein export, rather than mRNA export.
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Affiliation(s)
- Linh H Ngo
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
| | - Andrew G Bert
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
| | - B Kate Dredge
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
- Adelaide Centre for Epigenetics, School of Biomedicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
- South Australian immunoGENomics Cancer Institute (SAiGENCI), Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Tobias Williams
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Vincent Murphy
- Genome Stability Unit, St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Wanqiu Li
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
- Department of Pharmacology, Joint Laboratory of Guangdong-Hong Kong Universities for Vascular Homeostasis and Diseases, School of Medicine and Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, China
| | - William B Hamilton
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
| | - Kirstyn T Carey
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
| | - John Toubia
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
| | - Katherine A Pillman
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
- Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Dawei Liu
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia
| | - Jessica Desogus
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Jeffrey A Chao
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Andrew J Deans
- Genome Stability Unit, St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Gregory J Goodall
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia.
- Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia.
- Department of Medicine, University of Adelaide, Adelaide, South Australia, Australia.
| | - Vihandha O Wickramasinghe
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre and Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia.
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia.
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2
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Liu D, Dredge BK, Bert AG, Pillman KA, Toubia J, Guo W, Dyakov BA, Migault MM, Conn VM, Conn S, Gregory PA, Gingras AC, Patel D, Wu B, Goodall G. ESRP1 controls biogenesis and function of a large abundant multiexon circRNA. Nucleic Acids Res 2024; 52:1387-1403. [PMID: 38015468 PMCID: PMC10853802 DOI: 10.1093/nar/gkad1138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 10/24/2023] [Accepted: 11/13/2023] [Indexed: 11/29/2023] Open
Abstract
While the majority of circRNAs are formed from infrequent back-splicing of exons from protein coding genes, some can be produced at quite high level and in a regulated manner. We describe the regulation, biogenesis and function of circDOCK1(2-27), a large, abundant circular RNA that is highly regulated during epithelial-mesenchymal transition (EMT) and whose formation depends on the epithelial splicing regulator ESRP1. CircDOCK1(2-27) synthesis in epithelial cells represses cell motility both by diverting transcripts from DOCK1 mRNA production to circRNA formation and by direct inhibition of migration by the circRNA. HITS-CLIP analysis and CRISPR-mediated deletions indicate ESRP1 controls circDOCK1(2-27) biosynthesis by binding a GGU-containing repeat region in intron 1 and detaining its splicing until Pol II completes its 157 kb journey to exon 27. Proximity-dependent biotinylation (BioID) assay suggests ESRP1 may modify the RNP landscape of intron 1 in a way that disfavours communication of exon 1 with exon 2, rather than physically bridging exon 2 to exon 27. The X-ray crystal structure of RNA-bound ESRP1 qRRM2 domain reveals it binds to GGU motifs, with the guanines embedded in clamp-like aromatic pockets in the protein.
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Affiliation(s)
- Dawei Liu
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
| | - B Kate Dredge
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
| | - Andrew G Bert
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
| | - Katherine A Pillman
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005, Australia
| | - John Toubia
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
- ACRF Cancer Genomics Facility, Centre for Cancer Biology, SA Pathology and University of South Australia, Frome Road, Adelaide, SA 5000, Australia
| | - Wenting Guo
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, RNA Biomedical Institute, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Boris J A Dyakov
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health, 600 University Ave, Toronto, ON M5G 1X5, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Melodie M Migault
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
| | - Vanessa M Conn
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
- Flinders Health and Medical Research Institute, College of Medicine & Public Health, Flinders University, Bedford Park, SA, 5042, Australia
| | - Simon J Conn
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
- Flinders Health and Medical Research Institute, College of Medicine & Public Health, Flinders University, Bedford Park, SA, 5042, Australia
| | - Philip A Gregory
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health, 600 University Ave, Toronto, ON M5G 1X5, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Dinshaw Patel
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Baixing Wu
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, RNA Biomedical Institute, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Gregory J Goodall
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005, Australia
- Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia
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3
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Neumann DP, Pillman KA, Dredge BK, Bert AG, Phillips CA, Lumb R, Ramani Y, Bracken CP, Hollier BG, Selth LA, Beilharz TH, Goodall GJ, Gregory PA. The landscape of alternative polyadenylation during EMT and its regulation by the RNA-binding protein Quaking. RNA Biol 2024; 21:1-11. [PMID: 38112323 PMCID: PMC10732628 DOI: 10.1080/15476286.2023.2294222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2023] [Indexed: 12/21/2023] Open
Abstract
Epithelial-mesenchymal transition (EMT) plays important roles in tumour progression and is orchestrated by dynamic changes in gene expression. While it is well established that post-transcriptional regulation plays a significant role in EMT, the extent of alternative polyadenylation (APA) during EMT has not yet been explored. Using 3' end anchored RNA sequencing, we mapped the alternative polyadenylation (APA) landscape following Transforming Growth Factor (TGF)-β-mediated induction of EMT in human mammary epithelial cells and found APA generally causes 3'UTR lengthening during this cell state transition. Investigation of potential mediators of APA indicated the RNA-binding protein Quaking (QKI), a splicing factor induced during EMT, regulates a subset of events including the length of its own transcript. Analysis of QKI crosslinked immunoprecipitation (CLIP)-sequencing data identified the binding of QKI within 3' untranslated regions (UTRs) was enriched near cleavage and polyadenylation sites. Following QKI knockdown, APA of many transcripts is altered to produce predominantly shorter 3'UTRs associated with reduced gene expression. These findings reveal the changes in APA that occur during EMT and identify a potential role for QKI in this process.
