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Knudsen-Palmer DR, Raman P, Ettefa F, De Ravin L, Jose AM. Target-specific requirements for RNA interference can arise through restricted RNA amplification despite the lack of specialized pathways. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.02.07.527351. [PMID: 36798330 PMCID: PMC9934570 DOI: 10.1101/2023.02.07.527351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Since double-stranded RNA (dsRNA) is effective for silencing a wide variety of genes, all genes are typically considered equivalent targets for such RNA interference (RNAi). Yet, loss of some regulators of RNAi in the nematode C. elegans can selectively impair the silencing of some genes. Here we show that such selective requirements can be explained by an intersecting network of regulators acting on genes with differences in their RNA metabolism. In this network, the Maelstrom domain-containing protein RDE-10, the intrinsically disordered protein MUT-16, and the Argonaute protein NRDE-3 work together so that any two are required for silencing one somatic gene, but each is singly required for silencing another somatic gene, where only the requirement for NRDE-3 can be overcome by enhanced dsRNA processing. Quantitative models and their exploratory simulations led us to find that (1) changing cis-regulatory elements of the target gene can reduce the dependence on NRDE-3, (2) animals can recover from silencing in non-dividing cells and (3) cleavage and tailing of mRNAs with UG dinucleotides, which makes them templates for amplifying small RNAs, is enriched within 'pUG zones' matching the dsRNA. Similar crosstalk between pathways and restricted amplification could result in apparently selective silencing by endogenous RNAs.
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Affiliation(s)
- Daphne R. Knudsen-Palmer
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, USA. Biological Sciences Graduate Program, University of Maryland, College Park, USA
| | - Pravrutha Raman
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, USA. Biological Sciences Graduate Program, University of Maryland, College Park, USA
- Current address: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Farida Ettefa
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, USA. Biological Sciences Graduate Program, University of Maryland, College Park, USA
- Current address: Institute for Systems Genetics, New York University School of Medicine, New York, NY, USA
| | - Laura De Ravin
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, USA. Biological Sciences Graduate Program, University of Maryland, College Park, USA
| | - Antony M. Jose
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, USA. Biological Sciences Graduate Program, University of Maryland, College Park, USA
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Tao J, Cui J, Xu Y, Fan Y, Hong G, Zhou Q, Wang G, Li L, Han Y, Xu C, Wang W, Cai S, Zhang X. MAEL in human cancers and implications in prognostication and predicting benefit from immunotherapy over VEGFR/mTOR inhibitors in clear cell renal cell carcinoma: a bioinformatic analysis. Aging (Albany NY) 2024; 16:2090-2122. [PMID: 38301040 PMCID: PMC10911358 DOI: 10.18632/aging.205470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 12/13/2023] [Indexed: 02/03/2024]
Abstract
Maelstrom (MAEL), a novel cancer/testis-associated gene, may facilitate the initiation and progression of human malignancies, warranting comprehensive investigations. Single-cell and tissue-bulk transcriptomic data demonstrated higher MAEL expression in testis (spermatogonia/spermatocyte), kidney (proximal tubular cell), and brain (neuron/astrocyte), and corresponding cancers, including testicular germ cell tumor, glioma, papillary renal cell carcinoma, and clear cell renal cell carcinoma (ccRCC). Of these cancers, only in ccRCC did MAEL expression exhibit associations with both recurrence-free survival and overall survival. High MAEL expression was associated with an anti-inflammatory tumor immune microenvironment and VEGFR/mTOR activation in ccRCC tissues and high sensitivities to VEGFR/PI3K-AKT-mTOR inhibitors in ccRCC cell lines. Consistent with these, low rather than high MAEL expression indicated remarkable progression-free survival benefits from immune checkpoint inhibitor (ICI)-based immunotherapies over VEGFR/mTOR inhibitors in two large phase III trials (JAVELIN Renal 101 and CheckMate-025). MAEL is a biologically and clinically significant determinant with potential for prognostication after nephrectomy and patient selection for VEGFR/mTOR inhibitors and immunotherapy-based treatments.
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Affiliation(s)
- Jin Tao
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Jinshan Cui
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Yu Xu
- Burning Rock Biotech, Guangzhou, Guangdong, China
| | - Yafeng Fan
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Guodong Hong
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Qiaoxia Zhou
- Burning Rock Biotech, Guangzhou, Guangdong, China
| | | | - Leo Li
- Burning Rock Biotech, Guangzhou, Guangdong, China
| | - Yusheng Han
- Burning Rock Biotech, Guangzhou, Guangdong, China
| | - Chunwei Xu
- Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, Hangzhou, Zhejiang, China
| | - Wenxian Wang
- Department of Clinical Trial, The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Hangzhou, Zhejiang, China
| | - Shangli Cai
- Burning Rock Biotech, Guangzhou, Guangdong, China
| | - Xuepei Zhang
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
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Cheng YS, Chen HY, Lin YC, Lin YS, Yeh YC, Yeh YH, Cheng YH, Lin YM, Weng HY, Lin TY, Lin SC. The MAEL expression in mitochondria of human spermatozoa and the association with asthenozoospermia. Andrology 2023; 11:1286-1294. [PMID: 36779514 DOI: 10.1111/andr.13408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/19/2023] [Accepted: 02/05/2023] [Indexed: 02/14/2023]
Abstract
PURPOSE The maelstrom spermatogenic transposon silencer (MAEL) function in postmeiotic germ cells remains unclear, and its protein localization in human testis and spermatozoa awaits determination. This study aims to clarify the MAEL expression in human spermatogenesis and to explore its role in sperm function. MATERIALS AND METHODS Twenty-seven asthenozoospermic men, 40 normozoospermic controls, and three obstructive azoospermic men were enrolled. The transcripts of MAEL in the seminiferous epithelium and MAEL downstream targets were identified by bioinformatics analysis. MAEL protein expression in human testis and ejaculated sperms were examined by immunohistochemical and immunogold staining, respectively. The roles of MAEL in mitochondria function were investigated by siRNA knockdown in human H358 cells. The association between MAEL protein levels and clinical sperm features was evaluated. RESULTS Abundant MAEL was expressed in spermatid and spermatozoa of the human testis. Remarkably, MAEL was located in the mitochondria of ejaculated sperm, and bioinformatics analysis identified GPX4 and UBL4B as MAEL's downstream targets. Knockdown of MAEL sabotaged mitochondria function and reduced adenosine triphosphate (ATP) production in H358 cells. MAEL, GPX4, and UBL4B expression levels were significantly decreased in asthenozoospermic sperms than in controls. The MAEL protein levels were positively correlated with GPX4 and UBL4B in human sperm. Total motile sperm count (TMSC) was positively correlated with protein levels of MAEL, GPX4, and UBL4B in ejaculated sperms. CONCLUSIONS We highlight prominent MAEL expression in the intratesticular spermatid and the mitochondria of ejaculated spermatozoa. MAEL directly binds to GPX4 and UBL4B, and loss of MAEL induces mitochondrial dysfunction. MAEL-mitochondrial function-motility relationship might advance our understanding of the causes of asthenozoospermia.
