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Athanasouli M, Akduman N, Röseler W, Theam P, Rödelsperger C. Thousands of Pristionchus pacificus orphan genes were integrated into developmental networks that respond to diverse environmental microbiota. PLoS Genet 2023; 19:e1010832. [PMID: 37399201 DOI: 10.1371/journal.pgen.1010832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 06/15/2023] [Indexed: 07/05/2023] Open
Abstract
Adaptation of organisms to environmental change may be facilitated by the creation of new genes. New genes without homologs in other lineages are known as taxonomically-restricted orphan genes and may result from divergence or de novo formation. Previously, we have extensively characterized the evolution and origin of such orphan genes in the nematode model organism Pristionchus pacificus. Here, we employ large-scale transcriptomics to establish potential functional associations and to measure the degree of transcriptional plasticity among orphan genes. Specifically, we analyzed 24 RNA-seq samples from adult P. pacificus worms raised on 24 different monoxenic bacterial cultures. Based on coexpression analysis, we identified 28 large modules that harbor 3,727 diplogastrid-specific orphan genes and that respond dynamically to different bacteria. These coexpression modules have distinct regulatory architecture and also exhibit differential expression patterns across development suggesting a link between bacterial response networks and development. Phylostratigraphy revealed a considerably high number of family- and even species-specific orphan genes in certain coexpression modules. This suggests that new genes are not attached randomly to existing cellular networks and that integration can happen very fast. Integrative analysis of protein domains, gene expression and ortholog data facilitated the assignments of biological labels for 22 coexpression modules with one of the largest, fast-evolving module being associated with spermatogenesis. In summary, this work presents the first functional annotation for thousands of P. pacificus orphan genes and reveals insights into their integration into environmentally responsive gene networks.
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Affiliation(s)
- Marina Athanasouli
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany
| | - Nermin Akduman
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany
| | - Waltraud Röseler
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany
| | - Penghieng Theam
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany
| | - Christian Rödelsperger
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany
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2
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POUM2 homeostasis regulates intimal remodeling and cells fate in the anterior silk gland of the silkworm. Int J Biol Macromol 2023; 225:715-729. [PMID: 36403768 DOI: 10.1016/j.ijbiomac.2022.11.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 10/11/2022] [Accepted: 11/08/2022] [Indexed: 11/20/2022]
Abstract
Tissue/organ remodeling and cells fate determination play key roles in the life cycle of animals. However, they are still poorly understood in insects, especially in the silkworm. The anterior silk gland (ASG) of the silkworm is essential for the formation and performance of silk fibers, but the regulatory mechanism of ASG remodeling and cells fate determination is less known. Here we found that silencing of POUM2 caused shorter ASG length, intimal structural defects, silkworm spinning failure, and the resultant naked pupae death, but cells number was not affected. Cells staining showed that DNA endoreduplication was not affected in the ASG. Transmission electron microscopy and chitin staining showed cuticle proteins and chitin were greatly reduced in the ASG during the molting period. Transcriptional analysis showed the expression profiles of cuticle proteins and chitin synthase were similar to that of POUM2 during the molting period, and POUM2 down-regulation reduced the expression of cuticle proteins, chitin synthase, autophagy and apoptosis-related genes. While the phenotype resulting from POUM2 over-expression was similar to that of POUM2 down-regulation. Cells staining revealed marked cells apoptosis with cells number reduction and inhibition of DNA endoreduplication in the ASG. Transcriptional analysis showed the expression of autophagy and apoptosis-related genes, and some cuticle proteins and chitin synthase were significantly up-regulated. The results suggest that POUM2 homeostasis regulates ASG intimal remodeling and cells fate, thus affecting ASG development, silkworm spinning and metamorphosis. Our studies not only offer potential molecular targets for genetic improvement of silk performance and molecular breeding of the silkworm, but also provide new insights into POU factor-mediated tissue remodeling and cells fate determination in insects.
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3
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Riva C, Hajduskova M, Gally C, Suman SK, Ahier A, Jarriault S. A natural transdifferentiation event involving mitosis is empowered by integrating signaling inputs with conserved plasticity factors. Cell Rep 2022; 40:111365. [PMID: 36130499 PMCID: PMC9513805 DOI: 10.1016/j.celrep.2022.111365] [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: 08/16/2021] [Revised: 04/09/2022] [Accepted: 08/25/2022] [Indexed: 11/03/2022] Open
Abstract
Transdifferentiation, or direct cell reprogramming, is the conversion of one fully differentiated cell type into another. Whether core mechanisms are shared between natural transdifferentiation events when occurring with or without cell division is unclear. We have previously characterized the Y-to-PDA natural transdifferentiation in Caenorhabditis elegans, which occurs without cell division and requires orthologs of vertebrate reprogramming factors. Here, we identify a rectal-to-GABAergic transdifferentiation and show that cell division is required but not sufficient for conversion. We find shared mechanisms, including erasure of the initial identity, which requires the conserved reprogramming factors SEM-4/SALL, SOX-2, CEH-6/OCT, and EGL-5/HOX. We also find three additional and parallel roles of the Wnt signaling pathway: selection of a specific daughter, removal of the initial identity, and imposition of the precise final subtype identity. Our results support a model in which levels and antagonistic activities of SOX-2 and Wnt signaling provide a timer for the acquisition of final identity.
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Affiliation(s)
- Claudia Riva
- Development and Stem Cells Department, IGBMC, CNRS UMR 7104, Inserm U 1258, Université de Strasbourg, 67400 Illkirch, France
| | - Martina Hajduskova
- Development and Stem Cells Department, IGBMC, CNRS UMR 7104, Inserm U 1258, Université de Strasbourg, 67400 Illkirch, France
| | - Christelle Gally
- Development and Stem Cells Department, IGBMC, CNRS UMR 7104, Inserm U 1258, Université de Strasbourg, 67400 Illkirch, France.
| | - Shashi Kumar Suman
- Development and Stem Cells Department, IGBMC, CNRS UMR 7104, Inserm U 1258, Université de Strasbourg, 67400 Illkirch, France
| | - Arnaud Ahier
- Development and Stem Cells Department, IGBMC, CNRS UMR 7104, Inserm U 1258, Université de Strasbourg, 67400 Illkirch, France
| | - Sophie Jarriault
- Development and Stem Cells Department, IGBMC, CNRS UMR 7104, Inserm U 1258, Université de Strasbourg, 67400 Illkirch, France.
