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Lama J, Srivastav S, Tasnim S, Hubbard D, Hadjipanteli S, Smith BR, Macdonald SJ, Green L, Kelleher ES. Genetic variation in P-element dysgenic sterility is associated with double-strand break repair and alternative splicing of TE transcripts. PLoS Genet 2022; 18:e1010080. [PMID: 36477699 PMCID: PMC9762592 DOI: 10.1371/journal.pgen.1010080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 12/19/2022] [Accepted: 11/02/2022] [Indexed: 12/12/2022] Open
Abstract
The germline mobilization of transposable elements (TEs) by small RNA mediated silencing pathways is conserved across eukaryotes and critical for ensuring the integrity of gamete genomes. However, genomes are recurrently invaded by novel TEs through horizontal transfer. These invading TEs are not targeted by host small RNAs, and their unregulated activity can cause DNA damage in germline cells and ultimately lead to sterility. Here we use hybrid dysgenesis-a sterility syndrome of Drosophila caused by transposition of invading P-element DNA transposons-to uncover host genetic variants that modulate dysgenic sterility. Using a panel of highly recombinant inbred lines of Drosophila melanogaster, we identified two linked quantitative trait loci (QTL) that determine the severity of dysgenic sterility in young and old females, respectively. We show that ovaries of fertile genotypes exhibit increased expression of splicing factors that suppress the production of transposase encoding transcripts, which likely reduces the transposition rate and associated DNA damage. We also show that fertile alleles are associated with decreased sensitivity to double-stranded breaks and enhanced DNA repair, explaining their ability to withstand high germline transposition rates. Together, our work reveals a diversity of mechanisms whereby host genotype modulates the cost of an invading TE, and points to genetic variants that were likely beneficial during the P-element invasion.
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Affiliation(s)
- Jyoti Lama
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Satyam Srivastav
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Sadia Tasnim
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
| | - Donald Hubbard
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
| | - Savana Hadjipanteli
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
| | - Brittny R. Smith
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, United States of America
| | - Stuart J. Macdonald
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, United States of America
| | - Llewellyn Green
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
| | - Erin S. Kelleher
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
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2
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Conboy JG. A Deep Exon Cryptic Splice Site Promotes Aberrant Intron Retention in a Von Willebrand Disease Patient. Int J Mol Sci 2021; 22:13248. [PMID: 34948044 PMCID: PMC8706089 DOI: 10.3390/ijms222413248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 12/13/2022] Open
Abstract
A translationally silent single nucleotide mutation in exon 44 (E44) of the von Willebrand factor (VWF) gene is associated with inefficient removal of intron 44 in a von Willebrand disease (VWD) patient. This intron retention (IR) event was previously attributed to reordered E44 secondary structure that sequesters the normal splice donor site. We propose an alternative mechanism: the mutation introduces a cryptic splice donor site that interferes with the function of the annotated site to favor IR. We evaluated both models using minigene splicing reporters engineered to vary in secondary structure and/or cryptic splice site content. Analysis of splicing efficiency in transfected K562 cells suggested that the mutation-generated cryptic splice site in E44 was sufficient to induce substantial IR. Mutations predicted to vary secondary structure at the annotated site also had modest effects on IR and shifted the balance of residual splicing between the cryptic site and annotated site, supporting competition among the sites. Further studies demonstrated that introduction of cryptic splice donor motifs at other positions in E44 did not promote IR, indicating that interference with the annotated site is context dependent. We conclude that mutant deep exon splice sites can interfere with proper splicing by inducing IR.