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Affiliation(s)
- Yu-Sheng Cheng
- Department of Urology, National Cheng Kung University Hospital, College of, Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Hsing-Yi Chen
- Department of Urology, National Cheng Kung University Hospital, College of, Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Chiao Lin
- Department of Urology, National Cheng Kung University Hospital, College of, Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yi-Syuan Lin
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yi-Chun Yeh
- International Center for Wound Repair and Regeneration, National Cheng Kung University, Tainan, Taiwan
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yi-Hsuan Yeh
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yung-Hsuan Cheng
- Department of Urology, National Cheng Kung University Hospital, College of, Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yung-Ming Lin
- Department of Urology, National Cheng Kung University Hospital, College of, Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Han-Yu Weng
- Department of Urology, National Cheng Kung University Hospital, College of, Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Tsung-Yen Lin
- Department of Surgery, Division of Urology, National Cheng Kung University Hospital Dou-Liou Branch, Yunlin, Taiwan
| | - Shih-Chieh Lin
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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De Luca C, Gupta A, Bortvin A. Retrotransposon LINE-1 bodies in the cytoplasm of piRNA-deficient mouse spermatocytes: Ribonucleoproteins overcoming the integrated stress response. PLoS Genet 2023; 19:e1010797. [PMID: 37307272 DOI: 10.1371/journal.pgen.1010797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 05/23/2023] [Indexed: 06/14/2023] Open
Abstract
Transposable elements (TE) are mobile DNA sequences whose excessive proliferation endangers the host. Although animals have evolved robust TE-targeting defenses, including Piwi-interacting (pi)RNAs, retrotransposon LINE-1 (L1) still thrives in humans and mice. To gain insights into L1 endurance, we characterized L1 Bodies (LBs) and ORF1p complexes in germ cells of piRNA-deficient Maelstrom null mice. We report that ORF1p interacts with TE RNAs, genic mRNAs, and stress granule proteins, consistent with earlier studies. We also show that ORF1p associates with the CCR4-NOT deadenylation complex and PRKRA, a Protein Kinase R factor. Despite ORF1p interactions with these negative regulators of RNA expression, the stability and translation of LB-localized mRNAs remain unchanged. To scrutinize these findings, we studied the effects of PRKRA on L1 in cultured cells and showed that it elevates ORF1p levels and L1 retrotransposition. These results suggest that ORF1p-driven condensates promote L1 propagation, without affecting the metabolism of endogenous RNAs.
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Affiliation(s)
- Chiara De Luca
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, United States of Americ
| | - Anuj Gupta
- The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alex Bortvin
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland, United States of Americ
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Schneider BK, Sun S, Lee M, Li W, Skvir N, Neretti N, Vijg J, Secombe J. Expression of retrotransposons contributes to aging in Drosophila. Genetics 2023; 224:iyad073. [PMID: 37084379 PMCID: PMC10213499 DOI: 10.1093/genetics/iyad073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 12/12/2022] [Accepted: 04/11/2023] [Indexed: 04/23/2023] Open
Abstract
Retrotransposons are a class of transposable elements capable of self-replication and insertion into new genomic locations. Across species, the mobilization of retrotransposons in somatic cells has been suggested to contribute to the cell and tissue functional decline that occurs during aging. Retrotransposons are broadly expressed across cell types, and de novo insertions have been observed to correlate with tumorigenesis. However, the extent to which new retrotransposon insertions occur during normal aging and their effect on cellular and animal function remains understudied. Here, we use a single nucleus whole genome sequencing approach in Drosophila to directly test whether transposon insertions increase with age in somatic cells. Analyses of nuclei from thoraces and indirect flight muscles using a newly developed pipeline, Retrofind, revealed no significant increase in the number of transposon insertions with age. Despite this, reducing the expression of two different retrotransposons, 412 and Roo, extended lifespan, but did not alter indicators of health such as stress resistance. This suggests a key role for transposon expression and not insertion in regulating longevity. Transcriptomic analyses revealed similar changes to gene expression in 412 and Roo knockdown flies and highlighted changes to genes involved in proteolysis and immune function as potential contributors to the observed changes in longevity. Combined, our data show a clear link between retrotransposon expression and aging.
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Affiliation(s)
- Blair K Schneider
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Ave., Ullmann 809 Bronx, NY 10461, USA
| | - Shixiang Sun
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Ave., Price 468 Bronx, NY 10461, USA
| | - Moonsook Lee
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Ave., Price 468 Bronx, NY 10461, USA
| | - Wenge Li
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Ullmann 909 Bronx, NY 10461, USA
| | - Nicholas Skvir
- Department of Molecular biology, Cell biology and Biochemistry, Brown University, 70 Ship St., Providence 02903, USA
| | - Nicola Neretti
- Department of Molecular biology, Cell biology and Biochemistry, Brown University, 70 Ship St., Providence 02903, USA
| | - Jan Vijg
- Department of Genetics, Albert Einstein College of Medicine, 1301 Morris Park Ave., Price 468 Bronx, NY 10461, USA
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Julie Secombe
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Ave., Ullmann 809 Bronx, NY 10461, USA
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Zhou L, Ou S, Liang T, Li M, Xiao P, Cheng J, Zhou J, Yuan L. MAEL facilitates metabolic reprogramming and breast cancer progression by promoting the degradation of citrate synthase and fumarate hydratase via chaperone-mediated autophagy. FEBS J 2023. [PMID: 36866961 DOI: 10.1111/febs.16768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 01/15/2023] [Accepted: 01/30/2023] [Indexed: 03/04/2023]
Abstract
Metabolic reprogramming is a hallmark of cancer. Several studies have shown that inactivation of Krebs cycle enzymes, such as citrate synthase (CS) and fumarate hydratase (FH), facilitates aerobic glycolysis and cancer progression. MAEL has been shown to play an oncogenic role in bladder, liver, colon, and gastric cancers, but its role in breast cancer and metabolism is still unknown. Here, we demonstrated that MAEL promoted malignant behaviours and aerobic glycolysis in breast cancer cells. Mechanistically, MAEL interacted with CS/FH and HSAP8 via its MAEL domain and HMG domain, respectively, and then enhanced the binding affinity of CS/FH with HSPA8, facilitating the transport of CS/FH to the lysosome for degradation. MAEL-induced degradation of CS and FH could be suppressed by the lysosome inhibitors leupeptin and NH4 Cl, but not by the macroautophagy inhibitor 3-MA or the proteasome inhibitor MG132. These results suggested that MAEL promoted the degradation of CS and FH via chaperone-mediated autophagy (CMA). Further studies showed that the expression of MAEL was significantly and negatively correlated with CS and FH in breast cancer. Moreover, overexpression of CS or/and FH could reverse the oncogenic effects of MAEL. Taken together, MAEL promotes a metabolic shift from oxidative phosphorylation to glycolysis by inducing CMA-dependent degradation of CS and FH, thereby promoting breast cancer progression. These findings have elucidated a novel molecular mechanism of MAEL in cancer.