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A 4D single-cell protein atlas of transcription factors delineates spatiotemporal patterning during embryogenesis. Nat Methods 2021; 18:893-902. [PMID: 34312566 DOI: 10.1038/s41592-021-01216-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 06/17/2021] [Indexed: 12/27/2022]
Abstract
Complex biological processes such as embryogenesis require precise coordination of cell differentiation programs across both space and time. Using protein-fusion fluorescent reporters and four-dimensional live imaging, we present a protein expression atlas of transcription factors (TFs) mapped onto developmental cell lineages during Caenorhabditis elegans embryogenesis, at single-cell resolution. This atlas reveals a spatiotemporal combinatorial code of TF expression, and a cascade of lineage-specific, tissue-specific and time-specific TFs that specify developmental states. The atlas uncovers regulators of embryogenesis, including an unexpected role of a skin specifier in neurogenesis and the critical function of an uncharacterized TF in convergent muscle differentiation. At the systems level, the atlas provides an opportunity to model cell state-fate relationships, revealing a lineage-dependent state diversity within functionally related cells and a winding trajectory of developmental state progression. Collectively, this single-cell protein atlas represents a valuable resource for elucidating metazoan embryogenesis at the molecular and systems levels.
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Tang X, Engström Y. Regulation of immune and tissue homeostasis by Drosophila POU factors. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 109:24-30. [PMID: 30954681 DOI: 10.1016/j.ibmb.2019.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 03/17/2019] [Accepted: 04/01/2019] [Indexed: 06/09/2023]
Abstract
The innate immune system of insects deploys both cellular and humoral reactions in immunocompetent tissues for protection of insects against a variety of infections, including bacteria, fungi, and viruses. Transcriptional regulation of genes encoding antimicrobial peptides (AMPs), cytokines, and other immune effectors plays a pivotal role in maintenance of immune homeostasis both prior to and after infections. The POU/Oct transcription factor family is a subclass of the homeodomain proteins present in all metazoans. POU factors are involved in regulation of development, metabolism and immunity. Their role in regulation of immune functions has recently become evident, and involves control of tissue-specific, constitutive expression of immune effectors in barrier epithelia as well as positive and negative control of immune responses in gut and fat body. In addition, they have been shown to affect the composition of gut microbiota and play a role in regulation of intestinal stem cell activities. In this review, we summarize the current knowledge of how POU transcription factors control Drosophila immune homeostasis in healthy and infected insects. The role of POU factor isoform specific regulation of stem cell activities in Drosophila and mammals is also discussed.
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Affiliation(s)
- Xiongzhuo Tang
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-10691, Stockholm, Sweden
| | - Ylva Engström
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-10691, Stockholm, Sweden.
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6
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Novel exc Genes Involved in Formation of the Tubular Excretory Canals of Caenorhabditis elegans. G3-GENES GENOMES GENETICS 2019; 9:1339-1353. [PMID: 30885922 PMCID: PMC6505153 DOI: 10.1534/g3.119.200626] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Regulation of luminal diameter is critical to the function of small single-celled tubes, of which the seamless tubular excretory canals of Caenorhabditis elegans provide a tractable genetic model. Mutations in several sets of genes exhibit the Exc phenotype, in which canal luminal growth is visibly altered. Here, a focused reverse genomic screen of genes highly expressed in the canals found 18 genes that significantly affect luminal outgrowth or diameter. These genes encode novel proteins as well as highly conserved proteins involved in processes including gene expression, cytoskeletal regulation, and vesicular and transmembrane transport. In addition, two genes act as suppressors on a pathway of conserved genes whose products mediate vesicle movement from early to recycling endosomes. The results provide new tools for understanding the integration of cytoplasmic structure and physiology in forming and maintaining the narrow diameter of single-cell tubules.
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Intron-specific patterns of divergence of lin-11 regulatory function in the C. elegans nervous system. Dev Biol 2017; 424:90-103. [DOI: 10.1016/j.ydbio.2017.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 02/08/2017] [Accepted: 02/12/2017] [Indexed: 12/19/2022]
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The Caenorhabditis elegans Excretory System: A Model for Tubulogenesis, Cell Fate Specification, and Plasticity. Genetics 2017; 203:35-63. [PMID: 27183565 DOI: 10.1534/genetics.116.189357] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/07/2016] [Indexed: 12/12/2022] Open
Abstract
The excretory system of the nematode Caenorhabditis elegans is a superb model of tubular organogenesis involving a minimum of cells. The system consists of just three unicellular tubes (canal, duct, and pore), a secretory gland, and two associated neurons. Just as in more complex organs, cells of the excretory system must first adopt specific identities and then coordinate diverse processes to form tubes of appropriate topology, shape, connectivity, and physiological function. The unicellular topology of excretory tubes, their varied and sometimes complex shapes, and the dynamic reprogramming of cell identity and remodeling of tube connectivity that occur during larval development are particularly fascinating features of this organ. The physiological roles of the excretory system in osmoregulation and other aspects of the animal's life cycle are only beginning to be explored. The cellular mechanisms and molecular pathways used to build and shape excretory tubes appear similar to those used in both unicellular and multicellular tubes in more complex organs, such as the vertebrate vascular system and kidney, making this simple organ system a useful model for understanding disease processes.
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9
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Uyhelji HA, Cheng C, Besansky NJ. Transcriptomic differences between euryhaline and stenohaline malaria vector sibling species in response to salinity stress. Mol Ecol 2016; 25:2210-25. [PMID: 26945667 DOI: 10.1111/mec.13609] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 01/09/2016] [Accepted: 02/22/2016] [Indexed: 01/04/2023]
Abstract
Evolution of osmoregulatory systems is a key factor in the transition of species between fresh- and saltwater habitats. Anopheles coluzzii and Anopheles merus are stenohaline and euryhaline malaria vector mosquitoes belonging to a larger group of sibling species, the Anopheles gambiae complex, which radiated in Africa within the last 2 million years. Comparative ecological genomics of these vector species can provide insight into the mechanisms that permitted the rapid radiation of this species complex into habitats of contrasting salinity. Here, we use RNA-Seq to investigate gene expression differences between An. coluzzii and An. merus after briefly exposing both young and old larval instars of each species to either saltwater (SW) or freshwater (FW). Our study aims to identify candidate genes and pathways responsible for the greater SW tolerance of An. merus. Our results are congruent with the ability of gene induction to mediate salinity tolerance, with both species showing increasing amounts of differential gene expression between SW and FW as salt concentrations increase. Besides ion transporters such as AgAE2 that may serve as effectors for osmoregulation, we also find mitogen-activated protein kinases that may serve in a phosphorylation signalling pathway responding to salinity, and report potential cross-talk between the mosquito immune response and osmoregulation. This study provides a key step towards applying the growing molecular knowledge of these malaria vectors to improve understanding of their ecological tolerances and habitat occupancy.
