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Zhang X, Wang Y, Wang L, Zhang Y, Xing X, Zhao Z, Dong W, Moussian B, Zhang J. Determination of the larval precursor configuration of the Drosophila adult hindgut by G-TRACE analysis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2024; 168:104114. [PMID: 38552809 DOI: 10.1016/j.ibmb.2024.104114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 03/23/2024] [Accepted: 03/26/2024] [Indexed: 04/04/2024]
Abstract
The Drosophila hindgut is a classical model to study organogenesis. The adult hindgut originates from the precursor cells in the larval hindgut. However, the territory of these cells has still not been well determined. A ring of wingless (wg)-expressing cells lies at the anterior zone of both the larval and adult hindgut. The larval Wg ring was thought as a portion of precursor of the adult hindgut. By applying a cell lineage tracing tool (G-TRACE), we demonstrate that larval wg-expressing cells have no cell lineage contribution to the adult hindgut. Additionally, adult Wg ring cells do not divide and move posteriorly to replenish the hindgut tissue. Instead, we determine that the precursors of the adult pylorus and ileum are situated in the cubitus interruptus (ci)-expressing cells in the anterior zone, and deduce that the precursor stem cells of the adult rectum locate in the trunk region of the larval pylorus including hedgehog (hh)-expressing cells. Together, this research advances our understanding of cell lineage origins and the development of the Drosophila hindgut.
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Affiliation(s)
- Xubo Zhang
- Shanxi Key Laboratory of Nucleic Acid Biopesticides, Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, Shanxi, 030006, China.
| | - Yi Wang
- Shanxi Key Laboratory of Nucleic Acid Biopesticides, Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, Shanxi, 030006, China
| | - Lihua Wang
- Shanxi Key Laboratory of Nucleic Acid Biopesticides, Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, Shanxi, 030006, China
| | - Yue Zhang
- Shanxi Key Laboratory of Nucleic Acid Biopesticides, Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, Shanxi, 030006, China
| | - Xiaoyu Xing
- Shanxi Key Laboratory of Nucleic Acid Biopesticides, Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, Shanxi, 030006, China
| | - Zhangwu Zhao
- Shanxi Key Laboratory of Nucleic Acid Biopesticides, Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, Shanxi, 030006, China
| | - Wei Dong
- Shanxi Key Laboratory of Nucleic Acid Biopesticides, Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, Shanxi, 030006, China.
| | - Bernard Moussian
- INRAE, CNRS, Institut Sophia Agrobiotech, Sophia Antipolis, Université Côte d'Azur, 06108, Nice, France
| | - Jianzhen Zhang
- Shanxi Key Laboratory of Nucleic Acid Biopesticides, Institute of Applied Biology, College of Life Science, Shanxi University, Taiyuan, Shanxi, 030006, China.
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2
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Clark E, Battistara M, Benton MA. A timer gene network is spatially regulated by the terminal system in the Drosophila embryo. eLife 2022; 11:e78902. [PMID: 36524728 PMCID: PMC10065802 DOI: 10.7554/elife.78902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
In insect embryos, anteroposterior patterning is coordinated by the sequential expression of the 'timer' genes caudal, Dichaete, and odd-paired, whose expression dynamics correlate with the mode of segmentation. In Drosophila, the timer genes are expressed broadly across much of the blastoderm, which segments simultaneously, but their expression is delayed in a small 'tail' region, just anterior to the hindgut, which segments during germband extension. Specification of the tail and the hindgut depends on the terminal gap gene tailless, but beyond this the regulation of the timer genes is poorly understood. We used a combination of multiplexed imaging, mutant analysis, and gene network modelling to resolve the regulation of the timer genes, identifying 11 new regulatory interactions and clarifying the mechanism of posterior terminal patterning. We propose that a dynamic Tailless expression gradient modulates the intrinsic dynamics of a timer gene cross-regulatory module, delineating the tail region and delaying its developmental maturation.
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Affiliation(s)
- Erik Clark
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
- Department of Systems Biology, Harvard Medical SchoolBostonUnited States
- Department of Genetics, University of CambridgeCambridgeUnited Kingdom
| | - Margherita Battistara
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
- Department of Physiology, Development and Neuroscience, University of CambridgeCambridgeUnited Kingdom
| | - Matthew A Benton
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
- Developmental Biology Unit, EMBLHeidelbergGermany
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3
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McFann SE, Shvartsman SY, Toettcher JE. Putting in the Erk: Growth factor signaling and mesoderm morphogenesis. Curr Top Dev Biol 2022; 149:263-310. [PMID: 35606058 DOI: 10.1016/bs.ctdb.2022.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
It has long been known that FGF signaling contributes to mesoderm formation, a germ layer found in triploblasts that is composed of highly migratory cells that give rise to muscles and to the skeletal structures of vertebrates. FGF signaling activates several pathways in the developing mesoderm, including transient activation of the Erk pathway, which triggers mesodermal fate specification through the induction of the gene brachyury and activates morphogenetic programs that allow mesodermal cells to position themselves in the embryo. In this review, we discuss what is known about the generation and interpretation of transient Erk signaling in mesodermal tissues across species. We focus specifically on mechanisms that translate the level and duration of Erk signaling into cell fate and cell movement instructions and discuss strategies for further interrogating the role that Erk signaling dynamics play in mesodermal gastrulation and morphogenesis.