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Affiliation(s)
- Lin Zhou
- State Key Laboratory of Developmental Biology of Freshwater Fish & Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Science, Hunan Normal University, Changsha, China.,College of Clinical Laboratory, Changsha Medical University, China
| | - Shuobo Ou
- State Key Laboratory of Developmental Biology of Freshwater Fish & Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Science, Hunan Normal University, Changsha, China
| | - Ting Liang
- State Key Laboratory of Developmental Biology of Freshwater Fish & Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Science, Hunan Normal University, Changsha, China
| | - Meiling Li
- State Key Laboratory of Developmental Biology of Freshwater Fish & Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Science, Hunan Normal University, Changsha, China
| | - Pei Xiao
- State Key Laboratory of Developmental Biology of Freshwater Fish & Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Science, Hunan Normal University, Changsha, China
| | - Jiaxin Cheng
- State Key Laboratory of Developmental Biology of Freshwater Fish & Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Science, Hunan Normal University, Changsha, China
| | - Jianlin Zhou
- State Key Laboratory of Developmental Biology of Freshwater Fish & Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Science, Hunan Normal University, Changsha, China
| | - Liqin Yuan
- Department of General Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
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Luca CD, Gupta A, Bortvin A. Ribonucleoprotein condensation driven by retrotransposon LINE-1 sustains RNA integrity and translation in mouse spermatocytes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.09.523313. [PMID: 36712121 PMCID: PMC9882024 DOI: 10.1101/2023.01.09.523313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Transposable elements (TE) are mobile DNA sequences whose excessive proliferation endangers the host. Although animals have evolved robust TE-targeting defenses, including Piwi-interacting (pi)RNAs, retrotransposon LINE-1 (L1) still thrives in humans and mice. To gain insights into L1 endurance, we characterized L1 Bodies (LBs) and ORF1p complexes in germ cells of piRNA-deficient Maelstrom null mice. We report that ORF1p interacts with TE RNAs, genic mRNAs, and stress granule proteins, consistent with earlier studies. We also show that ORF1p associates with the CCR4-NOT deadenylation complex and PRKRA, a Protein Kinase R factor. Despite ORF1p interactions with these negative regulators of RNA expression, the stability and translation of LB-localized mRNAs remain unchanged. To scrutinize these findings, we studied the effects of PRKRA on L1 in cultured cells and showed that it elevates ORF1p levels and L1 retrotransposition. These results suggest that ORF1p-driven condensates promote L1 propagation, without affecting the metabolism of endogenous RNAs.
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8
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He WP, Yang GP, Yang ZX, Shen HW, You ZS, Yang GF. Maelstrom promotes tumor metastasis through regulation of FGFR4 and epithelial-mesenchymal transition in epithelial ovarian cancer. J Ovarian Res 2022; 15:55. [PMID: 35513870 PMCID: PMC9074322 DOI: 10.1186/s13048-022-00992-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 04/27/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Increasing evidence has indicated that Maelstrom (MAEL) plays an oncogenic role in various human carcinomas. However, the exact function and mechanisms by which MAEL acts in epithelial ovarian cancer (EOC) remain unclear. RESULTS This study demonstrated that MAEL was frequently overexpressed in EOC tissues and cell lines. Overexpression of MAEL was positively correlated with the histological grade of tumors, FIGO stage, and pT/pN/pM status (p < 0.05), and it also acted as an independent predictor of poor patient survival (p < 0.001). Ectopic overexpression of MAEL substantially promoted invasiveness/metastasis and induced epithelial-mesenchymal transition (EMT), whereas silencing MAEL by short hairpin RNA effectively inhibited its oncogenic function and attenuated EMT. Further study demonstrated that fibroblast growth factor receptor 4 (FGFR4) was a critical downstream target of MAEL in EOC, and the expression levels of FGFR4 were significantly associated with MAEL. (P < 0.05). CONCLUSION Our findings suggest that overexpression of MAEL plays a crucial oncogenic role in the development and progression of EOC through the upregulation of FGFR4 and subsequent induction of EMT, and also provide new insights on its potential as a therapeutic target for EOC.
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Affiliation(s)
- Wei-Peng He
- Department of Gynecology, the First Affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan Road II, Guangzhou, 510080, China
| | - Gui-Ping Yang
- Department of Gynecology, the First Affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan Road II, Guangzhou, 510080, China
| | - Zun-Xian Yang
- Department of Gynecology, the First Affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan Road II, Guangzhou, 510080, China
| | - Hong-Wei Shen
- Department of Gynecology, the First Affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan Road II, Guangzhou, 510080, China
| | - Ze-Shan You
- Department of Gynecology, the First Affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan Road II, Guangzhou, 510080, China
| | - Guo-Fen Yang
- Department of Gynecology, the First Affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan Road II, Guangzhou, 510080, China.
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Namba Y, Iwasaki YW, Nishida KM, Nishihara H, Sumiyoshi T, Siomi MC. Maelstrom functions in the production of Siwi-piRISC capable of regulating transposons in Bombyx germ cells. iScience 2022; 25:103914. [PMID: 35243263 PMCID: PMC8881725 DOI: 10.1016/j.isci.2022.103914] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 12/27/2021] [Accepted: 02/08/2022] [Indexed: 11/17/2022] Open
Affiliation(s)
- Yurika Namba
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan
| | - Yuka W. Iwasaki
- Department of Molecular Biology, Keio University School of Medicine, Tokyo 160-8582, Japan
- Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology, Saitama 332-0012, Japan
| | - Kazumichi M. Nishida
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan
| | - Hidenori Nishihara
- School of Life Science and Technology, Tokyo Institute of Technology, Kanagawa 226-8501, Japan
| | - Tetsutaro Sumiyoshi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan
| | - Mikiko C. Siomi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan
- Corresponding author
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10
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The birth of piRNAs: how mammalian piRNAs are produced, originated, and evolved. Mamm Genome 2021; 33:293-311. [PMID: 34724117 PMCID: PMC9114089 DOI: 10.1007/s00335-021-09927-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 10/15/2021] [Indexed: 11/24/2022]
Abstract
PIWI-interacting RNAs (piRNAs), small noncoding RNAs 24–35 nucleotides long, are essential for animal fertility. They play critical roles in a range of functions, including transposable element suppression, gene expression regulation, imprinting, and viral defense. In mammals, piRNAs are the most abundant small RNAs in adult testes and the only small RNAs that direct epigenetic modification of chromatin in the nucleus. The production of piRNAs is a complex process from transcription to post-transcription, requiring unique machinery often distinct from the biogenesis of other RNAs. In mice, piRNA biogenesis occurs in specialized subcellular locations, involves dynamic developmental regulation, and displays sexual dimorphism. Furthermore, the genomic loci and sequences of piRNAs evolve much more rapidly than most of the genomic regions. Understanding piRNA biogenesis should reveal novel RNA regulations recognizing and processing piRNA precursors and the forces driving the gain and loss of piRNAs during animal evolution. Such findings may provide the basis for the development of engineered piRNAs capable of modulating epigenetic regulation, thereby offering possible single-dose RNA therapy without changing the genomic DNA. In this review, we focus on the biogenesis of piRNAs in mammalian adult testes that are derived from long non-coding RNAs. Although piRNA biogenesis is believed to be evolutionarily conserved from fruit flies to humans, recent studies argue for the existence of diverse, mammalian-specific RNA-processing pathways that convert precursor RNAs into piRNAs, perhaps associated with the unique features of mammalian piRNAs or germ cell development. We end with the discussion of major questions in the field, including substrate recognition and the birth of new piRNAs.