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Affiliation(s)
- Daniel P. Neumann
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Katherine A. Pillman
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - B. Kate Dredge
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Andrew G. Bert
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Caroline A. Phillips
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Rachael Lumb
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Yesha Ramani
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Cameron P. Bracken
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
- Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Brett G. Hollier
- Australian Prostate Cancer Research Centre - Queensland, Centre for Genomics and Personalised Health, Faculty of Health, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
| | - Luke A. Selth
- Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
- Flinders Health and Medical Research Institute, Flinders University, Bedford Park, SA, Australia
| | - Traude H. Beilharz
- Development and Stem Cells Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia
| | - Gregory J. Goodall
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
- Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Philip A. Gregory
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
- Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA, Australia
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4
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Orang A, Dredge BK, Liu CY, Bracken JM, Chen CH, Sourdin L, Whitfield HJ, Lumb R, Boyle ST, Davis MJ, Samuel MS, Gregory PA, Khew-Goodall Y, Goodall GJ, Pillman KA, Bracken CP. Basonuclin-2 regulates extracellular matrix production and degradation. Life Sci Alliance 2023; 6:e202301984. [PMID: 37536977 PMCID: PMC10400885 DOI: 10.26508/lsa.202301984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 07/16/2023] [Accepted: 07/20/2023] [Indexed: 08/05/2023] Open
Abstract
Epithelial-mesenchymal transition is essential for tissue patterning and organization. It involves both regulation of cell motility and alterations in the composition and organization of the ECM-a complex environment of proteoglycans and fibrous proteins essential for tissue homeostasis, signaling in response to chemical and biomechanical stimuli, and is often dysregulated under conditions such as cancer, fibrosis, and chronic wounds. Here, we demonstrate that basonuclin-2 (BNC2), a mesenchymal-expressed gene, that is, strongly associated with cancer and developmental defects across genome-wide association studies, is a novel regulator of ECM composition and degradation. We find that at endogenous levels, BNC2 controls the expression of specific collagens, matrix metalloproteases, and other matrisomal components in breast cancer cells, and in fibroblasts that are primarily responsible for the production and processing of the ECM within the tumour microenvironment. In so doing, BNC2 modulates the motile and invasive properties of cancers, which likely explains the association of high BNC2 expression with increasing cancer grade and poor patient prognosis.
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Affiliation(s)
- Ayla Orang
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
| | - B Kate Dredge
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
| | - Chi Yau Liu
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
| | - Julie M Bracken
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
| | - Chun-Hsien Chen
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
| | - Laura Sourdin
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
| | - Holly J Whitfield
- Division of Bioinformatics, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
| | - Rachael Lumb
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
| | - Sarah T Boyle
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
| | - Melissa J Davis
- South Australian ImmunogGENomics Cancer Institute, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, Australia
- Division of Bioinformatics, Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
- Department of Medical Biology, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
- Department of Clinical Pathology, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
- Fraser Institute, University of Queensland, Wooloongabba, Australia
| | - Michael S Samuel
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
- Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, Australia
| | - Philip A Gregory
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
- Department of Medicine and School of Biological Sciences, University of Adelaide, Adelaide, Australia
| | - Yeesim Khew-Goodall
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
- Department of Medicine and School of Biological Sciences, University of Adelaide, Adelaide, Australia
| | - Gregory J Goodall
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
- Department of Medicine and School of Biological Sciences, University of Adelaide, Adelaide, Australia
| | - Katherine A Pillman
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
