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Herz M, Zarowiecki M, Wessels L, Pätzel K, Herrmann R, Braun C, Holroyd N, Huckvale T, Bergmann M, Spiliotis M, Koziol U, Berriman M, Brehm K. Genome-wide transcriptome analysis of Echinococcus multilocularis larvae and germinative cell cultures reveals genes involved in parasite stem cell function. Front Cell Infect Microbiol 2024; 14:1335946. [PMID: 38333034 PMCID: PMC10850878 DOI: 10.3389/fcimb.2024.1335946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/12/2024] [Indexed: 02/10/2024] Open
Abstract
The lethal zoonosis alveolar echinococcosis is caused by tumour-like growth of the metacestode stage of the tapeworm Echinococcus multilocularis within host organs. We previously demonstrated that metacestode proliferation is exclusively driven by somatic stem cells (germinative cells), which are the only mitotically active parasite cells that give rise to all differentiated cell types. The Echinococcus gene repertoire required for germinative cell maintenance and differentiation has not been characterised so far. We herein carried out Illumina sequencing on cDNA from Echinococcus metacestode vesicles, from metacestode tissue depleted of germinative cells, and from Echinococcus primary cell cultures. We identified a set of ~1,180 genes associated with germinative cells, which contained numerous known stem cell markers alongside genes involved in replication, cell cycle regulation, mitosis, meiosis, epigenetic modification, and nucleotide metabolism. Interestingly, we also identified 44 stem cell associated transcription factors that are likely involved in regulating germinative cell differentiation and/or pluripotency. By in situ hybridization and pulse-chase experiments, we also found a new general Echinococcus stem cell marker, EmCIP2Ah, and we provide evidence implying the presence of a slow cycling stem cell sub-population expressing the extracellular matrix factor Emkal1. RNA-Seq analyses on primary cell cultures revealed that metacestode-derived Echinococcus stem cells display an expanded differentiation capability and do not only form differentiated cell types of the metacestode, but also cells expressing genes specific for protoscoleces, adult worms, and oncospheres, including an ortholog of the schistosome praziquantel target, EmTRPMPZQ. Finally, we show that primary cell cultures contain a cell population expressing an ortholog of the tumour necrosis factor α receptor family and that mammalian TNFα accelerates the development of metacestode vesicles from germinative cells. Taken together, our analyses provide a robust and comprehensive characterization of the Echinococcus germinative cell transcriptome, demonstrate expanded differentiation capability of metacestode derived stem cells, and underscore the potential of primary germinative cell cultures to investigate developmental processes of the parasite. These data are relevant for studies into the role of Echinococcus stem cells in parasite development and will facilitate the design of anti-parasitic drugs that specifically act on the parasite germinative cell compartment.
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Affiliation(s)
- Michaela Herz
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | | | - Leonie Wessels
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Katharina Pätzel
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Ruth Herrmann
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Christiane Braun
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Nancy Holroyd
- Parasite Genomics, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Thomas Huckvale
- Parasite Genomics, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Monika Bergmann
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Markus Spiliotis
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Uriel Koziol
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
- Sección Biología Celular, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Matthew Berriman
- Parasite Genomics, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Klaus Brehm
- Consultant Laboratory for Echinococcosis, Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
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Parra AS, Johnston CA. Phase Separation as a Driver of Stem Cell Organization and Function during Development. J Dev Biol 2023; 11:45. [PMID: 38132713 PMCID: PMC10743522 DOI: 10.3390/jdb11040045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/04/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023] Open
Abstract
A properly organized subcellular composition is essential to cell function. The canonical organizing principle within eukaryotic cells involves membrane-bound organelles; yet, such structures do not fully explain cellular complexity. Furthermore, discrete non-membrane-bound structures have been known for over a century. Liquid-liquid phase separation (LLPS) has emerged as a ubiquitous mode of cellular organization without the need for formal lipid membranes, with an ever-expanding and diverse list of cellular functions that appear to be regulated by this process. In comparison to traditional organelles, LLPS can occur across wider spatial and temporal scales and involves more distinct protein and RNA complexes. In this review, we discuss the impacts of LLPS on the organization of stem cells and their function during development. Specifically, the roles of LLPS in developmental signaling pathways, chromatin organization, and gene expression will be detailed, as well as its impacts on essential processes of asymmetric cell division. We will also discuss how the dynamic and regulated nature of LLPS may afford stem cells an adaptable mode of organization throughout the developmental time to control cell fate. Finally, we will discuss how aberrant LLPS in these processes may contribute to developmental defects and disease.
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Xing Y, Larson K, Li J, Li WX. Canonical and non-canonical functions of STAT in germline stem cell maintenance. Dev Dyn 2023; 252:728-741. [PMID: 36866634 PMCID: PMC10238624 DOI: 10.1002/dvdy.576] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 02/01/2023] [Accepted: 02/09/2023] [Indexed: 02/24/2023] Open
Abstract
BACKGROUND Maintenance of the Drosophila male germline stem cells (GSCs) requires activation of the Janus kinase/signal transducer and activators of transcription (JAK/STAT) pathway by niche signals. The precise role of JAK/STAT signaling in GSC maintenance, however, remains incompletely understood. RESULTS Here, we show that, GSC maintenance requires both canonical and non-canonical JAK/STAT signaling, in which unphosphorylated STAT (uSTAT) maintains heterochromatin stability by binding to heterochromatin protein 1 (HP1). We found that GSC-specific overexpressing STAT, or even the transcriptionally inactive mutant STAT, increases GSC number and partially rescues the GSC-loss mutant phenotype due to reduced JAK activity. Furthermore, we found that both HP1 and STAT are transcriptional targets of the canonical JAK/STAT pathway in GSCs, and that GSCs exhibit higher heterochromatin content. CONCLUSIONS These results suggest that persistent JAK/STAT activation by niche signals leads to the accumulation of HP1 and uSTAT in GSCs, which promote heterochromatin formation important for maintaining GSC identity. Thus, the maintenance of Drosophila GSCs requires both canonical and non-canonical STAT functions within GSCs for heterochromatin regulation.
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Affiliation(s)
- Yalan Xing
- Department of Medicine, University of California at San Diego, La Jolla, CA 92093
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642
| | - Kimberly Larson
- Department of Medicine, University of California at San Diego, La Jolla, CA 92093
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642
| | - Jinghong Li
- Department of Medicine, University of California at San Diego, La Jolla, CA 92093
| | - Willis X. Li
- Department of Medicine, University of California at San Diego, La Jolla, CA 92093
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642
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Transcription Factors Active in the Anterior Blastema of Schmidtea mediterranea. Biomolecules 2021; 11:biom11121782. [PMID: 34944426 PMCID: PMC8698962 DOI: 10.3390/biom11121782] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 12/28/2022] Open
Abstract
Regeneration, the restoration of body parts after injury, is quite widespread in the animal kingdom. Species from virtually all Phyla possess regenerative abilities. Human beings, however, are poor regenerators. Yet, the progress of knowledge and technology in the fields of bioengineering, stem cells, and regenerative biology have fostered major advancements in regenerative medical treatments, which aim to regenerate tissues and organs and restore function. Human induced pluripotent stem cells can differentiate into any cell type of the body; however, the structural and cellular complexity of the human tissues, together with the inability of our adult body to control pluripotency, require a better mechanistic understanding. Planarians, with their capacity to regenerate lost body parts thanks to the presence of adult pluripotent stem cells could help providing such an understanding. In this paper, we used a top-down approach to shortlist blastema transcription factors (TFs) active during anterior regeneration. We found 44 TFs—31 of which are novel in planarian—that are expressed in the regenerating blastema. We analyzed the function of half of them and found that they play a role in the regeneration of anterior structures, like the anterior organizer, the positional instruction muscle cells, the brain, the photoreceptor, the intestine. Our findings revealed a glimpse of the complexity of the transcriptional network governing anterior regeneration in planarians, confirming that this animal model is the perfect playground to study in vivo how pluripotency copes with adulthood.
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Molina MD, Cebrià F. Decoding Stem Cells: An Overview on Planarian Stem Cell Heterogeneity and Lineage Progression. Biomolecules 2021; 11:1532. [PMID: 34680165 PMCID: PMC8533874 DOI: 10.3390/biom11101532] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 01/26/2023] Open
Abstract
Planarians are flatworms capable of whole-body regeneration, able to regrow any missing body part after injury or amputation. The extraordinary regenerative capacity of planarians is based upon the presence in the adult of a large population of somatic pluripotent stem cells. These cells, called neoblasts, offer a unique system to study the process of stem cell specification and differentiation in vivo. In recent years, FACS-based isolation of neoblasts, RNAi functional analyses as well as high-throughput approaches such as single-cell sequencing have allowed a rapid progress in our understanding of many different aspects of neoblast biology. Here, we summarize our current knowledge on the molecular signatures that define planarian neoblasts heterogeneity, which includes a percentage of truly pluripotent stem cells, and guide the commitment of pluripotent neoblasts into lineage-specific progenitor cells, as well as their differentiation into specific planarian cell types.
