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Jalloh B, Lancaster CL, Rounds JC, Brown BE, Leung SW, Banerjee A, Morton DJ, Bienkowski RS, Fasken MB, Kremsky IJ, Tegowski M, Meyer K, Corbett A, Moberg K. The Drosophila Nab2 RNA binding protein inhibits m 6A methylation and male-specific splicing of Sex lethal transcript in female neuronal tissue. eLife 2023; 12:e64904. [PMID: 37458420 PMCID: PMC10351920 DOI: 10.7554/elife.64904] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 06/23/2023] [Indexed: 07/20/2023] Open
Abstract
The Drosophila polyadenosine RNA binding protein Nab2, which is orthologous to a human protein lost in a form of inherited intellectual disability, controls adult locomotion, axon projection, dendritic arborization, and memory through a largely undefined set of target RNAs. Here, we show a specific role for Nab2 in regulating splicing of ~150 exons/introns in the head transcriptome and focus on retention of a male-specific exon in the sex determination factor Sex-lethal (Sxl) that is enriched in female neurons. Previous studies have revealed that this splicing event is regulated in females by N6-methyladenosine (m6A) modification by the Mettl3 complex. At a molecular level, Nab2 associates with Sxl pre-mRNA in neurons and limits Sxl m6A methylation at specific sites. In parallel, reducing expression of the Mettl3, Mettl3 complex components, or the m6A reader Ythdc1 rescues mutant phenotypes in Nab2 flies. Overall, these data identify Nab2 as an inhibitor of m6A methylation and imply significant overlap between Nab2 and Mettl3 regulated RNAs in neuronal tissue.
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Affiliation(s)
- Binta Jalloh
- Department of Biology, Emory UniversityAtlantaUnited States
- Department of Cell Biology Emory University School of MedicineAtlantaUnited States
- Graduate Program in Genetics and Molecular Biology, Emory UniversityAtlantaUnited States
| | - Carly L Lancaster
- Department of Biology, Emory UniversityAtlantaUnited States
- Department of Cell Biology Emory University School of MedicineAtlantaUnited States
- Graduate Program in Biochemistry, Cell and Developmental Biology, Emory UniversityAtlantaUnited States
| | - J Christopher Rounds
- Department of Biology, Emory UniversityAtlantaUnited States
- Department of Cell Biology Emory University School of MedicineAtlantaUnited States
- Graduate Program in Genetics and Molecular Biology, Emory UniversityAtlantaUnited States
| | - Brianna E Brown
- Department of Biology, Emory UniversityAtlantaUnited States
- Department of Cell Biology Emory University School of MedicineAtlantaUnited States
| | - Sara W Leung
- Department of Biology, Emory UniversityAtlantaUnited States
| | - Ayan Banerjee
- Department of Biology, Emory UniversityAtlantaUnited States
| | - Derrick J Morton
- Department of Biology, Emory UniversityAtlantaUnited States
- Emory Institutional Research and Academic Career Development Award (IRACDA), Fellowships in Research and Science Teaching (FIRST) Postdoctoral FellowshipAtlantaUnited States
| | - Rick S Bienkowski
- Department of Biology, Emory UniversityAtlantaUnited States
- Department of Cell Biology Emory University School of MedicineAtlantaUnited States
- Graduate Program in Genetics and Molecular Biology, Emory UniversityAtlantaUnited States
| | - Milo B Fasken
- Department of Biology, Emory UniversityAtlantaUnited States
| | | | - Matthew Tegowski
- Department of Biochemistry, Duke University School of MedicineDurhamUnited States
| | - Kate Meyer
- Department of Biochemistry, Duke University School of MedicineDurhamUnited States
- Department of Neurobiology, Duke University School of MedicineDurhamUnited States
| | - Anita Corbett
- Department of Biology, Emory UniversityAtlantaUnited States
| | - Ken Moberg
- Department of Cell Biology Emory University School of MedicineAtlantaUnited States
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Nanni AV, Martinez N, Graze R, Morse A, Newman JRB, Jain V, Vlaho S, Signor S, Nuzhdin SV, Renne R, McIntyre LM. Sex-biased expression is associated with chromatin state in D. melanogaster and D. simulans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.523946. [PMID: 36711631 PMCID: PMC9882225 DOI: 10.1101/2023.01.13.523946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We propose a new model for the association of chromatin state and sex-bias in expression. We hypothesize enrichment of open chromatin in the sex where we see expression bias (OS) and closed chromatin in the opposite sex (CO). In this study of D. melanogaster and D. simulans head tissue, sex-bias in expression is associated with H3K4me3 (open mark) in males for male-biased genes and in females for female-biased genes in both species. Sex-bias in expression is also largely conserved in direction and magnitude between the two species on the X and autosomes. In male-biased orthologs, the sex-bias ratio is more divergent between species if both species have H3K27me2me3 marks in females compared to when either or neither species has H3K27me2me3 in females. H3K27me2me3 marks in females are associated with male-bias in expression on the autosomes in both species, but on the X only in D. melanogaster . In female-biased orthologs the relationship between the species for the sex-bias ratio is similar regardless of the H3K27me2me3 marks in males. Female-biased orthologs are more similar in the ratio of sex-bias than male-biased orthologs and there is an excess of male-bias in expression in orthologs that gain/lose sex-bias. There is an excess of male-bias in sex-limited expression in both species suggesting excess male-bias is due to rapid evolution between the species. The X chromosome has an enrichment in male-limited H3K4me3 in both species and an enrichment of sex-bias in expression compared to the autosomes.
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Affiliation(s)
- Adalena V Nanni
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Natalie Martinez
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
| | - Rita Graze
- Department of Biological Sciences, Auburn University, Auburn, AL, USA
| | - Alison Morse
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Jeremy R B Newman
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Vaibhav Jain
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
| | - Srna Vlaho
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Sarah Signor
- Department of Biological Sciences, North Dakota State University, Fargo, ND, USA
| | - Sergey V Nuzhdin
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Rolf Renne
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Lauren M McIntyre
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
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Liu S, Wang T, Cheng Z, Liu J. N6-methyladenosine (m6A) RNA modification in the pathophysiology of heart failure: a narrative review. Cardiovasc Diagn Ther 2022; 12:908-925. [PMID: 36605077 PMCID: PMC9808110 DOI: 10.21037/cdt-22-277] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 10/21/2022] [Indexed: 11/16/2022]
Abstract
Background and Objective Heart failure is the end-stage of various cardiovascular diseases. Recent progress in molecular biology has facilitated the understanding of the mechanisms of heart failure development at the molecular level. N6-adenosine methylation (m6A) is a post-transcriptional modification of RNA. Recent research work reported that m6A regulates gene expression and subsequently affects the activation of cell signaling pathways related to heart failure. Moreover, m6A regulators like methyltransferase-like 3 (METTL3) were reported to participate in myocardium hypertrophy. However, the current research work related to the role of m6A participating in the occurrence of heart failure is rare in some aspects like immune cell infiltration and diabetic heart diseases. Thus, it is reasonable to review the current achievements and provide further study orientation. Methods We searched related literature using the keywords: m6A AND heart failure in PubMed, Web of Science and Medline. The language was confined to English. The published year of searched literature ranged from 2012 to 2022. The searched results were put into Endnote software for management. Two authors investigated the searching terms and reviewed the full text of selected terms. Key Content and Findings m6A and its regulators are involved in the metabolism of various types of RNAs. m6A modification can regulate various types of cell signaling pathways related to the heart failure via interaction with m6A regulators. m6A and its regulators broadly participate in the myocardium fibrosis, myocardium hypertrophy, myocardial cell apoptosis, and ischemic reperfusion injury. Specifically, m6A participates in the cell apoptosis via regulation of autophagy flux. However, the current research work does not have enough evidence to prove that m6A regulator played its specific effect on the target transcript via regulating the m6A level. Conclusions m6A and its regulators participates in the progression of heart failure via modifying the RNA level. Future investigation of m6A should focus on the interaction between the m6A regulators and targeted transcript. Besides, the regulation role of m6A in immune cell infiltration and diabetic heart diseases should also be focused.
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Affiliation(s)
- Sihan Liu
- Department of Cardiovascular Medicine, The Fourth Affiliated Hospital of China Medical University, Shenyang, China
| | - Tongyu Wang
- Department of Cardiovascular Medicine, The Fourth Affiliated Hospital of China Medical University, Shenyang, China
| | - Zeyi Cheng
- Department of Cardiac Surgery, Ruijin Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Jing Liu
- Department of Cardiovascular Medicine, The Fourth Affiliated Hospital of China Medical University, Shenyang, China
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Deng D, Xing S, Liu X, Ji Q, Zhai Z, Peng W. Transcriptome analysis of sex-biased gene expression in the spotted-wing Drosophila, Drosophila suzukii (Matsumura). G3 GENES|GENOMES|GENETICS 2022; 12:6588685. [PMID: 35587603 PMCID: PMC9339319 DOI: 10.1093/g3journal/jkac127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 05/11/2022] [Indexed: 11/16/2022]
Abstract
Sexual dimorphism occurs widely throughout insects and has profound influences on evolutionary path. Sex-biased genes are considered to account for most of phenotypic differences between sexes. In order to explore the sex-biased genes potentially associated with sexual dimorphism and sexual development in Drosophila suzukii, a major devastating and invasive crop pest, we conducted whole-organism transcriptome profiling and sex-biased gene expression analysis on adults of both sexes. We identified transcripts of genes involved in several sex-specific physiological and functional processes, including transcripts involved in sex determination, reproduction, olfaction, and innate immune signals. A total of 11,360 differentially expressed genes were identified in the comparison, and 1,957 differentially expressed genes were female-biased and 4,231 differentially expressed genes were male-biased. The pathway predominantly enriched for differentially expressed genes was related to spliceosome, which might reflect the differences in the alternative splicing mechanism between males and females. Twenty-two sex determination and 16 sex-related reproduction genes were identified, and expression pattern analysis revealed that the majority of genes were differentially expressed between sexes. Additionally, the differences in sex-specific olfactory and immune processes were analyzed and the sex-biased expression of these genes may play important roles in pheromone and odor detection, and immune response. As a valuable dataset, our sex-specific transcriptomic data can significantly contribute to the fundamental elucidation of the molecular mechanisms of sexual dimorphism in fruit flies, and may provide candidate genes potentially useful for the development of genetic sexing strains, an important tool for sterile insect technique applications against this economically important species.