- Department of Medicine and School of Biological Sciences, University of Adelaide, Adelaide, Australia
| | - Cameron P Bracken
- Centre for Cancer Biology, An Alliance of SA Pathology and University of South Australia, Adelaide, Australia
- Department of Medicine and School of Biological Sciences, University of Adelaide, Adelaide, Australia
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5
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Jensen KB, Dredge BK, Toubia J, Jin X, Iadevaia V, Goodall GJ, Proud CG. capCLIP: a new tool to probe translational control in human cells through capture and identification of the eIF4E-mRNA interactome. Nucleic Acids Res 2021; 49:e105. [PMID: 34255842 PMCID: PMC8501963 DOI: 10.1093/nar/gkab604] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 06/16/2021] [Accepted: 07/06/2021] [Indexed: 12/21/2022] Open
Abstract
Translation of eukaryotic mRNAs begins with binding of their m7G cap to eIF4E, followed by recruitment of other translation initiation factor proteins. We describe capCLIP, a novel method to comprehensively capture and quantify the eIF4E (eukaryotic initiation factor 4E) 'cap-ome' and apply it to examine the biological consequences of eIF4E-cap binding in distinct cellular contexts. First, we use capCLIP to identify the eIF4E cap-omes in human cells with/without the mTORC1 (mechanistic target of rapamycin, complex 1) inhibitor rapamycin, there being an emerging consensus that rapamycin inhibits translation of TOP (terminal oligopyrimidine) mRNAs by displacing eIF4E from their caps. capCLIP reveals that the representation of TOP mRNAs in the cap-ome is indeed systematically reduced by rapamycin, thus validating our new methodology. capCLIP also refines the requirements for a functional TOP sequence. Second, we apply capCLIP to probe the consequences of phosphorylation of eIF4E. We show eIF4E phosphorylation reduces overall eIF4E-mRNA association and, strikingly, causes preferential dissociation of mRNAs with short 5'-UTRs. capCLIP is a valuable new tool to probe the function of eIF4E and of other cap-binding proteins such as eIF4E2/eIF4E3.
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Affiliation(s)
- Kirk B Jensen
- Lifelong Health, South Australian Health and Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia.,School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - B Kate Dredge
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia
| | - John Toubia
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia.,ACRF Cancer Genomics Facility, Centre for Cancer Biology, SA Pathology and University of South Australia, Frome Road, Adelaide, SA 5000, Australia
| | - Xin Jin
- Lifelong Health, South Australian Health and Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia.,School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Valentina Iadevaia
- School of Biosciences and Medicine, University of Surrey, Guildford, Surrey GU2 7XH, UK
| | - Gregory J Goodall
- School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA 5005, Australia.,Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA 5000, Australia.,Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Christopher G Proud
- Lifelong Health, South Australian Health and Medical Research Institute, North Terrace, Adelaide, SA 5000, Australia.,School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA 5005, Australia
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6
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Fernandes RC, Toubia J, Townley S, Hanson AR, Dredge BK, Pillman KA, Bert AG, Winter JM, Iggo R, Das R, Obinata D, Sandhu S, Risbridger GP, Taylor RA, Lawrence MG, Butler LM, Zoubeidi A, Gregory PA, Tilley WD, Hickey TE, Goodall GJ, Selth LA. Post-transcriptional Gene Regulation by MicroRNA-194 Promotes Neuroendocrine Transdifferentiation in Prostate Cancer. Cell Rep 2021; 34:108585. [PMID: 33406413 DOI: 10.1016/j.celrep.2020.108585] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 10/23/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023] Open
Abstract
Potent therapeutic inhibition of the androgen receptor (AR) in prostate adenocarcinoma can lead to the emergence of neuroendocrine prostate cancer (NEPC), a phenomenon associated with enhanced cell plasticity. Here, we show that microRNA-194 (miR-194) is a regulator of epithelial-neuroendocrine transdifferentiation. In clinical prostate cancer samples, miR-194 expression and activity were elevated in NEPC and inversely correlated with AR signaling. miR-194 facilitated the emergence of neuroendocrine features in prostate cancer cells, a process mediated by its ability to directly target a suite of genes involved in cell plasticity. One such target was FOXA1, which encodes a transcription factor with a vital role in maintaining the prostate epithelial lineage. Importantly, a miR-194 inhibitor blocked epithelial-neuroendocrine transdifferentiation and inhibited the growth of cell lines and patient-derived organoids possessing neuroendocrine features. Overall, our study reveals a post-transcriptional mechanism regulating the plasticity of prostate cancer cells and provides a rationale for targeting miR-194 in NEPC.