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Affiliation(s)
- Sarah E McFann
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, United States; Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, United States
| | - Stanislav Y Shvartsman
- Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, United States; Department of Molecular Biology, Princeton University, Princeton, NJ, United States; Center for Computational Biology, Flatiron Institute, Simons Foundation, New York, NY, United States
| | - Jared E Toettcher
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States.
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4
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Keenan SE, Avdeeva M, Yang L, Alber DS, Wieschaus EF, Shvartsman SY. Dynamics of Drosophila endoderm specification. Proc Natl Acad Sci U S A 2022; 119:e2112892119. [PMID: 35412853 PMCID: PMC9169638 DOI: 10.1073/pnas.2112892119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 02/06/2022] [Indexed: 11/18/2022] Open
Abstract
During early Drosophila embryogenesis, a network of gene regulatory interactions orchestrates terminal patterning, playing a critical role in the subsequent formation of the gut. We utilized CRISPR gene editing at endogenous loci to create live reporters of transcription and light-sheet microscopy to monitor the individual components of the posterior gut patterning network across 90 min prior to gastrulation. We developed a computational approach for fusing imaging datasets of the individual components into a common multivariable trajectory. Data fusion revealed low intrinsic dimensionality of posterior patterning and cell fate specification in wild-type embryos. The simple structure that we uncovered allowed us to construct a model of interactions within the posterior patterning regulatory network and make testable predictions about its dynamics at the protein level. The presented data fusion strategy is a step toward establishing a unified framework that would explore how stochastic spatiotemporal signals give rise to highly reproducible morphogenetic outcomes.
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Affiliation(s)
- Shannon E. Keenan
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08540
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540
| | - Maria Avdeeva
- Center for Computational Biology, Flatiron Institute, Simons Foundation, New York, NY 10010
| | - Liu Yang
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540
| | - Daniel S. Alber
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08540
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540
| | - Eric F. Wieschaus
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540
| | - Stanislav Y. Shvartsman
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540
- Center for Computational Biology, Flatiron Institute, Simons Foundation, New York, NY 10010
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540
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5
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Ayuso M, Irwin R, Walsh C, Van Cruchten S, Van Ginneken C. Low birth weight female piglets show altered intestinal development, gene expression, and epigenetic changes at key developmental loci. FASEB J 2021; 35:e21522. [PMID: 33734504 DOI: 10.1096/fj.202002587r] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/15/2021] [Accepted: 02/26/2021] [Indexed: 12/15/2022]
Abstract
Intestinal development is compromised in low birth weight (LBW) pigs, negatively impacting their growth, health, and resilience. We investigated the molecular mechanisms of the altered intestinal maturation observed in neonatal and juvenile LBW female piglets by comparing the changes in intestinal morphology, gene expression, and methylation in LBW versus normal birth weight (NBW) female piglets. A total of 16 LBW/NBW sibling pairs were sacrificed at 0 hours, 8 hours, 10 days, and 8 weeks of age. The gastrointestinal tract was weighed, measured, and the small intestine was sampled for histomorphology, gene expression, and methylation analyses. Impaired intestinal development, with shorter villi and shallower crypts, was observed in LBW female piglets. The expression of intestinal development markers (ALPI and OLFM) rapidly peaked after birth in NBW but not in LBW female piglets. The lower expression of genes involved in nutrient digestion (ANPEP and SI) and barrier function (OCLN and CLDN4) in LBW, together with their delayed development of intestinal villi and crypts could help to explain the compromised health and growth potential of LBW female piglets. The changes in methylation observed in LBW in key regulators of intestinal development (OLFM4 and FZD5) suggest long-term effects of BW on intestinal gene expression, development, and function. Accordingly, experimental demethylation induced in IPEC-J2 cells led to increased expression of intestinal genes (MGA, DPP4, and GLUT2). Overall, we have identified the alterations in transcription or epigenetic marking at a number of genes critical to intestinal development, which may contribute to both the short- and long-term failure of LBW female piglets to thrive.