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Affiliation(s)
- Hilary A Uyhelji
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.,Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA.,Functional Genomics Team, Civil Aerospace Medical Institute, Federal Aviation Administration, Oklahoma City, OK, 73169, USA
| | - Changde Cheng
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.,Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Nora J Besansky
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.,Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
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10
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Vidal B, Santella A, Serrano-Saiz E, Bao Z, Chuang CF, Hobert O. C. elegans SoxB genes are dispensable for embryonic neurogenesis but required for terminal differentiation of specific neuron types. Development 2015; 142:2464-77. [PMID: 26153233 DOI: 10.1242/dev.125740] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 05/28/2015] [Indexed: 12/31/2022]
Abstract
Neurogenesis involves deeply conserved patterning molecules, such as the proneural basic helix-loop-helix transcription factors. Sox proteins and specifically members of the SoxB and SoxC groups are another class of conserved transcription factors with an important role in neuronal fate commitment and differentiation in various species. In this study, we examine the expression of all five Sox genes of the nematode C. elegans and analyze the effect of null mutant alleles of all members of the SoxB and SoxC groups on nervous system development. Surprisingly, we find that, unlike in other systems, neither of the two C. elegans SoxB genes sox-2 (SoxB1) and sox-3 (SoxB2), nor the sole C. elegans SoxC gene sem-2, is broadly expressed throughout the embryonic or adult nervous system and that all three genes are mostly dispensable for embryonic neurogenesis. Instead, sox-2 is required to maintain the developmental potential of blast cells that are generated in the embryo but divide only postembryonically to give rise to differentiated neuronal cell types. Moreover, sox-2 and sox-3 have selective roles in the terminal differentiation of specific neuronal cell types. Our findings suggest that the common themes of SoxB gene function across phylogeny lie in specifying developmental potential and, later on, in selectively controlling terminal differentiation programs of specific neuron types, but not in broadly controlling neurogenesis.
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Affiliation(s)
- Berta Vidal
- Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University Medical Center, New York, NY 10032, USA
| | - Anthony Santella
- Developmental Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Esther Serrano-Saiz
- Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University Medical Center, New York, NY 10032, USA
| | - Zhirong Bao
- Developmental Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Chiou-Fen Chuang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Oliver Hobert
- Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, Columbia University Medical Center, New York, NY 10032, USA
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Hench J, Henriksson J, Abou-Zied AM, Lüppert M, Dethlefsen J, Mukherjee K, Tong YG, Tang L, Gangishetti U, Baillie DL, Bürglin TR. The Homeobox Genes of Caenorhabditis elegans and Insights into Their Spatio-Temporal Expression Dynamics during Embryogenesis. PLoS One 2015; 10:e0126947. [PMID: 26024448 PMCID: PMC4448998 DOI: 10.1371/journal.pone.0126947] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Accepted: 04/09/2015] [Indexed: 11/18/2022] Open
Abstract
Homeobox genes play crucial roles for the development of multicellular eukaryotes. We have generated a revised list of all homeobox genes for Caenorhabditis elegans and provide a nomenclature for the previously unnamed ones. We show that, out of 103 homeobox genes, 70 are co-orthologous to human homeobox genes. 14 are highly divergent, lacking an obvious ortholog even in other Caenorhabditis species. One of these homeobox genes encodes 12 homeodomains, while three other highly divergent homeobox genes encode a novel type of double homeodomain, termed HOCHOB. To understand how transcription factors regulate cell fate during development, precise spatio-temporal expression data need to be obtained. Using a new imaging framework that we developed, Endrov, we have generated spatio-temporal expression profiles during embryogenesis of over 60 homeobox genes, as well as a number of other developmental control genes using GFP reporters. We used dynamic feedback during recording to automatically adjust the camera exposure time in order to increase the dynamic range beyond the limitations of the camera. We have applied the new framework to examine homeobox gene expression patterns and provide an analysis of these patterns. The methods we developed to analyze and quantify expression data are not only suitable for C. elegans, but can be applied to other model systems or even to tissue culture systems.
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Affiliation(s)
- Jürgen Hench
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Johan Henriksson
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Akram M. Abou-Zied
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Martin Lüppert
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Johan Dethlefsen
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Krishanu Mukherjee
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Yong Guang Tong
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Lois Tang
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Umesh Gangishetti
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
| | - David L. Baillie
- Dept. of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Thomas R. Bürglin
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
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Roberts-Galbraith RH, Newmark PA. On the organ trail: insights into organ regeneration in the planarian. Curr Opin Genet Dev 2015; 32:37-46. [PMID: 25703843 DOI: 10.1016/j.gde.2015.01.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 01/25/2015] [Accepted: 01/27/2015] [Indexed: 11/28/2022]
Abstract
Advances in stem cell biology have led to the derivation of diverse cell types, yet challenges remain in creating complex tissues and functional organs. Unlike humans, some animals regenerate all missing tissues and organs successfully after dramatic injuries. Studies of organisms with exceptional regenerative capacity, like planarians, could complement in vitro studies and reveal mechanistic themes underlying regeneration on the scale of whole organs and tissues. In this review, we outline progress in understanding planarian organ regeneration, with focus on recent studies of the nervous, digestive, and excretory systems. We further examine molecular mechanisms underlying establishment of diverse cell fates from the planarian stem cell pool. Finally, we explore conceptual directions for future studies of organ regeneration in planarians.
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Affiliation(s)
- Rachel H Roberts-Galbraith
- Howard Hughes Medical Institute and Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Phillip A Newmark
- Howard Hughes Medical Institute and Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
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13
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Simultaneous expression of multiple proteins under a single promoter in Caenorhabditis elegans via a versatile 2A-based toolkit. Genetics 2013; 196:605-13. [PMID: 24361941 DOI: 10.1534/genetics.113.160846] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Caenorhabditis elegans is a powerful in vivo model in which transgenesis is highly developed. However, while the analysis of biological phenomena often require the expression of more than one protein of interest, no reliable tool exists to ensure efficient concomitant and equivalent expression of more than two polypeptides from a single promoter. We report the use of viral 2A peptides, which trigger a "ribosomal-skip" or "STOP&GO" mechanism during translation, to express multiple proteins from a single vector in C. elegans. Although none of the viruses known to infect C. elegans contain 2A-like sequences, our results show that 2A peptides allow the production of separate functional proteins in all cell types and at all developmental stages tested in the worm. In addition, we constructed a toolkit including a 2A-based polycistronic plasmid and reagents to generate 2A-tagged fosmids. 2A peptides constitute an important tool to ensure the delivery of multiple polypeptides in specific cells, enabling several novel applications such as the reconstitution of multi-subunit complexes.
