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Chen J, Li C, Sheng Y, Zhang J, Pang L, Dong Z, Wu Z, Lu Y, Liu Z, Zhang Q, Guan X, Chen X, Huang J. Communication between the stem cell niche and an adjacent differentiation niche through miRNA and EGFR signaling orchestrates exit from the stem cell state in the Drosophila ovary. PLoS Biol 2024; 22:e3002515. [PMID: 38512963 PMCID: PMC10986965 DOI: 10.1371/journal.pbio.3002515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 04/02/2024] [Accepted: 01/22/2024] [Indexed: 03/23/2024] Open
Abstract
The signaling environment, or niche, often governs the initial difference in behavior of an adult stem cell and a derivative that initiates a path towards differentiation. The transition between an instructive stem cell niche and differentiation niche must generally have single-cell resolution, suggesting that multiple mechanisms might be necessary to sharpen the transition. Here, we examined the Drosophila ovary and found that Cap cells, which are key constituents of the germline stem cell (GSC) niche, express a conserved microRNA (miR-124). Surprisingly, loss of miR-124 activity in Cap cells leads to a defect in differentiation of GSC derivatives. We present evidence that the direct functional target of miR-124 in Cap cells is the epidermal growth factor receptor (EGFR) and that failure to limit EGFR expression leads to the ectopic expression of a key anti-differentiation BMP signal in neighboring somatic escort cells (ECs), which constitute a differentiation niche. We further found that Notch signaling connects EFGR activity in Cap cells to BMP expression in ECs. We deduce that the stem cell niche communicates with the differentiation niche through a mechanism that begins with the selective expression of a specific microRNA and culminates in the suppression of the major anti-differentiation signal in neighboring cells, with the functionally important overall role of sharpening the spatial distinction between self-renewal and differentiation environments.
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Affiliation(s)
- Jiani Chen
- Institute of Insect Sciences, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou, China
- Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Plant Precision Breeding Academy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Chaosqun Li
- Institute of Insect Sciences, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou, China
| | - Yifeng Sheng
- Institute of Insect Sciences, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou, China
| | - Junwei Zhang
- Institute of Insect Sciences, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou, China
| | - Lan Pang
- Institute of Insect Sciences, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou, China
- Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Plant Precision Breeding Academy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Zhi Dong
- Institute of Insect Sciences, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou, China
| | - Zhiwei Wu
- Institute of Insect Sciences, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou, China
| | - Yueqi Lu
- Institute of Insect Sciences, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou, China
| | - Zhiguo Liu
- Institute of Insect Sciences, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou, China
| | - Qichao Zhang
- Institute of Insect Sciences, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou, China
- Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Plant Precision Breeding Academy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
| | - Xueying Guan
- Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Plant Precision Breeding Academy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China
- Hainan Institute of Zhejiang University, Yazhou Bay Science and Technology City, Sanya, China
| | - Xuexin Chen
- Institute of Insect Sciences, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou, China
- Hainan Institute of Zhejiang University, Yazhou Bay Science and Technology City, Sanya, China
| | - Jianhua Huang
- Institute of Insect Sciences, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou, China
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2
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Wang N, Chen M, Zhou Y, Zhou WW, Zhu ZR. The microRNA pathway core genes are indispensable for development and reproduction in the brown planthopper, Nilaparvata lugens. INSECT MOLECULAR BIOLOGY 2023; 32:528-543. [PMID: 37162032 DOI: 10.1111/imb.12848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 04/28/2023] [Indexed: 05/11/2023]
Abstract
MicroRNAs (miRNAs) are small single-stranded non-coding RNAs involved in a variety of cellular events by regulating gene expression at the post-transcriptional level. Several core genes in miRNA biogenesis have been reported to participate in a wide range of physiological events, in some insect species. However, the functional significance of miRNA pathway core genes in Nilaparvata lugens remains unknown. In the present study, we conducted a systematic characterisation of five core genes involved in miRNA biogenesis. We first performed spatiotemporal expression analysis and found that miRNA core genes exhibited similar expression patterns, with high expression levels in eggs and relatively high transcriptional levels in the ovaries and fat bodies of females. RNA interference experiments showed that injecting third-instar nymphs with dsRNAs targeting the miRNA core genes, NlAgo1, NlDicer1, and NlDrosha resulted in high mortality rates and various degrees of body melanism, moulting defects, and wing deformities. Further investigations revealed that the suppression of miRNA core genes severely impaired ovarian development and oocyte maturation, resulting in significantly reduced fecundity and disruption of intercellular spaces between follicle cells. Moreover, the expression profiles of miR-34-5p, miR-275-3p, miR-317-3p, miR-14, Let-7-1, and miR-2a-3p were significantly altered in response to the knockdown of miRNA core genes mixture, suggesting that they play essential roles in regulating miRNA-mediated gene expression. Therefore, our results provide a solid theoretical basis for the miRNA pathway in N. lugens and suggest that the NlAgo1, NlDicer1, and NlDrosha-dependent miRNA core genes are essential for the development and reproduction of this agricultural pest.
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Affiliation(s)
- Ni Wang
- State Key Laboratory of Rice Biology, Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
- Hainan Institute, Zhejiang University, Sanya, China
| | - Min Chen
- State Key Laboratory of Rice Biology, Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
| | - Ying Zhou
- Hainan Institute, Zhejiang University, Sanya, China
| | - Wen-Wu Zhou
- State Key Laboratory of Rice Biology, Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
- Hainan Institute, Zhejiang University, Sanya, China
| | - Zeng-Rong Zhu
- State Key Laboratory of Rice Biology, Ministry of Agriculture and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects Pests, Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Insect Sciences, Zhejiang University, Hangzhou, China
- Hainan Institute, Zhejiang University, Sanya, China
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3
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Szarka-Kovács AB, Takács Z, Bence M, Erdélyi M, Jankovics F. Drosophila MESR4 Gene Ensures Germline Stem Cell Differentiation by Promoting the Transcription of bag of marbles. Cells 2022; 11:cells11132056. [PMID: 35805140 PMCID: PMC9265997 DOI: 10.3390/cells11132056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/22/2022] [Accepted: 06/24/2022] [Indexed: 12/02/2022] Open
Abstract
Ovarian germline stem cells (GSCs) of Drosophila melanogaster provide a valuable in vivo model to investigate how the adult stem cell identity is maintained and the differentiation of the daughter cells is regulated. GSCs are embedded into a specialized cellular microenvironment, the so-called stem cell niche. Besides the complex signaling interactions between the germ cells and the niche cells, the germ cell intrinsic mechanisms, such as chromatin regulation and transcriptional control, are also crucial in the decision about self-renewal and differentiation. The key differentiation regulator gene is the bag of marbles (bam), which is transcriptionally repressed in the GSCs and de-repressed in the differentiating daughter cell. Here, we show that the transcription factor MESR4 functions in the germline to promote GSC daughter differentiation. We find that the loss of MESR4 results in the accumulation of GSC daughter cells which fail to transit from the pre-cystoblast (pre-CB) to the differentiated cystoblast (CB) stage. The forced expression of bam can rescue this differentiation defect. By a series of epistasis experiments and a transcriptional analysis, we demonstrate that MESR4 positively regulates the transcription of bam. Our results suggest that lack of repression alone is not sufficient, but MESR4-mediated transcriptional activation is also required for bam expression.
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Affiliation(s)
- Alexandra Brigitta Szarka-Kovács
- Institute of Genetics, Biological Research Centre, Eötvös Loránd Research Network, H-6726 Szeged, Hungary; (A.B.S.-K.); (Z.T.); (M.B.)
- Doctoral School in Biology, University of Szeged, H-6720 Szeged, Hungary
| | - Zsanett Takács
- Institute of Genetics, Biological Research Centre, Eötvös Loránd Research Network, H-6726 Szeged, Hungary; (A.B.S.-K.); (Z.T.); (M.B.)
| | - Melinda Bence
- Institute of Genetics, Biological Research Centre, Eötvös Loránd Research Network, H-6726 Szeged, Hungary; (A.B.S.-K.); (Z.T.); (M.B.)
| | - Miklós Erdélyi
- Institute of Genetics, Biological Research Centre, Eötvös Loránd Research Network, H-6726 Szeged, Hungary; (A.B.S.-K.); (Z.T.); (M.B.)
- Correspondence: (M.E.); (F.J.)
| | - Ferenc Jankovics
- Institute of Genetics, Biological Research Centre, Eötvös Loránd Research Network, H-6726 Szeged, Hungary; (A.B.S.-K.); (Z.T.); (M.B.)
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, H-6720 Szeged, Hungary
- Correspondence: (M.E.); (F.J.)
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Lim LX, Isshiki W, Iki T, Kawaguchi S, Kai T. The Tudor Domain-Containing Protein, Kotsubu (CG9925), Localizes to the Nuage and Functions in piRNA Biogenesis in D. melanogaster. Front Mol Biosci 2022; 9:818302. [PMID: 35425810 PMCID: PMC9002060 DOI: 10.3389/fmolb.2022.818302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/11/2022] [Indexed: 11/30/2022] Open
Abstract
Silencing of transposable elements (TEs) by Piwi-interacting RNAs (piRNAs) is crucial for maintaining germline genome integrity and fertility in animals. To repress TEs, PIWI clade Argonaute proteins cooperate with several Tudor domain-containing (Tdrd) proteins at membraneless perinuclear organelles, called nuage, to produce piRNAs to repress transposons. Here, we identify and characterize Kotsubu (Kots), one of the Drosophila Tudor domain-containing protein-1 (Tdrd1) orthologs, encoded by the CG9925 gene, that localizes to the nuage in gonads. We further show the dynamic localization of Kots in the male germline, where it shows perinuclear signals in spermatogonia but forms large cytoplasmic condensates in the spermatocytes that overlap with components of piNG-body, a nuage-associated organelle. The loss of kots results in a notable upregulation of stellate and a corresponding reduction in the suppressor of stellate piRNAs in the mutants. Furthermore, a moderate yet significant reduction of other piRNAs was observed in kots mutant testes. Taken together, we propose that Kots functions in the piRNA pathway, predominantly in the male germline by forming discrete cytoplasmic granules.