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Affiliation(s)
- Miriam Ayuso
- Comparative Perinatal Development, Department of Veterinary Sciences, University of Antwerp, Wilrijk, Belgium
| | - Rachelle Irwin
- School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - Colum Walsh
- School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - Steven Van Cruchten
- Comparative Perinatal Development, Department of Veterinary Sciences, University of Antwerp, Wilrijk, Belgium
| | - Chris Van Ginneken
- Comparative Perinatal Development, Department of Veterinary Sciences, University of Antwerp, Wilrijk, Belgium
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6
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Abstract
The hedgehog (Hh) signaling pathway plays several diverse regulatory and patterning roles during organogenesis of the intestine and in the regulation of adult intestinal homeostasis. In the embryo, fetus, and adult, intestinal Hh signaling is paracrine: Hh ligands are expressed in the endodermally derived epithelium, while signal transduction is confined to the mesenchymal compartment, where at least a dozen distinct cell types are capable of responding to Hh signals. Epithelial Hh ligands not only regulate a variety of mesenchymal cell behaviors, but they also direct these mesenchymal cells to secrete additional soluble factors (e.g., Wnts, Bmps, inflammatory mediators) that feed back to regulate the epithelial cells themselves. Evolutionary conservation of the core Hh signaling pathway, as well as conservation of epithelial/mesenchymal cross talk in the intestine, has meant that work in many diverse model systems has contributed to our current understanding of the role of this pathway in intestinal organogenesis, which is reviewed here.
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Affiliation(s)
- Katherine D Walton
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA; ,
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - Deborah L Gumucio
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA; ,
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7
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Hildebrandt K, Bach N, Kolb D, Walldorf U. The homeodomain transcription factor Orthopedia is involved in development of the Drosophila hindgut. Hereditas 2020; 157:46. [PMID: 33213520 PMCID: PMC7678101 DOI: 10.1186/s41065-020-00160-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/11/2020] [Indexed: 12/20/2022] Open
Abstract
Background The Drosophila hindgut is commonly used model for studying various aspects of organogenesis like primordium establishment, further specification, patterning, and morphogenesis. During embryonic development of Drosophila, many transcriptional activators are involved in the formation of the hindgut. The transcription factor Orthopedia (Otp), a member of the 57B homeobox gene cluster, is expressed in the hindgut and nervous system of developing Drosophila embryos, but due to the lack of mutants no functional analysis has been conducted yet. Results We show that two different otp transcripts, a hindgut-specific and a nervous system-specific form, are present in the Drosophila embryo. Using an Otp antibody, a detailed expression analysis during hindgut development was carried out. Otp was not only expressed in the embryonic hindgut, but also in the larval and adult hindgut. To analyse the function of otp, we generated the mutant otp allele otpGT by ends-out gene targeting. In addition, we isolated two EMS-induced otp alleles in a genetic screen for mutants of the 57B region. All three otp alleles showed embryonic lethality with a severe hindgut phenotype. Anal pads were reduced and the large intestine was completely missing. This phenotype is due to apoptosis in the hindgut primordium and the developing hindgut. Conclusion Our data suggest that Otp is another important factor for hindgut development of Drosophila. As a downstream factor of byn Otp is most likely present only in differentiated hindgut cells during all stages of development rather than in stem cells.
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Affiliation(s)
- Kirsten Hildebrandt
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Saarland, Germany
| | - Nicole Bach
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Saarland, Germany
| | - Dieter Kolb
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Saarland, Germany
| | - Uwe Walldorf
- Developmental Biology, Saarland University, Building 61, 66421, Homburg/Saar, Saarland, Germany.
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8
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Cohen E, Sawyer JK, Peterson NG, Dow JAT, Fox DT. Physiology, Development, and Disease Modeling in the Drosophila Excretory System. Genetics 2020; 214:235-264. [PMID: 32029579 PMCID: PMC7017010 DOI: 10.1534/genetics.119.302289] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 11/04/2019] [Indexed: 02/06/2023] Open
Abstract
The insect excretory system contains two organ systems acting in concert: the Malpighian tubules and the hindgut perform essential roles in excretion and ionic and osmotic homeostasis. For over 350 years, these two organs have fascinated biologists as a model of organ structure and function. As part of a recent surge in interest, research on the Malpighian tubules and hindgut of Drosophila have uncovered important paradigms of organ physiology and development. Further, many human disease processes can be modeled in these organs. Here, focusing on discoveries in the past 10 years, we provide an overview of the anatomy and physiology of the Drosophila excretory system. We describe the major developmental events that build these organs during embryogenesis, remodel them during metamorphosis, and repair them following injury. Finally, we highlight the use of the Malpighian tubules and hindgut as accessible models of human disease biology. The Malpighian tubule is a particularly excellent model to study rapid fluid transport, neuroendocrine control of renal function, and modeling of numerous human renal conditions such as kidney stones, while the hindgut provides an outstanding model for processes such as the role of cell chirality in development, nonstem cell-based injury repair, cancer-promoting processes, and communication between the intestine and nervous system.