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Serrano-Saiz E, Poole RJ, Felton T, Zhang F, De La Cruz ED, Hobert O. Modular control of glutamatergic neuronal identity in C. elegans by distinct homeodomain proteins. Cell 2013; 155:659-73. [PMID: 24243022 DOI: 10.1016/j.cell.2013.09.052] [Citation(s) in RCA: 189] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 08/14/2013] [Accepted: 09/23/2013] [Indexed: 10/26/2022]
Abstract
The choice of using one of many possible neurotransmitter systems is a critical step in defining the identity of an individual neuron type. We show here that the key defining feature of glutamatergic neurons, the vesicular glutamate transporter EAT-4/VGLUT, is expressed in 38 of the 118 anatomically defined neuron classes of the C. elegans nervous system. We show that distinct cis-regulatory modules drive expression of eat-4/VGLUT in distinct glutamatergic neuron classes. We identify 13 different transcription factors, 11 of them homeodomain proteins, that act in distinct combinations in 25 different glutamatergic neuron classes to initiate and maintain eat-4/VGLUT expression. We show that the adoption of a glutamatergic phenotype is linked to the adoption of other terminal identity features of a neuron, including cotransmitter phenotypes. Examination of mouse orthologs of these homeodomain proteins resulted in the identification of mouse LHX1 as a regulator of glutamatergic neurons in the brainstem.
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Affiliation(s)
- Esther Serrano-Saiz
- Department of Biochemistry and Molecular Biophysics, HHMI, Columbia University Medical Center, New York, NY 10032, USA.
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15
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Dantoft W, Davis MM, Lindvall JM, Tang X, Uvell H, Junell A, Beskow A, Engström Y. The Oct1 homolog Nubbin is a repressor of NF-κB-dependent immune gene expression that increases the tolerance to gut microbiota. BMC Biol 2013; 11:99. [PMID: 24010524 PMCID: PMC3849502 DOI: 10.1186/1741-7007-11-99] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/30/2013] [Indexed: 11/10/2022] Open
Abstract
Background Innate immune responses are evolutionarily conserved processes that provide crucial protection against invading organisms. Gene activation by potent NF-κB transcription factors is essential both in mammals and Drosophila during infection and stress challenges. If not strictly controlled, this potent defense system can activate autoimmune and inflammatory stress reactions, with deleterious consequences for the organism. Negative regulation to prevent gene activation in healthy organisms, in the presence of the commensal gut flora, is however not well understood. Results We show that the Drosophila homolog of mammalian Oct1/POU2F1 transcription factor, called Nubbin (Nub), is a repressor of NF-κB/Relish-driven antimicrobial peptide gene expression in flies. In nub1 mutants, which lack Nub-PD protein, excessive expression of antimicrobial peptide genes occurs in the absence of infection, leading to a significant reduction of the numbers of cultivatable gut commensal bacteria. This aberrant immune gene expression was effectively blocked by expression of Nub from a transgene. We have identified an upstream regulatory region, containing a cluster of octamer sites, which is required for repression of antimicrobial peptide gene expression in healthy flies. Chromatin immunoprecipitation experiments demonstrated that Nub binds to octamer-containing promoter fragments of several immune genes. Gene expression profiling revealed that Drosophila Nub negatively regulates many genes that are involved in immune and stress responses, while it is a positive regulator of genes involved in differentiation and metabolism. Conclusions This study demonstrates that a large number of genes that are activated by NF-κB/Relish in response to infection are normally repressed by the evolutionarily conserved Oct/POU transcription factor Nub. This prevents uncontrolled gene activation and supports the existence of a normal gut flora. We suggest that Nub protein plays an ancient role, shared with mammalian Oct/POU transcription factors, to moderate responses to immune challenge, thereby increasing the tolerance to biotic stress.
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Affiliation(s)
- Widad Dantoft
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, SE-106 91, Stockholm, Sweden.
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16
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Tantin D. Oct transcription factors in development and stem cells: insights and mechanisms. Development 2013; 140:2857-66. [PMID: 23821033 DOI: 10.1242/dev.095927] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The POU domain family of transcription factors regulates developmental processes ranging from specification of the early embryo to terminal differentiation. About half of these factors display substantial affinity for an 8 bp DNA site termed the octamer motif, and are hence known as Oct proteins. Oct4 (Pou5f1) is a well-known Oct factor, but there are other Oct proteins with varied and essential roles in development. This Primer outlines our current understanding of Oct proteins and the regulatory mechanisms that govern their role in developmental processes and concludes with the assertion that more investigation into their developmental functions is needed.
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Affiliation(s)
- Dean Tantin
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
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17
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Kolotuev I, Hyenne V, Schwab Y, Rodriguez D, Labouesse M. A pathway for unicellular tube extension depending on the lymphatic vessel determinant Prox1 and on osmoregulation. Nat Cell Biol 2013; 15:157-68. [DOI: 10.1038/ncb2662] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Accepted: 11/26/2012] [Indexed: 01/14/2023]
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18
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Members of the NODE (Nanog and Oct4-associated deacetylase) complex and SOX-2 promote the initiation of a natural cellular reprogramming event in vivo. Proc Natl Acad Sci U S A 2012; 109:6596-601. [PMID: 22493276 DOI: 10.1073/pnas.1117031109] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Differentiated cells can be forced to change identity, either to directly adopt another differentiated identity or to revert to a pluripotent state. Direct reprogramming events can also occur naturally. We recently characterized such an event in Caenorhabditis elegans, in which a rectal cell switches to a neuronal cell. Here we have used this single-cell paradigm to investigate the molecular requirements of direct cell-type conversion, with a focus on the early steps. Our genetic analyses revealed the requirement of sem-4/Sall, egl-27/Mta, and ceh-6/Oct, members of the NODE complex recently identified in embryonic stem (ES) cells, and of the OCT4 partner sox-2, for the initiation of this natural direct reprogramming event. These four factors have been shown to individually impact on ES cell pluripotency; however, whether they act together to control cellular potential during development remained an open question. We further found that, in addition to acting at the same time, these factors physically associate, suggesting that they could act together as a NODE-like complex during this in vivo process. Finally, we have elucidated the functional domains in EGL-27/MTA that mediate its reprogramming activity in this system and have found that modulation of the posterior HOX protein EGL-5 is a downstream event to allow the initiation of Y identity change. Our data reveal unique in vivo functions in a natural direct reprogramming event for these genes that impact on ES cells pluripotency and suggest that conserved nuclear events could be shared between different cell plasticity phenomena across phyla.