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11
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Hale AT, Bastarache L, Morales DM, Wellons JC, Limbrick DD, Gamazon ER. Multi-omic analysis elucidates the genetic basis of hydrocephalus. Cell Rep 2021; 35:109085. [PMID: 33951428 PMCID: PMC8124085 DOI: 10.1016/j.celrep.2021.109085] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/01/2019] [Accepted: 04/14/2021] [Indexed: 11/17/2022] Open
Abstract
We conducted PrediXcan analysis of hydrocephalus risk in ten neurological tissues and whole blood. Decreased expression of MAEL in the brain was significantly associated (Bonferroni-adjusted p < 0.05) with hydrocephalus. PrediXcan analysis of brain imaging and genomics data in the independent UK Biobank (N = 8,428) revealed that MAEL expression in the frontal cortex is associated with white matter and total brain volumes. Among the top differentially expressed genes in brain, we observed a significant enrichment for gene-level associations with these structural phenotypes, suggesting an effect on disease risk through regulation of brain structure and integrity. We found additional support for these genes through analysis of the choroid plexus transcriptome of a murine model of hydrocephalus. Finally, differential protein expression analysis in patient cerebrospinal fluid recapitulated disease-associated expression changes in neurological tissues, but not in whole blood. Our findings provide convergent evidence highlighting the importance of tissue-specific pathways and mechanisms in the pathophysiology of hydrocephalus.
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Affiliation(s)
- Andrew T Hale
- Vanderbilt University School of Medicine, Medical Scientist Training Program, Nashville, TN 37232, USA; Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - Lisa Bastarache
- Department of Bioinformatics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Diego M Morales
- Division of Pediatric Neurosurgery, St. Louis Children's Hospital, St. Louis, MO 63110, USA
| | - John C Wellons
- Division of Pediatric Neurosurgery, Monroe Carell Jr. Children's Hospital of Vanderbilt University, Nashville, TN 37232, USA
| | - David D Limbrick
- Division of Pediatric Neurosurgery, St. Louis Children's Hospital, St. Louis, MO 63110, USA
| | - Eric R Gamazon
- Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Data Science Institute, Vanderbilt University, Nashville, TN 37232, USA; Clare Hall, University of Cambridge, Cambridge CB3 9AL, UK; MRC Epidemiology Unit, University of Cambridge, Cambridge CB3 9AL, UK.
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12
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Cruz-González A, Muñoz-Velasco I, Cottom-Salas W, Becerra A, Campillo-Balderas JA, Hernández-Morales R, Vázquez-Salazar A, Jácome R, Lazcano A. Structural analysis of viral ExoN domains reveals polyphyletic hijacking events. PLoS One 2021; 16:e0246981. [PMID: 33730017 PMCID: PMC7968707 DOI: 10.1371/journal.pone.0246981] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 02/24/2021] [Indexed: 12/15/2022] Open
Abstract
Nidoviruses and arenaviruses are the only known RNA viruses encoding a 3’-5’ exonuclease domain (ExoN). The proofreading activity of the ExoN domain has played a key role in the growth of nidoviral genomes, while in arenaviruses this domain partakes in the suppression of the host innate immune signaling. Sequence and structural homology analyses suggest that these proteins have been hijacked from cellular hosts many times. Analysis of the available nidoviral ExoN sequences reveals a high conservation level comparable to that of the viral RNA-dependent RNA polymerases (RdRp), which are the most conserved viral proteins. Two highly preserved zinc fingers are present in all nidoviral exonucleases, while in the arenaviral protein only one zinc finger can be identified. This is in sharp contrast with the reported lack of zinc fingers in cellular ExoNs, and opens the possibility of therapeutic strategies in the struggle against COVID-19.
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Affiliation(s)
- Adrián Cruz-González
- Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, México
| | - Israel Muñoz-Velasco
- Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, México
| | - Wolfgang Cottom-Salas
- Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, México
- Escuela Nacional Preparatoria, Plantel 8 Miguel E. Schulz, Universidad Nacional Autónoma de México, México City, México
| | - Arturo Becerra
- Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, México
| | | | | | - Alberto Vázquez-Salazar
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California, United States of America
| | - Rodrigo Jácome
- Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, México
- * E-mail: (AL); (RJ)
| | - Antonio Lazcano
- Facultad de Ciencias, Universidad Nacional Autónoma de México, México City, México
- El Colegio Nacional, México City, México
- * E-mail: (AL); (RJ)
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13
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Onishi R, Sato K, Murano K, Negishi L, Siomi H, Siomi MC. Piwi suppresses transcription of Brahma-dependent transposons via Maelstrom in ovarian somatic cells. SCIENCE ADVANCES 2020; 6:6/50/eaaz7420. [PMID: 33310860 PMCID: PMC7732180 DOI: 10.1126/sciadv.aaz7420] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 10/19/2020] [Indexed: 05/05/2023]
Abstract
Drosophila Piwi associates with PIWI-interacting RNAs (piRNAs) and represses transposons transcriptionally through heterochromatinization; however, this process is poorly understood. Here, we identify Brahma (Brm), the core adenosine triphosphatase of the SWI/SNF chromatin remodeling complex, as a new Piwi interactor, and show Brm involvement in activating transcription of Piwi-targeted transposons before silencing. Bioinformatic analyses indicated that Piwi, once bound to target RNAs, reduced the occupancies of SWI/SNF and RNA polymerase II (Pol II) on target loci, abrogating transcription. Artificial piRNA-driven targeting of Piwi to RNA transcripts enhanced repression of Brm-dependent reporters compared with Brm-independent reporters. This was dependent on Piwi cofactors, Gtsf1/Asterix (Gtsf1), Panoramix/Silencio (Panx), and Maelstrom (Mael), but not Eggless/dSetdb (Egg)-mediated H3K9me3 deposition. The λN-box B-mediated tethering of Mael to reporters repressed Brm-dependent genes in the absence of Piwi, Panx, and Gtsf1. We propose that Piwi, via Mael, can rapidly suppress transcription of Brm-dependent genes to facilitate heterochromatin formation.
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Affiliation(s)
- Ryo Onishi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan
| | - Kaoru Sato
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan
| | - Kensaku Murano
- Department of Molecular Biology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Lumi Negishi
- Central Laboratory, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo 113-0032, Japan
| | - Haruhiko Siomi
- Department of Molecular Biology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Mikiko C Siomi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan.