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Affiliation(s)
| | - Jessica K Sawyer
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, and
| | | | - Julian A T Dow
- Institute of Molecular, Cell, and Systems Biology, University of Glasgow, G12 8QQ, United Kingdom
| | - Donald T Fox
- Department of Cell Biology and
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, and
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9
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Abstract
The adult gastrointestinal tract (GI) is a series of connected organs (esophagus, stomach, small intestine, colon) that develop via progressive regional specification of a continuous tubular embryonic organ anlage. This chapter focuses on organogenesis of the small intestine. The intestine arises by folding of a flat sheet of endodermal cells into a tube of highly proliferative pseudostratified cells. Dramatic elongation of this tube is driven by rapid epithelial proliferation. Then, epithelial-mesenchymal crosstalk and physical forces drive a stepwise cascade that results in convolution of the tubular surface into finger-like projections called villi. Concomitant with villus formation, a sharp epithelial transcriptional boundary is defined between stomach and intestine. Finally, flask-like depressions called crypts are established to house the intestinal stem cells needed throughout life for epithelial renewal. New insights into these events are being provided by in vitro organoid systems, which hold promise for future regenerative engineering of the small intestine.
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Affiliation(s)
- Sha Wang
- University of Michigan, Cell and Developmental Biology Department, Ann Arbor, MI, United States
| | - Katherine D Walton
- University of Michigan, Cell and Developmental Biology Department, Ann Arbor, MI, United States.
| | - Deborah L Gumucio
- University of Michigan, Cell and Developmental Biology Department, Ann Arbor, MI, United States
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10
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Beaven R, Denholm B. Release and spread of Wingless is required to pattern the proximo-distal axis of Drosophila renal tubules. eLife 2018; 7:e35373. [PMID: 30095068 PMCID: PMC6086663 DOI: 10.7554/elife.35373] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 08/01/2018] [Indexed: 01/06/2023] Open
Abstract
Wingless/Wnts are signalling molecules, traditionally considered to pattern tissues as long-range morphogens. However, more recently the spread of Wingless was shown to be dispensable in diverse developmental contexts in Drosophila and vertebrates. Here we demonstrate that release and spread of Wingless is required to pattern the proximo-distal (P-D) axis of Drosophila Malpighian tubules. Wingless signalling, emanating from the midgut, directly activates odd skipped expression several cells distant in the proximal tubule. Replacing Wingless with a membrane-tethered version that is unable to diffuse from the Wingless producing cells results in aberrant patterning of the Malpighian tubule P-D axis and development of short, deformed ureters. This work directly demonstrates a patterning role for a released Wingless signal. As well as extending our understanding about the functional modes by which Wnts shape animal development, we anticipate this mechanism to be relevant to patterning epithelial tubes in other organs, such as the vertebrate kidney.