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5
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Vidaurre V, Chen X. Epigenetic regulation of drosophila germline stem cell maintenance and differentiation. Dev Biol 2021; 473:105-118. [PMID: 33610541 DOI: 10.1016/j.ydbio.2021.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 01/26/2021] [Accepted: 02/06/2021] [Indexed: 12/13/2022]
Abstract
Gametogenesis is one of the most extreme cellular differentiation processes that takes place in Drosophila male and female germlines. This process begins at the germline stem cell, which undergoes asymmetric cell division (ACD) to produce a self-renewed daughter that preserves its stemness and a differentiating daughter cell that undergoes epigenetic and genomic changes to eventually produce haploid gametes. Research in molecular genetics and cellular biology are beginning to take advantage of the continually advancing genomic tools to understand: (1) how germ cells are able to maintain their identity throughout the adult reproductive lifetime, and (2) undergo differentiation in a balanced manner. In this review, we focus on the epigenetic mechanisms that address these two questions through their regulation of germline-soma communication to ensure germline stem cell identity and activity.
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Affiliation(s)
- Velinda Vidaurre
- Department of Biology, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Baltimore, MD, 21218, USA
| | - Xin Chen
- Department of Biology, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Baltimore, MD, 21218, USA.
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6
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Piwi reduction in the aged niche eliminates germline stem cells via Toll-GSK3 signaling. Nat Commun 2020; 11:3147. [PMID: 32561720 PMCID: PMC7305233 DOI: 10.1038/s41467-020-16858-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 05/30/2020] [Indexed: 12/13/2022] Open
Abstract
Transposons are known to participate in tissue aging, but their effects on aged stem cells remain unclear. Here, we report that in the Drosophila ovarian germline stem cell (GSC) niche, aging-related reductions in expression of Piwi (a transposon silencer) derepress retrotransposons and cause GSC loss. Suppression of Piwi expression in the young niche mimics the aged niche, causing retrotransposon depression and coincident activation of Toll-mediated signaling, which promotes Glycogen synthase kinase 3 activity to degrade β-catenin. Disruption of β-catenin-E-cadherin-mediated GSC anchorage then results in GSC loss. Knocking down gypsy (a highly active retrotransposon) or toll, or inhibiting reverse transcription in the piwi-deficient niche, suppresses GSK3 activity and β-catenin degradation, restoring GSC-niche attachment. This retrotransposon-mediated impairment of aged stem cell maintenance may have relevance in many tissues, and could represent a viable therapeutic target for aging-related tissue degeneration.
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7
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Song J, Zhou S. Post-transcriptional regulation of insect metamorphosis and oogenesis. Cell Mol Life Sci 2020; 77:1893-1909. [PMID: 31724082 PMCID: PMC11105025 DOI: 10.1007/s00018-019-03361-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 10/18/2019] [Accepted: 10/30/2019] [Indexed: 12/17/2022]
Abstract
Metamorphic transformation from larvae to adults along with the high fecundity is key to insect success. Insect metamorphosis and reproduction are governed by two critical endocrines, juvenile hormone (JH), and 20-hydroxyecdysone (20E). Recent studies have established a crucial role of microRNA (miRNA) in insect metamorphosis and oogenesis. While miRNAs target genes involved in JH and 20E-signaling pathways, these two hormones reciprocally regulate miRNA expression, forming regulatory loops of miRNA with JH and 20E-signaling cascades. Insect metamorphosis and oogenesis rely on the coordination of hormones, cognate genes, and miRNAs for precise regulation. In addition, the alternative splicing of genes in JH and 20E-signaling pathways has distinct functions in insect metamorphosis and oogenesis. We, therefore, focus in this review on recent advances in post-transcriptional regulation, with the emphasis on the regulatory role of miRNA and alternative splicing, in insect metamorphosis and oogenesis. We will highlight important new findings of miRNA interactions with hormonal signaling and alternative splicing of JH receptor heterodimer gene Taiman.
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Affiliation(s)
- Jiasheng Song
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Shutang Zhou
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, 475004, China.
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8
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Hanyu-Nakamura K, Matsuda K, Cohen SM, Nakamura A. Pgc suppresses the zygotically acting RNA decay pathway to protect germ plasm RNAs in the Drosophila embryo. Development 2019; 146:dev.167056. [PMID: 30890569 DOI: 10.1242/dev.167056] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 03/11/2019] [Indexed: 11/20/2022]
Abstract
Specification of germ cells is pivotal to ensure continuation of animal species. In many animal embryos, germ cell specification depends on maternally supplied determinants in the germ plasm. Drosophila polar granule component (pgc) mRNA is a component of the germ plasm. pgc encodes a small protein that is transiently expressed in newly formed pole cells, the germline progenitors, where it globally represses mRNA transcription. pgc is also required for pole cell survival, but the mechanism linking transcriptional repression to pole cell survival remains elusive. We report that pole cells lacking pgc show premature loss of germ plasm mRNAs, including the germ cell survival factor nanos, and undergo apoptosis. We found that pgc- pole cells misexpress multiple miRNA genes. Reduction of miRNA pathway activity in pgc- embryos partially suppressed germ plasm mRNA degradation and pole cell death, suggesting that Pgc represses zygotic miRNA transcription in pole cells to protect germ plasm mRNAs. Interestingly, germ plasm mRNAs are protected from miRNA-mediated degradation in vertebrates, albeit by a different mechanism. Thus, independently evolved mechanisms are used to silence miRNAs during germ cell specification.
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Affiliation(s)
- Kazuko Hanyu-Nakamura
- Department of Germline Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan.,Laboratory for Germline Development, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan
| | - Kazuki Matsuda
- Laboratory for Germline Development, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan
| | - Stephen M Cohen
- Department of Cellular and Molecular Medicine, University of Copenhagen, 2200N Copenhagen, Denmark
| | - Akira Nakamura
- Department of Germline Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan .,Laboratory for Germline Development, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan.,Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
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9
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Heterochromatin protein 1 (HP1) is intrinsically required for post-transcriptional regulation of Drosophila Germline Stem Cell (GSC) maintenance. Sci Rep 2019; 9:4372. [PMID: 30867469 PMCID: PMC6416348 DOI: 10.1038/s41598-019-40152-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 02/07/2019] [Indexed: 01/05/2023] Open
Abstract
A very important open question in stem cells regulation is how the fine balance between GSCs self-renewal and differentiation is orchestrated at the molecular level. In the past several years much progress has been made in understanding the molecular mechanisms underlying intrinsic and extrinsic controls of GSC regulation but the complex gene regulatory networks that regulate stem cell behavior are only partially understood. HP1 is a dynamic epigenetic determinant mainly involved in heterochromatin formation, epigenetic gene silencing and telomere maintenance. Furthermore, recent studies have revealed the importance of HP1 in DNA repair, sister chromatid cohesion and, surprisingly, in positive regulation of gene expression. Here, we show that HP1 plays a crucial role in the control of GSC homeostasis in Drosophila. Our findings demonstrate that HP1 is required intrinsically to promote GSC self-renewal and progeny differentiation by directly stabilizing the transcripts of key genes involved in GSCs maintenance.
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10
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Shcherbata HR. miRNA functions in stem cells and their niches: lessons from the Drosophila ovary. CURRENT OPINION IN INSECT SCIENCE 2019; 31:29-36. [PMID: 31109670 DOI: 10.1016/j.cois.2018.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 07/09/2018] [Accepted: 07/16/2018] [Indexed: 06/09/2023]
Abstract
From the very beginning of the miRNA era, Drosophila has served as an excellent model for explanation of miRNA biogenesis. Now Drosophila continues to be used in numerous studies aiming to decipher biological roles of individual miRNAs in a living organism. MiRNAs have emerged as an important regulatory class that adjusts gene expression in response to stress; therefore, it is particularly important to elucidate miRNA-based regulatory networks that appear in response to fluctuations in intrinsic and extrinsic environments. This review explores the major advances in understanding condition-dependent roles of miRNAs in adult stem cell biology using the Drosophila ovarian germline stem cell niche community as a model system.
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Affiliation(s)
- Halyna R Shcherbata
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen, Germany; Institute of Cell Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
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11
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Cheng Y, Chen D. Fruit fly research in China. J Genet Genomics 2018; 45:583-592. [PMID: 30455037 DOI: 10.1016/j.jgg.2018.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/21/2018] [Accepted: 09/29/2018] [Indexed: 11/19/2022]
Abstract
Served as a model organism over a century, fruit fly has significantly pushed forward the development of global scientific research, including in China. The high similarity in genomic features between fruit fly and human enables this tiny insect to benefit the biomedical studies of human diseases. In the past decades, Chinese biologists have used fruit fly to make numerous achievements on understanding the fundamental questions in many diverse areas of biology. Here, we review some of the recent fruit fly studies in China, and mainly focus on those studies in the fields of stem cell biology, cancer therapy and regeneration medicine, neurological disorders and epigenetics.