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Affiliation(s)
- M. Dolores Molina
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
- Institute of Biomedicine of the University of Barcelona (IBUB), 08028 Barcelona, Spain
| | - Francesc Cebrià
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
- Institute of Biomedicine of the University of Barcelona (IBUB), 08028 Barcelona, Spain
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Li D, Taylor DH, van Wolfswinkel JC. PIWI-mediated control of tissue-specific transposons is essential for somatic cell differentiation. Cell Rep 2021; 37:109776. [PMID: 34610311 PMCID: PMC8532177 DOI: 10.1016/j.celrep.2021.109776] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 07/27/2021] [Accepted: 09/07/2021] [Indexed: 12/24/2022] Open
Abstract
PIWI proteins are known as mediators of transposon silencing in animal germlines but are also found in adult pluripotent stem cells of highly regenerative animals, where they are essential for regeneration. Study of the nuclear PIWI protein SMEDWI-2 in the planarian somatic stem cell system reveals an intricate interplay between transposons and cell differentiation in which a subset of transposons is inevitably activated during cell differentiation, and the PIWI protein is required to regain control. Absence of SMEDWI-2 leads to tissue-specific transposon derepression related to cell-type-specific chromatin remodeling events and in addition causes reduced accessibility of lineage-specific genes and defective cell differentiation, resulting in fatal tissue dysfunction. Finally, we show that additional PIWI proteins provide a stem-cell-specific second layer of protection in planarian neoblasts. These findings reveal a far-reaching role of PIWI proteins and PIWI-interacting RNAs (piRNAs) in stem cell biology and cell differentiation.
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Affiliation(s)
- Danyan Li
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - David H Taylor
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Josien C van Wolfswinkel
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA.
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Zheng H, Liu H, Xu Q, Wang W, Li L, Ye G, Wen X, Chen F, Yu Y. PI3K Plays an Essential Role in Planarian Regeneration and Tissue Maintenance. Front Cell Dev Biol 2021; 9:649656. [PMID: 34422792 PMCID: PMC8377419 DOI: 10.3389/fcell.2021.649656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 07/19/2021] [Indexed: 11/13/2022] Open
Abstract
Phosphatidylinositol 3-kinase (PI3K) signaling plays a central role in various biological processes, and its abnormality leads to a broad spectrum of human diseases, such as cancer, fibrosis, and immunological disorders. However, the mechanisms by which PI3K signaling regulates the behavior of stem cells during regeneration are poorly understood. Planarian flatworms possess abundant adult stem cells (called neoblasts) allowing them to develop remarkable regenerative capabilities, thus the animals represent an ideal model for studying stem cells and regenerative medicine in vivo. In this study, the spatiotemporal expression pattern of Djpi3k, a PI3K ortholog in the planarian Dugesia japonica, was investigated and suggests its potential role in wound response and tissue regeneration. A loss-of-function study was conducted using small molecules and RNA interference technique, providing evidence that PI3K signaling is required for blastema regrowth and cilia maintenance during planarian regeneration and homeostasis. Interestingly, the mitotic and apoptotic responses to amputation are substantially abated in PI3K inhibitor-treated regenerating animals, while knockdown of Djpi3k alleviates the mitotic response and postpones the peak of apoptotic cell death, which may contribute to the varying degrees of regenerative defects induced by the pharmacological and genetic approaches. These observations reveal novel roles for PI3K signaling in the regulation of the cellular responses to amputation during planarian regeneration and provide insights for investigating the disease-related genes in the regeneration-competent organism in vivo.
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Affiliation(s)
- Hanxue Zheng
- Laboratory of Tissue Engineering, College of Life Sciences, Northwest University, Xi'an, China
| | - Hongbo Liu
- Laboratory of Tissue Engineering, College of Life Sciences, Northwest University, Xi'an, China
| | - Qian Xu
- Laboratory of Tissue Engineering, College of Life Sciences, Northwest University, Xi'an, China
| | - Wenjun Wang
- Laboratory of Tissue Engineering, College of Life Sciences, Northwest University, Xi'an, China
| | - Linfeng Li
- Laboratory of Tissue Engineering, College of Life Sciences, Northwest University, Xi'an, China
| | - Gang Ye
- Laboratory of Tissue Engineering, College of Life Sciences, Northwest University, Xi'an, China
| | - Xiaomin Wen
- Laboratory of Tissue Engineering, College of Life Sciences, Northwest University, Xi'an, China
| | - Fulin Chen
- Laboratory of Tissue Engineering, College of Life Sciences, Northwest University, Xi'an, China.,Provincial Key Laboratory of Biotechnology of Shaanxi, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Medicine, Northwest University, Xi'an, China
| | - Yuan Yu
- Laboratory of Tissue Engineering, College of Life Sciences, Northwest University, Xi'an, China.,Provincial Key Laboratory of Biotechnology of Shaanxi, Northwest University, Xi'an, China.,Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, School of Medicine, Northwest University, Xi'an, China
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8
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Casale AM, Cappucci U, Piacentini L. Unravelling HP1 functions: post-transcriptional regulation of stem cell fate. Chromosoma 2021; 130:103-111. [PMID: 34128099 PMCID: PMC8426308 DOI: 10.1007/s00412-021-00760-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 05/17/2021] [Accepted: 06/01/2021] [Indexed: 12/20/2022]
Abstract
Heterochromatin protein 1 (HP1) is a non-histone chromosomal protein first identified in Drosophila as a major component of constitutive heterochromatin, required for stable epigenetic gene silencing in many species including humans. Over the years, several studies have highlighted additional roles of HP1 in different cellular processes including telomere maintenance, DNA replication and repair, chromosome segregation and, surprisingly, positive regulation of gene expression. In this review, we briefly summarize past research and recent results supporting the unexpected and emerging role of HP1 in activating gene expression. In particular, we discuss the role of HP1 in post-transcriptional regulation of mRNA processing because it has proved decisive in the control of germline stem cells homeostasis in Drosophila and has certainly added a new dimension to our understanding on HP1 targeting and functions in epigenetic regulation of stem cell behaviour.
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Affiliation(s)
- Assunta Maria Casale
- Department of Biology and Biotechnology "C. Darwin", Sapienza University of Rome, Rome, Italy.
| | - Ugo Cappucci
- Department of Biology and Biotechnology "C. Darwin", Sapienza University of Rome, Rome, Italy
| | - Lucia Piacentini
- Department of Biology and Biotechnology "C. Darwin", Sapienza University of Rome, Rome, Italy.
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9
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Tarashansky AJ, Musser JM, Khariton M, Li P, Arendt D, Quake SR, Wang B. Mapping single-cell atlases throughout Metazoa unravels cell type evolution. eLife 2021; 10:e66747. [PMID: 33944782 PMCID: PMC8139856 DOI: 10.7554/elife.66747] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/30/2021] [Indexed: 12/11/2022] Open
Abstract
Comparing single-cell transcriptomic atlases from diverse organisms can elucidate the origins of cellular diversity and assist the annotation of new cell atlases. Yet, comparison between distant relatives is hindered by complex gene histories and diversifications in expression programs. Previously, we introduced the self-assembling manifold (SAM) algorithm to robustly reconstruct manifolds from single-cell data (Tarashansky et al., 2019). Here, we build on SAM to map cell atlas manifolds across species. This new method, SAMap, identifies homologous cell types with shared expression programs across distant species within phyla, even in complex examples where homologous tissues emerge from distinct germ layers. SAMap also finds many genes with more similar expression to their paralogs than their orthologs, suggesting paralog substitution may be more common in evolution than previously appreciated. Lastly, comparing species across animal phyla, spanning sponge to mouse, reveals ancient contractile and stem cell families, which may have arisen early in animal evolution.
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Affiliation(s)
| | - Jacob M Musser
- European Molecular Biology Laboratory, Developmental Biology UnitHeidelbergGermany
| | | | - Pengyang Li
- Department of Bioengineering, Stanford UniversityStanfordUnited States
| | - Detlev Arendt
- European Molecular Biology Laboratory, Developmental Biology UnitHeidelbergGermany
- Centre for Organismal Studies, University of HeidelbergHeidelbergGermany
| | - Stephen R Quake
- Department of Bioengineering, Stanford UniversityStanfordUnited States
- Department of Applied Physics, Stanford UniversityStanfordUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
| | - Bo Wang
- Department of Bioengineering, Stanford UniversityStanfordUnited States
- Department of Developmental Biology, Stanford University School of MedicineStanfordUnited States
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10
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Stelman CR, Smith BM, Chandra B, Roberts-Galbraith RH. CBP/p300 homologs CBP2 and CBP3 play distinct roles in planarian stem cell function. Dev Biol 2021; 473:130-143. [PMID: 33607113 DOI: 10.1016/j.ydbio.2021.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 11/19/2022]
Abstract
Chromatin modifications function as critical regulators of gene expression and cellular identity, especially in the regulation and maintenance of the pluripotent state. However, many studies of chromatin modification in stem cells-and pluripotent stem cells in particular-are performed in mammalian stem cell culture, an in vitro condition mimicking a very transient state during mammalian development. Thus, new models for studying pluripotent stem cells in vivo could be helpful for understanding the roles of chromatin modification, for confirming prior in vitro studies, and for exploring evolution of the pluripotent state. The freshwater flatworm, Schmidtea mediterranea, is an excellent model for studying adult pluripotent stem cells, particularly in the context of robust, whole-body regeneration. To identify chromatin modifying and remodeling enzymes critical for planarian regeneration and stem cell maintenance, we took a candidate approach and screened planarian homologs of 25 genes known to regulate chromatin biology in other organisms. Through our study, we identified six genes with novel functions in planarian homeostasis, regeneration, and behavior. Of the list of genes characterized, we identified five planarian homologs of the mammalian CREB-Binding Protein (CBP) and p300 family of histone acetyltransferases, representing an expansion of this family in planarians. We find that two planarian CBP family members are required for planarian survival, with knockdown of Smed-CBP2 and Smed-CBP3 causing distinct defects in stem cell maintenance or function. Loss of CBP2 causes a quick, dramatic loss of stem cells, while knockdown of CBP3 affects stem cells more narrowly, influencing differentiation of several cell types that include neuronal subtypes and cells of the eye. Further, we find that Smed-CBP1 is required for planarian fissioning behavior. We propose that the division of labor among a diversified CBP family in planarians presents an opportunity to dissect specific functions of a broadly important histone acetyltransferase family.