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Affiliation(s)
- Dan Deng
- Hunan Provincial Key Laboratory of Animal Intestinal Function and Regulation, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan International Joint Laboratory of Animal Intestinal Ecology and Health, Hunan Normal University , Changsha 410081, China
| | - Shisi Xing
- Hunan Provincial Key Laboratory of Animal Intestinal Function and Regulation, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan International Joint Laboratory of Animal Intestinal Ecology and Health, Hunan Normal University , Changsha 410081, China
| | - Xuxiang Liu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Lab of Biopesticide and Chemical Biology, Ministry of Education, Institute of Biological Control, Fujian Agriculture and Forestry University , Fuzhou 350002, China
| | - Qinge Ji
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Lab of Biopesticide and Chemical Biology, Ministry of Education, Institute of Biological Control, Fujian Agriculture and Forestry University , Fuzhou 350002, China
| | - Zongzhao Zhai
- Hunan Provincial Key Laboratory of Animal Intestinal Function and Regulation, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan International Joint Laboratory of Animal Intestinal Ecology and Health, Hunan Normal University , Changsha 410081, China
| | - Wei Peng
- Hunan Provincial Key Laboratory of Animal Intestinal Function and Regulation, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan International Joint Laboratory of Animal Intestinal Ecology and Health, Hunan Normal University , Changsha 410081, China
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5
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Liu P, Zheng W, Qiao J, Li Z, Deng Z, Yuan Y, Zhang H. Early embryonic transcriptomes of Zeugodacus tau provide insight into sex determination and differentiation genes. INSECT SCIENCE 2022; 29:915-931. [PMID: 34553826 DOI: 10.1111/1744-7917.12974] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 08/26/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
Zeugodacus tau (Walker) is an invasive pest. The sterile insect technique is an environment-friendly method for pest control. Understanding the mechanism of sex determination will contribute to improving efficiency of this technique. In this study, we identified the transformer (tra) gene in Z. tau. One female-specific and two male-specific isoforms of tra were found in Z. tau, and the male-specific splicing pattern of tra was found to occur 5 h after egg laying. We performed transcriptome sequencing at 1 h (E1), 5 h (E5), and 9 h (E9) after egg laying and obtained high-quality transcriptome libraries of early embryo development. We identified 13 297 and 11 713 differentially expressed genes (DEGs) from E5 versus E1 and E9 versus E1 comparisons, respectively. To explore the potential functions of the DEGs during embryonic development, Gene Ontology, Clusters of Orthologous Groups of proteins, and Kyoto Encyclopedia of Genes and Genomes analyses were performed. Twenty-six genes potentially involved in sex determination or differentiation, including Maleness-on-the-Y (MoY), were identified in Z. tau. To verify the transcriptome results, 15 genes were selected for quantitative real-time PCR validation. The results were consistent with the transcriptome sequencing results. Moreover, U2 small nuclear riboprotein auxiliary factor (U2AF-50), female lethal d (fl(2)d), and virilizer (vir) were highly expressed at E5, indicating that they may be related to the sex-specific splicing of tra. Further functional analysis is needed to confirm this speculation. Our data provide an insight into the mechanism underlying sex determination and differentiation in tephritid species.
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Affiliation(s)
- Peipei Liu
- Key Laboratory of Horticultural Plant Biology (MOE), Hubei Hongshan Laboratory, China-Australia Joint Research Center for Horticultural and Urban Pests, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Wenping Zheng
- Key Laboratory of Horticultural Plant Biology (MOE), Hubei Hongshan Laboratory, China-Australia Joint Research Center for Horticultural and Urban Pests, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jiao Qiao
- Key Laboratory of Horticultural Plant Biology (MOE), Hubei Hongshan Laboratory, China-Australia Joint Research Center for Horticultural and Urban Pests, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Ziniu Li
- Key Laboratory of Horticultural Plant Biology (MOE), Hubei Hongshan Laboratory, China-Australia Joint Research Center for Horticultural and Urban Pests, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zhurong Deng
- Key Laboratory of Horticultural Plant Biology (MOE), Hubei Hongshan Laboratory, China-Australia Joint Research Center for Horticultural and Urban Pests, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yimin Yuan
- College of Environmental Design, Wuhan Institute of Design and Sciences, Wuhan, China
| | - Hongyu Zhang
- Key Laboratory of Horticultural Plant Biology (MOE), Hubei Hongshan Laboratory, China-Australia Joint Research Center for Horticultural and Urban Pests, Institute of Urban and Horticultural Entomology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
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6
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Horiuchi K, Kawamura T, Hamakubo T. Wilms' Tumor 1-Associating Protein complex regulates alternative splicing and polyadenylation at potential G-quadruplex-forming splice site sequences. J Biol Chem 2021; 297:101248. [PMID: 34582888 PMCID: PMC8605363 DOI: 10.1016/j.jbc.2021.101248] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 09/17/2021] [Accepted: 09/23/2021] [Indexed: 11/14/2022] Open
Abstract
Wilms’ tumor 1-associating protein (WTAP) is a core component of the N6-methyladenosine (m6A)-methyltransferase complex, along with VIRMA, CBLL1, ZC3H13 (KIAA0853), RBM15/15B, and METTL3/14, which generate m6A, a key RNA modification that affects various processes of RNA metabolism. WTAP also interacts with splicing factors; however, despite strong evidence suggesting a role of Drosophila WTAP homolog fl(2)d in alternative splicing (AS), its role in splicing regulation in mammalian cells remains elusive. Here we demonstrate using RNAi coupled with RNA-seq that WTAP, VIRMA, CBLL1, and ZC3H13 modulate AS, promoting exon skipping and intron retention in AS events that involve short introns/exons with higher GC content and introns with weaker polypyrimidine-tract and branch points. Further analysis of GC-rich sequences involved in AS events regulated by WTAP, together with minigene assay analysis, revealed potential G-quadruplex formation at splice sites where WTAP has an inhibitory effect. We also found that several AS events occur in the last exon of one isoform of MSL1 and WTAP, leading to competition for polyadenylation. Proteomic analysis also suggested that WTAP/CBLL1 interaction promotes recruitment of the 3′-end processing complex. Taken together, our results indicate that the WTAP complex regulates AS and alternative polyadenylation via inhibitory mechanisms in GC-rich sequences.
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Affiliation(s)
- Keiko Horiuchi
- Department of Protein-Protein Interaction Research, Institute for Advanced Medical Sciences, Nippon Medical School, Tokyo, 113-0011, Japan.
| | - Takeshi Kawamura
- Laboratory for Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Takao Hamakubo
- Department of Protein-Protein Interaction Research, Institute for Advanced Medical Sciences, Nippon Medical School, Tokyo, 113-0011, Japan.
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7
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Wang Y, Zhang L, Ren H, Ma L, Guo J, Mao D, Lu Z, Lu L, Yan D. Role of Hakai in m 6A modification pathway in Drosophila. Nat Commun 2021; 12:2159. [PMID: 33846330 PMCID: PMC8041851 DOI: 10.1038/s41467-021-22424-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 03/14/2021] [Indexed: 12/13/2022] Open
Abstract
N6-methyladenosine (m6A), the most abundant internal modification in eukaryotic mRNA, is installed by a multi-component writer complex; however, the exact roles of each component remain poorly understood. Here we show that a potential E3 ubiquitin ligase Hakai colocalizes and interacts with other m6A writer components, and Hakai mutants exhibit typical m6A pathway defects in Drosophila, such as lowered m6A levels in mRNA, aberrant Sxl alternative splicing, wing and behavior defects. Hakai, Vir, Fl(2)d and Flacc form a stable complex, and disruption of either Hakai, Vir or Fl(2)d led to the degradation of the other three components. Furthermore, MeRIP-seq indicates that the effective m6A modification is mostly distributed in 5’ UTRs in Drosophila, in contrast to the mammalian system. Interestingly, we demonstrate that m6A modification is deposited onto the Sxl mRNA in a sex-specific fashion, which depends on the m6A writer. Together, our work not only advances the understanding of mechanism and regulation of the m6A writer complex, but also provides insights into how Sxl cooperate with the m6A pathway to control its own splicing. Drosophila m6A writer complex regulates alternative splicing of the Sex-lethal gene. Here the authors show that a potential E3 ligase Hakai interacts with the fly m6A writer complex and that m6A level is reduced in Hakai mutant flies.
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Affiliation(s)
- Yanhua Wang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Lifeng Zhang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Hang Ren
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Lijuan Ma
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Jian Guo
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Decai Mao
- Gene Regulatory Lab, School of Medicine, Tsinghua University, Beijing, China
| | - Zhongwen Lu
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Lijun Lu
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Dong Yan
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China.
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Abstract
The central dogma of molecular biology introduced by Crick describes a linear flow of information from DNA to mRNA to protein. Since then it has become evident that RNA undergoes several maturation steps such as capping, splicing, 3'-end processing, and editing. Likewise, nucleotide modifications are common in mRNA and are present in all organisms impacting on the regulation of gene expression. The most abundant modification found in mRNA is N6-methyladenosine (m6A). Deposition of m6A is a nuclear process and is performed by a megadalton writer complex primarily on mRNAs, but also on microRNAs and lncRNAs. The m6A methylosome is composed of the enzymatic core components METTL3 and METTL14, and several auxiliary proteins necessary for its correct positioning and functioning, which are WTAP, VIRMA, FLACC, RBM15, and HAKAI. The m6A epimark is decoded by YTH domain-containing reader proteins YTHDC and YTHDF, but METTLs can act as "readers" as well. Eraser proteins, such as FTO and ALKBH5, can remove the methyl group. Here we review recent progress on the role of m6A in regulating gene expression in light of Crick's central dogma of molecular biology. In particular, we address the complexity of the writer complex from an evolutionary perspective to obtain insights into the mechanism of ancient m6A methylation and its regulation.
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Affiliation(s)
- Dario L Balacco
- School of Biosciences, College of Life and Environmental Sciences , University of Birmingham , Edgbaston, Birmingham B15 2TT , United Kingdom
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences , University of Birmingham , Edgbaston, Birmingham B15 2TT , United Kingdom
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9
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Duan HC, Wang Y, Jia G. Dynamic and reversible RNA N 6 -methyladenosine methylation. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 10:e1507. [PMID: 30252201 DOI: 10.1002/wrna.1507] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/01/2018] [Accepted: 08/20/2018] [Indexed: 12/31/2022]
Abstract
N6 -methyladenosine (m6 A) is the most abundant internal chemical modification in eukaryotic messenger RNAs (mRNAs). The discovery in 2011 that m6 A is reversed by the fat mass and obesity-associated protein stimulated extensive worldwide research efforts on the regulatory biological functions of dynamic m6 A and other RNA modifications. The epitranscriptomic mark m6 A is written, read, and erased through the activities of a complicated network of enzymes and other proteins. m6 A-binding proteins read m6 A marks and transduce their downstream regulatory effects by altering RNA metabolic processes. In this review, we summarize the current knowledge of m6 A modifications, with particular focus on the functions of its writer, eraser, and reader proteins in posttranscriptional gene regulation and discuss the impact of m6 A marks on human health. This article is categorized under: RNA Processing > RNA Editing and Modification RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Hong-Chao Duan
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Ye Wang
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Guifang Jia
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
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10
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Martinez NM, Gilbert WV. Pre-mRNA modifications and their role in nuclear processing. QUANTITATIVE BIOLOGY 2018; 6:210-227. [PMID: 30533247 DOI: 10.1007/s40484-018-0147-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Background Cellular non-coding RNAs are extensively modified post-transcriptionally, with more than 100 chemically distinct nucleotides identified to date. In the past five years, new sequencing based methods have revealed widespread decoration of eukaryotic messenger RNA with diverse RNA modifications whose functions in mRNA metabolism are only beginning to be known. Results Since most of the identified mRNA modifying enzymes are present in the nucleus, these modifications have the potential to function in nuclear pre-mRNA processing including alternative splicing. Here we review recent progress towards illuminating the role of pre-mRNA modifications in splicing and highlight key areas for future investigation in this rapidly growing field. Conclusions Future studies to identify which modifications are added to nascent pre-mRNA and to interrogate the direct effects of individual modifications are likely to reveal new mechanisms by which nuclear pre-mRNA processing is regulated.