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Affiliation(s)
- Rayzel C Fernandes
- Dame Roma Mitchell Cancer Research Laboratories and Freemasons Foundation Centre for Men's Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - John Toubia
- ACRF Cancer Genomics Facility, Centre for Cancer Biology, An alliance of SA Pathology and University of South Australia, Frome Road, Adelaide, SA 5005, Australia
| | - Scott Townley
- Dame Roma Mitchell Cancer Research Laboratories and Freemasons Foundation Centre for Men's Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Adrienne R Hanson
- Dame Roma Mitchell Cancer Research Laboratories and Freemasons Foundation Centre for Men's Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - B Kate Dredge
- Centre for Cancer Biology, An alliance of SA Pathology and University of South Australia, Adelaide, SA 5005, Australia
| | - Katherine A Pillman
- Centre for Cancer Biology, An alliance of SA Pathology and University of South Australia, Adelaide, SA 5005, Australia
| | - Andrew G Bert
- Centre for Cancer Biology, An alliance of SA Pathology and University of South Australia, Adelaide, SA 5005, Australia
| | - Jean M Winter
- Dame Roma Mitchell Cancer Research Laboratories and Freemasons Foundation Centre for Men's Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Richard Iggo
- Dame Roma Mitchell Cancer Research Laboratories and Freemasons Foundation Centre for Men's Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia; Institut Bergonié Unicancer, INSERM U1218, Bordeaux, France
| | - Rajdeep Das
- Dame Roma Mitchell Cancer Research Laboratories and Freemasons Foundation Centre for Men's Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia; Transplant Immunology Laboratory, Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Daisuke Obinata
- Department of Urology, Nihon University School of Medicine, Tokyo 173-8610, Japan; Department of Anatomy and Developmental Biology, Monash Partners Comprehensive Cancer Consortium, Monash Biomedicine Discovery Institute, Prostate Cancer Research Group, Monash University, Clayton, VIC 3168, Australia
| | -
- Department of Anatomy and Developmental Biology, Monash Partners Comprehensive Cancer Consortium, Monash Biomedicine Discovery Institute, Prostate Cancer Research Group, Monash University, Clayton, VIC 3168, Australia; Cancer Research Program, Cancer Research Division, Peter MacCallum Cancer Centre, University of Melbourne, Melbourne, VIC 3000, Australia
| | - Shahneen Sandhu
- Cancer Research Program, Cancer Research Division, Peter MacCallum Cancer Centre, University of Melbourne, Melbourne, VIC 3000, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, VIC 3000, Australia
| | - Gail P Risbridger
- Department of Anatomy and Developmental Biology, Monash Partners Comprehensive Cancer Consortium, Monash Biomedicine Discovery Institute, Prostate Cancer Research Group, Monash University, Clayton, VIC 3168, Australia; Cancer Research Program, Cancer Research Division, Peter MacCallum Cancer Centre, University of Melbourne, Melbourne, VIC 3000, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, VIC 3000, Australia
| | - Renea A Taylor
- Cancer Research Program, Cancer Research Division, Peter MacCallum Cancer Centre, University of Melbourne, Melbourne, VIC 3000, Australia; Department of Physiology, Monash Partners Comprehensive Cancer Consortium, Monash Biomedicine Discovery Institute, Prostate Cancer Research Group, Monash University, Clayton, VIC 3168, Australia
| | - Mitchell G Lawrence
- Department of Anatomy and Developmental Biology, Monash Partners Comprehensive Cancer Consortium, Monash Biomedicine Discovery Institute, Prostate Cancer Research Group, Monash University, Clayton, VIC 3168, Australia; Cancer Research Program, Cancer Research Division, Peter MacCallum Cancer Centre, University of Melbourne, Melbourne, VIC 3000, Australia
| | - Lisa M Butler
- South Australian Health and Medical Research Institute, Adelaide, SA 5000, Australia; Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Amina Zoubeidi
- The Vancouver Prostate Centre, University of British Columbia, Vancouver, BC V6H 3Z6, Canada
| | - Philip A Gregory
- Centre for Cancer Biology, An alliance of SA Pathology and University of South Australia, Adelaide, SA 5005, Australia; Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Wayne D Tilley
- Dame Roma Mitchell Cancer Research Laboratories and Freemasons Foundation Centre for Men's Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Theresa E Hickey
- Dame Roma Mitchell Cancer Research Laboratories and Freemasons Foundation Centre for Men's Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Gregory J Goodall
- Centre for Cancer Biology, An alliance of SA Pathology and University of South Australia, Adelaide, SA 5005, Australia; School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Luke A Selth
- Dame Roma Mitchell Cancer Research Laboratories and Freemasons Foundation Centre for Men's Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia; Flinders Health and Medical Research Institute, Flinders University, Bedford Park, SA 5042, Australia.