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Affiliation(s)
- Clara R Stelman
- Department of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Britessia M Smith
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Bidushi Chandra
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Rachel H Roberts-Galbraith
- Department of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Cellular Biology, University of Georgia, Athens, GA, USA.
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11
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Kim IV, Riedelbauch S, Kuhn CD. The piRNA pathway in planarian flatworms: new model, new insights. Biol Chem 2020; 401:1123-1141. [DOI: 10.1515/hsz-2019-0445] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/12/2020] [Indexed: 12/22/2022]
Abstract
AbstractPIWI-interacting RNAs (piRNAs) are small regulatory RNAs that associate with members of the PIWI clade of the Argonaute superfamily of proteins. piRNAs are predominantly found in animal gonads. There they silence transposable elements (TEs), regulate gene expression and participate in DNA methylation, thus orchestrating proper germline development. Furthermore, PIWI proteins are also indispensable for the maintenance and differentiation capabilities of pluripotent stem cells in free-living invertebrate species with regenerative potential. Thus, PIWI proteins and piRNAs seem to constitute an essential molecular feature of somatic pluripotent stem cells and the germline. In keeping with this hypothesis, both PIWI proteins and piRNAs are enriched in neoblasts, the adult stem cells of planarian flatworms, and their presence is a prerequisite for the proper regeneration and perpetual tissue homeostasis of these animals. The piRNA pathway is required to maintain the unique biology of planarians because, in analogy to the animal germline, planarian piRNAs silence TEs and ensure stable genome inheritance. Moreover, planarian piRNAs also contribute to the degradation of numerous protein-coding transcripts, a function that may be critical for neoblast differentiation. This review gives an overview of the planarian piRNA pathway and of its crucial function in neoblast biology.
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Affiliation(s)
- Iana V. Kim
- Gene regulation by Non-coding RNA, Elite Network of Bavaria and University of Bayreuth, Universitätsstrasse 30, D-95447 Bayreuth, Germany
| | - Sebastian Riedelbauch
- Gene regulation by Non-coding RNA, Elite Network of Bavaria and University of Bayreuth, Universitätsstrasse 30, D-95447 Bayreuth, Germany
| | - Claus-D. Kuhn
- Gene regulation by Non-coding RNA, Elite Network of Bavaria and University of Bayreuth, Universitätsstrasse 30, D-95447 Bayreuth, Germany
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12
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Kashima M, Agata K, Shibata N. What is the role of PIWI family proteins in adult pluripotent stem cells? Insights from asexually reproducing animals, planarians. Dev Growth Differ 2020; 62:407-422. [PMID: 32621324 DOI: 10.1111/dgd.12688] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/26/2020] [Accepted: 06/09/2020] [Indexed: 02/06/2023]
Abstract
Planarians have a remarkable regenerative ability owing to their adult pluripotent stem cells (aPSCs), which are called "neoblasts." Planarians maintain a considerable number of neoblasts throughout their adulthood to supply differentiated cells for the maintenance of tissue homeostasis and asexual reproduction (fission followed by regeneration). Thus, planarians serve as a good model to study the regulatory mechanisms of in vivo aPSCs. In asexually reproducing invertebrates, such as sponge, Hydra, and planaria, piwi family genes are the markers most commonly expressed in aPSCs. While piwi family genes are known as guardians against transposable elements in the germline cells of animals that only sexually propagate, their functions in the aPSC system have remained elusive. In this review, we introduce recent knowledge on the PIWI family proteins in the aPSC system in planarians and other organisms and discuss how PIWI family proteins contribute to the regulation of the aPSC system.
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Affiliation(s)
- Makoto Kashima
- College of Science and Engineering, Aoyama Gakuin University, Sagamihara Chuo Ku, Japan
| | - Kiyokazu Agata
- National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Japan
| | - Norito Shibata
- Department of Integrated Science and Technology, National Institute of Technology, Tsuyama College, Tsuyama-City, Japan
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13
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Kim IV, Duncan EM, Ross EJ, Gorbovytska V, Nowotarski SH, Elliott SA, Sánchez Alvarado A, Kuhn CD. Planarians recruit piRNAs for mRNA turnover in adult stem cells. Genes Dev 2019; 33:1575-1590. [PMID: 31537626 PMCID: PMC6824462 DOI: 10.1101/gad.322776.118] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 09/03/2019] [Indexed: 12/20/2022]
Abstract
In this study, Kim et al. set out to elucidate the molecular details of how PIWI proteins in planarian flatworms contribute to stem cell function and regeneration. Using novel biochemical tools, such as IP-seq, ribodepletion, HITS-CLIP, and SHAPE-MaP, the authors show that PIWI proteins enable planarians to repurpose piRNAs for critical roles in neoblast mRNA turnover. PIWI proteins utilize small RNAs called piRNAs to silence transposable elements, thereby protecting germline integrity. In planarian flatworms, PIWI proteins are essential for regeneration, which requires adult stem cells termed neoblasts. Here, we characterize planarian piRNAs and examine the roles of PIWI proteins in neoblast biology. We find that the planarian PIWI proteins SMEDWI-2 and SMEDWI-3 cooperate to degrade active transposons via the ping-pong cycle. Unexpectedly, we discover that SMEDWI-3 plays an additional role in planarian mRNA surveillance. While SMEDWI-3 degrades numerous neoblast mRNAs in a homotypic ping-pong cycle, it is also guided to another subset of neoblast mRNAs by antisense piRNAs and binds these without degrading them. Mechanistically, the distinct activities of SMEDWI-3 are primarily dictated by the degree of complementarity between target mRNAs and antisense piRNAs. Thus, PIWI proteins enable planarians to repurpose piRNAs for potentially critical roles in neoblast mRNA turnover.
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Affiliation(s)
- Iana V Kim
- Gene regulation by Non-coding RNA, Elite Network of Bavaria and University of Bayreuth, 95447 Bayreuth, Germany
| | - Elizabeth M Duncan
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Eric J Ross
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA.,Howard Hughes Medical Institute, Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Vladyslava Gorbovytska
- Gene regulation by Non-coding RNA, Elite Network of Bavaria and University of Bayreuth, 95447 Bayreuth, Germany
| | | | - Sarah A Elliott
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Alejandro Sánchez Alvarado
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA.,Howard Hughes Medical Institute, Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Claus-D Kuhn
- Gene regulation by Non-coding RNA, Elite Network of Bavaria and University of Bayreuth, 95447 Bayreuth, Germany
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14
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Ivankovic M, Haneckova R, Thommen A, Grohme MA, Vila-Farré M, Werner S, Rink JC. Model systems for regeneration: planarians. Development 2019; 146:146/17/dev167684. [PMID: 31511248 DOI: 10.1242/dev.167684] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Planarians are a group of flatworms. Some planarian species have remarkable regenerative abilities, which involve abundant pluripotent adult stem cells. This makes these worms a powerful model system for understanding the molecular and evolutionary underpinnings of regeneration. By providing a succinct overview of planarian taxonomy, anatomy, available tools and the molecular orchestration of regeneration, this Primer aims to showcase both the unique assets and the questions that can be addressed with this model system.