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Affiliation(s)
- Nicole M Martinez
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Wendy V Gilbert
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520, USA
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11
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Dynamic transcriptomic m 6A decoration: writers, erasers, readers and functions in RNA metabolism. Cell Res 2018; 28:616-624. [PMID: 29789545 PMCID: PMC5993786 DOI: 10.1038/s41422-018-0040-8] [Citation(s) in RCA: 892] [Impact Index Per Article: 148.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 04/22/2018] [Indexed: 02/06/2023] Open
Abstract
N6-methyladenosine (m6A) is a chemical modification present in multiple RNA species, being most abundant in mRNAs. Studies on enzymes or factors that catalyze, recognize, and remove m6A have revealed its comprehensive roles in almost every aspect of mRNA metabolism, as well as in a variety of physiological processes. This review describes the current understanding of the m6A modification, particularly the functions of its writers, erasers, readers in RNA metabolism, with an emphasis on its role in regulating the isoform dosage of mRNAs.
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12
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Xio is a component of the Drosophila sex determination pathway and RNA N6-methyladenosine methyltransferase complex. Proc Natl Acad Sci U S A 2018; 115:3674-3679. [PMID: 29555755 DOI: 10.1073/pnas.1720945115] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
N6-methyladenosine (m6A), the most abundant chemical modification in eukaryotic mRNA, has been implicated in Drosophila sex determination by modifying Sex-lethal (Sxl) pre-mRNA and facilitating its alternative splicing. Here, we identify a sex determination gene, CG7358, and rename it xio according to its loss-of-function female-to-male transformation phenotype. xio encodes a conserved ubiquitous nuclear protein of unknown function. We show that Xio colocalizes and interacts with all previously known m6A writer complex subunits (METTL3, METTL14, Fl(2)d/WTAP, Vir/KIAA1429, and Nito/Rbm15) and that loss of xio is associated with phenotypes that resemble other m6A factors, such as sexual transformations, Sxl splicing defect, held-out wings, flightless flies, and reduction of m6A levels. Thus, Xio encodes a member of the m6A methyltransferase complex involved in mRNA modification. Since its ortholog ZC3H13 (or KIAA0853) also associates with several m6A writer factors, the function of Xio in the m6A pathway is likely evolutionarily conserved.
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13
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Grmai L, Hudry B, Miguel-Aliaga I, Bach EA. Chinmo prevents transformer alternative splicing to maintain male sex identity. PLoS Genet 2018; 14:e1007203. [PMID: 29389999 PMCID: PMC5811060 DOI: 10.1371/journal.pgen.1007203] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 02/13/2018] [Accepted: 01/16/2018] [Indexed: 01/15/2023] Open
Abstract
Reproduction in sexually dimorphic animals relies on successful gamete production, executed by the germline and aided by somatic support cells. Somatic sex identity in Drosophila is instructed by sex-specific isoforms of the DMRT1 ortholog Doublesex (Dsx). Female-specific expression of Sex-lethal (Sxl) causes alternative splicing of transformer (tra) to the female isoform traF. In turn, TraF alternatively splices dsx to the female isoform dsxF. Loss of the transcriptional repressor Chinmo in male somatic stem cells (CySCs) of the testis causes them to "feminize", resembling female somatic stem cells in the ovary. This somatic sex transformation causes a collapse of germline differentiation and male infertility. We demonstrate this feminization occurs by transcriptional and post-transcriptional regulation of traF. We find that chinmo-deficient CySCs upregulate tra mRNA as well as transcripts encoding tra-splice factors Virilizer (Vir) and Female lethal (2)d (Fl(2)d). traF splicing in chinmo-deficient CySCs leads to the production of DsxF at the expense of the male isoform DsxM, and both TraF and DsxF are required for CySC sex transformation. Surprisingly, CySC feminization upon loss of chinmo does not require Sxl but does require Vir and Fl(2)d. Consistent with this, we show that both Vir and Fl(2)d are required for tra alternative splicing in the female somatic gonad. Our work reveals the need for transcriptional regulation of tra in adult male stem cells and highlights a previously unobserved Sxl-independent mechanism of traF production in vivo. In sum, transcriptional control of the sex determination hierarchy by Chinmo is critical for sex maintenance in sexually dimorphic tissues and is vital in the preservation of fertility.
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Affiliation(s)
- Lydia Grmai
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Bruno Hudry
- MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom
| | - Irene Miguel-Aliaga
- MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom
| | - Erika A. Bach
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
- Kimmel Stem Cell Center, New York University School of Medicine, New York, New York, United States of America
- * E-mail:
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14
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Kan L, Grozhik AV, Vedanayagam J, Patil DP, Pang N, Lim KS, Huang YC, Joseph B, Lin CJ, Despic V, Guo J, Yan D, Kondo S, Deng WM, Dedon PC, Jaffrey SR, Lai EC. The m 6A pathway facilitates sex determination in Drosophila. Nat Commun 2017; 8:15737. [PMID: 28675155 PMCID: PMC5500889 DOI: 10.1038/ncomms15737] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 04/21/2017] [Indexed: 12/29/2022] Open
Abstract
The conserved modification N6-methyladenosine (m6A) modulates mRNA processing and activity. Here, we establish the Drosophila system to study the m6A pathway. We first apply miCLIP to map m6A across embryogenesis, characterize its m6A ‘writer’ complex, validate its YTH ‘readers’ CG6422 and YT521-B, and generate mutants in five m6A factors. While m6A factors with additional roles in splicing are lethal, m6A-specific mutants are viable but present certain developmental and behavioural defects. Notably, m6A facilitates the master female determinant Sxl, since multiple m6A components enhance female lethality in Sxl sensitized backgrounds. The m6A pathway regulates Sxl processing directly, since miCLIP data reveal Sxl as a major intronic m6A target, and female-specific Sxl splicing is compromised in multiple m6A pathway mutants. YT521-B is a dominant m6A effector for Sxl regulation, and YT521-B overexpression can induce female-specific Sxl splicing. Overall, our transcriptomic and genetic toolkit reveals in vivo biologic function for the Drosophila m6A pathway. N6-methyladenosine (m6A) is a conserved RNA modification that has recently emerged as an important regulator of messenger RNA processing and activity. Here, the authors provide evidence that m6A pathway facilitates female-specific splicing of Sxl, regulating sex determination in Drosophila.
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Affiliation(s)
- Lijuan Kan
- Department of Developmental Biology, Sloan-Kettering Institute, 1275 York Ave, Box 252, New York City, New York 10065, USA
| | - Anya V Grozhik
- Department of Pharmacology, Weill Medical College, Cornell University, New York City, New York 10065, USA
| | - Jeffrey Vedanayagam
- Department of Developmental Biology, Sloan-Kettering Institute, 1275 York Ave, Box 252, New York City, New York 10065, USA
| | - Deepak P Patil
- Department of Pharmacology, Weill Medical College, Cornell University, New York City, New York 10065, USA
| | - Nan Pang
- Department of Developmental Biology, Sloan-Kettering Institute, 1275 York Ave, Box 252, New York City, New York 10065, USA
| | - Kok-Seong Lim
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Yi-Chun Huang
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306, USA
| | - Brian Joseph
- Department of Developmental Biology, Sloan-Kettering Institute, 1275 York Ave, Box 252, New York City, New York 10065, USA
| | - Ching-Jung Lin
- Department of Developmental Biology, Sloan-Kettering Institute, 1275 York Ave, Box 252, New York City, New York 10065, USA
| | - Vladimir Despic
- Department of Developmental Biology, Sloan-Kettering Institute, 1275 York Ave, Box 252, New York City, New York 10065, USA
| | - Jian Guo
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dong Yan
- Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Shu Kondo
- Invertebrate Genetics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Wu-Min Deng
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306, USA
| | - Peter C Dedon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Samie R Jaffrey
- Department of Pharmacology, Weill Medical College, Cornell University, New York City, New York 10065, USA
| | - Eric C Lai
- Department of Developmental Biology, Sloan-Kettering Institute, 1275 York Ave, Box 252, New York City, New York 10065, USA
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15
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Lence T, Soller M, Roignant JY. A fly view on the roles and mechanisms of the m 6A mRNA modification and its players. RNA Biol 2017; 14:1232-1240. [PMID: 28353398 PMCID: PMC5699544 DOI: 10.1080/15476286.2017.1307484] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
RNA modifications are an emerging layer of posttranscriptional gene regulation in eukaryotes. N6-methyladenosine (m6A) is among the most abundant modifications in mRNAs (mRNAs) that was shown to influence many physiological processes from yeast to mammals. Like DNA methylation, m6A in mRNA is dynamically regulated. A conserved methyltransferase complex catalyzes the deposition of the methyl group on adenosine, which can be removed by specific classes of demethylases. Furthermore, YTH-domain containing proteins can recognize this modification to mediate m6A-dependent activities. Here we review the functions and mechanisms of the main m6A players with a particular focus on Drosophila melanogaster.