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14
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Meng X, Zhang L, Hou J, Ma T, Pan C, Zhou Y, Han R, Ding Y, Peng H, Xiang Z, Li D, Han X. The mechanisms in the altered ontogenetic development and lung-related pathology in microcystin-leucine arginine (MC-LR)-paternal-exposed offspring mice. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 736:139678. [PMID: 32479959 DOI: 10.1016/j.scitotenv.2020.139678] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
A father's lifetime experience is a major risk factor for a range of diseases in an individual, and the consequences of the exposure can also be transmitted to his offspring. Our previous work has demonstrated that damage to testicular structures and decline in sperm quality in male mice can be caused by microcystin-leucine arginine (MC-LR), but the overall effects of the scope and extent of paternal exposure on health and disease in the offspring remain underexplored. Here, we report that MC-LR-paternal-exposed offspring mice showed reduced litter size and body weight accompanied by increased abnormalities in the lung. Analyses of the small noncoding RNAs (sncRNAs) in the sperm from MC-LR-exposed males demonstrated the downregulation of a wide range of piRNAs enriched for those target genes involved in the regulation of the embryo implantation pathways. Gene and protein expression analyses, as well as biochemical and functional studies, revealed suppressed expression of Hsp90α in testicular tissues from MC-LR-exposed males. Decreased Hsp90α in testicular tissues impaired the development of the offspring. In this study, we revealed that MC-LR alters the expression of Hsp90α in testicular tissues to cause changes in the expression profiles of sperm piRNAs produced by paternal mice. These changes lead to aberrant activation of the Wnt/β-catenin signaling pathway in pulmonary tissues of offspring mice, causing lung tissue damage and abnormal development. We hereby confirmed that MC-LR-induced alterations in epigenetic inheritance are capable of contributing to intergenerational developmental defects in paternal-exposed offspring mice.
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Affiliation(s)
- Xiannan Meng
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Ling Zhang
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Jiwei Hou
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Tan Ma
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Chun Pan
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Yuan Zhou
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Ruitong Han
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Yuanzhen Ding
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Haoran Peng
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Zou Xiang
- Department of Health Technology and Informatics, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
| | - Dongmei Li
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China.
| | - Xiaodong Han
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China.
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15
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SATO K, SIOMI MC. The piRNA pathway in Drosophila ovarian germ and somatic cells. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2020; 96:32-42. [PMID: 31932527 PMCID: PMC6974405 DOI: 10.2183/pjab.96.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 10/28/2019] [Indexed: 05/30/2023]
Abstract
RNA silencing refers to gene silencing pathways mediated by small non-coding RNAs, including microRNAs. Piwi-interacting RNAs (piRNAs) constitute the largest class of small non-coding RNAs in animal gonads, which repress transposons to protect the germline genome from the selfish invasion of transposons. Deterioration of the system causes DNA damage, leading to severe defects in gametogenesis and infertility. Studies using Drosophila ovaries show that piRNAs originate from specific genomic loci, termed piRNA clusters, and that in piRNA biogenesis, cluster transcripts are processed into mature piRNAs via three distinct pathways: initiator or responder for ping-pong piRNAs and trailing for phased piRNAs. piRNAs then assemble with PIWI members of the Argonaute family of proteins to form piRNA-induced RNA silencing complexes (piRISCs), the core engine of the piRNA-mediated silencing pathway. Upon piRISC assembly, the PIWI member, Piwi, is translocated to the nucleus and represses transposons co-transcriptionally by inducing local heterochromatin formation at target transposon loci.
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Affiliation(s)
- Kaoru SATO
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Mikiko C. SIOMI
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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16
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Ozata DM, Gainetdinov I, Zoch A, O'Carroll D, Zamore PD. PIWI-interacting RNAs: small RNAs with big functions. Nat Rev Genet 2019; 20:89-108. [PMID: 30446728 DOI: 10.1038/s41576-018-0073-3] [Citation(s) in RCA: 646] [Impact Index Per Article: 129.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In animals, PIWI-interacting RNAs (piRNAs) of 21-35 nucleotides in length silence transposable elements, regulate gene expression and fight viral infection. piRNAs guide PIWI proteins to cleave target RNA, promote heterochromatin assembly and methylate DNA. The architecture of the piRNA pathway allows it both to provide adaptive, sequence-based immunity to rapidly evolving viruses and transposons and to regulate conserved host genes. piRNAs silence transposons in the germ line of most animals, whereas somatic piRNA functions have been lost, gained and lost again across evolution. Moreover, most piRNA pathway proteins are deeply conserved, but different animals employ remarkably divergent strategies to produce piRNA precursor transcripts. Here, we discuss how a common piRNA pathway allows animals to recognize diverse targets, ranging from selfish genetic elements to genes essential for gametogenesis.
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Affiliation(s)
- Deniz M Ozata
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Ildar Gainetdinov
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Ansgar Zoch
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Dónal O'Carroll
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.,Wellcome Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, UK
| | - Phillip D Zamore
- RNA Therapeutics Institute and Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA, USA.
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17
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Chen K, Chen S, Xu J, Yu Y, Liu Z, Tan A, Huang Y. Maelstrom regulates spermatogenesis of the silkworm, Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 109:43-51. [PMID: 30970276 DOI: 10.1016/j.ibmb.2019.03.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 03/03/2019] [Accepted: 03/28/2019] [Indexed: 06/09/2023]
Abstract
The spermatogenesis of animal is essential for the reproduction and a very large number of genes participate in this procession. The Maelstrom (Mael) is identified essential for spermatogenesis in both Drosophila and mouse, though the mechanisms appear to differ. It was initially found that Mael gene is necessary for axis specification of oocytes in Drosophila, and recent studies suggested that Mael participates in the piRNA pathway. In this study, we obtained Bombyx mori Mael mutants by using a binary transgenic CRISPR/Cas9 system and analyzed the function of Mael in B. mori, a model lepidopteran insect. The results showed that BmMael is not necessary for piRNA pathway in the ovary of silkworm, whereas it might be essential for transposon elements (TEs) repression in testis. The BmMael mutation resulted in male sterility, and further analysis established that BmMael was essential for spermatogenesis. The spermatogenesis defects occurred in the elongation stage and resulted in nuclei concentration arrest. RNA-seq and qRT-PCR analyses demonstrated that spermatogenesis defects were associated with tight junctions and apoptosis. We also found that BmMael was not involved in the silkworm sex determination pathway. Our data provide insights into the biological function of BmMael in male spermatogenesis and might be useful for developing novel methods to control lepidopteron pests.
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Affiliation(s)
- Kai Chen
- 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
| | - Shuqing Chen
- 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
| | - Jun Xu
- 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
| | - Ye Yu
- 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
| | - Zulian Liu
- 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
| | - Anjiang Tan
- 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
| | - Yongping Huang
- 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.