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Affiliation(s)
- Robin Beaven
- Deanery of Biomedical SciencesUniversity of EdinburghEdinburghUnited Kingdom
| | - Barry Denholm
- Deanery of Biomedical SciencesUniversity of EdinburghEdinburghUnited Kingdom
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11
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Kuo DH, Hsiao YH. Duplicated FoxA genes in the leech Helobdella: Insights into the evolution of direct development in clitellate annelids. Dev Dyn 2018; 247:763-778. [PMID: 29396890 DOI: 10.1002/dvdy.24621] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/25/2018] [Accepted: 01/26/2018] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND As an adaptation to the land, the clitellate annelid had reorganized its embryogenesis to develop "directly" without the ancestral planktonic larval stage. To study the evolution of gut development in the directly developing clitellates, we characterized the expression pattern of the conserved gut gene, FoxA, in the embryonic development of the leech. RESULTS The leech has three FoxA paralogs. Hau-FoxA1 is first expressed in a subset of endoderm cells and then in the foregut and the midgut. Hau-FoxA2 is expressed in the stomodeum, which is secondarily derived from the anterior ectoderm in the clitellates rather than the tissue around the blastopore, the ancestral site of mouth formation in Phylum Annelida. Hau-FoxA3 is expressed during the morphogenesis of segmental ganglia from the ectodermal teloblast lineages, a clitellate-specific trait. Hau-FoxA1 and Hau-FoxA2 are also expressed during the morphogenesis of the leech-specific front sucker. CONCLUSIONS The expression patterns suggested that Hau-FoxA1 carries out most of the conserved function in the endoderm and gut development, while the other two duplicates appear to have evolved unique novel functions in the directly developing clitellate embryos. Therefore, neofunctionalization and co-option of FoxA might have made a significant contribution to the evolution of direct development in Clitellata. Developmental Dynamics 247:763-778, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Dian-Han Kuo
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Yu-Hsiang Hsiao
- Department of Life Science, National Taiwan University, Taipei, Taiwan
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12
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Feitosa NM, Pechmann M, Schwager EE, Tobias-Santos V, McGregor AP, Damen WGM, Nunes da Fonseca R. Molecular control of gut formation in the spider Parasteatoda tepidariorum. Genesis 2017; 55. [PMID: 28432834 DOI: 10.1002/dvg.23033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 02/23/2017] [Accepted: 03/16/2017] [Indexed: 12/16/2022]
Abstract
The development of a digestive system is an essential feature of bilaterians. Studies of the molecular control of gut formation in arthropods have been studied in detail in the fruit fly Drosophila melanogaster. However, little is known in other arthropods, especially in noninsect arthropods. To better understand the evolution of arthropod alimentary system, we investigate the molecular control of gut development in the spider Parasteatoda tepidariorum (Pt), the primary chelicerate model species for developmental studies. Orthologs of the ectodermal genes Pt-wingless (Pt-wg) and Pt-hedgehog (Pt-hh), of the endodermal genes, Pt-serpent (Pt-srp) and Pt-hepatocyte-nuclear factor-4 (Pt-hnf4) and of the mesodermal gene Pt-twist (Pt-twi) are expressed in the same germ layers during spider gut development as in D. melanogaster. Thus, our expression data suggest that the downstream molecular components involved in gut development in arthropods are conserved. However, Pt-forkhead (Pt-fkh) expression and function in spiders is considerably different from its D. melanogaster ortholog. Pt-fkh is expressed before gastrulation in a cell population that gives rise to endodermal and mesodermal precursors, suggesting a possible role for this factor in specification of both germ layers. To test this hypothesis, we knocked down Pt-fkh via RNA interference. Pt-fkh RNAi embryos not only fail to develop a proper gut, but also lack the mesodermal Pt-twi expressing cells. Thus, in spiders Pt-fkh specifies endodermal and mesodermal germ layers. We discuss the implications of these findings for the evolution and development of gut formation in Ecdysozoans.
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Affiliation(s)
- Natália Martins Feitosa
- Laboratório Integrado de Ciências Morfofuncionais, Núcleo em Ecologia e Desenvolvimento Socio-Ambiental de Macaé (NUPEM), Campus Macaé, Universidade Federal do Rio de Janeiro (UFRJ), Macaé, Rio de Janeiro, 27920-560, Brazil
| | - Matthias Pechmann
- Institute for Developmental Biology, University of Cologne, Cologne, North-Rhine Westphalia, 50674, Germany
| | - Evelyn E Schwager
- Department of Biological Sciences, University of Massachusetts Lowell, 198 Riverside Street, Lowell, Massachusetts, 01854
| | - Vitória Tobias-Santos
- Laboratório Integrado de Ciências Morfofuncionais, Núcleo em Ecologia e Desenvolvimento Socio-Ambiental de Macaé (NUPEM), Campus Macaé, Universidade Federal do Rio de Janeiro (UFRJ), Macaé, Rio de Janeiro, 27920-560, Brazil
| | - Alistair P McGregor
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford, OX3 0BP, United Kingdom
| | - Wim G M Damen
- Department of Genetics, Friedrich-Schiller-Universität Jena, Philosophenweg 12, Jena, 07743, Germany
| | - Rodrigo Nunes da Fonseca
- Laboratório Integrado de Ciências Morfofuncionais, Núcleo em Ecologia e Desenvolvimento Socio-Ambiental de Macaé (NUPEM), Campus Macaé, Universidade Federal do Rio de Janeiro (UFRJ), Macaé, Rio de Janeiro, 27920-560, Brazil.,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular (INCT-EM), Universidade Federal do Rio de Janeiro (UFRJ), 21941-599 Rio de Janeiro, Rio de Janeiro, Brazil
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13
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Chambers M, Turki-Judeh W, Kim MW, Chen K, Gallaher SD, Courey AJ. Mechanisms of Groucho-mediated repression revealed by genome-wide analysis of Groucho binding and activity. BMC Genomics 2017; 18:215. [PMID: 28245789 PMCID: PMC5331681 DOI: 10.1186/s12864-017-3589-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 02/13/2017] [Indexed: 12/24/2022] Open
Abstract