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Affiliation(s)
- Tina Lence
- a Laboratory of RNA Epigenetics , Institute of Molecular Biology (IMB) , Mainz , Germany
| | - Matthias Soller
- b School of Biosciences, College of Life and Environmental Sciences , University of Birmingham , Edgbaston, Birmingham , UK
| | - Jean-Yves Roignant
- a Laboratory of RNA Epigenetics , Institute of Molecular Biology (IMB) , Mainz , Germany
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16
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m6A modulates neuronal functions and sex determination in Drosophila. Nature 2016; 540:242-247. [DOI: 10.1038/nature20568] [Citation(s) in RCA: 324] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 10/21/2016] [Indexed: 12/28/2022]
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17
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Zhao BS, Roundtree IA, He C. Post-transcriptional gene regulation by mRNA modifications. Nat Rev Mol Cell Biol 2016; 18:31-42. [PMID: 27808276 DOI: 10.1038/nrm.2016.132] [Citation(s) in RCA: 1410] [Impact Index Per Article: 176.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The recent discovery of reversible mRNA methylation has opened a new realm of post-transcriptional gene regulation in eukaryotes. The identification and functional characterization of proteins that specifically recognize RNA N6-methyladenosine (m6A) unveiled it as a modification that cells utilize to accelerate mRNA metabolism and translation. N6-adenosine methylation directs mRNAs to distinct fates by grouping them for differential processing, translation and decay in processes such as cell differentiation, embryonic development and stress responses. Other mRNA modifications, including N1-methyladenosine (m1A), 5-methylcytosine (m5C) and pseudouridine, together with m6A form the epitranscriptome and collectively code a new layer of information that controls protein synthesis.
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Affiliation(s)
- Boxuan Simen Zhao
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA
| | - Ian A Roundtree
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA
| | - Chuan He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, Howard Hughes Medical Institute, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA
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18
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Lee H, Cho DY, Whitworth C, Eisman R, Phelps M, Roote J, Kaufman T, Cook K, Russell S, Przytycka T, Oliver B. Effects of Gene Dose, Chromatin, and Network Topology on Expression in Drosophila melanogaster. PLoS Genet 2016; 12:e1006295. [PMID: 27599372 PMCID: PMC5012587 DOI: 10.1371/journal.pgen.1006295] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 08/10/2016] [Indexed: 11/18/2022] Open
Abstract
Deletions, commonly referred to as deficiencies by Drosophila geneticists, are valuable tools for mapping genes and for genetic pathway discovery via dose-dependent suppressor and enhancer screens. More recently, it has become clear that deviations from normal gene dosage are associated with multiple disorders in a range of species including humans. While we are beginning to understand some of the transcriptional effects brought about by gene dosage changes and the chromosome rearrangement breakpoints associated with them, much of this work relies on isolated examples. We have systematically examined deficiencies of the left arm of chromosome 2 and characterize gene-by-gene dosage responses that vary from collapsed expression through modest partial dosage compensation to full or even over compensation. We found negligible long-range effects of creating novel chromosome domains at deletion breakpoints, suggesting that cases of gene regulation due to altered nuclear architecture are rare. These rare cases include trans de-repression when deficiencies delete chromatin characterized as repressive in other studies. Generally, effects of breakpoints on expression are promoter proximal (~100bp) or in the gene body. Effects of deficiencies genome-wide are in genes with regulatory relationships to genes within the deleted segments, highlighting the subtle expression network defects in these sensitized genetic backgrounds.
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Affiliation(s)
- Hangnoh Lee
- Section of Developmental Genomics, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Kidney and Digestive Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Dong-Yeon Cho
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Cale Whitworth
- Section of Developmental Genomics, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Kidney and Digestive Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Robert Eisman
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Melissa Phelps
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - John Roote
- Department of Genetics and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, United Kingdom
| | - Thomas Kaufman
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Kevin Cook
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Steven Russell
- Department of Genetics and Cambridge Systems Biology Centre, University of Cambridge, Cambridge, United Kingdom
| | - Teresa Przytycka
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Brian Oliver
- Section of Developmental Genomics, Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Kidney and Digestive Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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19
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Poley JD, Sutherland BJG, Jones SRM, Koop BF, Fast MD. Sex-biased gene expression and sequence conservation in Atlantic and Pacific salmon lice (Lepeophtheirus salmonis). BMC Genomics 2016; 17:483. [PMID: 27377915 PMCID: PMC4932673 DOI: 10.1186/s12864-016-2835-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 06/13/2016] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Salmon lice, Lepeophtheirus salmonis (Copepoda: Caligidae), are highly important ectoparasites of farmed and wild salmonids, and cause multi-million dollar losses to the salmon aquaculture industry annually. Salmon lice display extensive sexual dimorphism in ontogeny, morphology, physiology, behavior, and more. Therefore, the identification of transcripts with differential expression between males and females (sex-biased transcripts) may help elucidate the relationship between sexual selection and sexually dimorphic characteristics. RESULTS Sex-biased transcripts were identified from transcriptome analyses of three L. salmonis populations, including both Atlantic and Pacific subspecies. A total of 35-43 % of all quality-filtered transcripts were sex-biased in L. salmonis, with male-biased transcripts exhibiting higher fold change than female-biased transcripts. For Gene Ontology and functional analyses, a consensus-based approach was used to identify concordantly differentially expressed sex-biased transcripts across the three populations. A total of 127 male-specific transcripts (i.e. those without detectable expression in any female) were identified, and were enriched with reproductive functions (e.g. seminal fluid and male accessory gland proteins). Other sex-biased transcripts involved in morphogenesis, feeding, energy generation, and sensory and immune system development and function were also identified. Interestingly, as observed in model systems, male-biased L. salmonis transcripts were more frequently without annotation compared to female-biased or unbiased transcripts, suggesting higher rates of sequence divergence in male-biased transcripts. CONCLUSIONS Transcriptome differences between male and female L. salmonis described here provide key insights into the molecular mechanisms controlling sexual dimorphism in L. salmonis. This analysis offers targets for parasite control and provides a foundation for further analyses exploring critical topics such as the interaction between sex and drug resistance, sex-specific factors in host-parasite relationships, and reproductive roles within L. salmonis.
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Affiliation(s)
- Jordan D Poley
- Department of Pathology & Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave, Charlottetown, PE, C1A 4P3, Canada
| | - Ben J G Sutherland
- Department of Biology, Centre for Biomedical Research, University of Victoria, 3800 Finnerty Rd, Victoria, BC, V8W 3 N5, Canada.,Present address: Département de biologie, Institut de Biologie Intégrative et des Systèms (IBIS), Université Laval, 1030 Avenue de la Medecine, Québec, QC, Canada
| | - Simon R M Jones
- Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, BC, V9T 6 N7, Canada
| | - Ben F Koop
- Department of Biology, Centre for Biomedical Research, University of Victoria, 3800 Finnerty Rd, Victoria, BC, V8W 3 N5, Canada
| | - Mark D Fast
- Department of Pathology & Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Ave, Charlottetown, PE, C1A 4P3, Canada.
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20
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RNA binding proteins implicated in Xist-mediated chromosome silencing. Semin Cell Dev Biol 2016; 56:58-70. [PMID: 26816113 DOI: 10.1016/j.semcdb.2016.01.029] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 01/20/2016] [Accepted: 01/21/2016] [Indexed: 11/20/2022]
Abstract
Chromosome silencing by Xist RNA occurs in two steps; localisation in cis within the nuclear matrix to form a domain that corresponds to the territory of the inactive X chromosome elect, and transduction of silencing signals from Xist RNA to the underlying chromatin. Key factors that mediate these processes have been identified in a series of recent studies that harnessed comprehensive proteomic or genetic screening strategies. In this review we discuss these findings in light of prior knowledge both of Xist-mediated silencing and known functions/properties of the novel factors.
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21
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Fear JM, Arbeitman MN, Salomon MP, Dalton JE, Tower J, Nuzhdin SV, McIntyre LM. The Wright stuff: reimagining path analysis reveals novel components of the sex determination hierarchy in Drosophila melanogaster. BMC SYSTEMS BIOLOGY 2015; 9:53. [PMID: 26335107 PMCID: PMC4558766 DOI: 10.1186/s12918-015-0200-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 08/20/2015] [Indexed: 11/10/2022]
Abstract
BACKGROUND The Drosophila sex determination hierarchy is a classic example of a transcriptional regulatory hierarchy, with sex-specific isoforms regulating morphology and behavior. We use a structural equation modeling approach, leveraging natural genetic variation from two studies on Drosophila female head tissues--DSPR collection (596 F1-hybrids from crosses between DSPR sub-populations) and CEGS population (75 F1-hybrids from crosses between DGRP/Winters lines to a reference strain w1118)--to expand understanding of the sex hierarchy gene regulatory network (GRN). This approach is completely generalizable to any natural population, including humans. RESULTS We expanded the sex hierarchy GRN adding novel links among genes, including a link from fruitless (fru) to Sex-lethal (Sxl) identified in both populations. This link is further supported by the presence of fru binding sites in the Sxl locus. 754 candidate genes were added to the pathway, including the splicing factors male-specific lethal 2 and Rm62 as downstream targets of Sxl which are well-supported links in males. Independent studies of doublesex and transformer mutants support many additions, including evidence for a link between the sex hierarchy and metabolism, via Insulin-like receptor. CONCLUSIONS The genes added in the CEGS population were enriched for genes with sex-biased splicing and components of the spliceosome. A common goal of molecular biologists is to expand understanding about regulatory interactions among genes. Using natural alleles we can not only identify novel relationships, but using supervised approaches can order genes into a regulatory hierarchy. Combining these results with independent large effect mutation studies, allows clear candidates for detailed molecular follow-up to emerge.
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Affiliation(s)
- Justin M Fear
- Department of Molecular Genetics and Microbiology, University of Florida, CGRC Room 116, PO Box 100266, FL 32610-0266, Gainesville, FL, USA.
| | | | - Matthew P Salomon
- Molecular and Computational Biology, University of California, Los Angeles, CA, USA.
| | - Justin E Dalton
- Biomedical Science, Florida State University, Tallahassee, FL, USA.
| | - John Tower
- Molecular and Computational Biology, University of California, Los Angeles, CA, USA.
| | - Sergey V Nuzhdin
- Molecular and Computational Biology, University of California, Los Angeles, CA, USA.
| | - Lauren M McIntyre
- Department of Molecular Genetics and Microbiology, University of Florida, CGRC Room 116, PO Box 100266, FL 32610-0266, Gainesville, FL, USA.
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22
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Abstract
Sex-lethal (Sxl) encodes the master regulator of the sex determination pathway in Drosophila and acts by controlling sex identity in both soma and germ line. In females Sxl maintains its own expression by controlling the alternative splicing of its own mRNA. Here, we identify a novel sex determination gene, spenito (nito) that encodes a SPEN family protein. Loss of nito activity results in stem cell tumors in the female germ line as well as female-to-male somatic transformations. We show that Nito is a ubiquitous nuclear protein that controls the alternative splicing of the Sxl mRNA by interacting with Sxl protein and pre-mRNA, suggesting that it is directly involved in Sxl auto-regulation. Given that SPEN family proteins are frequently mutated in cancers, our results suggest that these factors might be implicated in tumorigenesis through splicing regulation.