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Affiliation(s)
- John G Conboy
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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3
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Yeom KH, Pan Z, Lin CH, Lim HY, Xiao W, Xing Y, Black DL. Tracking pre-mRNA maturation across subcellular compartments identifies developmental gene regulation through intron retention and nuclear anchoring. Genome Res 2021; 31:1106-1119. [PMID: 33832989 PMCID: PMC8168582 DOI: 10.1101/gr.273904.120] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 04/01/2021] [Indexed: 12/24/2022]
Abstract
Steps of mRNA maturation are important gene regulatory events that occur in distinct cellular locations. However, transcriptomic analyses often lose information on the subcellular distribution of processed and unprocessed transcripts. We generated extensive RNA-seq data sets to track mRNA maturation across subcellular locations in mouse embryonic stem cells, neuronal progenitor cells, and postmitotic neurons. We find disparate patterns of RNA enrichment between the cytoplasmic, nucleoplasmic, and chromatin fractions, with some genes maintaining more polyadenylated RNA in chromatin than in the cytoplasm. We bioinformatically defined four regulatory groups for intron retention, including complete cotranscriptional splicing, complete intron retention in the cytoplasmic RNA, and two intron groups present in nuclear and chromatin transcripts but fully excised in cytoplasm. We found that introns switch their regulatory group between cell types, including neuronally excised introns repressed by polypyrimidine track binding protein 1 (PTBP1). Transcripts for the neuronal gamma-aminobutyric acid (GABA) B receptor, 1 (Gabbr1) are highly expressed in mESCs but are absent from the cytoplasm. Instead, incompletely spliced Gabbr1 RNA remains sequestered on chromatin, where it is bound by PTBP1, similar to certain long noncoding RNAs. Upon neuronal differentiation, Gabbr1 RNA becomes fully processed and exported for translation. Thus, splicing repression and chromatin anchoring of RNA combine to allow posttranscriptional regulation of Gabbr1 over development. For this and other genes, polyadenylated RNA abundance does not indicate functional gene expression. Our data sets provide a rich resource for analyzing many other aspects of mRNA maturation in subcellular locations and across development.
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Affiliation(s)
- Kyu-Hyeon Yeom
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Zhicheng Pan
- Bioinformatics Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, California 90095, USA.,Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
| | - Chia-Ho Lin
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Han Young Lim
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA.,Molecular Biology Interdepartmental Doctoral Program, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Wen Xiao
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Yi Xing
- Center for Computational and Genomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Douglas L Black
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, California 90095, USA
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4
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Ghanim GE, Rio DC, Teixeira FK. Mechanism and regulation of P element transposition. Open Biol 2020; 10:200244. [PMID: 33352068 PMCID: PMC7776569 DOI: 10.1098/rsob.200244] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 11/26/2020] [Indexed: 12/05/2022] Open
Abstract
P elements were first discovered in the fruit fly Drosophila melanogaster as the causative agents of a syndrome of aberrant genetic traits called hybrid dysgenesis. This occurs when P element-carrying males mate with females that lack P elements and results in progeny displaying sterility, mutations and chromosomal rearrangements. Since then numerous genetic, developmental, biochemical and structural studies have culminated in a deep understanding of P element transposition: from the cellular regulation and repression of transposition to the mechanistic details of the transposase nucleoprotein complex. Recent studies have revealed how piwi-interacting small RNA pathways can act to control splicing of the P element pre-mRNA to modulate transposase production in the germline. A recent cryo-electron microscopy structure of the P element transpososome reveals an unusual DNA architecture at the transposon termini and shows that the bound GTP cofactor functions to position the transposon ends within the transposase active site. Genome sequencing efforts have shown that there are P element transposase-homologous genes (called THAP9) in other animal genomes, including humans. This review highlights recent and previous studies, which together have led to new insights, and surveys our current understanding of the biology, biochemistry, mechanism and regulation of P element transposition.
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Affiliation(s)
- George E. Ghanim
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - Donald C. Rio
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
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5
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Anande G, Deshpande NP, Mareschal S, Batcha AMN, Hampton HR, Herold T, Lehmann S, Wilkins MR, Wong JWH, Unnikrishnan A, Pimanda JE. RNA Splicing Alterations Induce a Cellular Stress Response Associated with Poor Prognosis in Acute Myeloid Leukemia. Clin Cancer Res 2020; 26:3597-3607. [PMID: 32122925 DOI: 10.1158/1078-0432.ccr-20-0184] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/13/2020] [Accepted: 02/26/2020] [Indexed: 11/16/2022]
Abstract
PURPOSE RNA splicing is a fundamental biological process that generates protein diversity from a finite set of genes. Recurrent somatic mutations of splicing factor genes are common in some hematologic cancers but are relatively uncommon in acute myeloid leukemia (AML, < 20% of patients). We examined whether RNA splicing differences exist in AML, even in the absence of splicing factor mutations. EXPERIMENTAL DESIGN We developed a bioinformatics pipeline to study alternative RNA splicing in RNA-sequencing data from large cohorts of patients with AML. RESULTS We have identified recurrent differential alternative splicing between patients with poor and good prognosis. These splicing events occurred even in patients without any discernible splicing factor mutations. Alternative splicing recurrently occurred in genes with specific molecular functions, primarily related to protein translation. Developing tools to predict the functional impact of alternative splicing on the translated protein, we discovered that approximately 45% of the splicing events directly affected highly conserved protein domains. Several splicing factors were themselves misspliced and the splicing of their target transcripts were altered. Studying differential gene expression in the same patients, we identified that alternative splicing of protein translation genes in ELNAdv patients resulted in the induction of an integrated stress response and upregulation of inflammation-related genes. Finally, using machine learning techniques, we identified a splicing signature of four genes which refine the accuracy of existing risk prognosis schemes and validated it in a completely independent cohort. CONCLUSIONS Our discoveries therefore identify aberrant alternative splicing as a molecular feature of adverse AML with clinical relevance.See related commentary by Bowman, p. 3503.