Background The transcriptional corepressor Groucho (Gro) is required for the function of many developmentally regulated DNA binding repressors, thus helping to define the gene expression profile of each cell during development. The ability of Gro to repress transcription at a distance together with its ability to oligomerize and bind to histones has led to the suggestion that Gro may spread along chromatin. However, much is unknown about the mechanism of Gro-mediated repression and about the dynamics of Gro targeting. Results Our chromatin immunoprecipitation sequencing analysis of temporally staged Drosophila embryos shows that Gro binds in a highly dynamic manner primarily to clusters of discrete (<1 kb) segments. Consistent with the idea that Gro may facilitate communication between silencers and promoters, Gro binding is enriched at both cis-regulatory modules, as well as within the promotors of potential target genes. While this Gro-recruitment is required for repression, our data show that it is not sufficient for repression. Integration of Gro binding data with transcriptomic analysis suggests that, contrary to what has been observed for another Gro family member, Drosophila Gro is probably a dedicated repressor. This analysis also allows us to define a set of high confidence Gro repression targets. Using publically available data regarding the physical and genetic interactions between these targets, we are able to place them in the regulatory network controlling development. Through analysis of chromatin associated pre-mRNA levels at these targets, we find that genes regulated by Gro in the embryo are enriched for characteristics of promoter proximal paused RNA polymerase II. Conclusions Our findings are inconsistent with a one-dimensional spreading model for long-range repression and suggest that Gro-mediated repression must be regulated at a post-recruitment step. They also show that Gro is likely a dedicated repressor that sits at a prominent highly interconnected regulatory hub in the developmental network. Furthermore, our findings suggest a role for RNA polymerase II pausing in Gro-mediated repression. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3589-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michael Chambers
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Wiam Turki-Judeh
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA.,Molecular Biology Institute, University of California, Los Angeles, CA, 90095, USA
| | - Min Woo Kim
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Kenny Chen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Sean D Gallaher
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA.,Department of Energy, Institute of Genomics and Proteomics, University of California, Los Angeles, CA, 90095, USA
| | - Albert J Courey
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA. .,Molecular Biology Institute, University of California, Los Angeles, CA, 90095, USA.
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14
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Gautam NK, Verma P, Tapadia MG. Drosophila Malpighian Tubules: A Model for Understanding Kidney Development, Function, and Disease. Results Probl Cell Differ 2017; 60:3-25. [PMID: 28409340 DOI: 10.1007/978-3-319-51436-9_1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The Malpighian tubules of insects are structurally simple but functionally important organs, and their integrity is important for the normal excretory process. They are functional analogs of human kidneys which are important physiological organs as they maintain water and electrolyte balance in the blood and simultaneously help the body to get rid of waste and toxic products after various metabolic activities. In addition, it receives early indications of insults to the body such as immune challenge and other toxic components and is essential for sustaining life. According to National Vital Statistics Reports 2016, renal dysfunction has been ranked as the ninth most abundant cause of death in the USA. This chapter provides detailed descriptions of Drosophila Malpighian tubule development, physiology, immune function and also presents evidences that Malpighian tubules can be used as a model organ system to address the fundamental questions in developmental and functional disorders of the kidney.
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Affiliation(s)
- Naveen Kumar Gautam
- Embryotoxicology Laboratory, Environmental Toxicology Division, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow, 226001, Uttar Pradesh, India
| | - Puja Verma
- Department of Zoology, Cytogenetics Laboratory, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India
| | - Madhu G Tapadia
- Department of Zoology, Cytogenetics Laboratory, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India.
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15
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A deep insight into the whole transcriptome of midguts, ovaries and salivary glands of the Amblyomma sculptum tick. Parasitol Int 2016; 66:64-73. [PMID: 27789388 DOI: 10.1016/j.parint.2016.10.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 01/31/2023]
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16
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Janssen R, Jörgensen M, Lagebro L, Budd GE. Fate and nature of the onychophoran mouth-anus furrow and its contribution to the blastopore. Proc Biol Sci 2015; 282:rspb.2014.2628. [PMID: 25788603 DOI: 10.1098/rspb.2014.2628] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The ancestral states of bilaterian development, and which living groups have conserved them the most, has been a controversial topic in biology for well over a hundred years. In recent years, the idea that gastrulation primitively proceeded via the formation of a slit-like blastopore that then evolved into either protostomy or deuterostomy has gained renewed attention and some molecular developmental support. One of the key pieces of evidence for this 'amphistomy' theory comes from the onychophorans, which form a clear ventral groove during gastrulation. The interpretation of this structure has, however, proved problematic. Based on expression patterns of forkhead (fkh), caudal (cad), brachyury (bra) and wingless (wg/Wnt1), we show that this groove does not correspond to the blastopore, even though both the mouth and anus later develop from it. Rather, the posterior pit appears to be the blastopore; the posterior of the groove later fuses with it to form the definitive anus. Onychophoran development therefore represents a case of 'concealed' deuterostomy. The new data from the onychophorans thus remove one of the key pieces of evidence for the amphistomy theory. Rather, in line with other recent results, it suggests that ancestral bilaterian development was deuterostomic.