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23
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Alarcón CR, Goodarzi H, Lee H, Liu X, Tavazoie S, Tavazoie SF. HNRNPA2B1 Is a Mediator of m(6)A-Dependent Nuclear RNA Processing Events. Cell 2015; 162:1299-308. [PMID: 26321680 DOI: 10.1016/j.cell.2015.08.011] [Citation(s) in RCA: 978] [Impact Index Per Article: 108.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 03/10/2015] [Accepted: 07/08/2015] [Indexed: 01/14/2023]
Abstract
N(6)-methyladenosine (m(6)A) is the most abundant internal modification of messenger RNA. While the presence of m(6)A on transcripts can impact nuclear RNA fates, a reader of this mark that mediates processing of nuclear transcripts has not been identified. We find that the RNA-binding protein HNRNPA2B1 binds m(6)A-bearing RNAs in vivo and in vitro and its biochemical footprint matches the m(6)A consensus motif. HNRNPA2B1 directly binds a set of nuclear transcripts and elicits similar alternative splicing effects as the m(6)A writer METTL3. Moreover, HNRNPA2B1 binds to m(6)A marks in a subset of primary miRNA transcripts, interacts with the microRNA Microprocessor complex protein DGCR8, and promotes primary miRNA processing. Also, HNRNPA2B1 loss and METTL3 depletion cause similar processing defects for these pri-miRNA precursors. We propose HNRNPA2B1 to be a nuclear reader of the m(6)A mark and to mediate, in part, this mark's effects on primary microRNA processing and alternative splicing. PAPERCLIP.
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Affiliation(s)
- Claudio R Alarcón
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY 10065, USA
| | - Hani Goodarzi
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY 10065, USA
| | - Hyeseung Lee
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY 10065, USA
| | - Xuhang Liu
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY 10065, USA
| | - Saeed Tavazoie
- Department of Biochemistry and Molecular Biophysics and Department of Systems Biology, Columbia University, New York, NY 10032, USA
| | - Sohail F Tavazoie
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY 10065, USA.
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25
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Schwartz S, Mumbach MR, Jovanovic M, Wang T, Maciag K, Bushkin GG, Mertins P, Ter-Ovanesyan D, Habib N, Cacchiarelli D, Sanjana NE, Freinkman E, Pacold ME, Satija R, Mikkelsen TS, Hacohen N, Zhang F, Carr SA, Lander ES, Regev A. Perturbation of m6A writers reveals two distinct classes of mRNA methylation at internal and 5' sites. Cell Rep 2014; 8:284-96. [PMID: 24981863 DOI: 10.1016/j.celrep.2014.05.048] [Citation(s) in RCA: 856] [Impact Index Per Article: 85.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/07/2014] [Accepted: 05/27/2014] [Indexed: 12/31/2022] Open
Abstract
N6-methyladenosine (m6A) is a common modification of mRNA with potential roles in fine-tuning the RNA life cycle. Here, we identify a dense network of proteins interacting with METTL3, a component of the methyltransferase complex, and show that three of them (WTAP, METTL14, and KIAA1429) are required for methylation. Monitoring m6A levels upon WTAP depletion allowed the definition of accurate and near single-nucleotide resolution methylation maps and their classification into WTAP-dependent and -independent sites. WTAP-dependent sites are located at internal positions in transcripts, topologically static across a variety of systems we surveyed, and inversely correlated with mRNA stability, consistent with a role in establishing "basal" degradation rates. WTAP-independent sites form at the first transcribed base as part of the cap structure and are present at thousands of sites, forming a previously unappreciated layer of transcriptome complexity. Our data shed light on the proteomic and transcriptional underpinnings of this RNA modification.
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Affiliation(s)
| | | | - Marko Jovanovic
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Tim Wang
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Karolina Maciag
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Graduate Program in Immunology, Division of Medical Sciences, Harvard Medical School, Boston, MA 02115, USA
| | - G Guy Bushkin
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Philipp Mertins
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Naomi Habib
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Davide Cacchiarelli
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Harvard Stem Cell Institute and Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | | | | | - Michael E Pacold
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Radiation Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA
| | - Rahul Satija
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Tarjei S Mikkelsen
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Harvard Stem Cell Institute and Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | - Nir Hacohen
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Feng Zhang
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences and Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Steven A Carr
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Eric S Lander
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02114, USA.
| | - Aviv Regev
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815, USA.
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26
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Anderson AM, Weasner BP, Weasner BM, Kumar JP. The Drosophila Wilms׳ Tumor 1-Associating Protein (WTAP) homolog is required for eye development. Dev Biol 2014; 390:170-80. [PMID: 24690230 DOI: 10.1016/j.ydbio.2014.03.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 03/04/2014] [Accepted: 03/19/2014] [Indexed: 11/17/2022]
Abstract
Sine Oculis (So), the founding member of the SIX family of homeobox transcription factors, binds to sequence specific DNA elements and regulates transcription of downstream target genes. It does so, in part, through the formation of distinct biochemical complexes with Eyes Absent (Eya) and Groucho (Gro). While these complexes play significant roles during development, they do not account for all So-dependent activities in Drosophila. It is thought that additional So-containing complexes make important contributions as well. This contention is supported by the identification of nearly two-dozen additional proteins that complex with So. However, very little is known about the roles that these additional complexes play in development. In this report we have used yeast two-hybrid screens and co-immunoprecipitation assays from Kc167 cells to identify a biochemical complex consisting of So and Fl(2)d, the Drosophila homolog of human Wilms׳ Tumor 1-Associating Protein (WTAP). We show that Fl(2)d protein is distributed throughout the entire eye-antennal imaginal disc and that loss-of-function mutations lead to perturbations in retinal development. The eye defects are manifested behind the morphogenetic furrow and result in part from increased levels of the pan-neuronal RNA binding protein Embryonic Lethal Abnormal Vision (Elav) and the RUNX class transcription factor Lozenge (Lz). We also provide evidence that So and Fl(2)d interact genetically in the developing eye. Wilms׳ tumor-1 (WT1), a binding partner of WTAP, is required for normal eye formation in mammals and loss-of-function mutations are associated with some versions of retinoblastoma. In contrast, WTAP and its homologs have not been implicated in eye development. To our knowledge, the results presented in this report are the first description of a role for WTAP in the retina of any seeing animal.
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Affiliation(s)
- Abigail M Anderson
- Department of Biology, Indiana University, Bloomington, IN 47405, United States
| | - Brandon P Weasner
- Department of Biology, Indiana University, Bloomington, IN 47405, United States
| | - Bonnie M Weasner
- Department of Biology, Indiana University, Bloomington, IN 47405, United States
| | - Justin P Kumar
- Department of Biology, Indiana University, Bloomington, IN 47405, United States.
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Horiuchi K, Kawamura T, Iwanari H, Ohashi R, Naito M, Kodama T, Hamakubo T. Identification of Wilms' tumor 1-associating protein complex and its role in alternative splicing and the cell cycle. J Biol Chem 2013; 288:33292-302. [PMID: 24100041 DOI: 10.1074/jbc.m113.500397] [Citation(s) in RCA: 246] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Wilms' tumor 1-associating protein (WTAP) is a putative splicing regulator that is thought to be required for cell cycle progression through the stabilization of cyclin A2 mRNA and mammalian early embryo development. To further understand how WTAP acts in the context of the cellular machinery, we identified its interacting proteins in human umbilical vein endothelial cells and HeLa cells using shotgun proteomics. Here we show that WTAP forms a novel protein complex including Hakai, Virilizer homolog, KIAA0853, RBM15, the arginine/serine-rich domain-containing proteins BCLAF1 and THRAP3, and certain general splicing regulators, most of which have reported roles in post-transcriptional regulation. The depletion of these respective components of the complex resulted in reduced cell proliferation along with G2/M accumulation. Double knockdown of the serine/arginine-rich (SR)-like proteins BCLAF1 and THRAP3 by siRNA resulted in a decrease in the nuclear speckle localization of WTAP, whereas the nuclear speckles were intact. Furthermore, we found that the WTAP complex regulates alternative splicing of the WTAP pre-mRNA by promoting the production of a truncated isoform, leading to a change in WTAP protein expression. Collectively, these findings show that the WTAP complex is a novel component of the RNA processing machinery, implying an important role in both posttranscriptional control and cell cycle regulation.
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Affiliation(s)
- Keiko Horiuchi
- From the Department of Quantitative Biology and Medicine and
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28
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Ruiz MF, Sarno F, Zorrilla S, Rivas G, Sánchez L. Biochemical and functional analysis of Drosophila-sciara chimeric sex-lethal proteins. PLoS One 2013; 8:e65171. [PMID: 23762307 PMCID: PMC3677924 DOI: 10.1371/journal.pone.0065171] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 04/21/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The Drosophila SXL protein controls sex determination and dosage compensation. It is a sex-specific factor controlling splicing of its own Sxl pre-mRNA (auto-regulation), tra pre-mRNA (sex determination) and msl-2 pre-mRNA plus translation of msl-2 mRNA (dosage compensation). Outside the drosophilids, the same SXL protein has been found in both sexes so that, in the non-drosophilids, SXL does not appear to play the key discriminating role in sex determination and dosage compensation that it plays in Drosophila. Comparison of SXL proteins revealed that its spatial organisation is conserved, with the RNA-binding domains being highly conserved, whereas the N- and C-terminal domains showing significant variation. This manuscript focuses on the evolution of the SXL protein itself and not on regulation of its expression. METHODOLOGY Drosophila-Sciara chimeric SXL proteins were produced. Sciara SXL represents the non-sex-specific function of ancient SXL in the non-drosophilids from which presumably Drosophila SXL evolved. Two questions were addressed. Did the Drosophila SXL protein have affected their functions when their N- and C-terminal domains were replaced by the corresponding ones of Sciara? Did the Sciara SXL protein acquire Drosophila sex-specific functions when the Drosophila N- and C-terminal domains replaced those of Sciara? The chimeric SXL proteins were analysed in vitro to study their binding affinity and cooperative properties, and in vivo to analyse their effect on sex determination and dosage compensation by producing Drosophila flies that were transgenic for the chimeric SXL proteins. CONCLUSIONS The sex-specific properties of extant Drosophila SXL protein depend on its global structure rather than on a specific domain. This implies that the modifications, mainly in the N- and C-terminal domains, that occurred in the SXL protein during its evolution within the drosophilid lineage represent co-evolutionary changes that determine the appropriate folding of SXL to carry out its sex-specific functions.