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Affiliation(s)
- Ying Cheng
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Dahua Chen
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
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12
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Abstract
Gametogenesis represents the most dramatic cellular differentiation pathways in both female and male flies. At the genome level, meiosis ensures that diploid germ cells become haploid gametes. At the epigenome level, extensive changes are required to turn on and shut off gene expression in a precise spatiotemporally controlled manner. Research applying conventional molecular genetics and cell biology, in combination with rapidly advancing genomic tools have helped us to investigate (1) how germ cells maintain lineage specificity throughout their adult reproductive lifetime; (2) what molecular mechanisms ensure proper oogenesis and spermatogenesis, as well as protect genome integrity of the germline; (3) how signaling pathways contribute to germline-soma communication; and (4) if such communication is important. In this chapter, we highlight recent discoveries that have improved our understanding of these questions. On the other hand, restarting a new life cycle upon fertilization is a unique challenge faced by gametes, raising questions that involve intergenerational and transgenerational epigenetic inheritance. Therefore, we also discuss new developments that link changes during gametogenesis to early embryonic development-a rapidly growing field that promises to bring more understanding to some fundamental questions regarding metazoan development.
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13
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Camargo C, Wu K, Fishilevich E, Narva KE, Siegfried BD. Knockdown of RNA interference pathway genes in western corn rootworm, Diabrotica virgifera virgifera, identifies no fitness costs associated with Argonaute 2 or Dicer-2. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2018; 148:103-110. [PMID: 29891360 DOI: 10.1016/j.pestbp.2018.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 04/07/2018] [Accepted: 04/07/2018] [Indexed: 06/08/2023]
Abstract
The use of transgenic crops that induce silencing of essential genes using double-stranded RNA (dsRNA) through RNA interference (RNAi) in western corn rootworm, Diabrotica virgifera virgifera, is likely to be an important component of new technologies for the control of this important corn pest. Previous studies have demonstrated that the dsRNA response in D. v. virgifera depends on the presence of RNAi pathway genes including Dicer-2 and Argonaute 2, and that downregulation of these genes limits the lethality of environmental dsRNA. A potential resistance mechanism to lethal dsRNA may involve loss of function of RNAi pathway genes. Howver, the potential for resistance to evolve may depend on whether these pathway genes have essential functions such that the loss of function of core proteins in the RNAi pathway will have fitness costs in D. v. virgifera. Fitness costs associated with potential resistance mechanisms have a central role in determining how resistance can evolve to RNAi technologies in western corn rootworm. We evaluated the effect of dsRNA and microRNA pathway gene knockdown on the development of D. v. virgifera larvae through short-term and long-term exposures to dsRNA for Dicer and Argonaute genes. Downregulation of Argonaute 2, Dicer-2, Dicer-1 did not significantly affect larval survivorship or development through short and long-term exposure to dsRNA. However, downregulation of Argonaute 1 reduced larval survivorship and delayed development. The implications of these results as they relate to D. v. virgifera resistance to lethal dsRNA are discussed.
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Affiliation(s)
- Carolina Camargo
- Department of Entomology and Nematology, University of Florida, 1881 Natural Area Drive, Steinmetz Hall, Gainesville, FL 32611, United States
| | - Ke Wu
- Department of Entomology and Nematology, University of Florida, 1881 Natural Area Drive, Steinmetz Hall, Gainesville, FL 32611, United States
| | - Elane Fishilevich
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN 46268, United States
| | - Kenneth E Narva
- Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN 46268, United States
| | - Blair D Siegfried
- Department of Entomology and Nematology, University of Florida, 1881 Natural Area Drive, Steinmetz Hall, Gainesville, FL 32611, United States.
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Chen D, Wang S, Tao X, Zhou L, Wang J, Sun F, Sun M, Gao X. Hsp83 regulates the fate of germline stem cells in Drosophila ovary. J Genet Genomics 2018; 45:219-222. [PMID: 29705561 DOI: 10.1016/j.jgg.2018.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 12/29/2017] [Accepted: 01/10/2018] [Indexed: 01/16/2023]
Affiliation(s)
- Dongsheng Chen
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, Wuhu 241000, China; The Institute of Bioinformatics, College of Life Sciences, Anhui Normal University, Wuhu 241000, China.
| | - Shuang Wang
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Xiaoqian Tao
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Lijuan Zhou
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Jian Wang
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Fuling Sun
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Mingzhong Sun
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Xiaoli Gao
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
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15
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Chartier A, Joly W, Simonelig M. Measurement of mRNA Poly(A) Tail Lengths in Drosophila Female Germ Cells and Germ-Line Stem Cells. Methods Mol Biol 2018; 1463:93-102. [PMID: 27734350 DOI: 10.1007/978-1-4939-4017-2_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
mRNA regulation by poly(A) tail length variations plays an important role in many developmental processes. Recent advances have shown that, in particular, deadenylation (the shortening of mRNA poly(A) tails) is essential for germ-line stem cell biology in the Drosophila ovary. Therefore, a rapid and accurate method to analyze poly(A) tail lengths of specific mRNAs in this tissue is valuable. Several methods of poly(A) test (PAT) assays have been reported to measure mRNA poly(A) tail lengths in vivo. Here, we describe two of these methods (PAT and ePAT) that we have adapted for Drosophila ovarian germ cells and germ-line stem cells.
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Affiliation(s)
- Aymeric Chartier
- mRNA Regulation and Development, Institut de Génétique Humaine, CNRS UPR1142 and University of Montpellier, 141 rue de la Cardonille, 34396, Montpellier Cedex 5, France
| | - Willy Joly
- mRNA Regulation and Development, Institut de Génétique Humaine, CNRS UPR1142 and University of Montpellier, 141 rue de la Cardonille, 34396, Montpellier Cedex 5, France
| | - Martine Simonelig
- mRNA Regulation and Development, Institut de Génétique Humaine, CNRS UPR1142 and University of Montpellier, 141 rue de la Cardonille, 34396, Montpellier Cedex 5, France
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16
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Distinct fitness costs associated with the knockdown of RNAi pathway genes in western corn rootworm adults. PLoS One 2017; 12:e0190208. [PMID: 29267401 PMCID: PMC5739497 DOI: 10.1371/journal.pone.0190208] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/11/2017] [Indexed: 12/26/2022] Open
Abstract
RNA interference (RNAi) based approaches can potentially be used to control insect pests. These approaches may depend on the usage of microRNA (miRNA) or double stranded RNA (dsRNA) mediated gene knockdown, which likely involves proteins that regulate these pathways, such as Argonaute 1 (Ago1), Argonaute 2 (Ago2), Dicer 1 (Dcr1), Dicer 2 (Dcr2), and Drosha in insects. We previously performed functional characterization of Ago2 and Dcr2 of western corn rootworm (WCR), Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) and observed that knockdown of Ago2 and Dcr2 ameliorated the lethal effect induced by the dsRNA-mediated knockdown of an essential gene in WCR, thereby confirming the involvement of Ago2 and Dcr2 in the dsRNA pathway. In the current study, we identified and characterized additional members of the Argonaute and Dicer gene families, namely Ago1, Ago3, Aubergine, and Dcr1, in a previously developed WCR transcriptome. We also identified a Drosha homolog in the same transcriptome. We evaluated the impacts on WCR adult fitness associated with the dsRNA-mediated knockdown of Ago1, Ago2, Dcr1, Dcr2, and Drosha genes. Among these putative RNAi pathway genes, only the knockdown of Ago1 incurred significant fitness costs such as reduced survival and oviposition rate, as well as decreased egg viability. The present study, to our knowledge, represents the first report showing that Ago1 is critical to the survival of insect adults. Our findings suggest that Ago1 plays an essential role in broader life stages of an insect than previously thought. Importantly, since fitness costs were not observed, downregulation or loss of function of RNAi pathway genes such as Ago2 or Dcr2 may confer resistance to pest control measures that rely on the normal functions of these genes. However, the precise roles of these genes under field conditions (i.e., in the presence of possible viral pathogens) requires further investigation.
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17
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Chen D, Tao X, Zhou L, Sun F, Sun M, Fang X. Spaghetti, a homolog of human RPAP3 (RNA polymerase II-associated protein 3), determines the fate of germline stem cells in Drosophila ovary. Cell Biol Int 2017; 42:769-780. [PMID: 29110400 DOI: 10.1002/cbin.10900] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/22/2017] [Indexed: 11/11/2022]
Abstract
The Drosophila ovary provides an attractive model for studying the extrinsic or intrinsic factors that regulate the fate of germline stem cells (GSCs). Using this model, we identified a new role for Drosophila spaghetti (spag), encoding a homolog of human RNA polymerase II-associated protein 3 (RPAP3), in regulating the fate of ovarian GSCs. Results from spag knockdown and genetic mosaic studies suggest that spag functions as an intrinsic factor for GSCs maintenance. Loss of Spag by, either spag RNAi or null mutation failed to trigger apoptosis in ovarian GSCs. Overexpression of spag led to negligible increases in the number of GSC/Cystoblast (CB) cells, suggesting that an excess of Spag is not sufficient to accelerate the proliferation of GSCs or delay CBs' differentiation. Our study provides evidence supporting that spag is involved in adult stem cells maintenance. In addition, the RNAi screen results showed that knockdown of Hsp90, one of known Spag interacting partners, led to loss of ovarian GSCs in Drosophila. Heterozygous mutations in hsp90 (hsp90/+) dramatically accelerated the GSC loss in spag RNAi ovaries, suggesting that the Spag-contained complex possibly plays an essential role in controlling the GSCs fate.