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18
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Specchia V, Puricella A, D'Attis S, Massari S, Giangrande A, Bozzetti MP. Drosophila melanogaster as a Model to Study the Multiple Phenotypes, Related to Genome Stability of the Fragile-X Syndrome. Front Genet 2019; 10:10. [PMID: 30815010 PMCID: PMC6381874 DOI: 10.3389/fgene.2019.00010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/11/2019] [Indexed: 12/14/2022] Open
Abstract
Fragile-X syndrome is one of the most common forms of inherited mental retardation and autistic behaviors. The reduction/absence of the functional FMRP protein, coded by the X-linked Fmr1 gene in humans, is responsible for the syndrome. Patients exhibit a variety of symptoms predominantly linked to the function of FMRP protein in the nervous system like autistic behavior and mild-to-severe intellectual disability. Fragile-X (FraX) individuals also display cellular and morphological traits including branched dendritic spines, large ears, and macroorchidism. The dFmr1 gene is the Drosophila ortholog of the human Fmr1 gene. dFmr1 mutant flies exhibit synaptic abnormalities, behavioral defects as well as an altered germline development, resembling the phenotypes observed in FraX patients. Therefore, Drosophila melanogaster is considered a good model to study the physiopathological mechanisms underlying the Fragile-X syndrome. In this review, we explore how the multifaceted roles of the FMRP protein have been addressed in the Drosophila model and how the gained knowledge may open novel perspectives for understanding the molecular defects causing the disease and for identifying novel therapeutical targets.
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Affiliation(s)
- Valeria Specchia
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, DiSTeBA, Università del Salento, Lecce, Italy
| | - Antonietta Puricella
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, DiSTeBA, Università del Salento, Lecce, Italy
| | - Simona D'Attis
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, DiSTeBA, Università del Salento, Lecce, Italy
| | - Serafina Massari
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, DiSTeBA, Università del Salento, Lecce, Italy
| | - Angela Giangrande
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France.,Université de Strasbourg, Illkirch, France
| | - Maria Pia Bozzetti
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, DiSTeBA, Università del Salento, Lecce, Italy
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19
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Chang TH, Mattei E, Gainetdinov I, Colpan C, Weng Z, Zamore PD. Maelstrom Represses Canonical Polymerase II Transcription within Bi-directional piRNA Clusters in Drosophila melanogaster. Mol Cell 2019; 73:291-303.e6. [PMID: 30527661 PMCID: PMC6551610 DOI: 10.1016/j.molcel.2018.10.038] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 10/05/2018] [Accepted: 10/24/2018] [Indexed: 11/18/2022]
Abstract
In Drosophila, 23-30 nt long PIWI-interacting RNAs (piRNAs) direct the protein Piwi to silence germline transposon transcription. Most germline piRNAs derive from dual-strand piRNA clusters, heterochromatic transposon graveyards that are transcribed from both genomic strands. These piRNA sources are marked by the heterochromatin protein 1 homolog Rhino (Rhi), which facilitates their promoter-independent transcription, suppresses splicing, and inhibits transcriptional termination. Here, we report that the protein Maelstrom (Mael) represses canonical, promoter-dependent transcription in dual-strand clusters, allowing Rhi to initiate piRNA precursor transcription. Mael also represses promoter-dependent transcription at sites outside clusters. At some loci, Mael repression requires the piRNA pathway, while at others, piRNAs play no role. We propose that by repressing canonical transcription of individual transposon mRNAs, Mael helps Rhi drive non-canonical transcription of piRNA precursors without generating mRNAs encoding transposon proteins.
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MESH Headings
- Animals
- Argonaute Proteins/genetics
- Argonaute Proteins/metabolism
- Binding Sites
- Chromosomal Proteins, Non-Histone/genetics
- Chromosomal Proteins, Non-Histone/metabolism
- DNA Transposable Elements
- Drosophila Proteins/genetics
- Drosophila Proteins/metabolism
- Drosophila melanogaster/enzymology
- Drosophila melanogaster/genetics
- Gene Expression Regulation
- Promoter Regions, Genetic
- Protein Binding
- RNA Helicases/genetics
- RNA Helicases/metabolism
- RNA Polymerase II/genetics
- RNA Polymerase II/metabolism
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- RNA, Small Interfering/biosynthesis
- RNA, Small Interfering/genetics
- Transcription, Genetic
- RNA, Guide, CRISPR-Cas Systems
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Affiliation(s)
- Timothy H Chang
- RNA Therapeutics Institute and Howard Hughes Medical Institute, Worcester, MA, USA
| | - Eugenio Mattei
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA
| | - Ildar Gainetdinov
- RNA Therapeutics Institute and Howard Hughes Medical Institute, Worcester, MA, USA
| | - Cansu Colpan
- RNA Therapeutics Institute and Howard Hughes Medical Institute, Worcester, MA, USA
| | - Zhiping Weng
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
| | - Phillip D Zamore
- RNA Therapeutics Institute and Howard Hughes Medical Institute, Worcester, MA, USA.
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20
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Sato K, Siomi MC. Two distinct transcriptional controls triggered by nuclear Piwi-piRISCs in the Drosophila piRNA pathway. Curr Opin Struct Biol 2018; 53:69-76. [DOI: 10.1016/j.sbi.2018.06.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 06/19/2018] [Indexed: 01/21/2023]
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21
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Czech B, Munafò M, Ciabrelli F, Eastwood EL, Fabry MH, Kneuss E, Hannon GJ. piRNA-Guided Genome Defense: From Biogenesis to Silencing. Annu Rev Genet 2018; 52:131-157. [PMID: 30476449 PMCID: PMC10784713 DOI: 10.1146/annurev-genet-120417-031441] [Citation(s) in RCA: 303] [Impact Index Per Article: 50.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
PIWI-interacting RNAs (piRNAs) and their associated PIWI clade Argonaute proteins constitute the core of the piRNA pathway. In gonadal cells, this conserved pathway is crucial for genome defense, and its main function is to silence transposable elements. This is achieved through posttranscriptional and transcriptional gene silencing. Precursors that give rise to piRNAs require specialized transcription and transport machineries because piRNA biogenesis is a cytoplasmic process. The ping-pong cycle, a posttranscriptional silencing mechanism, combines the cleavage-dependent silencing of transposon RNAs with piRNA production. PIWI proteins also function in the nucleus, where they scan for nascent target transcripts with sequence complementarity, instructing transcriptional silencing and deposition of repressive chromatin marks at transposon loci. Although studies have revealed numerous factors that participate in each branch of the piRNA pathway, the precise molecular roles of these factors often remain unclear. In this review, we summarize our current understanding of the mechanisms involved in piRNA biogenesis and function.