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Affiliation(s)
- Mario Ivankovic
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Radmila Haneckova
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.,Department of Tissue Dynamics and Regeneration, Max Planck Institute for Biophysical Chemistry, am Fassberg 11, 37077 Göttingen, Germany
| | - Albert Thommen
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.,The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Markus A Grohme
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Miquel Vila-Farré
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.,Department of Tissue Dynamics and Regeneration, Max Planck Institute for Biophysical Chemistry, am Fassberg 11, 37077 Göttingen, Germany
| | - Steffen Werner
- FOM Institute AMOLF, Department of Systems Biology, Science Park 104, 1098 XG, Amsterdam, The Netherlands
| | - Jochen C Rink
- Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany .,Department of Tissue Dynamics and Regeneration, Max Planck Institute for Biophysical Chemistry, am Fassberg 11, 37077 Göttingen, Germany
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15
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Wang C, Yang ZZ, Guo FH, Shi S, Han XS, Zeng A, Lin H, Jing Q. Heat shock protein DNAJA1 stabilizes PIWI proteins to support regeneration and homeostasis of planarian Schmidtea mediterranea. J Biol Chem 2019; 294:9873-9887. [PMID: 31076507 DOI: 10.1074/jbc.ra118.004445] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 04/25/2019] [Indexed: 12/16/2022] Open
Abstract
PIWI proteins are key regulators of germline and somatic stem cells throughout different evolutionary lineages. However, how PIWI proteins themselves are regulated remains largely unknown. To identify candidate proteins that interact with PIWI proteins and regulate their stability, here we established a yeast two-hybrid (Y2H) assay in the planarian species Schmidtea mediterranea We show that DNAJA1, a heat shock protein 40 family member, interacts with the PIWI protein SMEDWI-2, as validated by the Y2H screen and co-immunoprecipitation assays. We found that DNAJA1 is enriched in planarian adult stem cells, the nervous system, and intestinal tissues. DNAJA1-knockdown abolished planarian regeneration and homeostasis, compromised stem cell maintenance and PIWI-interacting RNA (piRNA) biogenesis, and deregulated SMEDWI-1/2 target genes. Mechanistically, we observed that DNAJA1 is required for the stability of SMEDWI-1 and SMEDWI-2 proteins. Furthermore, we noted that human DNAJA1 binds to Piwi-like RNA-mediated gene silencing 1 (PIWIL1) and is required for PIWIL1 stability in human gastric cancer cells. In summary, our results reveal not only an evolutionarily conserved functional link between PIWI and DNAJA1 that is essential for PIWI protein stability and piRNA biogenesis, but also an important role of DNAJA1 in the control of proteins involved in stem cell regulation.
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Affiliation(s)
- Chen Wang
- From the Shanghai Institute of Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China.,the CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China, and
| | - Zhen-Zhen Yang
- From the Shanghai Institute of Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China
| | - Fang-Hao Guo
- the CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China, and
| | - Shuo Shi
- From the Shanghai Institute of Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China
| | - Xiao-Shuai Han
- the CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China, and
| | - An Zeng
- the CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China, and
| | - Haifan Lin
- From the Shanghai Institute of Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China, .,the Yale Stem Cell Center, Yale School of Medicine, New Haven, Connecticut 06511
| | - Qing Jing
- the CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China, and
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16
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Cheng X, Li Y, Guo Q, Tian Q, Zhang Y, Fang H, Zhang S, Guo Y. A planarian RPS3 homolog is critical to the modulation of planarian regeneration. Gene 2019; 691:153-159. [PMID: 30615916 DOI: 10.1016/j.gene.2018.12.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/24/2018] [Accepted: 12/10/2018] [Indexed: 11/13/2022]
Abstract
Planarians are an important model for stem cell and regeneration biology, because they can regenerate any missing body structure in a short time. As an important component of ribosomes, ribosomal proteins can synthesize proteins and play a central role in cell cycle checkpoint, cell survival/senescence/apoptosis, and organismal growth and development. In this study, we identified and amplified the homologous gene of RPS3 in Dugesia japonica. Double-stranded RNA mediated RNAi revealed that when the Dj-RPS3 function was lost by planarians; they did not form blastemas and died 100%. Further investigation, confirmed that Dj-RPS3 was involved in regulating the proliferative and early differentiation of neoblasts.
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Affiliation(s)
- Xina Cheng
- School of Life Sciences, Zhengzhou University, No. 100 Science Avenue, Zhengzhou, Henan 450001, China
| | - Yingzhao Li
- School of Life Sciences, Zhengzhou University, No. 100 Science Avenue, Zhengzhou, Henan 450001, China
| | - Qi Guo
- School of Life Sciences, Zhengzhou University, No. 100 Science Avenue, Zhengzhou, Henan 450001, China
| | - Qingnan Tian
- School of Life Sciences, Zhengzhou University, No. 100 Science Avenue, Zhengzhou, Henan 450001, China
| | - Yizhe Zhang
- School of Life Sciences, Zhengzhou University, No. 100 Science Avenue, Zhengzhou, Henan 450001, China
| | - Huimin Fang
- School of Life Sciences, Zhengzhou University, No. 100 Science Avenue, Zhengzhou, Henan 450001, China
| | - Shoutao Zhang
- School of Life Sciences, Zhengzhou University, No. 100 Science Avenue, Zhengzhou, Henan 450001, China; Henan Key Laboratory of Bioactive Macromolecules, Zhengzhou, Henan, China.
| | - Yanan Guo
- School of Life Sciences, Zhengzhou University, No. 100 Science Avenue, Zhengzhou, Henan 450001, China; Henan Key Laboratory of Bioactive Macromolecules, Zhengzhou, Henan, China.
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17
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Prospectively Isolated Tetraspanin + Neoblasts Are Adult Pluripotent Stem Cells Underlying Planaria Regeneration. Cell 2019; 173:1593-1608.e20. [PMID: 29906446 DOI: 10.1016/j.cell.2018.05.006] [Citation(s) in RCA: 155] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 03/01/2018] [Accepted: 05/01/2018] [Indexed: 12/15/2022]
Abstract
Proliferating cells known as neoblasts include pluripotent stem cells (PSCs) that sustain tissue homeostasis and regeneration of lost body parts in planarians. However, the lack of markers to prospectively identify and isolate these adult PSCs has significantly hampered their characterization. We used single-cell RNA sequencing (scRNA-seq) and single-cell transplantation to address this long-standing issue. Large-scale scRNA-seq of sorted neoblasts unveiled a novel subtype of neoblast (Nb2) characterized by high levels of PIWI-1 mRNA and protein and marked by a conserved cell-surface protein-coding gene, tetraspanin 1 (tspan-1). tspan-1-positive cells survived sub-lethal irradiation, underwent clonal expansion to repopulate whole animals, and when purified with an anti-TSPAN-1 antibody, rescued the viability of lethally irradiated animals after single-cell transplantation. The first prospective isolation of an adult PSC bridges a conceptual dichotomy between functionally and molecularly defined neoblasts, shedding light on mechanisms governing in vivo pluripotency and a source of regeneration in animals. VIDEO ABSTRACT.
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18
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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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19
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Characterizing the role of SWI/SNF-related chromatin remodeling complexes in planarian regeneration and stem cell function. Stem Cell Res 2018; 32:91-103. [DOI: 10.1016/j.scr.2018.09.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 08/18/2018] [Accepted: 09/06/2018] [Indexed: 11/21/2022] Open
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20
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Strand NS, Allen JM, Zayas RM. Post-translational regulation of planarian regeneration. Semin Cell Dev Biol 2018; 87:58-68. [PMID: 29705300 DOI: 10.1016/j.semcdb.2018.04.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 02/07/2023]
Abstract
Most mammals cannot easily overcome degenerative disease or traumatic injuries. In contrast, an innate ability to regenerate is observed across animal phyla. Freshwater planarians are amongst the organisms that are capable of stem cell-mediated whole-body regeneration and have served as an exemplary model to study how pluripotency is maintained and regulated in vivo. Here, we review findings on the role of post-translational modifications and the genes regulating phosphorylation, ubiquitylation, and chromatin remodeling in planarian regeneration. Furthermore, we discuss how technological advances for identifying cellular targets of these processes will fill gaps in our knowledge of the signaling mechanisms that underlie regeneration in planarians, which should inform how tissue repair can be stimulated in non-regenerative model organisms and in humans.
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Affiliation(s)
- Nicholas S Strand
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - John M Allen
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
| | - Ricardo M Zayas
- Department of Biology, San Diego State University, San Diego, CA 92182, USA.
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21
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Neoblast-enriched zinc finger protein FIR1 triggers local proliferation during planarian regeneration. Protein Cell 2018; 10:43-59. [PMID: 29557542 PMCID: PMC6321819 DOI: 10.1007/s13238-018-0512-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 01/09/2018] [Indexed: 11/30/2022] Open
Abstract
Regeneration, relying mainly on resident adult stem cells, is widespread. However, the mechanism by which stem cells initiate proliferation during this process in vivo is unclear. Using planarian as a model, we screened 46 transcripts showing potential function in the regulation of local stem cell proliferation following 48 h regeneration. By analyzing the regeneration defects and the mitotic activity of animals under administration of RNA interference (RNAi), we identified factor for initiating regeneration 1 (Fir1) required for local proliferation. Our findings reveal that Fir1, enriched in neoblasts, promotes planarian regeneration in any tissue-missing context. Further, we demonstrate that DIS3 like 3′-5′ exoribonuclease 2 (Dis3l2) is required for Fir1 phenotype. Besides, RNAi knockdown of Fir1 causes a decrease of neoblast wound response genes following amputation. These findings suggest that Fir1 recognizes regenerative signals and promotes DIS3L2 proteins to trigger neoblast proliferation following amputation and provide a mechanism critical for stem cell response to injury.