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Affiliation(s)
- Dongsheng Chen
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, #1 Beijing East Road, Wuhu, Anhui, 241000, P.R. China.,The Institute of Bioinformatics, College of Life Sciences, Anhui Normal University, Wuhu, 241000, China
| | - Xiaoqian Tao
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, #1 Beijing East Road, Wuhu, Anhui, 241000, P.R. China
| | - Lijuan Zhou
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, #1 Beijing East Road, Wuhu, Anhui, 241000, P.R. China
| | - Fuling Sun
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, #1 Beijing East Road, Wuhu, Anhui, 241000, P.R. China
| | - Mingzhong Sun
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, #1 Beijing East Road, Wuhu, Anhui, 241000, P.R. China
| | - Xin Fang
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Sciences, Anhui Normal University, #1 Beijing East Road, Wuhu, Anhui, 241000, P.R. China
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18
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Ye W, Liu X, Guo J, Sun X, Sun Y, Shen B, Zhou D, Zhu C. piRNA-3878 targets P450 (CpCYP307B1) to regulate pyrethroid resistance in Culex pipiens pallens. Parasitol Res 2017; 116:2489-2497. [PMID: 28698948 DOI: 10.1007/s00436-017-5554-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 06/30/2017] [Indexed: 11/24/2022]
Abstract
Piwi-interacting RNAs (piRNAs) are a novel class of noncoding single-strand RNAs. They play an important role in the germ cell maintenance, brain development, epigenetic regulation of cancer, and antiviral function. However, little is known about the relationship between the piRNAs and insecticide resistance in mosquitoes. In this study, we reported that piRNA-3878 was related with pyrethroid resistance in Culex pipiens pallens. The expression level of piRNA-3878 was lower in both laboratory and field-collected deltamethrin-resistant (DR) strains. Overexpression of piRNA-3878 increased the susceptibility of the DR strain, while inhibiting the expression of piRNA-3878 in DS strain made the mosquitoes more resistant to deltamethrin. Furthermore, we identified that CpCYP307B1 was the target of piRNA-3878. The mosquito mortality rate was increased after downregulating the expression of CpCYP307B1. These findings revealed that piRNA-3878 could target CpCYP307B1 to regulate pyrethroid resistance.
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Affiliation(s)
- Wenyun Ye
- Department of Pathogen Biology, Nanjing Medical University, 101 Longmian Road, Jiangning District, Nanjing, Jiangsu, 211166, China
| | - Xianmiao Liu
- Department of Pathogen Biology, Nanjing Medical University, 101 Longmian Road, Jiangning District, Nanjing, Jiangsu, 211166, China
| | - Juxin Guo
- Department of Pathogen Biology, Nanjing Medical University, 101 Longmian Road, Jiangning District, Nanjing, Jiangsu, 211166, China
| | - Xueli Sun
- Department of Pathogen Biology, Nanjing Medical University, 101 Longmian Road, Jiangning District, Nanjing, Jiangsu, 211166, China
| | - Yan Sun
- Department of Pathogen Biology, Nanjing Medical University, 101 Longmian Road, Jiangning District, Nanjing, Jiangsu, 211166, China
| | - Bo Shen
- Department of Pathogen Biology, Nanjing Medical University, 101 Longmian Road, Jiangning District, Nanjing, Jiangsu, 211166, China
| | - Dan Zhou
- Department of Pathogen Biology, Nanjing Medical University, 101 Longmian Road, Jiangning District, Nanjing, Jiangsu, 211166, China.
| | - Changliang Zhu
- Department of Pathogen Biology, Nanjing Medical University, 101 Longmian Road, Jiangning District, Nanjing, Jiangsu, 211166, China
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19
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Paces J, Nic M, Novotny T, Svoboda P. Literature review of baseline information to support the risk assessment of RNAi‐based GM plants. ACTA ACUST UNITED AC 2017. [PMCID: PMC7163844 DOI: 10.2903/sp.efsa.2017.en-1246] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jan Paces
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
| | | | | | - Petr Svoboda
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
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20
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Specchia V, D'Attis S, Puricella A, Bozzetti MP. dFmr1 Plays Roles in Small RNA Pathways of Drosophila melanogaster. Int J Mol Sci 2017; 18:ijms18051066. [PMID: 28509881 PMCID: PMC5454977 DOI: 10.3390/ijms18051066] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/09/2017] [Accepted: 05/10/2017] [Indexed: 11/16/2022] Open
Abstract
Fragile-X syndrome is the most common form of inherited mental retardation accompanied by other phenotypes, including macroorchidism. The disorder originates with mutations in the Fmr1 gene coding for the FMRP protein, which, with its paralogs FXR1 and FXR2, constitute a well-conserved family of RNA-binding proteins. Drosophila melanogaster is a good model for the syndrome because it has a unique fragile X-related gene: dFmr1. Recently, in addition to its confirmed role in the miRNA pathway, a function for dFmr1 in the piRNA pathway, operating in Drosophila gonads, has been established. In this review we report a summary of the piRNA pathways occurring in gonads with a special emphasis on the relationship between the piRNA genes and the crystal-Stellate system; we also analyze the roles of dFmr1 in the Drosophila gonads, exploring their genetic and biochemical interactions to reveal some unexpected connections.
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Affiliation(s)
- Valeria Specchia
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali (DiSTeBA)-University of Salento, 73100 Lecce, Italy.
| | - Simona D'Attis
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali (DiSTeBA)-University of Salento, 73100 Lecce, Italy.
| | - Antonietta Puricella
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali (DiSTeBA)-University of Salento, 73100 Lecce, Italy.
| | - Maria Pia Bozzetti
- Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali (DiSTeBA)-University of Salento, 73100 Lecce, Italy.
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21
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Bam-dependent deubiquitinase complex can disrupt germ-line stem cell maintenance by targeting cyclin A. Proc Natl Acad Sci U S A 2017; 114:6316-6321. [PMID: 28484036 DOI: 10.1073/pnas.1619188114] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Drosophila germ-line stem cells (GSCs) provide an excellent model to study the regulatory mechanisms of stem cells in vivo. Bag of marbles (bam) has been demonstrated to be necessary and sufficient to promote GSC and cystoblast differentiation. Despite extensive investigation of its regulation and genetic functions, the biochemical nature of the Bam protein has been unknown. Here, we report that Bam is an ubiquitin-associated protein and controls the turnover of cyclin A (CycA). Mechanistically, we found that Bam associated with Otu to form a deubiquitinase complex that stabilized CycA by deubiquitination, thus providing a mechanism to explain how ectopic expression of Bam in GSCs promotes differentiation. Collectively, our findings not only identify a biochemical function of Bam, which contributes to GSC fate determination, but also emphasizes the critical role of proper expression of cyclin proteins mediated by both ubiquitination and deubiquitination pathways in balancing stem cell self-renewal and differentiation.
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22
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Yang H, Li M, Hu X, Xin T, Zhang S, Zhao G, Xuan T, Li M. MicroRNA-dependent roles of Drosha and Pasha in the Drosophila larval ovary morphogenesis. Dev Biol 2016; 416:312-23. [DOI: 10.1016/j.ydbio.2016.06.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/17/2016] [Accepted: 06/17/2016] [Indexed: 01/04/2023]
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23
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Dallaire A, Simard MJ. The implication of microRNAs and endo-siRNAs in animal germline and early development. Dev Biol 2016; 416:18-25. [PMID: 27287880 DOI: 10.1016/j.ydbio.2016.06.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/31/2016] [Accepted: 06/06/2016] [Indexed: 01/13/2023]
Abstract
Germ cells provide maternal mRNAs that are stored in the oocyte, and later translated at a specific time of development. In this context, gene regulation depends mainly on post-transcriptional mechanisms that contribute to keep maternal transcripts in a stable and translationally silent state. In recent years, small non-coding RNAs, such as microRNAs have emerged as key post-transcriptional regulators of gene expression. microRNAs control the translation efficiency and/or stability of targeted mRNAs. microRNAs are present in animal germ cells and maternally inherited microRNAs are abundant in early embryos. However, it is not known how microRNAs control the stability and translation of maternal transcripts. In this review, we will discuss the implication of germline microRNAs in regulating animal oogenesis and early embryogenesis as well as compare their roles with endo-siRNAs, small RNA species that share key molecular components with the microRNA pathway.
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Affiliation(s)
- Alexandra Dallaire
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Centre (Hôtel-Dieu de Québec), Quebec City, Québec, Canada G1R 2J6; Laval University Cancer Research Centre, Quebec City, Québec, Canada G1R 2J6
| | - Martin J Simard
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Centre (Hôtel-Dieu de Québec), Quebec City, Québec, Canada G1R 2J6; Laval University Cancer Research Centre, Quebec City, Québec, Canada G1R 2J6.
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24
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Major spliceosome defects cause male infertility and are associated with nonobstructive azoospermia in humans. Proc Natl Acad Sci U S A 2016; 113:4134-9. [PMID: 27035939 DOI: 10.1073/pnas.1513682113] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Processing of pre-mRNA into mRNA is an important regulatory mechanism in eukaryotes that is mediated by the spliceosome, a huge and dynamic ribonucleoprotein complex. Splicing defects are implicated in a spectrum of human disease, but the underlying mechanistic links remain largely unresolved. Using a genome-wide association approach, we have recently identified single nucleotide polymorphisms in humans that associate with nonobstructive azoospermia (NOA), a common cause of male infertility. Here, using genetic manipulation of corresponding candidate loci in Drosophila, we show that the spliceosome component SNRPA1/U2A is essential for male fertility. Loss of U2A in germ cells of the Drosophila testis does not affect germline stem cells, but does result in the accumulation of mitotic spermatogonia that fail to differentiate into spermatocytes and mature sperm. Lack of U2A causes insufficient splicing of mRNAs required for the transition of germ cells from proliferation to differentiation. We show that germ cell-specific disruption of other components of the major spliceosome manifests with the same phenotype, demonstrating that mRNA processing is required for the differentiation of spermatogonia. This requirement is conserved, and expression of human SNRPA1 fully restores spermatogenesis in U2A mutant flies. We further report that several missense mutations in human SNRPA1 that inhibit the assembly of the major spliceosome dominantly disrupt spermatogonial differentiation in Drosophila. Collectively, our findings uncover a conserved and specific requirement for the major spliceosome during the transition from spermatogonial proliferation to differentiation in the male testis, suggesting that spliceosome defects affecting the differentiation of human spermatogonia contribute to NOA.