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Affiliation(s)
- Benjamin Czech
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Marzia Munafò
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Filippo Ciabrelli
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Evelyn L Eastwood
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Martin H Fabry
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Emma Kneuss
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
| | - Gregory J Hannon
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge CB2 0RE, United Kingdom; ,
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22
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Yashiro R, Murota Y, Nishida KM, Yamashiro H, Fujii K, Ogai A, Yamanaka S, Negishi L, Siomi H, Siomi MC. Piwi Nuclear Localization and Its Regulatory Mechanism in Drosophila Ovarian Somatic Cells. Cell Rep 2018; 23:3647-3657. [DOI: 10.1016/j.celrep.2018.05.051] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 04/25/2018] [Accepted: 05/16/2018] [Indexed: 10/28/2022] Open
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23
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Yamashiro H, Siomi MC. PIWI-Interacting RNA in Drosophila: Biogenesis, Transposon Regulation, and Beyond. Chem Rev 2017; 118:4404-4421. [PMID: 29281264 DOI: 10.1021/acs.chemrev.7b00393] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PIWI-interacting RNAs (piRNAs) are germline-enriched small RNAs that control transposons to maintain genome integrity. To achieve this, upon being processed from piRNA precursors, most of which are transcripts of intergenic piRNA clusters, piRNAs bind PIWI proteins, germline-specific Argonaute proteins, to form effector complexes. The mechanism of this piRNA-mediated transposon silencing pathway is fundamentally similar to that of siRNA/miRNA-dependent gene silencing in that a small RNA guides its partner Argonaute protein to target gene transcripts for repression via RNA-RNA base pairing. However, the uniqueness of this piRNA pathway has emerged through intensive genetic, biochemical, bioinformatic, and structural investigations. Here, we review the studies that elucidated the piRNA pathway, mainly in Drosophila, by describing both historical and recent progress. Studies in other species that have made important contributions to the field are also described.
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Affiliation(s)
- Haruna Yamashiro
- Department of Biological Sciences, Graduate School of Science , The University of Tokyo , Tokyo 113-0032 , Japan
| | - Mikiko C Siomi
- Department of Biological Sciences, Graduate School of Science , The University of Tokyo , Tokyo 113-0032 , Japan
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24
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Kulkarni A, Extavour CG. Convergent evolution of germ granule nucleators: A hypothesis. Stem Cell Res 2017; 24:188-194. [PMID: 28801028 DOI: 10.1016/j.scr.2017.07.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 06/18/2017] [Accepted: 07/15/2017] [Indexed: 11/26/2022] Open
Abstract
Germ cells have been considered "the ultimate stem cell" because they alone, during normal development of sexually reproducing organisms, are able to give rise to all organismal cell types. Morphological descriptions of a specialized cytoplasm termed 'germ plasm' and associated electron dense ribonucleoprotein (RNP) structures called 'germ granules' within germ cells date back as early as the 1800s. Both germ plasm and germ granules are implicated in germ line specification across metazoans. However, at a molecular level, little is currently understood about the molecular mechanisms that assemble these entities in germ cells. The discovery that in some animals, the gene products of a small number of lineage-specific genes initiate the assembly (also termed nucleation) of germ granules and/or germ plasm is the first step towards facilitating a better understanding of these complex biological processes. Here, we draw on research spanning over 100years that supports the hypothesis that these nucleator genes may have evolved convergently, allowing them to perform analogous roles across animal lineages.
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Affiliation(s)
- Arpita Kulkarni
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
| | - Cassandra G Extavour
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA; Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
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Li XD, Zhang JX, Jiang LJ, Wang FW, Liu LL, Liao YJ, Jin XH, Chen WH, Chen X, Guo SJ, Zhou FJ, Zeng YX, Guan XY, Liu ZW, Xie D. Overexpression of maelstrom promotes bladder urothelial carcinoma cell aggressiveness by epigenetically downregulating MTSS1 through DNMT3B. Oncogene 2016; 35:6281-6292. [PMID: 27181205 DOI: 10.1038/onc.2016.165] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Revised: 02/29/2016] [Accepted: 03/31/2016] [Indexed: 12/15/2022]
Abstract
We have recently identified and characterized a novel oncogene, maelstrom (MAEL) from 1q24, in the pathogenesis of hepatocellular carcinoma. In this study, MAEL was investigated for its oncogenic role in urothelial carcinoma of the bladder (UCB) tumorigenesis/aggressiveness and underlying molecular mechanisms. Here, we report that overexpression of MAEL in UCB is important in the acquisition of an aggressive and/or poor prognostic phenotype. In UCB cell lines, knockdown of MAEL by short hairpin RNA is sufficient to inhibit cell growth, invasiveness/metastasis and suppressed epithelial-mesenchymal transition (EMT), whereas ectopic overexpression of MAEL promoted cell growth, invasive and/or metastatic capacity and enhanced EMT both in vitro and in vivo. We further demonstrate that MAEL could induce UCB cell EMT by downregulating a critical downstream target, the metastasis suppressor 1 (MTSS1) gene, ultimately leading to an increased invasiveness of cancer cells. Notably, overexpression of MAEL in UCB cells substantially enhanced the enrichment of DNA methyltrans-ferase (DNMT)3B and histone deacetylase (HDAC)1/2 on the promoter of the MTSS1, and thereby epigenetically suppressing the MTSS1 transcription. Downregulation of MTSS1 by MAEL in UCB cells is partially dependent on DNMT3B. Furthermore, we identify that beside the gene amplification of MAEL, miR-186 is a key negative regulator of MAEL and downregulation of miR-186 is another important mechanism for MAEL overexpression in UCBs. These data suggest that overexpression of MAEL, caused by gene amplification and/or decreased miR-186, has a critical oncogenic role in UCB pathogenesis by downregulation of MTSS1, and MAEL could be used as a novel prognostic marker and/or effective therapeutic target for human UCB.
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Affiliation(s)
- X-D Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - J-X Zhang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
- Department of Oncology, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - L-J Jiang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - F-W Wang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - L-L Liu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Y-J Liao
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - X-H Jin
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - W-H Chen
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - X Chen
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - S-J Guo
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - F-J Zhou
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Y-X Zeng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - X-Y Guan
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
- Department of Clinical Oncology, The University of Hong Kong, Hong Kong, China
| | - Z-W Liu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
- Department of Urology, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - D Xie
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
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Roles for small noncoding RNAs in silencing of retrotransposons in the mammalian brain. Proc Natl Acad Sci U S A 2016; 113:12697-12702. [PMID: 27791114 DOI: 10.1073/pnas.1609287113] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Piwi-interacting RNAs (piRNAs), long thought to be restricted to germline, have recently been discovered in neurons of Aplysia, with a role in the epigenetic regulation of gene expression underlying long-term memory. We here ask whether piwi/piRNAs are also expressed and have functional roles in the mammalian brain. Large-scale RNA sequencing and subsequent analysis of protein expression revealed the presence in brain of several piRNA biogenesis factors including a mouse piwi (Mili), as well as small RNAs, albeit at low levels, resembling conserved piRNAs in mouse testes [primarily LINE1 (long interspersed nuclear element1) retrotransposon-derived]. Despite the seeming low expression of these putative piRNAs, single-base pair CpG methylation analyses across the genome of Mili/piRNA-deficient (Mili-/- ) mice demonstrate that brain genomic DNA is preferentially hypomethylated within intergenic areas and LINE1 promoter areas of the genome. Furthermore, Mili mutant mice exhibit behavioral deficits such as hyperactivity and reduced anxiety. These results suggest that putative piRNAs exist in mammalian brain, and similar to the role of piRNAs in testes, they may be involved in the silencing of retrotransposons, which in brain have critical roles in contributing to genomic heterogeneity underlying adaptation, stress response, and brain pathology. We also describe the presence of another class of small RNAs in the brain, with features of endogenous siRNAs, which may have taken over the role of invertebrate piRNAs in their capacity to target both transposons, as well as protein-coding genes. Thus, RNA interference through gene and retrotransposon silencing previously encountered in Aplysia may also have potential roles in the mammalian brain.