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22
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Clémot M, Molla-Herman A, Mathieu J, Huynh JR, Dostatni N. The replicative histone chaperone CAF-1 is essential for the maintenance of identity and genome integrity in adult stem cells. Development 2018; 145:dev.161190. [DOI: 10.1242/dev.161190] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 07/20/2018] [Indexed: 12/14/2022]
Abstract
Chromatin packaging and modifications are important to define the identity of stem cells. How chromatin properties are retained over multiple cycles of stem cell replication, while generating differentiating progeny at the same time, remains a challenging question. The chromatin assembly factor CAF-1 is a conserved histone chaperone, which assembles histones H3 and H4 onto newly synthesized DNA during replication and repair. Here, we investigated the role of CAF-1 in the maintenance of germline stem cells (GSCs) in Drosophila ovaries. We depleted P180, the large subunit of CAF-1, in germ cells and found that it was required in GSCs to maintain their identity. In the absence of P180, GSCs still harbor stem cell properties but concomitantly express markers of differentiation. In addition, P180-depleted germ cells exhibit elevated levels of DNA damage and de-repression of the transposable I-element. These DNA damages activate p53- and Chk2-dependent checkpoints pathways, leading to cell death and female sterility. Altogether, our work demonstrates that chromatin dynamics mediated by CAF-1 play an important role in both the regulation of stem cell identity and genome integrity.
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Affiliation(s)
- Marie Clémot
- Institut Curie, PSL Research University, CNRS, Sorbonne Université, Nuclear Dynamics, Paris, France
| | - Anahi Molla-Herman
- Institut Curie, PSL Research University, CNRS, Inserm, Sorbonne Université, Genetics and Developmental Biology, Paris, France
| | - Juliette Mathieu
- Institut Curie, PSL Research University, CNRS, Inserm, Sorbonne Université, Genetics and Developmental Biology, Paris, France
| | - Jean-René Huynh
- Institut Curie, PSL Research University, CNRS, Inserm, Sorbonne Université, Genetics and Developmental Biology, Paris, France
| | - Nathalie Dostatni
- Institut Curie, PSL Research University, CNRS, Sorbonne Université, Nuclear Dynamics, Paris, France
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23
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Small RNAome sequencing delineates the small RNA landscape of pluripotent adult stem cells in the planarian Schmidtea mediterranea. GENOMICS DATA 2017; 14:114-125. [PMID: 29124009 PMCID: PMC5671611 DOI: 10.1016/j.gdata.2017.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 10/15/2017] [Accepted: 10/17/2017] [Indexed: 12/22/2022]
Abstract
Small noncoding RNAs play a pivotal role in the regulation of gene expression, and are key regulators of animal development. Freshwater planarian exhibits an extraordinary ability to regenerate any missing body parts, representing an emerging model for studying mechanism underlying stem cell regulation and tissue regeneration. Here, we utilized next-generation sequencing (NGS) to identify small RNAs that are expressed in planarian adult stem cells, and are implicated in tissue regeneration. We profiled microRNAs (miRNAs), piwi-interacting RNA (piRNAs), small rDNA-derived RNAs (srRNAs) and endogenous interfering RNAs (endo-siRNAs) population from size 18–30 nt, measured the expression of 244 conserved miRNAs, and identified 41 novel miRNAs and 64 novel endo-siRNAs. Expression profiling analyses revealed that most piRNAs and srRNAs are up-regulated during regeneration, and that the most abundantly expressed srRNAs are from 5.8s and 28s rRNA. Furthermore, a target prediction method was adopted to investigate the anti-correlation of small RNAs and mRNA expression. We built up a gene regulatory network based on the genes that are targeted by dynamically changed small RNAs. These results expand the known small RNA repertoire in planarian, and provide valuable insights and a rich resource for understanding the small RNAs landscape in stem cell-mediated regeneration.
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24
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Cheloufi S, Hochedlinger K. Emerging roles of the histone chaperone CAF-1 in cellular plasticity. Curr Opin Genet Dev 2017; 46:83-94. [PMID: 28692904 PMCID: PMC5813839 DOI: 10.1016/j.gde.2017.06.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/07/2017] [Accepted: 06/09/2017] [Indexed: 10/19/2022]
Abstract
During embryonic development, cells become progressively restricted in their differentiation potential. This is thought to be regulated by dynamic changes in chromatin structure and associated modifications, which act together to stabilize distinct specialized cell lineages. Remarkably, differentiated cells can be experimentally reprogrammed to a stem cell-like state or to alternative lineages. Thus, cellular reprogramming provides a valuable platform to study the mechanisms that normally safeguard cell identity and uncover factors whose manipulation facilitates cell fate transitions. Recent work has identified the chromatin assembly factor complex CAF-1 as a potent barrier to cellular reprogramming. In addition, CAF-1 has been implicated in the reversion of pluripotent cells to a totipotent-like state and in various lineage conversion paradigms, suggesting that modulation of CAF-1 levels may endow cells with a developmentally more plastic state. Here, we review these exciting results, discuss potential mechanisms and speculate on the possibility of exploiting chromatin assembly pathways to manipulate cell identity.
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Affiliation(s)
- Sihem Cheloufi
- Department of Molecular Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA; Center for Regenerative Medicine, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA; Cancer Center, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA; Harvard Stem Cell Institute, 1350 Massachusetts Avenue, Cambridge, MA 02138, USA
| | - Konrad Hochedlinger
- Department of Molecular Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA; Center for Regenerative Medicine, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA; Cancer Center, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA; Harvard Stem Cell Institute, 1350 Massachusetts Avenue, Cambridge, MA 02138, USA.
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25
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Genome-Wide Analysis of Polyadenylation Events in Schmidtea mediterranea. G3-GENES GENOMES GENETICS 2016; 6:3035-3048. [PMID: 27489207 PMCID: PMC5068929 DOI: 10.1534/g3.116.031120] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In eukaryotes, 3' untranslated regions (UTRs) play important roles in regulating posttranscriptional gene expression. The 3'UTR is defined by regulated cleavage/polyadenylation of the pre-mRNA. The advent of next-generation sequencing technology has now enabled us to identify these events on a genome-wide scale. In this study, we used poly(A)-position profiling by sequencing (3P-Seq) to capture all poly(A) sites across the genome of the freshwater planarian, Schmidtea mediterranea, an ideal model system for exploring the process of regeneration and stem cell function. We identified the 3'UTRs for ∼14,000 transcripts and thus improved the existing gene annotations. We found 97 transcripts, which are polyadenylated within an internal exon, resulting in the shrinking of the ORF and loss of a predicted protein domain. Around 40% of the transcripts in planaria were alternatively polyadenylated (ApA), resulting either in an altered 3'UTR or a change in coding sequence. We identified specific ApA transcript isoforms that were subjected to miRNA mediated gene regulation using degradome sequencing. In this study, we also confirmed a tissue-specific expression pattern for alternate polyadenylated transcripts. The insights from this study highlight the potential role of ApA in regulating the gene expression essential for planarian regeneration.
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26
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Yin S, Huang Y, Zhangfang Y, Zhong X, Li P, Huang J, Liu D, Songyang Z. SmedOB1 is Required for Planarian Homeostasis and Regeneration. Sci Rep 2016; 6:34013. [PMID: 27654173 PMCID: PMC5032016 DOI: 10.1038/srep34013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 09/06/2016] [Indexed: 12/29/2022] Open
Abstract
The planarian flatworm is an emerging model that is useful for studying homeostasis and regeneration due to its unique adult stem cells (ASCs). Previously, planaria were found to share mammalian TTAGGG chromosome ends and telomerases; however, their telomere protection proteins have not yet been identified. In Schmidtea mediterranea, we identified a homologue of the human protection of telomeres 1 (POT1) with an OB-fold (SmedOB1). SmedOB1 is evolutionarily conserved among species and is ubiquitously expressed throughout the whole body. Feeding with SmedOB1 double-stranded RNAs (dsRNAs) led to homeostasis abnormalities in the head and pharynx. Furthermore, several ASC progeny markers were downregulated, and regeneration was impaired. Here we found that SmedOB1 is required for telomeric DNA-protein complex formation and it associates with the telomere TTAGGG sequence in vitro. Moreover, DNA damage and apoptosis signals in planarian were significantly affected by SmedOB1 RNAi. We also confirmed these phenotypes in Dugesia japonica, another flatworm species. Our work identified a novel telomere-associated protein SmedOB1 in planarian, which is required for planarian homeostasis and regeneration. The phylogenetic and functional conservations of SmedOB1 provide one mechanism by which planarians maintain telomere and genome stability to ensure their immortality and shed light on the regeneration medicine of humans.
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Affiliation(s)
- Shanshan Yin
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yan Huang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yingnan Zhangfang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xiaoqin Zhong
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Pengqing Li
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Junjiu Huang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Dan Liu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, USA
| | - Zhou Songyang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol and Institute of Healthy Aging Research, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.,Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, USA
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27
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Vásquez-Doorman C, Petersen CP. The NuRD complex component p66 suppresses photoreceptor neuron regeneration in planarians. ACTA ACUST UNITED AC 2016; 3:168-78. [PMID: 27606067 PMCID: PMC5011480 DOI: 10.1002/reg2.58] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 06/01/2016] [Accepted: 06/08/2016] [Indexed: 12/13/2022]
Abstract
Regeneration involves precise control of cell fate to produce an appropriate complement of tissues formed within a blastema. Several chromatin-modifying complexes have been identified as required for regeneration in planarians, but it is unclear whether this class of molecules uniformly promotes the production of differentiated cells. We identify a function for p66, encoding a DNA-binding protein component of the NuRD (nucleosome remodeling and deacetylase) complex, as well as the chromodomain helicase chd4, in suppressing production of photoreceptor neurons (PRNs) in planarians. This suppressive effect appeared restricted to PRNs because p66 inhibition did not influence numbers of eye pigment cup cells (PCCs) and decreased numbers of brain neurons and epidermal progenitors. PRNs from p66(RNAi) animals differentiated with some abnormalities but nonetheless produced arrestin+ projections to the brain. p66 inhibition produced excess ovo+otxA+ PRN progenitors without affecting numbers of ovo+otxA- PCC progenitors, and ovo and otxA were each required for the p66(RNAi) excess PRN phenotype. Together these results suggest that p66 acts through the NuRD complex to suppress PRN production by limiting expression of lineage-specific transcription factors.