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Scimone ML, Srivastava M, Bell GW, Reddien PW. A regulatory program for excretory system regeneration in planarians. Development 2011; 138:4387-98. [PMID: 21937596 DOI: 10.1242/dev.068098] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Planarians can regenerate any missing body part, requiring mechanisms for the production of organ systems in the adult, including their prominent tubule-based filtration excretory system called protonephridia. Here, we identify a set of genes, Six1/2-2, POU2/3, hunchback, Eya and Sall, that encode transcription regulatory proteins that are required for planarian protonephridia regeneration. During regeneration, planarian stem cells are induced to form a cell population in regeneration blastemas expressing Six1/2-2, POU2/3, Eya, Sall and Osr that is required for excretory system formation. POU2/3 and Six1/2-2 are essential for these precursor cells to form. Eya, Six1/2-2, Sall, Osr and POU2/3-related genes are required for vertebrate kidney development. We determined that planarian and vertebrate excretory cells express homologous proteins involved in reabsorption and waste modification. Furthermore, we identified novel nephridia genes. Our results identify a transcriptional program and cellular mechanisms for the regeneration of an excretory organ and suggest that metazoan excretory systems are regulated by genetic programs that share a common evolutionary origin.
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Affiliation(s)
- M Lucila Scimone
- Howard Hughes Medical Institute, Whitehead Institute, and Department of Biology, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA 02142, USA
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20
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Wang JQ, Hou L, Yi N, Zhang RF, Zou XY. Molecular analysis and its expression of a pou homeobox protein gene during development and in response to salinity stress from brine shrimp, Artemia sinica. Comp Biochem Physiol A Mol Integr Physiol 2011; 161:36-43. [PMID: 21911072 DOI: 10.1016/j.cbpa.2011.08.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 08/29/2011] [Accepted: 08/29/2011] [Indexed: 10/17/2022]
Abstract
Brine shrimps of the genus Artemia are aquatic species of economic importance because of their important significance to aquaculture and are used as a model species in physiology and developmental biology. Research on Artemia POU homeobox gene function will enhance our understanding of the physiological and developmental processes of POU homeobox gene in animals. Herein, a full-length cDNA encoding an Artemia POU homeobox protein gene 1 (APH-1) from Artemia sinica (designated as As-APH-1) was cloned and characterized by a reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA end (RACE) method. The As-APH-1 gene encoded a protein of 388 amino acid polypeptide with a calculated molecular mass of 42.85kDa and an isoelectric point of 6.90 and the protein belongs to the POU III family. Multiple sequence alignments revealed that A. sinica As-APH-1 protein sequence shared a conserved POU homeobox domain with other species. The early and persistent expression of As-APH-1 in the naupliar stages by semi-quantitative RT-PCR and whole-mount embryonic immunohistochemistry suggest that As-APH-1 functions very early in the salt gland and may be required continuously in this organ. Later in development, expression of As-APH-1 begins to dramatically decrease and disappear in salt gland of the sub-adult Artemia. In addition, we also discovered that As-APH-1 increased obviously as the salinity increased, indicating that As-APH-1 might be used as a good indicator of salinity stress. In summary, we are the first to identify the As-APH-1 gene and to determine its gene expression patterns in early embryogenesis stages and in different salinity stress in brine shrimp, A. sinica. The result of expression of As-APH-1 affected by salinity changes will provide us further understanding of the underlying mechanisms of osmoregulation in Artemia early embryonic development.
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Affiliation(s)
- Jia-Qing Wang
- College of Science and Technology, Shenyang Agricultural University, Fushun, PR China
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21
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Junell A, Uvell H, Davis MM, Edlundh-Rose E, Antonsson Å, Pick L, Engström Y. The POU transcription factor Drifter/Ventral veinless regulates expression of Drosophila immune defense genes. Mol Cell Biol 2010; 30:3672-84. [PMID: 20457811 PMCID: PMC2897550 DOI: 10.1128/mcb.00223-10] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 04/13/2010] [Accepted: 05/02/2010] [Indexed: 01/02/2023] Open
Abstract
Innate immunity operates as a first line of defense in multicellular organisms against infections caused by different classes of microorganisms. Antimicrobial peptides (AMPs) are synthesized constitutively in barrier epithelia to protect against microbial attack and are also upregulated in response to infection. Here, we implicate Drifter/Ventral veinless (Dfr/Vvl), a class III POU domain transcription factor, in tissue-specific regulation of the innate immune defense of Drosophila. We show that Dfr/Vvl is highly expressed in a range of immunocompetent tissues, including the male ejaculatory duct, where its presence overlaps with and drives the expression of cecropin, a potent broad-spectrum AMP. Dfr/Vvl overexpression activates transcription of several AMP genes in uninfected flies in a Toll pathway- and Imd pathway-independent manner. Dfr/Vvl activates a CecA1 reporter gene both in vitro and in vivo by binding to an upstream enhancer specific for the male ejaculatory duct. Further, Dfr/Vvl and the homeodomain protein Caudal (Cad) activate transcription synergistically via this enhancer. We propose that the POU protein Dfr/Vvl acts together with other regulators in a combinatorial manner to control constitutive AMP gene expression in a gene-, tissue-, and sex-specific manner, thus promoting a first-line defense against infection in tissues that are readily exposed to pathogens.