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7
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Pillman KA, Phillips CA, Roslan S, Toubia J, Dredge BK, Bert AG, Lumb R, Neumann DP, Li X, Conn SJ, Liu D, Bracken CP, Lawrence DM, Stylianou N, Schreiber AW, Tilley WD, Hollier BG, Khew-Goodall Y, Selth LA, Goodall GJ, Gregory PA. miR-200/375 control epithelial plasticity-associated alternative splicing by repressing the RNA-binding protein Quaking. EMBO J 2018; 37:embj.201899016. [PMID: 29871889 PMCID: PMC6028027 DOI: 10.15252/embj.201899016] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/22/2018] [Accepted: 03/24/2018] [Indexed: 12/25/2022] Open
Abstract
Members of the miR‐200 family are critical gatekeepers of the epithelial state, restraining expression of pro‐mesenchymal genes that drive epithelial–mesenchymal transition (EMT) and contribute to metastatic cancer progression. Here, we show that miR‐200c and another epithelial‐enriched miRNA, miR‐375, exert widespread control of alternative splicing in cancer cells by suppressing the RNA‐binding protein Quaking (QKI). During EMT, QKI‐5 directly binds to and regulates hundreds of alternative splicing targets and exerts pleiotropic effects, such as increasing cell migration and invasion and restraining tumour growth, without appreciably affecting mRNA levels. QKI‐5 is both necessary and sufficient to direct EMT‐associated alternative splicing changes, and this splicing signature is broadly conserved across many epithelial‐derived cancer types. Importantly, several actin cytoskeleton‐associated genes are directly targeted by both QKI and miR‐200c, revealing coordinated control of alternative splicing and mRNA abundance during EMT. These findings demonstrate the existence of a miR‐200/miR‐375/QKI axis that impacts cancer‐associated epithelial cell plasticity through widespread control of alternative splicing.
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Affiliation(s)
- Katherine A Pillman
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Caroline A Phillips
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Suraya Roslan
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - John Toubia
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - B Kate Dredge
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Andrew G Bert
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Rachael Lumb
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Daniel P Neumann
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Xiaochun Li
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Simon J Conn
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia.,Flinders Centre for Innovation in Cancer, College of Medicine & Public Health, Flinders University, Adelaide, SA, Australia
| | - Dawei Liu
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Cameron P Bracken
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia.,Discipline of Medicine, The University of Adelaide, Adelaide, SA, Australia
| | - David M Lawrence
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Nataly Stylianou
- Institute of Health and Biomedical Innovation, Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Queensland University of Technology, Brisbane, Qld, Australia
| | - Andreas W Schreiber
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Wayne D Tilley
- Dame Roma Mitchell Cancer Research Laboratories, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia.,Freemasons Foundation Centre for Men's Health, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - Brett G Hollier
- Institute of Health and Biomedical Innovation, Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Queensland University of Technology, Brisbane, Qld, Australia
| | - Yeesim Khew-Goodall
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia.,Discipline of Medicine, The University of Adelaide, Adelaide, SA, Australia.,School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SA, Australia
| | - Luke A Selth
- Dame Roma Mitchell Cancer Research Laboratories, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia.,Freemasons Foundation Centre for Men's Health, Adelaide Medical School, University of Adelaide, Adelaide, SA, Australia
| | - Gregory J Goodall
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia .,Discipline of Medicine, The University of Adelaide, Adelaide, SA, Australia.,School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SA, Australia
| | - Philip A Gregory
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia .,Discipline of Medicine, The University of Adelaide, Adelaide, SA, Australia
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8
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Bracken CP, Li X, Wright JA, Lawrence DM, Pillman KA, Salmanidis M, Anderson MA, Dredge BK, Gregory PA, Tsykin A, Neilsen C, Thomson DW, Bert AG, Leerberg JM, Yap AS, Jensen KB, Khew-Goodall Y, Goodall GJ. Genome-wide identification of miR-200 targets reveals a regulatory network controlling cell invasion. EMBO J 2014; 33:2040-56. [PMID: 25069772 DOI: 10.15252/embj.201488641] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The microRNAs of the miR-200 family maintain the central characteristics of epithelia and inhibit tumor cell motility and invasiveness. Using the Ago-HITS-CLIP technology for transcriptome-wide identification of direct microRNA targets in living cells, along with extensive validation to verify the reliability of the approach, we have identified hundreds of miR-200a and miR-200b targets, providing insights into general features of miRNA target site selection. Gene ontology analysis revealed a predominant effect of miR-200 targets in widespread coordinate control of actin cytoskeleton dynamics. Functional characterization of the miR-200 targets indicates that they constitute subnetworks that underlie the ability of cancer cells to migrate and invade, including coordinate effects on Rho-ROCK signaling, invadopodia formation, MMP activity, and focal adhesions. Thus, the miR-200 family maintains the central characteristics of the epithelial phenotype by acting on numerous targets at multiple levels, encompassing both cytoskeletal effectors that control actin filament organization and dynamics, and upstream signals that locally regulate the cytoskeleton to maintain cell morphology and prevent cell migration.