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Affiliation(s)
| | - Christian P Petersen
- Department of Molecular Biosciences Northwestern University Evanston Illinois 60208; Robert Lurie Comprehensive Cancer Center Northwestern University Evanston Illinois 60208
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Wang C, Han XS, Li FF, Huang S, Qin YW, Zhao XX, Jing Q. Forkhead containing transcription factor Albino controls tetrapyrrole-based body pigmentation in planarian. Cell Discov 2016; 2:16029. [PMID: 27551436 PMCID: PMC4969599 DOI: 10.1038/celldisc.2016.29] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 07/12/2016] [Indexed: 01/22/2023] Open
Abstract
Pigmentation processes occur from invertebrates to mammals. Owing to the complexity of the pigmentary system, in vivo animal models for pigmentation study are limited. Planarians are capable of regenerating any missing part including the dark-brown pigments, providing a promising model for pigmentation study. However, the molecular mechanism of planarian body pigmentation is poorly understood. We found in an RNA interference screen that a forkhead containing transcription factor, Albino, was required for pigmentation without affecting survival or other regeneration processes. In addition, the body color recovered after termination of Albino double stranded RNA feeding owing to the robust stem cell system. Further expression analysis revealed a spatial and temporal correlation between Albino and pigmentation process. Gene expression arrays revealed that the expression of three tetrapyrrole biosynthesis enzymes, ALAD, ALAS and PBGD, was impaired upon Albino RNA interference. RNA interference of PBGD led to a similar albinism phenotype caused by Albino RNA interference. Moreover, PBGD was specifically expressed in pigment cells and can serve as a pigment cell molecular marker. Our results revealed that Albino controls planarian body color pigmentation dominantly via regulating tetrapyrrole biogenesis. These results identified Albino as the key regulator of the tetrapyrrole-based planarian body pigmentation, suggesting a role of Albino during stem cell-pigment cell fate decision and provided new insights into porphyria pathogenesis.
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Affiliation(s)
- Chen Wang
- Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine & Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China
| | - Xiao-Shuai Han
- Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine & Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China
| | - Fang-Fang Li
- Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine & Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China
| | - Shuang Huang
- Department of Cardiology, Changhai Hospital , Shanghai, China
| | - Yong-Wen Qin
- Department of Cardiology, Changhai Hospital , Shanghai, China
| | - Xian-Xian Zhao
- Department of Cardiology, Changhai Hospital , Shanghai, China
| | - Qing Jing
- Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine & Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; Department of Cardiology, Changhai Hospital, Shanghai, China
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Shibata N, Kashima M, Ishiko T, Nishimura O, Rouhana L, Misaki K, Yonemura S, Saito K, Siomi H, Siomi M, Agata K. Inheritance of a Nuclear PIWI from Pluripotent Stem Cells by Somatic Descendants Ensures Differentiation by Silencing Transposons in Planarian. Dev Cell 2016; 37:226-37. [DOI: 10.1016/j.devcel.2016.04.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 01/18/2016] [Accepted: 04/11/2016] [Indexed: 11/29/2022]
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Molinaro AM, Pearson BJ. In silico lineage tracing through single cell transcriptomics identifies a neural stem cell population in planarians. Genome Biol 2016; 17:87. [PMID: 27150006 PMCID: PMC4858873 DOI: 10.1186/s13059-016-0937-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 04/08/2016] [Indexed: 12/01/2022] Open
Abstract
Background The planarian Schmidtea mediterranea is a master regenerator with a large adult stem cell compartment. The lack of transgenic labeling techniques in this animal has hindered the study of lineage progression and has made understanding the mechanisms of tissue regeneration a challenge. However, recent advances in single-cell transcriptomics and analysis methods allow for the discovery of novel cell lineages as differentiation progresses from stem cell to terminally differentiated cell. Results Here we apply pseudotime analysis and single-cell transcriptomics to identify adult stem cells belonging to specific cellular lineages and identify novel candidate genes for future in vivo lineage studies. We purify 168 single stem and progeny cells from the planarian head, which were subjected to single-cell RNA sequencing (scRNAseq). Pseudotime analysis with Waterfall and gene set enrichment analysis predicts a molecularly distinct neoblast sub-population with neural character (νNeoblasts) as well as a novel alternative lineage. Using the predicted νNeoblast markers, we demonstrate that a novel proliferative stem cell population exists adjacent to the brain. Conclusions scRNAseq coupled with in silico lineage analysis offers a new approach for studying lineage progression in planarians. The lineages identified here are extracted from a highly heterogeneous dataset with minimal prior knowledge of planarian lineages, demonstrating that lineage purification by transgenic labeling is not a prerequisite for this approach. The identification of the νNeoblast lineage demonstrates the usefulness of the planarian system for computationally predicting cellular lineages in an adult context coupled with in vivo verification. Electronic supplementary material The online version of this article (doi:10.1186/s13059-016-0937-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alyssa M Molinaro
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Bret J Pearson
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON, Canada. .,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada. .,Ontario Institute for Cancer Research, Toronto, ON, M5G0A4, Canada.
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Pang Q, Gao L, Hu W, An Y, Deng H, Zhang Y, Sun X, Zhu G, Liu B, Zhao B. De Novo Transcriptome Analysis Provides Insights into Immune Related Genes and the RIG-I-Like Receptor Signaling Pathway in the Freshwater Planarian (Dugesia japonica). PLoS One 2016; 11:e0151597. [PMID: 26986572 PMCID: PMC4795655 DOI: 10.1371/journal.pone.0151597] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 03/01/2016] [Indexed: 02/06/2023] Open
Abstract
Background The freshwater planarian Dugesia japonica (D. japonica) possesses extraordinary ability to regenerate lost organs or body parts. Interestingly, in the process of regeneration, there is little wound infection, suggesting that D. japonica has a formidable innate immune system. The importance of immune system prompted us to search for immune-related genes and RIG-I-like receptor signaling pathways. Results Transcriptome sequencing of D. japonica was performed on an IlluminaHiSeq2000 platform. A total of 27,180 transcripts were obtained by Trinity assembler. CEGMA analysis and mapping of all trimmed reads back to the assembly result showed that our transcriptome assembly covered most of the whole transcriptome. 23,888 out of 27,180 transcripts contained ORF (open reading fragment), and were highly similar to those in Schistosoma mansoni using BLASTX analysis. 8,079 transcripts (29.7%) and 8,668 (31.9%) were annotated by Blast2GO and KEGG respectively. A DYNLRB-like gene was cloned to verify its roles in the immune response. Finally, the expression patterns of 4 genes (RIG-I, TRAF3, TRAF6, P38) in the RIG-I-like receptor signaling pathway were detected, and the results showed they are very likely to be involved in planarian immune response. Conclusion RNA-Seq analysis based on the next-generation sequencing technology was an efficient approach to discover critical genes and to understand their corresponding biological functions. Through GO and KEGG analysis, several critical and conserved signaling pathways and genes related to RIG-I-like receptor signaling pathway were identified. Four candidate genes were selected to identify their expression dynamics in the process of pathogen stimulation. These annotated transcripts of D. japonica provide a useful resource for subsequent investigation of other important pathways.