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Affiliation(s)
- Anna Junell
- Department of Molecular Biology and Functional Genomics, Stockholm University, SE-106 91 Stockholm, Sweden, Department of Entomology, University of Maryland, 4112 Plant Sciences Building, College Park, Maryland 20742-4454
| | - Hanna Uvell
- Department of Molecular Biology and Functional Genomics, Stockholm University, SE-106 91 Stockholm, Sweden, Department of Entomology, University of Maryland, 4112 Plant Sciences Building, College Park, Maryland 20742-4454
| | - Monica M. Davis
- Department of Molecular Biology and Functional Genomics, Stockholm University, SE-106 91 Stockholm, Sweden, Department of Entomology, University of Maryland, 4112 Plant Sciences Building, College Park, Maryland 20742-4454
| | - Esther Edlundh-Rose
- Department of Molecular Biology and Functional Genomics, Stockholm University, SE-106 91 Stockholm, Sweden, Department of Entomology, University of Maryland, 4112 Plant Sciences Building, College Park, Maryland 20742-4454
| | - Åsa Antonsson
- Department of Molecular Biology and Functional Genomics, Stockholm University, SE-106 91 Stockholm, Sweden, Department of Entomology, University of Maryland, 4112 Plant Sciences Building, College Park, Maryland 20742-4454
| | - Leslie Pick
- Department of Molecular Biology and Functional Genomics, Stockholm University, SE-106 91 Stockholm, Sweden, Department of Entomology, University of Maryland, 4112 Plant Sciences Building, College Park, Maryland 20742-4454
| | - Ylva Engström
- Department of Molecular Biology and Functional Genomics, Stockholm University, SE-106 91 Stockholm, Sweden, Department of Entomology, University of Maryland, 4112 Plant Sciences Building, College Park, Maryland 20742-4454
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22
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Armstrong KR, Chamberlin HM. Coordinate regulation of gene expression in the C. elegans excretory cell by the POU domain protein CEH-6. Mol Genet Genomics 2009; 283:73-87. [PMID: 19921263 DOI: 10.1007/s00438-009-0497-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Accepted: 10/23/2009] [Indexed: 11/24/2022]
Abstract
Excretory renal organs are critical in animals for osmoregulation and the elimination of waste. Renal organs across a range of species exhibit cellular and molecular similarities. For example, class III POU-homeodomain transcription factors are expressed in the renal organs of many invertebrates and vertebrates. However, the functional role for these factors is not well characterized. To better understand the role of class III POU-homeodomain proteins in animal excretory systems, we have characterized a set of genes expressed in the Caenorhabditis elegans excretory cell, and determined their regulation by the POU-III transcription factor CEH-6. Our molecular and biochemical studies show that CEH-6 regulates a subset of genes expressed in the excretory cell. Additionally, we find that the CEH-6-dependent genes share two molecular features: they contain at least one octamer regulatory element and they encode for transport and channel proteins. This work suggests that a role for POU-III factors in renal organs is to coordinate the expression of a set of functionally related genes.
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Affiliation(s)
- Kristin R Armstrong
- Department of Molecular Genetics, Ohio State University, 938 Biological Sciences Building, 484 W. 12th Avenue, Columbus, OH 43210, USA
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23
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Fluorescent in situ hybridization reveals multiple expression domains for SpBrn1/2/4 and identifies a unique ectodermal cell type that co-expresses the ParaHox gene SpLox. Gene Expr Patterns 2009; 9:324-8. [DOI: 10.1016/j.gep.2009.02.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 02/11/2009] [Accepted: 02/13/2009] [Indexed: 11/19/2022]
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24
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A Caenorhabditis elegans model for epithelial-neuronal transdifferentiation. Proc Natl Acad Sci U S A 2008; 105:3790-5. [PMID: 18308937 DOI: 10.1073/pnas.0712159105] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding transdifferentiation-the conversion of one differentiated cell type into another-is important from both basic science and clinical perspectives. In Caenorhabditis elegans, an epithelial cell named Y is initially part of the rectum but later appears to withdraw, migrate, and then become a motor neuron named PDA. Here, we show that this represents a bona fide transdifferentiation event: Y has epithelial hallmarks without detectable neural characteristics, and PDA has no residual epithelial characteristics. Using available mutants and laser microsurgery, we found that transdifferentiation does not depend on fusion with a neighboring cell or require migration of Y away from the rectum, that other rectal epithelial cells are not competent to transdifferentiate, and that transdifferentiation requires the EGL-5 and SEM-4 transcription factors and LIN-12/Notch signaling. Our results establish Y-to-PDA transdifferentiation as a genetically tractable model for deciphering the mechanisms underlying cellular plasticity in vivo.
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25
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Peden E, Kimberly E, Gengyo-Ando K, Mitani S, Xue D. Control of sex-specific apoptosis in C. elegans by the BarH homeodomain protein CEH-30 and the transcriptional repressor UNC-37/Groucho. Genes Dev 2007; 21:3195-207. [PMID: 18056429 PMCID: PMC2081983 DOI: 10.1101/gad.1607807] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Accepted: 10/12/2007] [Indexed: 11/24/2022]
Abstract
Apoptosis is essential for proper development and tissue homeostasis in metazoans. It plays a critical role in generating sexual dimorphism by eliminating structures that are not needed in a specific sex. The molecular mechanisms that regulate sexually dimorphic apoptosis are poorly understood. Here we report the identification of the ceh-30 gene as a key regulator of sex-specific apoptosis in Caenorhabditis elegans. Loss-of-function mutations in ceh-30 cause the ectopic death of male-specific CEM neurons. ceh-30 encodes a BarH homeodomain protein that acts downstream from the terminal sex determination gene tra-1, but upstream of, or in parallel to, the cell-death-initiating gene egl-1 to protect CEM neurons from undergoing apoptosis in males. The second intron of the ceh-30 gene contains two adjacent cis-elements that are binding sites for TRA-1A and a POU-type homeodomain protein UNC-86 and acts as a sensor to regulate proper specification of the CEM cell fate. Surprisingly, the N terminus of CEH-30 but not its homeodomain is critical for CEH-30's cell death inhibitory activity in CEMs and contains a conserved eh1/FIL domain that is important for the recruitment of the general transcriptional repressor UNC-37/Groucho. Our study suggests that ceh-30 defines a critical checkpoint that integrates the sex determination signal TRA-1 and the cell fate determination and survival signal UNC-86 to control the sex-specific activation of the cell death program in CEMs through the general transcription repressor UNC-37.