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Affiliation(s)
- María Fernanda Ruiz
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Francesca Sarno
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Silvia Zorrilla
- Instituto de Química-Física “Rocasolano”, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Germán Rivas
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Lucas Sánchez
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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29
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Jia G, Fu Y, He C. Reversible RNA adenosine methylation in biological regulation. Trends Genet 2012; 29:108-15. [PMID: 23218460 DOI: 10.1016/j.tig.2012.11.003] [Citation(s) in RCA: 285] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/01/2012] [Accepted: 11/05/2012] [Indexed: 01/20/2023]
Abstract
N(6)-methyladenosine (m(6)A) is a ubiquitous modification in mRNA and other RNAs across most eukaryotes. For many years, however, the exact functions of m(6)A were not clearly understood. The discovery that the fat mass and obesity-associated protein (FTO) is an m(6)A demethylase indicates that this modification is reversible and dynamically regulated, suggesting that it has regulatory roles. In addition, it has been shown that m(6)A affects cell fate decisions in yeast and plant development. Recent affinity-based m(6)A profiling in mouse and human cells further showed that this modification is a widespread mark in coding and noncoding RNA (ncRNA) transcripts and is likely dynamically regulated throughout developmental processes. Therefore, reversible RNA methylation, analogous to reversible DNA and histone modifications, may affect gene expression and cell fate decisions by modulating multiple RNA-related cellular pathways, which potentially provides rapid responses to various cellular and environmental signals, including energy and nutrient availability in mammals.
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Affiliation(s)
- Guifang Jia
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
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30
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Agarwala SD, Blitzblau HG, Hochwagen A, Fink GR. RNA methylation by the MIS complex regulates a cell fate decision in yeast. PLoS Genet 2012; 8:e1002732. [PMID: 22685417 PMCID: PMC3369947 DOI: 10.1371/journal.pgen.1002732] [Citation(s) in RCA: 184] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 04/10/2012] [Indexed: 12/20/2022] Open
Abstract
For the yeast Saccharomyces cerevisiae, nutrient limitation is a key developmental signal causing diploid cells to switch from yeast-form budding to either foraging pseudohyphal (PH) growth or meiosis and sporulation. Prolonged starvation leads to lineage restriction, such that cells exiting meiotic prophase are committed to complete sporulation even if nutrients are restored. Here, we have identified an earlier commitment point in the starvation program. After this point, cells, returned to nutrient-rich medium, entered a form of synchronous PH development that was morphologically and genetically indistinguishable from starvation-induced PH growth. We show that lineage restriction during this time was, in part, dependent on the mRNA methyltransferase activity of Ime4, which played separable roles in meiotic induction and suppression of the PH program. Normal levels of meiotic mRNA methylation required the catalytic domain of Ime4, as well as two meiotic proteins, Mum2 and Slz1, which interacted and co-immunoprecipitated with Ime4. This MIS complex (Mum2, Ime4, and Slz1) functioned in both starvation pathways. Together, our results support the notion that the yeast starvation response is an extended process that progressively restricts cell fate and reveal a broad role of post-transcriptional RNA methylation in these decisions. Cellular differentiation involves the limitation of cellular potential in response to developmental cues. Budding yeast cells differentiate in response to nutrient availability. In the presence of nutrients, cells divide mitotically by producing round, yeast-form buds. Under nutrient limitation, cells can either divide under a pseudo-hyphal (PH) foraging program or undergo meiosis to form protective spores. We show here that developmental commitment occurs in two distinct phases. When nutrients were removed, cells first became committed to a starvation response, during which they entered the meiotic program. If nutrient limitation persisted, cells became committed to meiosis and sporulation. By contrast, if nutrients were returned at this point, cells synchronously initiated PH foraging growth. We found that both sporulation and PH growth were governed by RNA methylation, and we identified an mRNA–methyltransferase complex comprising Mum2, Ime4, and Slz1 as a central regulator of these developmental trajectories. Our results indicate that the yeast starvation response is an extended developmental process and reveal a fundamental role for post-transcriptional RNA modification in controlling cell fate.
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Affiliation(s)
- Sudeep D. Agarwala
- Whitehead Institute, Cambridge, Massachusetts, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | | | - Andreas Hochwagen
- Whitehead Institute, Cambridge, Massachusetts, United States of America
| | - Gerald R. Fink
- Whitehead Institute, Cambridge, Massachusetts, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
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31
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Schetelig MF, Milano A, Saccone G, Handler AM. Male only progeny in Anastrepha suspensa by RNAi-induced sex reversion of chromosomal females. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2012; 42:51-57. [PMID: 22079281 DOI: 10.1016/j.ibmb.2011.10.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 10/11/2011] [Accepted: 10/17/2011] [Indexed: 05/31/2023]
Abstract
In Tephritidae sex determination is established by orthologs to the Drosophila melanogaster transformer and transformer-2 genes, though the primary signals for sex determination differ. The presence of the Y chromosome in the tephritid species is critical for male differentiation, while the ratio of X chromosomes to autosome ploidy is critical in drosophilids. Here the isolation, expression and function of tra and tra-2 orthologs are described for the agriculturally important tephritid, Anastrepha suspensa, and their possible use in genetically modified organisms for biologically-based pest management. The Astra and Astra-2 genes are highly conserved in structure, regulation and function with respect to those known from other tephritid species. Sex-specific transcripts for Astra were detected, one in females and three in males, whereas Astra-2 had a single common transcript found in both sexes. To test the function of these genes, Astra and Astra-2 dsRNA was injected into A. suspensa embryos from a transgenic strain having a Y-linked DsRed marker integration, allowing XY males to be distinguished from XX phenotypic males. Nearly all XX embryos developed into fully masculinized phenotypic male adults with no apparent female morphology. Upon dissection abnormal hypertrophic gonads were revealed in XX pseudomales but not in the XY males. Our findings suggest that Astra and Astra-2 are both necessary for female development, and that the potential exists for producing a male-only population when either gene alone, or both genes simultaneously, are knocked-down.
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Affiliation(s)
- Marc F Schetelig
- USDA/ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL 32608, USA
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32
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The translation initiation factor eIF4E regulates the sex-specific expression of the master switch gene Sxl in Drosophila melanogaster. PLoS Genet 2011; 7:e1002185. [PMID: 21829374 PMCID: PMC3145617 DOI: 10.1371/journal.pgen.1002185] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Accepted: 05/20/2011] [Indexed: 11/27/2022] Open
Abstract
In female fruit flies, Sex-lethal (Sxl) turns off the X chromosome dosage compensation system by a mechanism involving a combination of alternative splicing and translational repression of the male specific lethal-2 (msl-2) mRNA. A genetic screen identified the translation initiation factor eif4e as a gene that acts together with Sxl to repress expression of the Msl-2 protein. However, eif4e is not required for Sxl mediated repression of msl-2 mRNA translation. Instead, eif4e functions as a co-factor in Sxl-dependent female-specific alternative splicing of msl-2 and also Sxl pre-mRNAs. Like other factors required for Sxl regulation of splicing, eif4e shows maternal-effect female-lethal interactions with Sxl. This female lethality can be enhanced by mutations in other co-factors that promote female-specific splicing and is caused by a failure to properly activate the Sxl-positive autoregulatory feedback loop in early embryos. In this feedback loop Sxl proteins promote their own synthesis by directing the female-specific alternative splicing of Sxl-Pm pre-mRNAs. Analysis of pre-mRNA splicing when eif4e activity is compromised demonstrates that Sxl-dependent female-specific splicing of both Sxl-Pm and msl-2 pre-mRNAs requires eif4e activity. Consistent with a direct involvement in Sxl-dependent alternative splicing, eIF4E is associated with unspliced Sxl-Pm pre-mRNAs and is found in complexes that contain early acting splicing factors—the U1/U2 snRNP protein Sans-fils (Snf), the U1 snRNP protein U1-70k, U2AF38, U2AF50, and the Wilms' Tumor 1 Associated Protein Fl(2)d—that have been directly implicated in Sxl splicing regulation. Gene expression in eukaryotes is a complex process that occurs in several discrete steps. Some of those steps are separated into different sub-cellular compartments and thus might be expected to occur independently of one another and involve entirely distinct factors. For example pre-mRNA splicing takes place in the nucleus where it is coupled with transcription, while mRNA translation requires export to the cytoplasm and ribosome loading. We describe studies on the fruit fly Drosophila which indicate that a cytoplasmic translation initiation factor, the cap binding protein eIF4E, plays a key role in alternative splicing in the nucleus. When eIF4E activity is compromised, we observe defects in sex-specific splicing of pre-mRNAs that are regulated by the sex determination master switch gene Sex-lethal. Our data argue that eIF4E likely plays a direct role in the regulation of alternative splicing by Sex-lethal.
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Small TW, Pickering JG. Nuclear degradation of Wilms tumor 1-associating protein and survivin splice variant switching underlie IGF-1-mediated survival. J Biol Chem 2009; 284:24684-95. [PMID: 19605357 DOI: 10.1074/jbc.m109.034629] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
WTAP (Wilms tumor 1-associating protein) is a recently identified nuclear protein that is essential for mouse embryo development. The Drosophila homolog of WTAP, Fl(2)d, regulates pre-mRNA splicing; however, the role of WTAP in mammalian cells is uncertain. To elucidate a context for WTAP action, we screened growth and survival factors for their effects on WTAP expression in vascular smooth muscle cells (SMCs), a cell type previously found to express WTAP dynamically. This revealed that insulin-like growth factor-1 (IGF-1) uniquely reduced WTAP abundance. This decline in WTAP proved to be necessary for IGF-1 to confer its antiapoptotic properties, which were blocked by transducing the WTAP gene into SMCs. WTAP down-regulation by IGF-1 was mediated by an IGF-1 receptor-phosphatidylinositol 3-kinase-Akt signaling axis that directed WTAP degradation via a nuclear 26 S proteasome. Moreover, by promoting the degradation of WTAP, IGF-1 shifted the pre-mRNA splicing program for the survival factor, survivin, to reduce expression of survivin-2B, which is proapoptotic, and increase expression of survivin, which is antiapoptotic. Knockdown of survivin-2B rescued the ability of IGF-1 to promote survival when WTAP was overexpressed. These data uncover a novel regulatory cascade for human SMC survival based on adjusting the nuclear abundance of WTAP to define the splice variant balance among survivin isoforms.
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Affiliation(s)
- Theodore W Small
- Robarts Research Institute, University of Western Ontario, London, Ontario N6A 5K8, Canada
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Zhong S, Li H, Bodi Z, Button J, Vespa L, Herzog M, Fray RG. MTA is an Arabidopsis messenger RNA adenosine methylase and interacts with a homolog of a sex-specific splicing factor. THE PLANT CELL 2008; 20:1278-88. [PMID: 18505803 PMCID: PMC2438467 DOI: 10.1105/tpc.108.058883] [Citation(s) in RCA: 415] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 04/23/2008] [Accepted: 05/12/2008] [Indexed: 05/18/2023]
Abstract
N6-Methyladenosine is a ubiquitous modification identified in the mRNA of numerous eukaryotes, where it is present within both coding and noncoding regions. However, this base modification does not alter the coding capacity, and its biological significance remains unclear. We show that Arabidopsis thaliana mRNA contains N6-methyladenosine at levels similar to those previously reported for animal cells. We further show that inactivation of the Arabidopsis ortholog of the yeast and human mRNA adenosine methylase (MTA) results in failure of the developing embryo to progress past the globular stage. We also demonstrate that the arrested seeds are deficient in mRNAs containing N6-methyladenosine. Expression of MTA is strongly associated with dividing tissues, particularly reproductive organs, shoot meristems, and emerging lateral roots. Finally, we show that MTA interacts in vitro and in vivo with At FIP37, a homolog of the Drosophila protein FEMALE LETHAL2D and of human WILMS' TUMOUR1-ASSOCIATING PROTEIN. The results reported here provide direct evidence for an essential function for N6-methyladenosine in a multicellular eukaryote, and the interaction with At FIP37 suggests possible RNA processing events that might be regulated or altered by this base modification.