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Affiliation(s)
- Qiuxiang Pang
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo 255049, China
- Anti-aging & Regenerative Medicine Research Institution, School of Life Sciences, Shandong University of Technology, Zibo 255049, China
| | - Lili Gao
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo 255049, China
- Anti-aging & Regenerative Medicine Research Institution, School of Life Sciences, Shandong University of Technology, Zibo 255049, China
| | - Wenjing Hu
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo 255049, China
- Anti-aging & Regenerative Medicine Research Institution, School of Life Sciences, Shandong University of Technology, Zibo 255049, China
| | - Yang An
- Immolife-biotech Co., Ltd., Nanjing 210000, China
| | - Hongkuan Deng
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo 255049, China
- Anti-aging & Regenerative Medicine Research Institution, School of Life Sciences, Shandong University of Technology, Zibo 255049, China
| | - Yichao Zhang
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo 255049, China
| | - Xiaowen Sun
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo 255049, China
| | - Guangzhong Zhu
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo 255049, China
| | - Baohua Liu
- Anti-aging & Regenerative Medicine Research Institution, School of Life Sciences, Shandong University of Technology, Zibo 255049, China
- Shenzhen University Health Science Center, Shenzhen 518060, China
- * E-mail: (BSZ); (BHL)
| | - Bosheng Zhao
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo 255049, China
- * E-mail: (BSZ); (BHL)
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Zhang K, Gao Y, Li J, Burgess R, Han J, Liang H, Zhang Z, Liu Y. A DNA binding winged helix domain in CAF-1 functions with PCNA to stabilize CAF-1 at replication forks. Nucleic Acids Res 2016; 44:5083-94. [PMID: 26908650 PMCID: PMC4914081 DOI: 10.1093/nar/gkw106] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 02/15/2016] [Indexed: 02/05/2023] Open
Abstract
Chromatin assembly factor 1 (CAF-1) is a histone H3–H4 chaperone that deposits newly synthesized histone (H3–H4)2 tetramers during replication-coupled nucleosome assembly. However, how CAF-1 functions in this process is not yet well understood. Here, we report the crystal structure of C terminus of Cac1 (Cac1C), a subunit of yeast CAF-1, and the function of this domain in stabilizing CAF-1 at replication forks. We show that Cac1C forms a winged helix domain (WHD) and binds DNA in a sequence-independent manner. Mutations in Cac1C that abolish DNA binding result in defects in transcriptional silencing and increased sensitivity to DNA damaging agents, and these defects are exacerbated when combined with Cac1 mutations deficient in PCNA binding. Similar phenotypes are observed for corresponding mutations in mouse CAF-1. These results reveal a mechanism conserved in eukaryotic cells whereby the ability of CAF-1 to bind DNA is important for its association with the DNA replication forks and subsequent nucleosome assembly.
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Affiliation(s)
- Kuo Zhang
- State Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan Gao
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Jingjing Li
- State Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China
| | - Rebecca Burgess
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Junhong Han
- State Key Laboratory of Biotherapy and Cancer Center, Division of Abdominal Cancer, West China Hospital, Sichuan University, and National Collaborative innovation Center for Biotherapy, Chengdu 610041, China
| | - Huanhuan Liang
- State Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China
| | - Zhiguo Zhang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Yingfang Liu
- State Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China
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Heterochromatin components in germline stem cell maintenance. Sci Rep 2015; 5:17463. [PMID: 26626305 PMCID: PMC4667240 DOI: 10.1038/srep17463] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 10/30/2015] [Indexed: 01/23/2023] Open
Abstract
Stem cell maintenance requires expression of genes essential for stemness and repression of differentiation genes. How this is achieved remains incompletely understood. Here we investigate the requirement for central components of heterochromatin, Heterochromatin Protein 1 (HP1) and the histone H3 lys9 methyltransferase Su(var)3-9, in the Drosophila male germline stem cell (GSC) self-renewal, a paradigm for studying adult stem cell behavior. We found that mutations or RNAi knock down of HP1 or Su(var)3-9 cause loss of GSCs, accompanied by defects in cell division or survival and premature expression of the differentiation gene bag of marbles (bam). Conversely, over-expressing HP1 increases GSC number in wildtype flies and, strikingly, restores fertility to the sterile hopscotch (hop) mutant flies that lack niche signals. These results suggest that the central components of heterochromatin play roles including repressing differentiation genes in Drosophila male GSC maintenance.
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Epigenetics and Shared Molecular Processes in the Regeneration of Complex Structures. Stem Cells Int 2015; 2016:6947395. [PMID: 26681954 PMCID: PMC4670690 DOI: 10.1155/2016/6947395] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 05/30/2015] [Indexed: 12/27/2022] Open
Abstract
The ability to regenerate complex structures is broadly represented in both plant and animal kingdoms. Although regenerative abilities vary significantly amongst metazoans, cumulative studies have identified cellular events that are broadly observed during regenerative events. For example, structural damage is recognized and wound healing initiated upon injury, which is followed by programmed cell death in the vicinity of damaged tissue and a burst in proliferation of progenitor cells. Sustained proliferation and localization of progenitor cells to site of injury give rise to an assembly of differentiating cells known as the regeneration blastema, which fosters the development of new tissue. Finally, preexisting tissue rearranges and integrates with newly differentiated cells to restore proportionality and function. While heterogeneity exists in the basic processes displayed during regenerative events in different species—most notably the cellular source contributing to formation of new tissue—activation of conserved molecular pathways is imperative for proper regulation of cells during regeneration. Perhaps the most fundamental of such molecular processes entails chromatin rearrangements, which prime large changes in gene expression required for differentiation and/or dedifferentiation of progenitor cells. This review provides an overview of known contributions to regenerative processes by noncoding RNAs and chromatin-modifying enzymes involved in epigenetic regulation.
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Lim RSM, Kai T. A piece of the pi(e): The diverse roles of animal piRNAs and their PIWI partners. Semin Cell Dev Biol 2015; 47-48:17-31. [PMID: 26582251 DOI: 10.1016/j.semcdb.2015.10.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Small non-coding RNAs are indispensable to many biological processes. A class of endogenous small RNAs, termed PIWI-interacting RNAs (piRNAs) because of their association with PIWI proteins, has known roles in safeguarding the genome against inordinate transposon mobilization, embryonic development, and stem cell regulation, among others. This review discusses the biogenesis of animal piRNAs and their diverse functions together with their PIWI protein partners, both in the germline and in somatic cells, and highlights the evolutionarily conserved aspects of these molecular players in animal biology.
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Affiliation(s)
- Robyn S M Lim
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
| | - Toshie Kai
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.
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Heterochromatin Protein 1β (HP1β) has distinct functions and distinct nuclear distribution in pluripotent versus differentiated cells. Genome Biol 2015; 16:213. [PMID: 26415775 PMCID: PMC4587738 DOI: 10.1186/s13059-015-0760-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Accepted: 08/25/2015] [Indexed: 11/22/2022] Open
Abstract
Background Pluripotent embryonic stem cells (ESCs) have the unique ability to differentiate into every cell type and to self-renew. These characteristics correlate with a distinct nuclear architecture, epigenetic signatures enriched for active chromatin marks and hyperdynamic binding of structural chromatin proteins. Recently, several chromatin-related proteins have been shown to regulate ESC pluripotency and/or differentiation, yet the role of the major heterochromatin proteins in pluripotency is unknown. Results Here we identify Heterochromatin Protein 1β (HP1β) as an essential protein for proper differentiation, and, unexpectedly, for the maintenance of pluripotency in ESCs. In pluripotent and differentiated cells HP1β is differentially localized and differentially associated with chromatin. Deletion of HP1β, but not HP1α, in ESCs provokes a loss of the morphological and proliferative characteristics of embryonic pluripotent cells, reduces expression of pluripotency factors and causes aberrant differentiation. However, in differentiated cells, loss of HP1β has the opposite effect, perturbing maintenance of the differentiation state and facilitating reprogramming to an induced pluripotent state. Microscopy, biochemical fractionation and chromatin immunoprecipitation reveal a diffuse nucleoplasmic distribution, weak association with chromatin and high expression levels for HP1β in ESCs. The minor fraction of HP1β that is chromatin-bound in ESCs is enriched within exons, unlike the situation in differentiated cells, where it binds heterochromatic satellite repeats and chromocenters. Conclusions We demonstrate an unexpected duality in the role of HP1β: it is essential in ESCs for maintaining pluripotency, while it is required for proper differentiation in differentiated cells. Thus, HP1β function both depends on, and regulates, the pluripotent state. Electronic supplementary material The online version of this article (doi:10.1186/s13059-015-0760-8) contains supplementary material, which is available to authorized users.
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Abstract
Epigenetics studies the emergence of different phenotypes from a single genotype. Although these processes are essential to cellular differentiation and transcriptional memory, they are also widely used in all branches of the tree of life by organisms that require plastic but stable adaptation to their physical and social environment. Because of the inherent flexibility of epigenetic regulation, a variety of biological phenomena can be traced back to evolutionary adaptations of few conserved molecular pathways that converge on chromatin. For these reasons chromatin biology and epigenetic research have a rich history of chasing discoveries in a variety of model organisms, including yeast, flies, plants and humans. Many more fascinating examples of epigenetic plasticity lie outside the realm of model organisms and have so far been only sporadically investigated at a molecular level; however, recent progress on sequencing technology and genome editing tools have begun to blur the lines between model and non-model organisms, opening numerous new avenues for investigation. Here, I review examples of epigenetic phenomena in non-model organisms that have emerged as potential experimental systems, including social insects, fish and flatworms, and are becoming accessible to molecular approaches.
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Affiliation(s)
- Roberto Bonasio
- Epigenetics Program, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Yu Z, Liu J, Deng WM, Jiao R. Histone chaperone CAF-1: essential roles in multi-cellular organism development. Cell Mol Life Sci 2015; 72:327-37. [PMID: 25292338 PMCID: PMC11114026 DOI: 10.1007/s00018-014-1748-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 09/16/2014] [Accepted: 09/29/2014] [Indexed: 01/01/2023]
Abstract
More and more studies have shown chromatin remodelers and histone modifiers play essential roles in regulating developmental patterns by organizing specific chromosomal architecture to establish programmed transcriptional profiles, with implications that histone chaperones execute a coordinating role in these processes. Chromatin assembly factor-1 (CAF-1), an evolutionarily conserved three-subunit protein complex, was identified as a histone chaperone coupled with DNA replication and repair in cultured mammalian cells and yeasts. Interestingly, recent findings indicate CAF-1 may have important regulatory roles during development by interacting with specific transcription factors and epigenetic regulators. In this review, we focus on the essential roles of CAF-1 in regulating heterochromatin organization, asymmetric cell division, and specific signal transduction through epigenetic modulations of the chromatin. In the end, we aim at providing a current image of facets of CAF-1 as a histone chaperone to orchestrate cell proliferation and differentiation during multi-cellular organism development.