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Affiliation(s)
- Erin Peden
- Department of Molecular, Cellular and Developmental Biology University of Colorado, Boulder, Colorado 80309, USA
| | - Elizabeth Kimberly
- Department of Molecular, Cellular and Developmental Biology University of Colorado, Boulder, Colorado 80309, USA
| | - Keiko Gengyo-Ando
- Department of Physiology, Tokyo Women’s Medical University, School of Medicine and CREST, Japan Science and Technology, Tokyo, 162-8666, Japan
| | - Shohei Mitani
- Department of Physiology, Tokyo Women’s Medical University, School of Medicine and CREST, Japan Science and Technology, Tokyo, 162-8666, Japan
| | - Ding Xue
- Department of Molecular, Cellular and Developmental Biology University of Colorado, Boulder, Colorado 80309, USA
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26
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Mah AK, Armstrong KR, Chew DS, Chu JS, Tu DK, Johnsen RC, Chen N, Chamberlin HM, Baillie DL. Transcriptional regulation of AQP-8, a Caenorhabditis elegans aquaporin exclusively expressed in the excretory system, by the POU homeobox transcription factor CEH-6. J Biol Chem 2007; 282:28074-86. [PMID: 17660295 DOI: 10.1074/jbc.m703305200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Due to the ever changing environmental conditions in soil, regulation of osmotic homeostasis in the soil-dwelling nematode Caenorhabditis elegans is critical. AQP-8 is a C. elegans aquaporin that is expressed in the excretory cell, a renal equivalent tissue, where the protein participates in maintaining water balance. To better understand the regulation of AQP-8, we undertook a promoter analysis to identify the aqp-8 cis-regulatory elements. Using progressive 5' deletions of upstream sequence, we have mapped an essential regulatory region to roughly 300 bp upstream of the translational start site of aqp-8. Analysis of this region revealed a sequence corresponding to a known DNA functional element (octamer motif), which interacts with POU homeobox transcription factors. Phylogenetic footprinting showed that this site is perfectly conserved in four nematode species. The octamer site's function was further confirmed by deletion analyses, mutagenesis, functional studies, and electrophoretic mobility shift assays. Of the three POU homeobox proteins encoded in the C. elegans genome, CEH-6 is the only member that is expressed in the excretory cell. We show that expression of AQP-8 is regulated by CEH-6 by performing RNA interference experiments. CEH-6's mammalian ortholog, Brn1, is expressed both in the kidney and the central nervous system and binds to the same octamer consensus binding site to drive gene expression. These parallels in transcriptional control between Brn1 and CEH-6 suggest that C. elegans may well be an appropriate model for determining gene-regulatory networks in the developing vertebrate kidney.
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Affiliation(s)
- Allan K Mah
- Department Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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27
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Choi J, Richards KL, Cinar HN, Newman AP. N-ethylmaleimide sensitive factor is required for fusion of the C. elegans uterine anchor cell. Dev Biol 2006; 297:87-102. [PMID: 16769048 DOI: 10.1016/j.ydbio.2006.04.471] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 04/27/2006] [Accepted: 04/28/2006] [Indexed: 01/17/2023]
Abstract
The fusion of the Caenorhabditis elegans uterine anchor cell (AC) with the uterine-seam cell (utse) is an excellent model system for studying cell-cell fusion, which is essential to animal development. We obtained an egg-laying defective (Egl) mutant in which the AC fails to fuse with the utse. This defect is highly specific: other aspects of utse development and other cell fusions appear to occur normally. We find that defect is due to a missense mutation in the nsf-1 gene, which encodes N-ethylmaleimide-sensitive factor (NSF), an intracellular membrane fusion factor. There are two NSF-1 isoforms, which are expressed in distinct tissues through two separate promoters. NSF-1L is expressed in the uterus, including the AC. We find that nsf-1 is required cell-autonomously in the AC for its fusion with the utse. Our results establish AC fusion as a paradigm for studying cell fusion at single cell resolution and demonstrate that the NSF ATPase is a key player in this process.
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Affiliation(s)
- Jaebok Choi
- Verna and Marrs Maclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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28
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Zhao Z, Fang L, Chen N, Johnsen RC, Stein L, Baillie DL. Distinct regulatory elements mediate similar expression patterns in the excretory cell of Caenorhabditis elegans. J Biol Chem 2005; 280:38787-94. [PMID: 16159881 DOI: 10.1074/jbc.m505701200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Identification of cis-regulatory elements and their binding proteins constitutes an important part of understanding gene function and regulation. It is well accepted that co-expressed genes tend to share transcriptional elements. However, recent findings indicate that co-expression data show poor correlation with co-regulation data even in unicellular yeast. This motivates us to experimentally explore whether it is possible that co-expressed genes are subject to differential regulatory control using the excretory cell of Caenorhabditis elegans as an example. Excretory cell is a functional equivalent of human kidney. Transcriptional regulation of gene expression in the cell is largely unknown. We isolated a 10-bp excretory cell-specific cis-element, Ex-1, from a pgp-12 promoter. The significance of the element has been demonstrated by its capacity of converting an intestine-specific promoter into an excretory cell-specific one. We also isolated a cDNA encoding an Ex-1 binding transcription factor, DCP-66, using a yeast one-hybrid screen. Role of the factor in regulation of pgp-12 expression has been demonstrated both in vitro and in vivo. Search for occurrence of Ex-1 reveals that only a small portion of excretory cell-specific promoters contain Ex-1. Two other distinct cis-elements isolated from two different promoters can also dictate the excretory cell-specific expression but are independent of regulation by DCP-66. The results indicate that distinct regulatory elements are able to mediate the similar expression patterns.
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Affiliation(s)
- Zhongying Zhao
- Department of Genome Science, University of Washington, Seattle, Washington 98195-7730, USA.
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29
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Couthier A, Smith J, McGarr P, Craig B, Gilleard JS. Ectopic expression of a Haemonchus contortus GATA transcription factor in Caenorhabditis elegans reveals conserved function in spite of extensive sequence divergence. Mol Biochem Parasitol 2004; 133:241-53. [PMID: 14698436 DOI: 10.1016/j.molbiopara.2003.10.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Comparative analysis between Caenorhabditis elegans and other nematode species offers a powerful approach to study gene function. C. elegans also has great potential as a surrogate expression system to study the function of genes from parasitic nematode species where transgenic methodologies are unavailable. However there is little information on the extent to which the biology of C. elegans is conserved with other nematode species and very few parasitic nematode genes have yet been functionally expressed in C. elegans. We have identified and characterised a homologue of the C. elegans GATA transcription factor elt-2, a central regulator of endoderm development, from the parasitic nematode Haemonchus contortus. The H. contortus ELT-2 polypeptide is present in endoderm nuclei throughout embryonic and post-embryonic development, except for in the infective L3 stage, and our experiments reveal that the development of the H. contortus endodermal lineage is strikingly similar to that of C. elegans. Sequence conservation between the H. contortus and C. elegans ELT-2 polypeptides broadly reflects function since the major region of sequence identity corresponds to the DNA binding domain. However, the overall level of sequence identity is remarkably low with the only other major region of identity corresponding to an unusual zinc finger domain. In spite of this, ectopic expression of the H. contortus elt-2 gene in transgenic C. elegans is sufficient to activate a programme of endodermal differentiation demonstrating that function is highly conserved. This approach of ectopic expression using an inducible promoter provides an effective way in which to use C. elegans for the in vivo functional analysis of parasitic nematode genes.