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Affiliation(s)
- Cameron P Bracken
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia Discipline of Medicine, University of Adelaide, Adelaide, SA, Australia
| | - Xiaochun Li
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - Josephine A Wright
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - David M Lawrence
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - Katherine A Pillman
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - Marika Salmanidis
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - Matthew A Anderson
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - B Kate Dredge
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
| | - Philip A Gregory
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia Discipline of Medicine, University of Adelaide, Adelaide, SA, Australia
| | - Anna Tsykin
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - Corine Neilsen
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - Daniel W Thomson
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - Andrew G Bert
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - Joanne M Leerberg
- Division of Molecular Cell Biology, Institute for Molecular Bioscience University of Queensland, St Lucia, Brisbane, Qld, Australia
| | - Alpha S Yap
- Division of Molecular Cell Biology, Institute for Molecular Bioscience University of Queensland, St Lucia, Brisbane, Qld, Australia
| | - Kirk B Jensen
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
| | - Yeesim Khew-Goodall
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
| | - Gregory J Goodall
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia Discipline of Medicine, University of Adelaide, Adelaide, SA, Australia School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, Australia
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9
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Dredge BK, Jensen KB. NeuN/Rbfox3 nuclear and cytoplasmic isoforms differentially regulate alternative splicing and nonsense-mediated decay of Rbfox2. PLoS One 2011; 6:e21585. [PMID: 21747913 PMCID: PMC3126832 DOI: 10.1371/journal.pone.0021585] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Accepted: 06/06/2011] [Indexed: 12/14/2022] Open
Abstract
Anti-NeuN (Neuronal Nuclei) is a monoclonal antibody used extensively to specifically detect post-mitotic neurons. Anti-NeuN reactivity is predominantly nuclear; by western it detects multiple bands ranging in molecular weight from 45 kDa to >75 kDa. Expression screening putatively identified R3hdm2 as NeuN; however immunoprecipitation and mass spectrometry of the two major NeuN species at 45-50 kDa identified both as the RNA binding protein Rbfox3 (a member of the Fox family of alternative splicing factors), confirming and extending the identification of the 45 kDa band as Rbfox3 by Kim et al. Mapping of the anti-NeuN reactive epitopes in both R3hdm2 and Rbfox3 reveals a common proline- and glutamine-rich domain that lies at the N-terminus of the Rbfox3 protein. Our data suggests that alternative splicing of the Rbfox3 pre-mRNA itself leads to the production of four protein isoforms that migrate in the 45-50 kDa range, and that one of these splicing choices regulates Rbfox3/NeuN sub-cellular steady-state distribution, through the addition or removal of a short C-terminal extension containing the second half of a bipartite hydrophobic proline-tyrosine nuclear localization signal. Rbfox3 regulates alternative splicing of the Rbfox2 pre-mRNA, producing a message encoding a dominant negative form of the Rbfox2 protein. We show here that nuclear Rbfox3 isoforms can also enhance the inclusion of cryptic exons in the Rbfox2 mRNA, resulting in nonsense-mediated decay of the message, thereby contributing to the negative regulation of Rbfox2 by Rbfox3 through a novel mechanism.
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Affiliation(s)
- B Kate Dredge
- School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, Australia.
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10
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Wiszniak SE, Dredge BK, Jensen KB. HuB (elavl2) mRNA is restricted to the germ cells by post-transcriptional mechanisms including stabilisation of the message by DAZL. PLoS One 2011; 6:e20773. [PMID: 21695151 PMCID: PMC3113899 DOI: 10.1371/journal.pone.0020773] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 05/09/2011] [Indexed: 11/19/2022] Open
Abstract
The ability of germ cells to carry out a gene regulatory program distinct from the surrounding somatic tissue, and their capacity to specify an entire new organism has made them a focus of many studies that seek to understand how specific regulatory mechanisms, particularly post-transcriptional mechanisms, contribute to cell fate. In zebrafish, germ cells are specified through the inheritance of cytoplasmic determinants, termed the germ plasm, which contains a number of maternal mRNAs and proteins. Investigation of several of these messages has revealed that the restricted localisation of these mRNAs to the germ plasm and subsequent germ cells is due to cis-acting sequence elements present in their 3'UTRs. Here we show that a member of the Hu family of RNA-binding proteins, HuB, is maternally provided in the zebrafish embryo and exhibits germ cell specific expression during embryogenesis. Restriction of HuB mRNA to the germ cells is dependent on a number of sequence elements in its 3'UTR, which act to degrade the mRNA in the soma and stabilise it in the germ cells. In addition, we show that the germ cell specific RNA-binding protein DAZL is able to promote HuB mRNA stability and translation in germ cells, and further demonstrate that these activities require a 30 nucleotide element in the 3'UTR. Our study suggests that DAZL specifically binds the HuB 3'UTR and protects the message from degradation and/or enhances HuB translation, leading to the germ cell specific expression of HuB protein.