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Affiliation(s)
- Govardhan Anande
- Adult Cancer Program, Lowy Cancer Research Centre & Prince of Wales Clinical School, University of New South Wales Sydney, New South Wales, Australia
| | - Nandan P Deshpande
- School of Biotechnology and Biomolecular Sciences, University of New South Wales Sydney, New South Wales, Australia
| | - Sylvain Mareschal
- Hematology Centre, Karolinska University Hospital and Department of Medicine, Karolinska Institutet, Huddinge, Stockholm, Sweden
| | - Aarif M N Batcha
- Institute of Medical Data Processing, Biometrics and Epidemiology, Faculty of Medicine, LMU Munich, Munich, Germany.,Data Integration for Future Medicine, LMU Munich, Munich, Germany
| | - Henry R Hampton
- Adult Cancer Program, Lowy Cancer Research Centre & Prince of Wales Clinical School, University of New South Wales Sydney, New South Wales, Australia
| | - Tobias Herold
- Department of Medicine III, University Hospital, LMU Munich, Munich, Germany.,Research Unit Apoptosis in Hematopoietic Stem Cells, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich, Germany
| | - Soren Lehmann
- Hematology Centre, Karolinska University Hospital and Department of Medicine, Karolinska Institutet, Huddinge, Stockholm, Sweden.,Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Marc R Wilkins
- School of Biotechnology and Biomolecular Sciences, University of New South Wales Sydney, New South Wales, Australia
| | - Jason W H Wong
- Adult Cancer Program, Lowy Cancer Research Centre & Prince of Wales Clinical School, University of New South Wales Sydney, New South Wales, Australia.,School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Ashwin Unnikrishnan
- Adult Cancer Program, Lowy Cancer Research Centre & Prince of Wales Clinical School, University of New South Wales Sydney, New South Wales, Australia.
| | - John E Pimanda
- Adult Cancer Program, Lowy Cancer Research Centre & Prince of Wales Clinical School, University of New South Wales Sydney, New South Wales, Australia. .,Department of Pathology, School of Medical Sciences, University of New South Wales Sydney, New South Wales, Australia.,Department of Haematology, Prince of Wales Hospital, Sydney, New South Wales, Australia
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6
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Jacob AG, Smith CWJ. Intron retention as a component of regulated gene expression programs. Hum Genet 2017; 136:1043-1057. [PMID: 28391524 PMCID: PMC5602073 DOI: 10.1007/s00439-017-1791-x] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 03/29/2017] [Indexed: 12/16/2022]
Abstract
Intron retention has long been an exemplar of regulated splicing with case studies of individual events serving as models that provided key mechanistic insights into the process of splicing control. In organisms such as plants and budding yeast, intron retention is well understood as a major mechanism of gene expression regulation. In contrast, in mammalian systems, the extent and functional significance of intron retention have, until recently, remained greatly underappreciated. Technical challenges to the global detection and quantitation of transcripts with retained introns have often led to intron retention being overlooked or dismissed as “noise”. Now, however, with the wealth of information available from high-throughput deep sequencing, combined with focused computational and statistical analyses, we are able to distinguish clear intron retention patterns in various physiological and pathological contexts. Several recent studies have demonstrated intron retention as a central component of gene expression programs during normal development as well as in response to stress and disease. Furthermore, these studies revealed various ways in which intron retention regulates protein isoform production, RNA stability and translation efficiency, and rapid induction of expression via post-transcriptional splicing of retained introns. In this review, we highlight critical findings from these transcriptomic studies and discuss commonalties in the patterns prevalent in intron retention networks at the functional and regulatory levels.
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Affiliation(s)
- Aishwarya G Jacob
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Christopher W J Smith
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK.
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