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Affiliation(s)
- Annabelle Couthier
- Department of Veterinary Parasitology, Faculty of Veterinary Medicine, Institute of Comparative Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
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30
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Abstract
Developmental pattern formation allows cells within a tissue or organ to coordinate their development and establish cell types in relationship to one another. To better characterize the developmental patterning events within one organ, the C. elegans hindgut, we have analyzed the expression pattern of several genes using green fluorescent protein-based reporter transgenes. In wild-type animals, these genes are expressed in subsets of hindgut cells rather than in individual cell types. In mutant animals, we find that some, but not all, genes expressed in cells with altered development exhibit a corresponding alteration of gene expression. The results are consistent with a model where a combination of factors contribute to each cell's fate, and address how developmental information converges to specify cell types.
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Affiliation(s)
- Stephen T Sewell
- Department of Molecular Genetics, Ohio State University, Columbus, OH 43210, USA
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31
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Wada S, Tokuoka M, Shoguchi E, Kobayashi K, Di Gregorio A, Spagnuolo A, Branno M, Kohara Y, Rokhsar D, Levine M, Saiga H, Satoh N, Satou Y. A genomewide survey of developmentally relevant genes in Ciona intestinalis. II. Genes for homeobox transcription factors. Dev Genes Evol 2003; 213:222-34. [PMID: 12736825 DOI: 10.1007/s00427-003-0321-0] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2002] [Accepted: 03/11/2003] [Indexed: 11/25/2022]
Abstract
Homeobox-containing genes play crucial roles in various developmental processes, including body-plan specification, pattern formation and cell-type specification. The present study searched the draft genome sequence and cDNA/EST database of the basal chordate Ciona intestinalis to identify 83 homeobox-containing genes in this animal. This number of homeobox genes in the Ciona genome is smaller than that in the Caenorhabditis elegans, Drosophila melanogaster, human and mouse genomes. Of the 83 genes, 76 have possible human orthologues and 7 may be unique to Ciona. The ascidian homeobox genes were classified into 11 classes, including Hox class, NK class, Paired class, POU class, LIM class, TALE class, SIX class, Prox class, Cut class, ZFH class and HNF1 class, according to the classification scheme devised for known homeobox genes. As to the Hox cluster, the Ciona genome contains single copies of each of the paralogous groups, suggesting that there is a single Hox cluster, if any, but genes orthologous to Hox7, 8, 9 and 11 were not found in the genome. In addition, loss of genes had occurred independently in the Ciona lineage and was noticed in Gbx of the EHGbox subclass, Sax, NK3, Vax and vent of the NK class, Cart, Og9, Anf and Mix of the Paired class, POU-I, III, V and VI of the POU class, Lhx6/7 of the LIM class, TGIF of the TALE class, Cux and SATB of the Cut class, and ZFH1 of the ZFH class, which might have reduced the number of Ciona homeobox genes. Interestingly, one of the newly identified Ciona intestinalis genes and its vertebrate counterparts constitute a novel subclass of HNF1 class homeobox genes. Furthermore, evidence for the gene structures and expression of 54 of the 83 homeobox genes was provided by analysis of ESTs, suggesting that cDNAs for these 54 genes are available. The present data thus reveal the repertoire of homeodomain-containing transcription factors in the Ciona genome, which will be useful for future research on the development and evolution of chordates.
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Affiliation(s)
- Shuichi Wada
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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Abstract
The Drosophila trachealess gene encodes a basic-helix-loop-helix-PAS transcription factor that controls the formation of the trachea and salivary duct. An ortholog of trachealess was identified in the brine shrimp, Artemia franciscana, and was shown to be highly conserved by sequence identity. Expression of Artemia trachealess was observed at two sites during development: the naupliar salt gland and the juvenile thoracic epipod. These two organs function at their respective times of development in osmoregulation, an important aspect of brine shrimp physiology. This extends the range of putative functions of trachealess to include formation of osmoregulatory, respiratory, and ductile organs.
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Affiliation(s)
- Brian Mitchell
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, 27599-3280, USA
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Candiani S, Castagnola P, Oliveri D, Pestarino M. Cloning and developmental expression of AmphiBrn1/2/4, a POU III gene in amphioxus. Mech Dev 2002; 116:231-4. [PMID: 12128231 DOI: 10.1016/s0925-4773(02)00146-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The large family encoding POU transcription factors has been described in several species. In particular, class III POU genes regulate critical steps of vertebrate and invertebrate neurogenesis. A novel amphioxus class III POU gene, AmphiBrn1/2/4, has been isolated and its spatio-temporal expression has been reported. AmphiBrn1/2/4 is first expressed in the dorsal epiblast, then throughout the neural plate except for a gap at level of the anterior region of the cerebral vesicle. Transcripts are also detected in the primordium of gill slits, pharynx and left Hatschek's diverticulum.
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Affiliation(s)
- Simona Candiani
- Dipartimento di Biologia Sperimentale, Ambientale e Applicata, Università di Genova, viale Benedetto XV 5, Italy
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O'Brien EK, Degnan BM. Pleiotropic developmental expression of HasPOU-III, a class III POU gene, in the gastropod Haliotis asinina. Mech Dev 2002; 114:129-32. [PMID: 12175498 DOI: 10.1016/s0925-4773(02)00037-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
HasPOU-III is expressed in multiple cell types during the first 3 days of development of the gastropod Haliotis asinina. HasPOU-III expression begins in two bilaterally symmetrical sets of cells on the ventral ectodermal surface of the trochophore larva; one set are putative foot mucous cells. After torsion, HasPOU-III transcripts transiently appear in the developing ganglia of the central nervous system. At the end of larval morphogenesis, HasPOU-III expression is initiated in dorsoposterior cells of the visceral mass, in the posterior cells of the statocyst and in the developing radular sac. These expression patterns in Haliotis, a spiralian lophotrochozoan, are similar to POU Class III genes in other bilaterians where expression occurs in secretory cells and the developing nervous system.
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Affiliation(s)
- Elizabeth K O'Brien
- Department of Zoology and Entomology, University of Queensland, Brisbane, Queensland 4072, Australia
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