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25
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Zhai L, Wang L, Teng F, Zhou L, Zhang W, Xiao J, Liu Y, Deng W. Argonaute and Argonaute-Bound Small RNAs in Stem Cells. Int J Mol Sci 2016; 17:208. [PMID: 26861290 PMCID: PMC4783940 DOI: 10.3390/ijms17020208] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 01/28/2016] [Accepted: 02/01/2016] [Indexed: 12/15/2022] Open
Abstract
Small RNAs are essential for a variety of cellular functions. Argonaute (AGO) proteins are associated with all of the different classes of small RNAs, and are indispensable in small RNA-mediated regulatory pathways. AGO proteins have been identified in various types of stem cells in diverse species from plants and animals. This review article highlights recent progress on how AGO proteins and AGO-bound small RNAs regulate the self-renewal and differentiation of distinct stem cell types, including pluripotent, germline, somatic, and cancer stem cells.
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Affiliation(s)
- Lihong Zhai
- Medical College, Hubei University of Arts and Science, Xiangyang 441053, Hubei, China.
| | - Lin Wang
- Xiangyang Oral Hospital, Xiangyang 441003, Hubei, China.
| | - Feng Teng
- Medical College, Hubei University of Arts and Science, Xiangyang 441053, Hubei, China.
| | - Lanting Zhou
- Medical College, Hubei University of Arts and Science, Xiangyang 441053, Hubei, China.
| | - Wenjing Zhang
- Medical College, Hubei University of Arts and Science, Xiangyang 441053, Hubei, China.
| | - Juan Xiao
- Medical College, Hubei University of Arts and Science, Xiangyang 441053, Hubei, China.
| | - Ying Liu
- Department of Neurosurgery, Medical School, the Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
- Center for Stem Cell and Regenerative Medicine, the Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
| | - Wenbin Deng
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, CA 95817, USA.
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children, Sacramento, CA 95817, USA.
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26
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Fu Z, Geng C, Wang H, Yang Z, Weng C, Li H, Deng L, Liu L, Liu N, Ni J, Xie T. Twin Promotes the Maintenance and Differentiation of Germline Stem Cell Lineage through Modulation of Multiple Pathways. Cell Rep 2015; 13:1366-1379. [DOI: 10.1016/j.celrep.2015.10.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Revised: 08/12/2015] [Accepted: 10/05/2015] [Indexed: 11/28/2022] Open
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27
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Li C, Kan L, Chen Y, Zheng X, Li W, Zhang W, Cao L, Lin X, Ji S, Huang S, Zhang G, Liu X, Tao Y, Wu S, Chen D. Ci antagonizes Hippo signaling in the somatic cells of the ovary to drive germline stem cell differentiation. Cell Res 2015; 25:1152-70. [PMID: 26403189 DOI: 10.1038/cr.2015.114] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 08/02/2015] [Accepted: 08/06/2015] [Indexed: 12/17/2022] Open
Abstract
Many stem cell populations are tightly regulated by their local microenvironment (niche), which comprises distinct types of stromal cells. However, little is known about mechanisms by which niche subgroups coordinately determine the stem cell fate. Here we identify that Yki, the key Hippo pathway component, is essential for escort cell (EC) function in promoting germline differentiation in Drosophila ovary. We found that Hedgehog (Hh) signals emanating primarily from cap cells support the function of ECs, where Cubitus interruptus (Ci), the Hh signaling effector, acts to inhibit Hippo kinase cascade activity. Mechanistically, we found that Ci competitively interacts with Hpo and impairs the Hpo-Wts signaling complex formation, thereby promoting Yki nuclear localization. The actions of Ci ensure effective Yki signaling to antagonize Sd/Tgi/Vg-mediated default repression in ECs. This study uncovers a mechanism explaining how subgroups of niche cells coordinate to determine the stem cell fate via Hh-Hippo signaling crosstalk, and enhances our understanding of mechanistic regulations of the oncogenic Yki/YAP signaling.
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Affiliation(s)
- Chaoyi Li
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang, Beijing 100101, China
| | - Lijuan Kan
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang, Beijing 100101, China
| | - Yan Chen
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Xiudeng Zheng
- Centre for Computational and Evolutionary Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Weini Li
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang, Beijing 100101, China
| | - Wenxin Zhang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang, Beijing 100101, China
| | - Lei Cao
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Xiaohui Lin
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Shanming Ji
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang, Beijing 100101, China
| | - Shoujun Huang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang, Beijing 100101, China
| | - Guoqiang Zhang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang, Beijing 100101, China
| | - Xiaohui Liu
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yi Tao
- Centre for Computational and Evolutionary Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Shian Wu
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Dahua Chen
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Datun Road, Chaoyang, Beijing 100101, China
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28
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Mugat B, Akkouche A, Serrano V, Armenise C, Li B, Brun C, Fulga TA, Van Vactor D, Pélisson A, Chambeyron S. MicroRNA-Dependent Transcriptional Silencing of Transposable Elements in Drosophila Follicle Cells. PLoS Genet 2015; 11:e1005194. [PMID: 25993106 PMCID: PMC4451950 DOI: 10.1371/journal.pgen.1005194] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 04/02/2015] [Indexed: 12/21/2022] Open
Abstract
RNA interference-related silencing mechanisms concern very diverse and distinct biological processes, from gene regulation (via the microRNA pathway) to defense against molecular parasites (through the small interfering RNA and the Piwi-interacting RNA pathways). Small non-coding RNAs serve as specificity factors that guide effector proteins to ribonucleic acid targets via base-pairing interactions, to achieve transcriptional or post-transcriptional regulation. Because of the small sequence complementarity required for microRNA-dependent post-transcriptional regulation, thousands of microRNA (miRNA) putative targets have been annotated in Drosophila. In Drosophila somatic ovarian cells, genomic parasites, such as transposable elements (TEs), are transcriptionally repressed by chromatin changes induced by Piwi-interacting RNAs (piRNAs) that prevent them from invading the germinal genome. Here we show, for the first time, that a functional miRNA pathway is required for the piRNA-mediated transcriptional silencing of TEs in this tissue. Global miRNA depletion, caused by tissue- and stage-specific knock down of drosha (involved in miRNA biogenesis), AGO1 or gawky (both responsible for miRNA activity), resulted in loss of TE-derived piRNAs and chromatin-mediated transcriptional de-silencing of TEs. This specific TE de-repression was also observed upon individual titration (by expression of the complementary miRNA sponge) of two miRNAs (miR-14 and miR-34) as well as in a miR-14 loss-of-function mutant background. Interestingly, the miRNA defects differentially affected TE- and 3' UTR-derived piRNAs. To our knowledge, this is the first indication of possible differences in the biogenesis or stability of TE- and 3' UTR-derived piRNAs. This work is one of the examples of detectable phenotypes caused by loss of individual miRNAs in Drosophila and the first genetic evidence that miRNAs have a role in the maintenance of genome stability via piRNA-mediated TE repression.
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Affiliation(s)
- Bruno Mugat
- Institut de Génétique Humaine, Centre National de la Recherche Scientifique, Montpellier, France
| | - Abdou Akkouche
- Institut de Génétique Humaine, Centre National de la Recherche Scientifique, Montpellier, France
| | - Vincent Serrano
- Institut de Génétique Humaine, Centre National de la Recherche Scientifique, Montpellier, France
| | - Claudia Armenise
- Institut de Génétique Humaine, Centre National de la Recherche Scientifique, Montpellier, France
| | - Blaise Li
- Institut de Génétique Humaine, Centre National de la Recherche Scientifique, Montpellier, France
| | - Christine Brun
- Institut de Génétique Humaine, Centre National de la Recherche Scientifique, Montpellier, France
| | - Tudor A. Fulga
- Department of Cell Biology and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, United States of America
| | - David Van Vactor
- Department of Cell Biology and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Alain Pélisson
- Institut de Génétique Humaine, Centre National de la Recherche Scientifique, Montpellier, France
| | - Séverine Chambeyron
- Institut de Génétique Humaine, Centre National de la Recherche Scientifique, Montpellier, France
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29
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N6-methyladenine DNA modification in Drosophila. Cell 2015; 161:893-906. [PMID: 25936838 DOI: 10.1016/j.cell.2015.04.018] [Citation(s) in RCA: 427] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 02/25/2015] [Accepted: 03/25/2015] [Indexed: 12/20/2022]
Abstract
DNA N(6)-methyladenine (6mA) modification is commonly found in microbial genomes and plays important functions in regulating numerous biological processes in bacteria. However, whether 6mA occurs and what its potential roles are in higher-eukaryote cells remain unknown. Here, we show that 6mA is present in Drosophila genome and that the 6mA modification is dynamic and is regulated by the Drosophila Tet homolog, DNA 6mA demethylase (DMAD), during embryogenesis. Importantly, our biochemical assays demonstrate that DMAD directly catalyzes 6mA demethylation in vitro. Further genetic and sequencing analyses reveal that DMAD is essential for development and that DMAD removes 6mA primarily from transposon regions, which correlates with transposon suppression in Drosophila ovary. Collectively, we uncover a DNA modification in Drosophila and describe a potential role of the DMAD-6mA regulatory axis in controlling development in higher eukaryotes.