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Affiliation(s)
- Ralf Janssen
- Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden
| | - Mette Jörgensen
- Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden
| | - Linda Lagebro
- Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden
| | - Graham E Budd
- Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden
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17
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Varma D, Bülow MH, Pesch YY, Loch G, Hoch M. Forkhead, a new cross regulator of metabolism and innate immunity downstream of TOR in Drosophila. JOURNAL OF INSECT PHYSIOLOGY 2014; 69:80-88. [PMID: 24842780 DOI: 10.1016/j.jinsphys.2014.04.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 04/08/2014] [Accepted: 04/14/2014] [Indexed: 06/03/2023]
Abstract
Antimicrobial peptides (AMPs) are conserved cationic peptides which act both as defense molecules of the host immune system and as regulators of the commensal microbiome. Expression of AMPs is induced in response to infection by the Toll and Imd pathway. Under non-infected conditions, the transcription factor dFOXO directly regulates a set of AMP expression at low levels when nutrients are limited. Here we have analyzed whether target of rapamycin (TOR), another major regulator of growth and metabolism, also modulates AMP responses in Drosophila. We found that downregulation of TOR by feeding the drug rapamycin or by overexpressing the negative TOR regulators TSC1/TSC2, resulted in a specific induction of the AMPs Diptericin (Dpt) and Metchnikowin (Mtk). In contrast, overexpression of Rheb, which positively regulates TOR led to a repression of the two AMPs. Genetic and pharmacological experiments indicate that Dpt and Mtk activation is controlled by the transcription factor Forkhead (FKH), the founding member of the FoxO family. Shuttling of FKH from the cytoplasm to the nucleus is induced in the fat body and in the posterior midgut in response to TOR downregulation. The FKH-dependent induction of Dpt and Mtk can be triggered in dFOXO null mutants and in immune-compromised Toll and IMD pathway mutants indicating that FKH acts in parallel to these regulators. Together, we have discovered that FKH is the second conserved member of the FoxO family cross-regulating metabolism and innate immunity. dFOXO and FKH, which are activated upon downregulation of insulin or TOR activities, respectively, act in parallel to induce different sets of AMPs, thereby modulating the immune status of metabolic tissues such as the fat body or the gut in response to the oscillating energy status of the organism.
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Affiliation(s)
- Disha Varma
- Developmental Genetics and Molecular Physiology, LIMES Institute, University of Bonn, Carl-Troll-Str. 31, 53115 Bonn, Germany
| | - Margret H Bülow
- Developmental Genetics and Molecular Physiology, LIMES Institute, University of Bonn, Carl-Troll-Str. 31, 53115 Bonn, Germany
| | - Yanina-Yasmin Pesch
- Developmental Genetics and Molecular Physiology, LIMES Institute, University of Bonn, Carl-Troll-Str. 31, 53115 Bonn, Germany
| | - Gerrit Loch
- Developmental Genetics and Molecular Physiology, LIMES Institute, University of Bonn, Carl-Troll-Str. 31, 53115 Bonn, Germany
| | - Michael Hoch
- Developmental Genetics and Molecular Physiology, LIMES Institute, University of Bonn, Carl-Troll-Str. 31, 53115 Bonn, Germany.