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Abstract
Understanding the molecular mechanisms behind the capacity of cancer cells to adapt to the tumor microenvironment and to anticancer therapies is a major challenge. In this context, cancer is believed to be an evolutionary process where random mutations and the selection process shape the mutational pattern and phenotype of cancer cells. This article challenges the notion of randomness of some cancer-associated mutations by describing molecular mechanisms involving stress-mediated biogenesis of mRNA-derived small RNAs able to target and increase the local mutation rate of the genomic loci they originate from. It is proposed that the probability of some mutations at specific loci could be increased in a stress-specific and RNA-depending manner. This would increase the probability of generating mutations that could alleviate stress situations, such as those triggered by anticancer drugs. Such a mechanism is made possible because tumor- and anticancer drug-associated stress situations trigger both cellular reprogramming and inflammation, which leads cancer cells to express molecular tools allowing them to “attack” and mutate their own genome in an RNA-directed manner.
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Affiliation(s)
- Didier Auboeuf
- Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, Laboratory of Biology and Modelling of the Cell, Lyon, France
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Lazzaretti D, Veith K, Kramer K, Basquin C, Urlaub H, Irion U, Bono F. The bicoid mRNA localization factor Exuperantia is an RNA-binding pseudonuclease. Nat Struct Mol Biol 2016; 23:705-13. [PMID: 27376588 DOI: 10.1038/nsmb.3254] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 06/09/2016] [Indexed: 12/20/2022]
Abstract
Anterior patterning in Drosophila is mediated by the localization of bicoid (bcd) mRNA at the anterior pole of the oocyte. Exuperantia (Exu) is a putative exonuclease (EXO) associated with bcd and required for its localization. We present the crystal structure of Exu, which reveals a dimeric assembly with each monomer consisting of a 3'-5' EXO-like domain and a sterile alpha motif (SAM)-like domain. The catalytic site is degenerate and inactive. Instead, the EXO-like domain mediates dimerization and RNA binding. We show that Exu binds RNA directly in vitro, that the SAM-like domain is required for RNA binding activity and that Exu binds a structured element present in the bcd 3' untranslated region with high affinity. Through structure-guided mutagenesis, we show that Exu dimerization is essential for bcd localization. Our data demonstrate that Exu is a noncanonical RNA-binding protein with EXO-SAM-like domain architecture that interacts with its target RNA as a homodimer.
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Affiliation(s)
| | - Katharina Veith
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Katharina Kramer
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics, Institute for Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Claire Basquin
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics, Institute for Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Uwe Irion
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Fulvia Bono
- Max Planck Institute for Developmental Biology, Tübingen, Germany
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Czech B, Hannon GJ. One Loop to Rule Them All: The Ping-Pong Cycle and piRNA-Guided Silencing. Trends Biochem Sci 2016; 41:324-337. [PMID: 26810602 PMCID: PMC4819955 DOI: 10.1016/j.tibs.2015.12.008] [Citation(s) in RCA: 300] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/17/2015] [Accepted: 12/22/2015] [Indexed: 01/06/2023]
Abstract
The PIWI-interacting RNA (piRNA) pathway is a conserved defense mechanism that protects the genetic information of animal germ cells from the deleterious effects of molecular parasites, such as transposons. Discovered nearly a decade ago, this small RNA silencing system comprises PIWI-clade Argonaute proteins and their associated RNA-binding partners, the piRNAs. In this review, we highlight recent work that has advanced our understanding of how piRNAs preserve genome integrity across generations. We discuss the mechanism of piRNA biogenesis, give an overview of common themes as well as differences in piRNA-mediated silencing between species, and end by highlighting known and emerging functions of piRNAs.
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Affiliation(s)
- Benjamin Czech
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge, CB2 0RE, UK.
| | - Gregory J Hannon
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, University of Cambridge, Cambridge, CB2 0RE, UK.
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Yang F, Wang PJ. Multiple LINEs of retrotransposon silencing mechanisms in the mammalian germline. Semin Cell Dev Biol 2016; 59:118-125. [PMID: 26957474 DOI: 10.1016/j.semcdb.2016.03.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 02/29/2016] [Accepted: 03/01/2016] [Indexed: 02/07/2023]
Abstract
Retrotransposons play an important role in genome evolution but pose acute challenges to host genome integrity, particularly in early stage germ cells where epigenetic control is relaxed to permit genome-wide reprogramming. In most species, the inability to silence retrotransposons in the germline is usually associated with sterility. LINE1 is the most abundant retrotransposon type in the mammalian genome. Mammalian germ cells employ multiple mechanisms to suppress retrotransposon activity, including small non-coding piRNAs, DNA methylation, and repressive histone modifications. Novel factors contributing to the epigenetic silencing of retrotransposons in the germline continue to be identified. Recent studies have provided insight into how epigenetic changes associated with retrotransposon activation impact on fertility.
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Affiliation(s)
- Fang Yang
- Department of Biomedical Sciences, University of Pennsylvania School of Veterinary Medicine, 3800 Spruce Street, Philadelphia, PA 19104, USA
| | - P Jeremy Wang
- Department of Biomedical Sciences, University of Pennsylvania School of Veterinary Medicine, 3800 Spruce Street, Philadelphia, PA 19104, USA.
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PGL germ granule assembly protein is a base-specific, single-stranded RNase. Proc Natl Acad Sci U S A 2016; 113:1279-84. [PMID: 26787882 DOI: 10.1073/pnas.1524400113] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cellular RNA-protein (RNP) granules are ubiquitous and have fundamental roles in biology and RNA metabolism, but the molecular basis of their structure, assembly, and function is poorly understood. Using nematode "P-granules" as a paradigm, we focus on the PGL granule scaffold protein to gain molecular insights into RNP granule structure and assembly. We first identify a PGL dimerization domain (DD) and determine its crystal structure. PGL-1 DD has a novel 13 α-helix fold that creates a positively charged channel as a homodimer. We investigate its capacity to bind RNA and discover unexpectedly that PGL-1 DD is a guanosine-specific, single-stranded endonuclease. Discovery of the PGL homodimer, together with previous results, suggests a model in which the PGL DD dimer forms a fundamental building block for P-granule assembly. Discovery of the PGL RNase activity expands the role of RNP granule assembly proteins to include enzymatic activity in addition to their job as structural scaffolds.
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piRNA biogenesis in the germline: From transcription of piRNA genomic sources to piRNA maturation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:82-92. [DOI: 10.1016/j.bbagrm.2015.09.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 08/25/2015] [Accepted: 09/01/2015] [Indexed: 12/22/2022]
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Sato K, Siomi MC. Functional and structural insights into the piRNA factor Maelstrom. FEBS Lett 2015; 589:1688-93. [DOI: 10.1016/j.febslet.2015.03.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 03/19/2015] [Indexed: 10/23/2022]
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