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Abstract
Stem cells give rise to tissues and organs during development and maintain their integrity during adulthood. They have the potential to self-renew or differentiate at each division. To ensure proper organ growth and homeostasis, self-renewal versus differentiation decisions need to be tightly controlled. Systematic genetic studies in Drosophila melanogaster are revealing extensive regulatory networks that control the switch between stem cell self-renewal and differentiation in the germline. These networks, which are based primarily on mutual translational repression, act via interlocked feedback loops to provide robustness to this important fate decision.
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Affiliation(s)
- Maija Slaidina
- Howard Hughes Medical Institute and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016 Howard Hughes Medical Institute and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016
| | - Ruth Lehmann
- Howard Hughes Medical Institute and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016 Howard Hughes Medical Institute and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016
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31
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Huang H, Li Y, Szulwach KE, Zhang G, Jin P, Chen D. AGO3 Slicer activity regulates mitochondria-nuage localization of Armitage and piRNA amplification. ACTA ACUST UNITED AC 2014; 206:217-30. [PMID: 25049272 PMCID: PMC4107788 DOI: 10.1083/jcb.201401002] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The endonuclease AGO3 and mitochondria-associated protein Zucchini together control the dynamic subcellular localization of Armitage between mitochondria and germline granules to regulate secondary piRNA amplification. In Drosophila melanogaster the reciprocal “Ping-Pong” cycle of PIWI-interacting RNA (piRNA)–directed RNA cleavage catalyzed by the endonuclease (or “Slicer”) activities of the PIWI proteins Aubergine (Aub) and Argonaute3 (AGO3) has been proposed to expand the secondary piRNA population. However, the role of AGO3/Aub Slicer activity in piRNA amplification remains to be explored. We show that AGO3 Slicer activity is essential for piRNA amplification and that AGO3 inhibits the homotypic Aub:Aub Ping-Pong process in a Slicer-independent manner. We also find that expression of an AGO3 Slicer mutant causes ectopic accumulation of Armitage, a key component in the primary piRNA pathway, in the Drosophila melanogaster germline granules known as nuage. AGO3 also coexists and interacts with Armitage in the mitochondrial fraction. Furthermore, AGO3 acts in conjunction with the mitochondria-associated protein Zucchini to control the dynamic subcellular localization of Armitage between mitochondria and nuage in a Slicer-dependent fashion. Collectively, our findings uncover a new mechanism that couples mitochondria with nuage to regulate secondary piRNA amplification.
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Affiliation(s)
- Haidong Huang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yujing Li
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322
| | - Keith E Szulwach
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322
| | - Guoqiang Zhang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Peng Jin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322
| | - Dahua Chen
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
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32
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He J, Xuan T, Xin T, An H, Wang J, Zhao G, Li M. Evidence for chromatin-remodeling complex PBAP-controlled maintenance of the Drosophila ovarian germline stem cells. PLoS One 2014; 9:e103473. [PMID: 25068272 PMCID: PMC4113433 DOI: 10.1371/journal.pone.0103473] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 06/30/2014] [Indexed: 11/19/2022] Open
Abstract
In the Drosophila oogenesis, germline stem cells (GSCs) continuously self-renew and differentiate into daughter cells for consecutive germline lineage commitment. This developmental process has become an in vivo working platform for studying adult stem cell fate regulation. An increasing number of studies have shown that while concerted actions of extrinsic signals from the niche and intrinsic regulatory machineries control GSC self-renewal and germline differentiation, epigenetic regulation is implicated in the process. Here, we report that Brahma (Brm), the ATPase subunit of the Drosophila SWI/SNF chromatin-remodeling complexes, is required for maintaining GSC fate. Removal or knockdown of Brm function in either germline or niche cells causes a GSC loss, but does not disrupt normal germline differentiation within the germarium evidenced at the molecular and morphological levels. There are two Drosophila SWI/SNF complexes: the Brm-associated protein (BAP) complex and the polybromo-containing BAP (PBAP) complex. More genetic studies reveal that mutations in polybromo/bap180, rather than gene encoding Osa, the BAP complex-specific subunit, elicit a defect in GSC maintenance reminiscent of the brm mutant phenotype. Further genetic interaction test suggests a functional association between brm and polybromo in controlling GSC self-renewal. Taken together, studies in this paper provide the first demonstration that Brm in the form of the PBAP complex functions in the GSC fate regulation.
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Affiliation(s)
- Jie He
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P R China
| | - Tao Xuan
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P R China
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, P R China
- * E-mail: (TX); (ML)
| | - Tianchi Xin
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P R China
| | - Hongbo An
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P R China
| | - Jinye Wang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, P R China
| | - Gengchun Zhao
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P R China
| | - Mingfa Li
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, P R China
- * E-mail: (TX); (ML)
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Ryazansky SS, Mikhaleva EA, Olenkina OV. Essential functions of microRNAs in animal reproductive organs. Mol Biol 2014. [DOI: 10.1134/s0026893314030182] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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34
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Temme C, Simonelig M, Wahle E. Deadenylation of mRNA by the CCR4-NOT complex in Drosophila: molecular and developmental aspects. Front Genet 2014; 5:143. [PMID: 24904643 PMCID: PMC4033318 DOI: 10.3389/fgene.2014.00143] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 05/02/2014] [Indexed: 11/13/2022] Open
Abstract
Controlled shortening of the poly(A) tail of mRNAs is the first step in eukaryotic mRNA decay and can also be used for translational inactivation of mRNAs. The CCR4-NOT complex is the most important among a small number of deadenylases, enzymes catalyzing poly(A) tail shortening. Rates of poly(A) shortening differ between mRNAs as the CCR4-NOT complex is recruited to specific mRNAs by means of either sequence-specific RNA binding proteins or miRNAs. This review summarizes our current knowledge concerning the subunit composition and deadenylation activity of the Drosophila CCR4-NOT complex and the mechanisms by which the complex is recruited to particular mRNAs. We discuss genetic data implicating the complex in the regulation of specific mRNAs, in particular in the context of development.
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Affiliation(s)
- Claudia Temme
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg Halle, Germany
| | - Martine Simonelig
- Genetics and Development, Institute of Human Genetics - CNRS UPR1142 Montpellier, France
| | - Elmar Wahle
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg Halle, Germany
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35
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A regulatory network of Drosophila germline stem cell self-renewal. Dev Cell 2014; 28:459-73. [PMID: 24576427 DOI: 10.1016/j.devcel.2014.01.020] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 11/24/2013] [Accepted: 01/22/2014] [Indexed: 12/24/2022]
Abstract
Stem cells possess the capacity to generate two cells of distinct fate upon division: one cell retaining stem cell identity and the other cell destined to differentiate. These cell fates are established by cell-type-specific genetic networks. To comprehensively identify components of these networks, we performed a large-scale RNAi screen in Drosophila female germline stem cells (GSCs) covering ∼25% of the genome. The screen identified 366 genes that affect GSC maintenance, differentiation, or other processes involved in oogenesis. Comparison of GSC regulators with neural stem cell self-renewal factors identifies common and cell-type-specific self-renewal genes. Importantly, we identify the histone methyltransferase Set1 as a GSC-specific self-renewal factor. Loss of Set1 in neural stem cells does not affect cell fate decisions, suggesting a differential requirement of H3K4me3 in different stem cell lineages. Altogether, our study provides a resource that will help to further dissect the networks underlying stem cell self-renewal.
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36
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León K, Gallay N, Poupon A, Reiter E, Dalbies-Tran R, Crepieux P. Integrating microRNAs into the complexity of gonadotropin signaling networks. Front Cell Dev Biol 2013; 1:3. [PMID: 25364708 PMCID: PMC4206998 DOI: 10.3389/fcell.2013.00003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 12/12/2013] [Indexed: 12/13/2022] Open
Abstract
Follicle-stimulating hormone (FSH) is a master endocrine regulator of mammalian reproductive functions. Hence, it is used to stimulate folliculogenesis in assisted reproductive technologies (ART), both in women and in breeding animals. However, the side effects that hormone administration induces in some instances jeopardize the success of ART. Similarly, the luteinizing hormone (LH) is also of paramount importance in the reproductive function because it regulates steroidogenesis and the LH surge is a pre-requisite to ovulation. Gaining knowledge as extensive as possible on gonadotropin-induced biological responses could certainly lead to precise selection of their effects in vivo by the use of selective agonists at the hormone receptors. Hence, over the years, numerous groups have contributed to decipher the cellular events induced by FSH and LH in their gonadal target cells. Although little is known on the effect of gonadotropins on microRNA expression so far, recent data have highlighted that a microRNA regulatory network is likely to superimpose on the signaling protein network. No doubt that this will dramatically alter our current understanding of the gonadotropin-induced signaling networks. This is the topic of this review to present this additional level of complexity within the gonadotropin signaling network, in the context of recent findings on the microRNA machinery in the gonad.