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Affiliation(s)
- Sophie E. Wiszniak
- Discipline of Biochemistry, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
| | - B. Kate Dredge
- Discipline of Biochemistry, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
| | - Kirk B. Jensen
- Discipline of Biochemistry, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
- * E-mail:
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11
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Dredge BK, Stefani G, Engelhard CC, Darnell RB. Nova autoregulation reveals dual functions in neuronal splicing. EMBO J 2005; 24:1608-20. [PMID: 15933722 PMCID: PMC1142566 DOI: 10.1038/sj.emboj.7600630] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Accepted: 02/23/2005] [Indexed: 01/12/2023] Open
Abstract
The Nova family of neuron-specific RNA-binding proteins were originally identified as targets in an autoimmune neurologic disease characterized by failure of motor inhibition. Nova-1 regulates alternative splicing of pre-mRNAs encoding the inhibitory neurotransmitter receptor subunits GABA(A)Rgamma2 and GlyRalpha2 by directly binding intronic elements, resulting in enhancement of exon inclusion. Here we identify exon E4 in the Nova-1 pre-mRNA itself, encoding a phosphorylated protein domain, as an additional target of Nova-dependent splicing regulation in the mouse spinal cord. Nova binding to E4 is necessary and sufficient for Nova-dependent exon exclusion. E4 harbors five repeats of the known Nova-binding tetranucleotide YCAY and mutation of these elements destroys Nova-dependent regulation. Furthermore, swapping of the sites from Nova-1 and GABA(A)Rgamma2 indicates that the ability of Nova to enhance or repress alternative exon inclusion is dependent on the position of the Nova-binding element within the pre-mRNA. These studies demonstrate that in addition to its previously described role as a splicing activator, Nova autoregulates its own expression by acting as a splicing repressor.
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Affiliation(s)
- B Kate Dredge
- Laboratory of Molecular Neuro-Oncology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Giovanni Stefani
- Laboratory of Molecular Neuro-Oncology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Caitlin C Engelhard
- Laboratory of Molecular Neuro-Oncology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Robert B Darnell
- Laboratory of Molecular Neuro-Oncology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
- Laboratory of Molecular Neuro-Oncology, Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA. Tel.: +1 212 327 7460; Fax: +1 212 327 7109; E-mail:
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12
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Abstract
Nova is a neuron-specific RNA binding protein targeted in patients with the autoimmune disorder paraneoplastic opsoclonus-myoclonus ataxia, which is characterized by failure of inhibition of brainstem and spinal motor systems. Here, we have biochemically confirmed the observation that splicing regulation of the inhibitory GABA(A) receptor gamma2 (GABA(A)Rgamma2) subunit pre-mRNA exon E9 is disrupted in mice lacking Nova-1. To elucidate the mechanism by which Nova-1 regulates GABA(A)Rgamma2 alternative splicing, we systematically screened minigenes derived from the GABA(A)Rgamma2 and human beta-globin genes for their ability to support Nova-dependent splicing in transient transfection assays. These studies demonstrate that Nova-1 acts directly on GABA(A)Rgamma2 pre-mRNA to regulate E9 splicing and identify an intronic region that is necessary and sufficient for Nova-dependent enhancement of exon inclusion, which we term the NISE (Nova-dependent intronic splicing enhancer) element. The NISE element (located 80 nucleotides upstream of the splice acceptor site of the downstream exon E10) is composed of repeats of the sequence YCAY, consistent with previous studies of the mechanism by which Nova binds RNA. Mutation of these repeats abolishes binding of Nova-1 to the RNA in vitro and Nova-dependent splicing regulation in vivo. These data provide a molecular basis for understanding Nova regulation of GABA(A)Rgamma2 alternative splicing and suggest that general dysregulation of Nova's splicing enhancer function may underlie the neurologic defects seen in Nova's absence.
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MESH Headings
- Alternative Splicing
- Animals
- Antigens, Neoplasm
- Base Sequence
- Blotting, Western
- Cell Line
- Collodion/pharmacology
- DNA, Complementary/metabolism
- Dose-Response Relationship, Drug
- Enhancer Elements, Genetic
- Exons
- Gene Expression Regulation
- Globins/genetics
- Humans
- Introns
- Mice
- Mice, Transgenic
- Models, Genetic
- Molecular Sequence Data
- Mutation
- Nerve Tissue Proteins/genetics
- Neuro-Oncological Ventral Antigen
- Plasmids/metabolism
- Protein Binding
- RNA, Messenger/metabolism
- RNA-Binding Proteins/genetics
- Receptors, GABA-A/genetics
- Receptors, GABA-A/metabolism
- Recombinant Fusion Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Nucleic Acid
- Transfection
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Affiliation(s)
- B Kate Dredge
- Laboratory of Molecular Neuro-Oncology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10021, USA
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13
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Abstract
Splicing of pre-messenger RNA is regulated differently in the brain compared with other tissues. Recognition of aberrations in splicing events that are associated with neurological disease has contributed to our understanding of disease pathogenesis in some cases. Neuron-specific proteins involved in RNA splicing and metabolism are also affected in several neurological disorders. These findings have begun to bridge what we know about the mechanisms regulating neuron-specific splicing and our understanding of neural function and disease.