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Affiliation(s)
- Silin Zhong
- Plant Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom
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35
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Small TW, Penalva LO, Pickering JG. Vascular biology and the sex of flies: regulation of vascular smooth muscle cell proliferation by wilms' tumor 1-associating protein. Trends Cardiovasc Med 2008; 17:230-4. [PMID: 17936204 DOI: 10.1016/j.tcm.2007.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 08/24/2007] [Accepted: 08/27/2007] [Indexed: 11/17/2022]
Abstract
Smooth muscle cells (SMCs) are called on to proliferate during vascular repair but must return to a nonproliferative state if remodeling is to terminate appropriately. One gene that has recently been implicated in the acquisition of SMC replicative quiescence is Wilms' tumor 1-associating protein (WTAP). Wilms' tumor 1-associating protein is a nuclear constituent of uncertain function that, as the name implies, interacts with the Wilms' tumor 1 tumor suppressor gene product (WT1). Wilms' tumor 1-associating protein is essential for embryonic development, and recent data suggest that WTAP regulates the proliferation of both SMCs and endothelial cells. In SMCs, WTAP appears to be antiproliferative, inhibiting G(1)-to-S phase cell cycle transition and also promoting apoptosis. These effects could be the result of WTAP suppressing the transcriptional activity of WT1 in SMCs. Interestingly, the Drosophila homologue of WTAP, fl(2)d, is a protein essential for alternative splicing regulation and sexual determination in this species. Wilms' tumor 1-associating protein may thus also play a role in messenger RNA processing in mammalian cells, either dependent on or independent of its interaction with WT1. The putative actions of WTAP as a regulator of transcriptional and posttranscriptional events and emerging evidence for a WTAP-WT1 axis in vascular cells suggest that WTAP is a vital and multifaceted regulator of vascular remodeling.
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Affiliation(s)
- Theodore W Small
- Department of Medicine (Cardiology), Robarts Research Institute, London Health Sciences Centre, University of Western Ontario, London, ON, Canada N6A 5K8
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36
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Morrison AA, Viney RL, Ladomery MR. The post-transcriptional roles of WT1, a multifunctional zinc-finger protein. Biochim Biophys Acta Rev Cancer 2007; 1785:55-62. [PMID: 17980713 DOI: 10.1016/j.bbcan.2007.10.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 09/28/2007] [Accepted: 10/03/2007] [Indexed: 11/19/2022]
Abstract
WT1 was first described in 1990 as a tumour suppressor gene associated with Wilms tumour (nephroblastoma). It encodes a typical transcription factor with four C(2)-H(2) zinc fingers in the C-terminus. However WT1 is surprisingly complex at multiple levels: it is involved in the development of several organ systems; and is both a tumour suppressor and oncogene. Here we review evidence that has accumulated over the past decade to suggest that as well as binding DNA, WT1 also binds mRNA targets via its zinc fingers and interacts with several splice factors. WT1's first reported post-transcriptional function is also reviewed. WT1's complex roles in development and disease now need to be understood in terms of both DNA and mRNA targets.
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Affiliation(s)
- Avril A Morrison
- Centre for Research in Biomedicine, Faculty of Health and Life Sciences, University of the West of England, Coldharbour Lane, Bristol BS16 1QY, UK
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37
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Horiuchi K, Umetani M, Minami T, Okayama H, Takada S, Yamamoto M, Aburatani H, Reid PC, Housman DE, Hamakubo T, Kodama T. Wilms' tumor 1-associating protein regulates G2/M transition through stabilization of cyclin A2 mRNA. Proc Natl Acad Sci U S A 2006; 103:17278-83. [PMID: 17088532 PMCID: PMC1634838 DOI: 10.1073/pnas.0608357103] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Wilms' tumor 1-associating protein (WTAP) has been reported to be a ubiquitously expressed nuclear protein. Although a relation to splicing factors has been postulated, its actual physiological function still remains to be elucidated. To investigate the role of WTAP, we generated WTAP-knockout mice and performed small interfering RNA (siRNA)-mediated knockdown analyses in primary cultured cells. In DNA microarrays using human umbilical vein endothelial cells, WTAP-targeted siRNA treatment resulted in markedly reduced expression of cell-cycle-related genes. siRNA-mediated WTAP knockdown down-regulated the stability of cyclin A2 mRNA through a nine-nucleotide essential sequence in cyclin A2 mRNA 3' UTR. WTAP knockdown induced G2 accumulation, which is partially rescued by adenoviral overexpression of cyclin A2. Moreover, WTAP-null mice exhibited proliferative failure with death resulting at approximately embryonic day 6.5, an etiology almost identical to cyclin A2-null mice. Collectively, these findings establish WTAP as an essential factor for the stabilization of cyclin A2 mRNA, thereby regulating G2/M cell-cycle transition.
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Affiliation(s)
| | - Michihisa Umetani
- Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | | | - Hiroto Okayama
- Department of Biochemistry and Molecular Biology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shinji Takada
- Okazaki Institute for Integrative Biosciences, National Institute of Natural Sciences, Okazaki 444-8787, Japan
| | - Masayuki Yamamoto
- Center for Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba 305-8577, Japan; and
| | - Hiroyuki Aburatani
- Genome Science Division, Research Center for Advanced Science and Technology, University of Tokyo, Meguro, Tokyo 153-8904, Japan
| | | | - David E. Housman
- **Center for Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
- To whom correspondence may be addressed. E-mail:
or
| | - Takao Hamakubo
- *Laboratory for Systems Biology and Medicine and
- To whom correspondence may be addressed. E-mail:
or
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Ortega A. Localization of the Drosophila protein FL(2)D in somatic cells and female gonads. Cell Tissue Res 2005; 320:361-7. [PMID: 15778853 DOI: 10.1007/s00441-004-1049-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2004] [Accepted: 11/10/2004] [Indexed: 10/25/2022]
Abstract
The Drosophila gene female-lethal(2)d [fl(2)d] has been implicated in the alternative splicing regulation of genes involved in sexual determination, such as Sex-lethal and transformer, and in the alternative splicing of the gene Ultrabithorax. Here, the expression and subcellular localization of the FL(2)D protein is reported. FL(2)D is ubiquitously expressed in embryos, in imaginal discs of larvae and in ovaries. In Schneider cells, the protein is detected throughout the nucleoplasm, excluding the nucleolus, and partially co-localizes with SXL in nuclear speckles. In addition, FL(2)D associates with multiple transcriptionally active loci on salivary gland polytene chromosomes, consistent with the proposal that the protein is involved in the post-transcriptional regulation of a variety of genes. Interestingly, the localization of FL(2)D in nurse cells changes during oogenesis, from a rather diffuse early nuclear pattern in the germarium to a preferential accumulation at the nuclear periphery of nurse cells of developing cysts.
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Affiliation(s)
- A Ortega
- European Molecular Biology Laboratory, Heidelberg, Germany.
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39
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Penalva LOF, Sánchez L. RNA binding protein sex-lethal (Sxl) and control of Drosophila sex determination and dosage compensation. Microbiol Mol Biol Rev 2003; 67:343-59, table of contents. [PMID: 12966139 PMCID: PMC193869 DOI: 10.1128/mmbr.67.3.343-359.2003] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the past two decades, scientists have elucidated the molecular mechanisms behind Drosophila sex determination and dosage compensation. These two processes are controlled essentially by two different sets of genes, which have in common a master regulatory gene, Sex-lethal (Sxl). Sxl encodes one of the best-characterized members of the family of RNA binding proteins. The analysis of different mechanisms involved in the regulation of the three identified Sxl target genes (Sex-lethal itself, transformer, and male specific lethal-2) has contributed to a better understanding of translation repression, as well as constitutive and alternative splicing. Studies using the Drosophila system have identified the features of the protein that contribute to its target specificity and regulatory functions. In this article, we review the existing data concerning Sxl protein, its biological functions, and the regulation of its target genes.
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Affiliation(s)
- Luiz O F Penalva
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina 27710, USA.
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Förch P, Valcárcel J. Splicing regulation in Drosophila sex determination. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2003; 31:127-51. [PMID: 12494765 DOI: 10.1007/978-3-662-09728-1_5] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- P Förch
- Gene Expression Programme, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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Ortega A, Niksic M, Bachi A, Wilm M, Sánchez L, Hastie N, Valcárcel J. Biochemical function of female-lethal (2)D/Wilms' tumor suppressor-1-associated proteins in alternative pre-mRNA splicing. J Biol Chem 2003; 278:3040-7. [PMID: 12444081 DOI: 10.1074/jbc.m210737200] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Genetic and molecular data have implicated the Drosophila gene female-lethal (2)d (fl (2)d) in alternative splicing regulation of genes involved in sexual determination. Sex-specific splicing is under the control of the female-specific regulatory protein sex-lethal (SXL). Co-immunoprecipitation and mass spectrometry results indicate that SXL and FL (2)D form a complex and that the protein VIRILIZER and a Ran-binding protein implicated in protein nuclear import are also present in complexes containing FL (2)D. A human homolog of FL (2)D was identified and cloned. Interestingly, this gene encodes a protein (WTAP) that was previously found to interact with the Wilms' tumor suppressor-1 (WT1), an isoform of which binds to and co-localizes with splicing factors. Alternative splicing of transformer pre-mRNA, a target of SXL regulation, was affected by immunodepletion of hFL (2)D/WTAP from HeLa nuclear extracts, thus arguing for a biochemical function of FL (2)D/WTAP proteins in splicing regulation.