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Affiliation(s)
- Kelly León
- BIOS Group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, Nouzilly, France; CNRS, UMR7247, Nouzilly, France; Université François Rabelais Tours, France
| | - Nathalie Gallay
- BIOS Group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, Nouzilly, France; CNRS, UMR7247, Nouzilly, France; Université François Rabelais Tours, France
| | - Anne Poupon
- BIOS Group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, Nouzilly, France; CNRS, UMR7247, Nouzilly, France; Université François Rabelais Tours, France
| | - Eric Reiter
- BIOS Group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, Nouzilly, France; CNRS, UMR7247, Nouzilly, France; Université François Rabelais Tours, France
| | - Rozenn Dalbies-Tran
- BINGO Group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, Nouzilly, France; CNRS, UMR7247, Nouzilly, France; Université François Rabelais Tours, France
| | - Pascale Crepieux
- BIOS Group, INRA, UMR85, Unité Physiologie de la Reproduction et des Comportements, Nouzilly, France; CNRS, UMR7247, Nouzilly, France; Université François Rabelais Tours, France
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37
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Joly W, Chartier A, Rojas-Rios P, Busseau I, Simonelig M. The CCR4 deadenylase acts with Nanos and Pumilio in the fine-tuning of Mei-P26 expression to promote germline stem cell self-renewal. Stem Cell Reports 2013; 1:411-24. [PMID: 24286029 PMCID: PMC3841267 DOI: 10.1016/j.stemcr.2013.09.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 09/26/2013] [Accepted: 09/27/2013] [Indexed: 11/28/2022] Open
Abstract
Translational regulation plays an essential role in Drosophila ovarian germline stem cell (GSC) biology. GSC self-renewal requires two translational repressors, Nanos (Nos) and Pumilio (Pum), which repress the expression of differentiation factors in the stem cells. The molecular mechanisms underlying this translational repression remain unknown. Here, we show that the CCR4 deadenylase is required for GSC self-renewal and that Nos and Pum act through its recruitment onto specific mRNAs. We identify mei-P26 mRNA as a direct and major target of Nos/Pum/CCR4 translational repression in the GSCs. mei-P26 encodes a protein of the Trim-NHL tumor suppressor family that has conserved functions in stem cell lineages. We show that fine-tuning Mei-P26 expression by CCR4 plays a key role in GSC self-renewal. These results identify the molecular mechanism of Nos/Pum function in GSC self-renewal and reveal the role of CCR4-NOT-mediated deadenylation in regulating the balance between GSC self-renewal and differentiation. The CCR4 deadenylase is required for female germline stem cell self-renewal Nos/Pum recruit CCR4-NOT for translational repression in germline stem cells mei-P26 mRNA is a major target of translational repression by Nos/Pum/CCR4 Fine-tuning of mei-P26 by CCR4 is required for germline stem cell self-renewal
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Affiliation(s)
- Willy Joly
- mRNA Regulation and Development, Institute of Human Genetics, CNRS UPR1142, 141 Rue de la Cardonille, 34396 Montpellier Cedex 5, France
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Pushpavalli SNCVL, Sarkar A, Bag I, Hunt CR, Ramaiah MJ, Pandita TK, Bhadra U, Pal-Bhadra M. Argonaute-1 functions as a mitotic regulator by controlling Cyclin B during Drosophila early embryogenesis. FASEB J 2013; 28:655-66. [PMID: 24165481 DOI: 10.1096/fj.13-231167] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The role of Ago-1 in microRNA (miRNA) biogenesis has been thoroughly studied, but little is known about its involvement in mitotic cell cycle progression. In this study, we established evidence of the regulatory role of Ago-1 in cell cycle control in association with the G2/M cyclin, cyclin B. Immunostaining of early embryos revealed that the maternal effect gene Ago-1 is essential for proper chromosome segregation, mitotic cell division, and spindle fiber assembly during early embryonic development. Ago-1 mutation resulted in the up-regulation of cyclin B-Cdk1 activity and down-regulation of p53, grp, mei-41, and wee1. The increased expression of cyclin B in Ago-1 mutants caused less stable microtubules and probably does not produce enough force to push the nuclei to the cortex, resulting in a decreased number of pole cells. The role of cyclin B in mitotic defects was further confirmed by suppressing the defects in the presence of one mutant copy of cyclin B. We identified involvement of 2 novel embryonic miRNAs--miR-981 and miR--317-for spatiotemporal regulation of cyclin B. In summary, our results demonstrate that the haploinsufficiency of maternal Ago-1 disrupts mitotic chromosome segregation and spindle fiber assembly via miRNA-guided control during early embryogenesis in Drosophila. The increased expression of cyclin B-Cdk1 and decreased activity of the Cdk1 inhibitor and cell cycle checkpoint proteins (mei-41 and grp) in Ago-1 mutant embryos allow the nuclei to enter into mitosis prematurely, even before completion of DNA replication. Thus, our results have established a novel role of Ago-1 as a regulator of the cell cycle.
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Xin T, Xuan T, Tan J, Li M, Zhao G, Li M. The Drosophila putative histone acetyltransferase Enok maintains female germline stem cells through regulating Bruno and the niche. Dev Biol 2013; 384:1-12. [PMID: 24120347 DOI: 10.1016/j.ydbio.2013.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 09/29/2013] [Accepted: 10/02/2013] [Indexed: 12/16/2022]
Abstract
Maintenance of adult stem cells is largely dependent on the balance between their self-renewal and differentiation. The Drosophila ovarian germline stem cells (GSCs) provide a powerful in vivo system for studying stem cell fate regulation. It has been shown that maintaining the GSC population involves both genetic and epigenetic mechanisms. Although the role of epigenetic regulation in this process is evident, the underlying mechanisms remain to be further explored. In this study, we find that Enoki mushroom (Enok), a Drosophila putative MYST family histone acetyltransferase controls GSC maintenance in the ovary at multiple levels. Removal or knockdown of Enok in the germline causes a GSC maintenance defect. Further studies show that the cell-autonomous role of Enok in maintaining GSCs is not dependent on the BMP/Bam pathway. Interestingly, molecular studies reveal an ectopic expression of Bruno, an RNA binding protein, in the GSCs and their differentiating daughter cells elicited by the germline Enok deficiency. Misexpression of Bruno in GSCs and their immediate descendants results in a GSC loss that can be exacerbated by incorporating one copy of enok mutant allele. These data suggest a role for Bruno in Enok-controlled GSC maintenance. In addition, we observe that Enok is required for maintaining GSCs non-autonomously. Compromised expression of enok in the niche cells impairs the niche maintenance and BMP signal output, thereby causing defective GSC maintenance. This is the first demonstration that the niche size control requires an epigenetic mechanism. Taken together, studies in this paper provide new insights into the GSC fate regulation.
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Affiliation(s)
- Tianchi Xin
- MoE Key Laboratory of Developmental Genetics and Neuropsychiatric Diseases, Bio-X Institutes, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 200240 Shanghai, PR China
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40
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Abstract
MicroRNAs (miRNAs) are ~22 nt RNAs that coordinate vast regulatory networks in animals and thereby influence myriad processes. This Review examines evidence that miRNAs have continuous roles in adults in ways that are separable from developmental control. Adult-specific activities for miRNAs have been described in various stem cell populations, in the context of neural function and cardiovascular biology, in metabolism and ageing, and during cancer. In addition to reviewing recent results, we also discuss methods for studying miRNA activities specifically in adults and evaluate their relative strengths and weaknesses. A fuller understanding of continuous functions of miRNAs in adults has bearing on efforts and opportunities to manipulate miRNAs for therapeutic purposes.
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Affiliation(s)
- Kailiang Sun
- Sloan-Kettering Institute, Department of Developmental Biology, 1275 York Ave, Box 252, New York, NY 10065
| | - Eric C. Lai
- Sloan-Kettering Institute, Department of Developmental Biology, 1275 York Ave, Box 252, New York, NY 10065
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41
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Smibert P, Yang JS, Azzam G, Liu JL, Lai EC. Homeostatic control of Argonaute stability by microRNA availability. Nat Struct Mol Biol 2013; 20:789-95. [PMID: 23708604 PMCID: PMC3702675 DOI: 10.1038/nsmb.2606] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 05/10/2013] [Indexed: 12/18/2022]
Abstract
Homeostatic mechanisms regulate the abundance of several components in small-RNA pathways. We used Drosophila and mammalian systems to demonstrate a conserved homeostatic system in which the status of miRNA biogenesis controls Argonaute protein stability. Clonal analyses of multiple mutants of core Drosophila miRNA factors revealed that stability of the miRNA effector AGO1 is dependent on miRNA biogenesis. Reciprocally, ectopic transcription of miRNAs within in vivo clones induced accumulation of AGO1, as did genetic interference with the ubiquitin-proteasome system. In mouse cells, we found that the stability of Ago2 declined in Dicer-knockout cells and was rescued by proteasome blockade or introduction of either Dicer plasmid or Dicer-independent miRNA constructs. Notably, Dicer-dependent miRNA constructs generated pre-miRNAs that bound Ago2 but did not rescue Ago2 stability. We conclude that Argonaute levels are finely tuned by cellular availability of mature miRNAs and the ubiquitin-proteasome system.
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Affiliation(s)
- Peter Smibert
- Department of Developmental Biology, Sloan-Kettering Institute, New York, New York, USA
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42
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Li Y, Zhang Q, Carreira-Rosario A, Maines JZ, McKearin DM, Buszczak M. Mei-p26 cooperates with Bam, Bgcn and Sxl to promote early germline development in the Drosophila ovary. PLoS One 2013; 8:e58301. [PMID: 23526974 PMCID: PMC3603962 DOI: 10.1371/journal.pone.0058301] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 02/01/2013] [Indexed: 01/17/2023] Open
Abstract
In the Drosophila female germline, spatially and temporally specific translation of mRNAs governs both stem cell maintenance and the differentiation of their progeny. However, the mechanisms that control and coordinate different modes of translational repression within this lineage remain incompletely understood. Here we present data showing that Mei-P26 associates with Bam, Bgcn and Sxl and nanos mRNA during early cyst development, suggesting that this protein helps to repress the translation of nanos mRNA. Together with recently published studies, these data suggest that Mei-P26 mediates both GSC self-renewal and germline differentiation through distinct modes of translational repression depending on the presence of Bam.