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Affiliation(s)
- B K Dredge
- Laboratory of Molecular Neuro-oncology, Rockefeller University, New York, New York 10021, USA
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14
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Jensen KB, Dredge BK, Stefani G, Zhong R, Buckanovich RJ, Okano HJ, Yang YY, Darnell RB. Nova-1 regulates neuron-specific alternative splicing and is essential for neuronal viability. Neuron 2000; 25:359-71. [PMID: 10719891 DOI: 10.1016/s0896-6273(00)80900-9] [Citation(s) in RCA: 303] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We have combined genetic and biochemical approaches to analyze the function of the RNA-binding protein Nova-1, the paraneoplastic opsoclonus-myoclonus ataxia (POMA) antigen. Nova-1 null mice die postnatally from a motor deficit associated with apoptotic death of spinal and brainstem neurons. Nova-1 null mice show specific splicing defects in two inhibitory receptor pre-mRNAs, glycine alpha2 exon 3A (GlyRalpha2 E3A) and GABA(A) exon gamma2L. Nova protein in brain extracts specifically bound to a previously identified GlyRalpha2 intronic (UCAUY)3 Nova target sequence, and Nova-1 acted directly on this element to increase E3A splicing in cotransfection assays. We conclude that Nova-1 binds RNA in a sequence-specific manner to regulate neuronal pre-mRNA alternative splicing; the defect in splicing in Nova-1 null mice provides a model for understanding the motor dysfunction in POMA.
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Affiliation(s)
- K B Jensen
- Laboratory of Molecular Neuro-Oncology, The Rockefeller University, New York, New York 10021, USA
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Abstract
The sequence of part of the rfb region of Vibrio cholerae serogroup O139 and the physical map of a 35-kb region of the O139 chromosome have been determined. The O139 rfb region presented contains a number of open reading frames which show similarities to other rfb and capsular biosynthesis genes found in members of the Enterobacteriaceae family and in V. cholerae O1. The cloned and sequenced region can complement the defects in O139 antigen biosynthesis in transposon insertions within the O139 rfb cluster. Linkage is demonstrated among IS1358 of V. cholerae O139, the rfb region, and the recently reported otnA and otnB genes (E. M. Bik, A. E. Bunschoten, R. D. Gouw, and F. R. Mooi, EMBO J. 14:209-216, 1995). In addition, the whole of this region has been linked to the rfaD gene. Furthermore, determination of the sequence flanking IS1358 has revealed homology to other rfb-like genes. The exact site of insertion with respect to rfaD is defined for the novel DNAs of both the Bengal and the Argentinian O139 isolates.
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Affiliation(s)
- U H Stroeher
- Department of Microbiology and Immunology, University of Adelaide, South Australia
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Stroeher UH, Jedani KE, Dredge BK, Morona R, Brown MH, Karageorgos LE, Albert MJ, Manning PA. Genetic rearrangements in the rfb regions of Vibrio cholerae O1 and O139. Proc Natl Acad Sci U S A 1995; 92:10374-8. [PMID: 7479787 PMCID: PMC40799 DOI: 10.1073/pnas.92.22.10374] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The recent emergence of a pathogenic new non-O1 serotype (O139) of Vibrio cholerae has led to numerous studies in an attempt to identify the origins of this new strain. Our studies indicate that O139 strains have clear differences in the surface polysaccharides when compared with O1 strains: the lipopolysaccharide can be described as semi-rough. Southern hybridization with the O1 rfb region demonstrates that O139 strains no longer contain any of the rfb genes required for the synthesis of the O1 O-antigen or its modification and also lack at least 6 kb of additional contiguous DNA. However, O139 strains have retained rfaD and have a single open reading frame closely related to three small open reading frames of the O1 rfb region. This region is closely related to the H-repeat of Escherichia coli and to the transposases of a number of insertion sequence elements and has all the features of an insertion sequence element that has been designated VcIS1. Transposon insertion mutants defective in O139 O-antigen (and capsule) biosynthesis map to the same fragment as VcIS1. Preliminary sequence data of complementing clones indicate that this DNA encodes a galactosyl-transferase and other enzymes for the utilization of galactose in polysaccharide biosynthesis. We propose a mechanism by which both the Ogawa serotype of O1 strains and the O139 serotype strains may have evolved.
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Affiliation(s)
- U H Stroeher
- Department of Microbiology and Immunology, University of Adelaide, South Australia
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