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Affiliation(s)
- Zhongsheng Yu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, The Chinese Academy of Sciences, Datun Road 15, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100080 China
| | - Jiyong Liu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, The Chinese Academy of Sciences, Datun Road 15, Beijing, 100101 China
- Guangzhou Hoffmann Institute of Immunology, School of Basic Sciences, Guangzhou Medical University, Dongfengxi Road 195, Guangzhou, 510182 China
| | - Wu-Min Deng
- Department of Biological Science, Florida State University, Tallahassee, FL 32304-4295 USA
| | - Renjie Jiao
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, The Chinese Academy of Sciences, Datun Road 15, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100080 China
- Guangzhou Hoffmann Institute of Immunology, School of Basic Sciences, Guangzhou Medical University, Dongfengxi Road 195, Guangzhou, 510182 China
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Robb SMC, Sánchez Alvarado A. Histone modifications and regeneration in the planarian Schmidtea mediterranea. Curr Top Dev Biol 2014; 108:71-93. [PMID: 24512706 DOI: 10.1016/b978-0-12-391498-9.00004-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The freshwater planarian Schmidtea mediterranea has emerged as a powerful model system for studying regeneration and adult stem cell (ASC) biology. This is largely due to the developmental plasticity of these organisms and the abundant distribution and experimental accessibility of their ASCs. Techniques such as whole mount in situ hybridization, dsRNA-mediated interference, halogenated thymidine analogs for defining cell lineages, and fluorescence-activated cell sorting among other methods, have allowed researchers to interrogate the biology and attendant pluripotent stem cells of these animals in great detail. Therefore, it has now become possible to interrogate and define the roles that epigenetic states may play in regulating ASCs, and by extension, regeneration proper. Here, we provide a primer on the types and number of histone families found in S. mediterranea, known as epigenetic marks of these molecules and a survey of epigenetic modifying enzymes encoded by the planarian genome. We also review experimental evidence indicating that such modifications may in fact play key roles in determining the activities of planarian stem cells.
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Affiliation(s)
- Sofia M C Robb
- Department of Plant Pathology & Microbiology, University of California-Riverside, California, USA; Institute for Integrative Genome Biology, University of California-Riverside, California, USA; Department of Botany & Plant Sciences, University of California-Riverside, California, USA
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van Wolfswinkel JC. Piwi and Potency: PIWI Proteins in Animal Stem Cells and Regeneration. Integr Comp Biol 2014; 54:700-13. [DOI: 10.1093/icb/icu084] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Zhou Y, Xu J, Liu Y, Li J, Chang C, Xu C. Rat hepatocytes weighted gene co-expression network analysis identifies specific modules and hub genes related to liver regeneration after partial hepatectomy. PLoS One 2014; 9:e94868. [PMID: 24743545 PMCID: PMC3990548 DOI: 10.1371/journal.pone.0094868] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Accepted: 03/19/2014] [Indexed: 11/20/2022] Open
Abstract
The recovery of liver mass is mainly mediated by proliferation of hepatocytes after 2/3 partial hepatectomy (PH) in rats. Studying the gene expression profiles of hepatocytes after 2/3 PH will be helpful to investigate the molecular mechanisms of liver regeneration (LR). We report here the first application of weighted gene co-expression network analysis (WGCNA) to analyze the biological implications of gene expression changes associated with LR. WGCNA identifies 12 specific gene modules and some hub genes from hepatocytes genome-scale microarray data in rat LR. The results suggest that upregulated MCM5 may promote hepatocytes proliferation during LR; BCL3 may play an important role by activating or inhibiting NF-kB pathway; MAPK9 may play a permissible role in DNA replication by p38 MAPK inactivation in hepatocytes proliferation stage. Thus, WGCNA can provide novel insight into understanding the molecular mechanisms of LR.
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Affiliation(s)
- Yun Zhou
- College of Life Science, Henan Normal University, Xinxiang, Henan, China
- Key Laboratory of Cell Differentiation and Regulation, Henan Normal University, Xinxiang, Henan, China
- College of Computer and Information Engineering, Henan Normal University, Xinxiang, Henan, China
- * E-mail: (YZ); (CSX)
| | - Jiucheng Xu
- College of Computer and Information Engineering, Henan Normal University, Xinxiang, Henan, China
| | - Yunqing Liu
- College of Life Science, Henan Normal University, Xinxiang, Henan, China
- Key Laboratory of Cell Differentiation and Regulation, Henan Normal University, Xinxiang, Henan, China
| | - Juntao Li
- College of Mathematics and Information Science, Henan Normal University, Xinxiang, Henan, China
| | - Cuifang Chang
- College of Life Science, Henan Normal University, Xinxiang, Henan, China
- Key Laboratory of Cell Differentiation and Regulation, Henan Normal University, Xinxiang, Henan, China
| | - Cunshuan Xu
- College of Life Science, Henan Normal University, Xinxiang, Henan, China
- Key Laboratory of Cell Differentiation and Regulation, Henan Normal University, Xinxiang, Henan, China
- * E-mail: (YZ); (CSX)
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Adler CE, Seidel CW, McKinney SA, Sánchez Alvarado A. Selective amputation of the pharynx identifies a FoxA-dependent regeneration program in planaria. eLife 2014; 3:e02238. [PMID: 24737865 PMCID: PMC3985184 DOI: 10.7554/elife.02238] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 03/07/2014] [Indexed: 01/08/2023] Open
Abstract
Planarian flatworms regenerate every organ after amputation. Adult pluripotent stem cells drive this ability, but how injury activates and directs stem cells into the appropriate lineages is unclear. Here we describe a single-organ regeneration assay in which ejection of the planarian pharynx is selectively induced by brief exposure of animals to sodium azide. To identify genes required for pharynx regeneration, we performed an RNAi screen of 356 genes upregulated after amputation, using successful feeding as a proxy for regeneration. We found that knockdown of 20 genes caused a wide range of regeneration phenotypes and that RNAi of the forkhead transcription factor FoxA, which is expressed in a subpopulation of stem cells, specifically inhibited regrowth of the pharynx. Selective amputation of the pharynx therefore permits the identification of genes required for organ-specific regeneration and suggests an ancient function for FoxA-dependent transcriptional programs in driving regeneration. DOI: http://dx.doi.org/10.7554/eLife.02238.001.
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Affiliation(s)
- Carolyn E Adler
- Stowers Institute for Medical Research, Kansas City, United States
| | - Chris W Seidel
- Stowers Institute for Medical Research, Kansas City, United States
| | - Sean A McKinney
- Stowers Institute for Medical Research, Kansas City, United States
| | - Alejandro Sánchez Alvarado
- Stowers Institute for Medical Research, Kansas City, United States
- Howard Hughes Medical Institute, Stowers Institute for Medical Research, Kansas City, United States
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SILAC Proteomics of Planarians Identifies Ncoa5 as a Conserved Component of Pluripotent Stem Cells. Cell Rep 2013; 5:1142-55. [DOI: 10.1016/j.celrep.2013.10.035] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 08/09/2013] [Accepted: 10/21/2013] [Indexed: 12/19/2022] Open
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Jaber-Hijazi F, Lo PJKP, Mihaylova Y, Foster JM, Benner JS, Tejada Romero B, Chen C, Malla S, Solana J, Ruzov A, Aziz Aboobaker A. Planarian MBD2/3 is required for adult stem cell pluripotency independently of DNA methylation. Dev Biol 2013; 384:141-53. [PMID: 24063805 PMCID: PMC3824064 DOI: 10.1016/j.ydbio.2013.09.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 09/09/2013] [Accepted: 09/16/2013] [Indexed: 12/12/2022]
Abstract
Planarian adult stem cells (pASCs) or neoblasts represent an ideal system to study the evolution of stem cells and pluripotency as they underpin an unrivaled capacity for regeneration. We wish to understand the control of differentiation and pluripotency in pASCs and to understand how conserved, convergent or divergent these mechanisms are across the Bilateria. Here we show the planarian methyl-CpG Binding Domain 2/3 (mbd2/3) gene is required for pASC differentiation during regeneration and tissue homeostasis. The genome does not have detectable levels of 5-methylcytosine (5mC) and we find no role for a potential DNA methylase. We conclude that MBD proteins may have had an ancient role in broadly controlling animal stem cell pluripotency, but that DNA methylation is not involved in planarian stem cell differentiation. A single ancestral MBD2/3 protein is present in the planarian Schmidtea mediterranea. The genome of S. mediterranea does not have pervasive cytosine methylation. MBD2/3 is required for pluripotent stem cell differentiation down multiple but not all cell lineages. MBD2/3 may have had an ancestral role in regulating stem cell pluripotency.
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Affiliation(s)
- Farah Jaber-Hijazi
- Department of Zoology, Tinbergen Building, South Parks Road, University of Oxford, Oxford OX1 3PS, United Kingdom
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