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Affiliation(s)
- Yun Li
- Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Qiao Zhang
- Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Arnaldo Carreira-Rosario
- Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Jean Z. Maines
- Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
| | - Dennis M. McKearin
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Michael Buszczak
- Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States of America
- * E-mail:
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43
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Wang GH, Jiang L, Zhu L, Cheng TC, Niu WH, Yan YF, Xia QY. Characterization of Argonaute family members in the silkworm, Bombyx mori. INSECT SCIENCE 2013; 20:78-91. [PMID: 23955828 DOI: 10.1111/j.1744-7917.2012.01555.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The Argonaute protein family is a highly conserved group of proteins, which have been implicated in RNA silencing in both plants and animals. Here, four members of the Argonaute family were systemically identified based on the genome sequence of Bombyx mori. Based on their sequence similarity, BmAgo1 and BmAgo2 belong to the Ago subfamily, while BmAgo3 and BmPiwi are in the Piwi subfamily. Phylogenetic analysis reveals that silkworm Argonaute family members are conserved in insects. Conserved amino acid residues involved in recognition of the 5' end of the small RNA guide strand and of the conserved (aspartate, aspartate and histidine [DDH]) motif present in their PIWI domains suggest that these four Argonaute family members may have conserved slicer activities. The results of microarray expression analysis show that there is a low expression level for B. mori Argonaute family members in different tissues and different developmental stages, except for BmPiwi. All four B. mori Argonaute family members are upregulated upon infection with B. mori nucleopolyhedrovirus. The complete coding sequence of BmPiwi, the homolog of Drosophila piwi, was cloned and its expression occurred mainly in the area where spermatogonia and spermatocytes appear. Our results provide an overview of the B. mori Argonaute family members and suggest that they may have multiple roles. In addition, this is also the first report, to our knowledge, of the response of RNA silencing machinery to DNA virus infection in insects.
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Affiliation(s)
- Gen-Hong Wang
- State Key Laboratory of Silkworm Genome Biology, School of Biotechnology, Southwest, Chongqing, China
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Abstract
One of the most important and evolutionarily conserved strategies to control gene expression in higher metazoa is posttranscriptional regulation via small regulatory RNAs such as microRNAs (miRNAs), endogenous small interfering RNAs (endo-siRNAs), and piwi-interacting RNAs (piRNAs). Primordial germ cells, which are defined by their totipotent potential and noted for their dependence on posttranscriptional regulation by RNA-binding proteins, rely on these small regulatory RNAs for virtually every aspect of their development, including specification, migration, and differentiation into competent gametes. Here, we review current knowledge of the roles miRNAs, endo-siRNAs, and piRNAs play at all stages of germline development in various organisms, focusing on studies in the mouse.
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Affiliation(s)
- Matthew S Cook
- Department of Urology, University of California, San Francisco, California, USA.
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microRNA-independent recruitment of Argonaute 1 to nanos mRNA through the Smaug RNA-binding protein. EMBO Rep 2012. [PMID: 23184089 DOI: 10.1038/embor.2012.192] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Argonaute (Ago) proteins are typically recruited to target messenger RNAs via an associated small RNA such as a microRNA (miRNA). Here, we describe a new mechanism of Ago recruitment through the Drosophila Smaug RNA-binding protein. We show that Smaug interacts with the Ago1 protein, and that Ago1 interacts with and is required for the translational repression of the Smaug target, nanos mRNA. The Ago1/nanos mRNA interaction does not require a miRNA, but it does require Smaug. Taken together, our data suggest a model whereby Smaug directly recruits Ago1 to nanos mRNA in a miRNA-independent manner, thereby repressing translation.
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Bamezai S, Rawat VP, Buske C. Concise Review: The Piwi-piRNA Axis: Pivotal Beyond Transposon Silencing. Stem Cells 2012; 30:2603-11. [DOI: 10.1002/stem.1237] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 08/29/2012] [Indexed: 01/21/2023]
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Eun SH, Stoiber PM, Wright HJ, McMurdie KE, Choi CH, Gan Q, Lim C, Chen X. MicroRNAs downregulate Bag of marbles to ensure proper terminal differentiation in the Drosophila male germline. Development 2012; 140:23-30. [PMID: 23154414 DOI: 10.1242/dev.086397] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In many adult stem cell lineages, the continuous production of functional differentiated cells depends on the maintenance of progenitor cells in an undifferentiated and proliferative state, as well as the subsequent commitment to proper terminal differentiation. In the Drosophila male germline stem cell (GSC) lineage, a key differentiation factor, Bag of marbles (Bam), is required for the transition from proliferative spermatogonia to differentiating spermatocytes. We show that bam mRNA, but not Bam, is present in spermatocytes, suggesting that bam is regulated post-transcriptionally. Consistent with this, repression of Bam accumulation is achieved by microRNAs via the bam 3'UTR. When the bam 3'UTR was substituted with the 3'UTR of a constitutively expressed α-Tubulin, Bam became stabilized in spermatocytes. Moreover, such a persistent expression of Bam in spermatocytes was recapitulated by specifically mutating the putative miR-275/miR-306 recognition site at the bam 3'UTR. In addition, overexpression of miR-275 or miR-306 in spermatogonial cells resulted in a delay of the proliferation-to-differentiation transition and resembled the bam loss-of-function phenotype, suggesting that these microRNAs are sufficient to downregulate Bam. Finally, the failure of Bam downregulation in spermatocytes affected spermatid terminal differentiation and resulted in increased male sterility. Our results demonstrate that microRNAs control the stem cell differentiation pathway through regulating Bam, the downregulation of which is crucial for proper spermatid terminal differentiation.
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Affiliation(s)
- Suk Ho Eun
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
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Somorjai IML, Lohmann JU, Holstein TW, Zhao Z. Stem cells: a view from the roots. Biotechnol J 2012; 7:704-22. [PMID: 22581706 DOI: 10.1002/biot.201100349] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 03/15/2012] [Accepted: 04/12/2012] [Indexed: 12/22/2022]
Abstract
In both plants and animals, regeneration requires the activation of stem cells. This is possibly related to the origin and requirements of multicellularity. Although long diverged from a common ancestry, plant and animal models such as Arabidopsis, Drosophila and mouse share considerable similarities in stem cell regulation. This includes stem cell niche organisation, epigenetic modification of DNA and histones, and the role of small RNA machinery in differentiation and pluripotency states. Dysregulation of any of these can lead to premature ageing, patterning and specification defects, as well as cancers. Moreover, emerging basal animal and plant systems are beginning to provide important clues concerning the diversity and evolutionary history of stem cell regulatory mechanisms in eukaryotes. This review provides a comparative framework, highlighting both the commonalities and differences among groups, which should promote the intelligent design of artificial stem cell systems, and thereby fuel the field of biomaterials science.
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Affiliation(s)
- Ildiko M L Somorjai
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany.
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Papagiannouli F, Lohmann I. Shaping the niche: lessons from the Drosophila testis and other model systems. Biotechnol J 2012; 7:723-36. [PMID: 22488937 DOI: 10.1002/biot.201100352] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 01/31/2012] [Accepted: 02/27/2012] [Indexed: 11/12/2022]
Abstract
Stem cells are fascinating, as they supply the cells that construct our adult bodies and replenish, as we age, worn out, damaged, and diseased tissues. Stem cell regulation relies on intrinsic signals but also on inputs emanating from the neighbouring niche. The Drosophila testis provides an excellent system for studying such processes. Although recent advances have uncovered several signalling, cytoskeletal and other factors affecting niche homeostasis and testis differentiation, many aspects of niche regulation and maintenance remain unsolved. In this review, we discuss aspects of niche establishment and integrity not yet fully understood and we compare it to the current knowledge in other model systems such as vertebrates and plants. We also address specific questions on stem cell maintenance and niche regulation in the Drosophila testis under the control of Hox genes. Finally, we provide insights on the striking functional conservation of homologous genes in plants and animals and their respective stem cell niches. Elucidating conserved mechanisms of stem cell control in both lineages could reveal the importance underlying this conservation and justify the evolutionary pressure to adapt homologous molecules for performing the same task.
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Affiliation(s)
- Fani Papagiannouli
- Centre for Organismal Studies (COS) Heidelberg and CellNetworks - Cluster of Excellence, Heidelberg, Germany.
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Li Y, Maines JZ, Tastan OY, McKearin DM, Buszczak M. Mei-P26 regulates the maintenance of ovarian germline stem cells by promoting BMP signaling. Development 2012; 139:1547-56. [PMID: 22438571 DOI: 10.1242/dev.077412] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In the Drosophila ovary, bone morphogenetic protein (BMP) ligands maintain germline stem cells (GSCs) in an undifferentiated state. The activation of the BMP pathway within GSCs results in the transcriptional repression of the differentiation factor bag of marbles (bam). The Nanos-Pumilio translational repressor complex and the miRNA pathway also help to promote GSC self-renewal. How the activities of different transcriptional and translational regulators are coordinated to keep the GSC in an undifferentiated state remains uncertain. Data presented here show that Mei-P26 cell-autonomously regulates GSC maintenance in addition to its previously described role of promoting germline cyst development. Within undifferentiated germ cells, Mei-P26 associates with miRNA pathway components and represses the translation of a shared target mRNA, suggesting that Mei-P26 can enhance miRNA-mediated silencing in specific contexts. In addition, disruption of mei-P26 compromises BMP signaling, resulting in the inappropriate expression of bam in germ cells immediately adjacent to the cap cell niche. Loss of mei-P26 results in premature translation of the BMP antagonist Brat in germline stem cells. These data suggest that Mei-P26 has distinct functions in the ovary and participates in regulating the fates of both GSCs and their differentiating daughters.
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Affiliation(s)
- Yun Li
- Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9148, USA
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