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Affiliation(s)
- Angeles Ortega
- Gene Expression Programme, European Molecular Biology Laboratory, Heidelberg, Germany
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Niessen M, Schneiter R, Nothiger R. Molecular identification of virilizer, a gene required for the expression of the sex-determining gene Sex-lethal in Drosophila melanogaster. Genetics 2001; 157:679-88. [PMID: 11156988 PMCID: PMC1461513 DOI: 10.1093/genetics/157.2.679] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Sex-lethal (Sxl) is a central switch gene in somatic sexual development of Drosophila melanogaster. Female-specific expression of Sxl relies on autoregulatory splicing of Sxl pre-mRNA by SXL protein. This process requires the function of virilizer (vir). Besides its role in Sxl splicing, vir is essential for male and female viability and is also required for the production of eggs capable of embryonic development. We have identified vir molecularly and found that it produces a single transcript of 6 kb that is ubiquitously expressed in male and female embryos throughout development. This transcript encodes a nuclear protein of 210 kD that cannot be assigned to a known protein family. VIR contains a putative transmembrane domain, a coiled-coil region and PEST sequences. We have characterized five different alleles of vir. Those alleles that affect both sexes are associated with large truncations of the protein, while alleles that affect only the female-specific functions are missense mutations that lie relatively close to each other, possibly defining a region important for the regulation of Sxl.
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Affiliation(s)
- M Niessen
- Zoological Institute, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
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Singh R, Banerjee H, Green MR. Differential recognition of the polypyrimidine-tract by the general splicing factor U2AF65 and the splicing repressor sex-lethal. RNA (NEW YORK, N.Y.) 2000; 6:901-11. [PMID: 10864047 PMCID: PMC1369966 DOI: 10.1017/s1355838200000376] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The polypyrimidine-tract (Py-tract) adjacent to 3' splice sites is an essential splicing signal and is recognized by several proteins, including the general splicing factor U2AF65 and the highly specific splicing repressor Sex-lethal (SXL). They both contain ribonucleoprotein-consensus RNA-binding motifs. However, U2AF65 recognizes a wide variety of Py-tracts, whereas SXL recognizes specific Py-tracts such as the nonsex-specific Py-tract of the transformer pre-mRNA. It is not understood how these seemingly similar proteins differentially recognize the Py-tract. To define these interactions, we used chemical interference and protection assays, saturation mutagenesis, and RNAs containing modified nucleotides. We find that these proteins recognize distinct features of the RNA. First, although uracils within the Py-tract are protected from chemical modification by both of these proteins, modification of any one of seven uracils by hydrazine, or any of eight phosphates by ethylnitrosourea strongly interfered with the binding of SXL only. Second, the 2' hydroxyl groups or backbone conformation appeared important for the binding of SXL, but not U2AF65. Third, although any of the bases (cytosine >> adenine > guanine) could substitute for uracils for U2AF65 binding, only guanine partially substituted for certain uracils for SXL binding. The different dependence on individual contacts and nucleotide preference may provide a basis for the different RNA-binding specificities and thus functions of U2AF65 and SXL in 3' splice site choice.
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Affiliation(s)
- R Singh
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, 80309, USA.
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Penalva LO, Ruiz MF, Ortega A, Granadino B, Vicente L, Segarra C, Valcárcel J, Sánchez L. The Drosophila fl(2)d gene, required for female-specific splicing of Sxl and tra pre-mRNAs, encodes a novel nuclear protein with a HQ-rich domain. Genetics 2000; 155:129-39. [PMID: 10790389 PMCID: PMC1461084 DOI: 10.1093/genetics/155.1.129] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The Drosophila gene female-lethal(2)d [fl(2)d] interacts genetically with the master regulatory gene for sex determination, Sex-lethal. Both genes are required for the activation of female-specific patterns of alternative splicing on transformer and Sex-lethal pre-mRNAs. We have used P-element-mediated mutagenesis to identify the fl(2)d gene. The fl(2)d transcription unit generates two alternatively spliced mRNAs that can encode two protein isoforms differing at their amino terminus. The larger isoform contains a domain rich in histidine and glutamine but has no significant homology to proteins in databases. Several lines of evidence indicate that this protein is responsible for fl(2)d function. First, the P-element insertion that inactivates fl(2)d interrupts this ORF. Second, amino acid changes within this ORF have been identified in fl(2)d mutants, and the nature of the changes correlates with the severity of the mutations. Third, all of the phenotypes associated with fl(2)d mutations can be rescued by expression of this cDNA in transgenic flies. Fl(2)d protein can be detected in extracts from Drosophila cell lines, embryos, larvae, and adult animals, without apparent differences between sexes, as well as in adult ovaries. Consistent with a possible function in posttranscriptional regulation, Fl(2)d protein has nuclear localization and is enriched in nuclear extracts.
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Affiliation(s)
- L O Penalva
- Gene Expression Programme, European Molecular Biology Laboratory, D-69117 Heidelberg, Germany
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Bhattacharya A, Sudha S, Chandra HS, Steward R. flex, an X-linked female-lethal mutation in Drosophila melanogaster controls the expression of Sex-lethal. Development 1999; 126:5485-93. [PMID: 10556072 DOI: 10.1242/dev.126.23.5485] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Sex-lethal (Sxl) gene is required in Drosophila females for sexual differentiation of the soma, for gem cell differentiation and dosage compensation. We have isolated three new alleles of female-lethal-on-X (flex), an X-linked female-lethal mutation and have characterized its function in sex determination. SXL protein is missing in flex/flex embryos, however transcription from both Sxl(Pe), the early Sxl promoter and Sxl(Pm), the late maintenance promoter, is normal in flex homozygotes. In flex/flex embryos, Sxl mRNA is spliced in the male mode. Analysis of flex germline clones shows that it also functions in oogenesis, but in contrast to Sxl mutants that show an early arrest tumorous phenotype, flex mutant egg chambers develop to stage 10. In flex ovarian clones, Sxl RNA is also spliced in the male form. Hence, flex is a sex-specific regulator of Sxl functioning in both the soma and the germline. Genetic interaction studies show that flex does not enhance female lethality of Sxl loss-of-function alleles but it rescues the male-specific lethality of both of the gain-of-function Sxl mutations, Sxl(M1)and Sxl(M4.) In contrast to mutations in splicing regulators of Sxl, the female lethality of flex is not rescued by either Sxl(M1)or Sxl(M4). Based on these observations, we propose that flex regulates Sxl at a post-splicing stage and regulates either its translation or the stability of the SXL protein.
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Affiliation(s)
- A Bhattacharya
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
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Abstract
Alternative splicing of pre-mRNAs is a powerful and versatile regulatory mechanism that can effect quantitative control of gene expression and functional diversification of proteins. It contributes to major developmental decisions and also to fine tuning of gene function. Genetic and biochemical approaches have identified cis-acting regulatory elements and trans-acting factors that control alternative splicing of specific pre-mRNAs. Both approaches are contributing to an understanding of their mode of action. Some alternative splicing decisions are controlled by specific factors whose expression is highly restricted during development, but others may be controlled by more modest variations in the levels of general factors acting cooperatively or antagonistically. Certain factors play active roles in both constitutive splicing and regulation of alternative splicing. Cooperative and antagonistic effects integrated at regulatory elements are likely to be important for specificity and for finely tuned differences in cell-type-specific alternative splicing patterns.
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Affiliation(s)
- A J Lopez
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
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SchüŁtt C, Hilfiker A, Nöthiger R. virilizer regulates Sex-lethal in the germline of Drosophila melanogaster. Development 1998; 125:1501-7. [PMID: 9502731 DOI: 10.1242/dev.125.8.1501] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In Drosophila, the gene Sex-lethal (Sxl) is required for female development. It controls sexual differentiation in the soma, dosage compensation and oogenesis. The continuous production of SXL proteins in XX animals is maintained by autoregulation and depends on virilizer (vir). This gene is required in somatic cells for the female-specific splicing of Sxl primary transcripts and for an unknown vital process in both sexes. In the soma, clones of XX cells lacking Sxl or vir are sexually transformed and form male structures; in the germline, XX cells mutant for Sxl extensively proliferate, but are unable to differentiate. We now studied the role of vir in the germline by generating germline chimeras. We found that XX germ cells mutant for vir, in contrast to cells mutant for Sxl, perform oogenesis. We show that the early production of SXL in undifferentiated germ cells is independent of vir while, later in oogenesis, expression of Sxl becomes dependent on vir. We conclude that the early SXL proteins are sufficient for the production of eggs whereas the later SXL proteins are dispensable for this process. However, vir must be active in the female germline to allow normal embryonic development because maternal products of vir are required for the early post-transcriptional regulation of Sxl in XX embryos and for a vital process in embryos of both sexes.
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Affiliation(s)
- C SchüŁtt
- Zoological Institute, University of Zürich, Zürich, Switzerland
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A search for additional X-linked genes affecting sex determination inDrosophila melanogaster. J Genet 1998. [DOI: 10.1007/bf02933038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Penalva LO, Sakamoto H, Navarro-Sabaté A, Sakashita E, Granadino B, Segarra C, Sánchez L. Regulation of the gene Sex-lethal: a comparative analysis of Drosophila melanogaster and Drosophila subobscura. Genetics 1996; 144:1653-64. [PMID: 8978052 PMCID: PMC1207716 DOI: 10.1093/genetics/144.4.1653] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The Drosophila gene Sex-lethal (Sxl) controls the processes of sex determination and dosage compensation. A Drosophila subobscura genomic fragment containing all the exons and the late and early promotors in the Sxl gene of D. melanogaster was isolated. Early Sxl expression in D. subobscura seems to be controlled at the transcriptional level, possibly by the X:A signal. In the region upstream of the early Sxl transcription initiation site are two conserved regions suggested to be involved in the early activation of Sxl. Late Sxl expression in D. subobscura produces four transcripts in adult females and males. In males, the transcripts have an additional exon which contains three translational stop codons so that a truncated, presumably nonfunctional Sxl protein is produced. The Sxl pre-mRNA of D. subobscura lacks the poly-U sequence presented at the polypirimidine tract of the 3' splice site of the male-specific exon present in D. melanogaster. Introns 2 and 3 contain the Sxl-binding poly-U stretches, whose localization in intron 2 varies but in intron 3 is conserved. The Sxl protein is fully conserved at the amino acid level in both species.
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Affiliation(s)
- L O Penalva
- Centro de Investigaciones Biológicas (C.S.I.C.), Madrid, Spain
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Abstract
For 600 million years, the two best-understood metazoan species, the nematode Caenorhabditis elegans and fruit fly Drosophila melanogaster, have developed independent strategies for solving a biological problem faced by essentially all metazoans: how to generate two sexes in the proper proportions. The genetic program for sexual dimorphism has been a major focus of research in these two organisms almost from the moment they were chosen for study, and it may now be the best-understood general aspect of their development. In this review, we compare and contrast the strategies used for sex determination (including dosage compensation) between "the fly" and "the worm" and the way this understanding has come about. Although no overlap has been found among the molecules used by flies and worms to achieve sex determination, striking similarities have been found in the genetic strategies used by these two species to differentiate their sexes.
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Affiliation(s)
- T W Cline
- Department of Molecular and Cell Biology, University of California, Berkeley 94720-3204, USA
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