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18
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Bipartite recognition of DNA by TCF/Pangolin is remarkably flexible and contributes to transcriptional responsiveness and tissue specificity of wingless signaling. PLoS Genet 2014; 10:e1004591. [PMID: 25188465 PMCID: PMC4154663 DOI: 10.1371/journal.pgen.1004591] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Accepted: 07/08/2014] [Indexed: 11/19/2022] Open
Abstract
The T-cell factor (TCF) family of transcription factors are major mediators of Wnt/β-catenin signaling in metazoans. All TCFs contain a High Mobility Group (HMG) domain that possesses specific DNA binding activity. In addition, many TCFs contain a second DNA binding domain, the C-clamp, which binds to DNA motifs referred to as Helper sites. While HMG and Helper sites are both important for the activation of several Wnt dependent cis-regulatory modules (W-CRMs), the rules of what constitutes a functional HMG-Helper site pair are unknown. In this report, we employed a combination of in vitro binding, reporter gene analysis and bioinformatics to address this question, using the Drosophila family member TCF/Pangolin (TCF/Pan) as a model. We found that while there were constraints for the orientation and spacing of HMG-Helper pairs, the presence of a Helper site near a HMG site in any orientation increased binding and transcriptional response, with some orientations displaying tissue-specific patterns. We found that altering an HMG-Helper site pair from a sub-optimal to optimal orientation/spacing dramatically increased the responsiveness of a W-CRM in several fly tissues. In addition, we used the knowledge gained to bioinformatically identify two novel W-CRMs, one that was activated by Wnt/β-catenin signaling in the prothoracic gland, a tissue not previously connected to this pathway. In sum, this work extends the importance of Helper sites in fly W-CRMs and suggests that the type of HMG-Helper pair is a major factor in setting the threshold for Wnt activation and tissue-responsiveness. Regulation of gene expression is controlled in large part by proteins known as transcription factors, which bind to specific DNA sequences in the genome. The DNA binding domains of transcription factors recognize short stretches (5–11 base pairs) of DNA with considerable sequence degeneracy. This means that a single DNA binding domain, on its own, cannot find its targets in the vast excess of genomic sequence. We are studying this question using TCF/Pangolin, a Drosophila transcription factor that mediates Wnt/β-catenin signaling, an important developmental cell-cell communication pathway. TCF/Pangolin contains two DNA binding domains that bind to a pair of DNA motifs known as HMG and Helper sites. We used a combination of biochemistry, genetics and bioinformatics to elucidate the spacing and orientation constraints of HMG-Helper site pairs. We found that HMG-Helper site spacing/orientation influenced the sensitivity of a target to Wnt signaling, as well as its tissue-responsiveness. We used this information to improve our ability to search the Drosophila genome for Wnt targets, one of which was activated by the pathway in the fly ring gland, the major endocrine organ in insects. Our work is relevant to related mammalian TCF family members, which are implicated in development, stem cell biology and the progression of cancer.
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Eriksson BJ, Tait NN. Early development in the velvet worm Euperipatoides kanangrensis Reid 1996 (Onychophora: Peripatopsidae). ARTHROPOD STRUCTURE & DEVELOPMENT 2012; 41:483-93. [PMID: 22430148 PMCID: PMC3437555 DOI: 10.1016/j.asd.2012.02.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 02/11/2012] [Accepted: 02/29/2012] [Indexed: 05/31/2023]
Abstract
We present here a description of early development in the onychophoran Euperipatoides kanangrensis with emphasis on processes that are ambiguously described in older literature. Special focus has been on the pattern of early cleavage, blastoderm and germinal disc development and gastrulation. The formation of the blastopore, stomodeum and proctodeum is described from sectioned material using light and transmission electron microscopy as well as whole-mount material stained for nuclei and gene expression. The early cleavages were found to be superficial, contrary to earlier descriptions of cleavage in yolky, ovoviviparous onychophorans. Also, contrary to earlier descriptions, the embryonic anterior-posterior axis is not predetermined in the egg. Our data support the view of a blastopore that becomes elongated and slit-like, resembling some of the earliest descriptions. From gene expression data, we concluded that the position of the proctodeum is the most posterior pit in the developing embryo. This description of early development adds to our knowledge of the staging of embryonic development in onychophorans necessary for studies on the role of developmental changes in evolution.
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Affiliation(s)
- Bo Joakim Eriksson
- Department of Zoology, University of Cambridge, Downing Street, CB2 3EJ Cambridge, United Kingdom.
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20
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Embryonic expression of Drosophila ceramide synthase schlank in developing gut, CNS and PNS. Gene Expr Patterns 2011; 11:501-10. [PMID: 21907829 DOI: 10.1016/j.gep.2011.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 08/17/2011] [Accepted: 08/19/2011] [Indexed: 12/17/2022]
Abstract
Schlank is a member of the highly conserved ceramide synthase family and controls growth and body fat in Drosophila. Ceramide synthases are key enzymes in the sphingolipid de novo synthesis pathway. Ceramide synthase proteins and the (dihydro)ceramide produced are involved in a variety of biological processes among them apoptosis and neurodegeneration. The full extent of their involvement in these processes will require a precise analysis of the distribution and expression pattern of ceramide synthases. Paralogs of the ceramide synthase family have been found in all eukaryotes studied, however the mRNA and protein expression patterns have not yet been analysed systematically. In this study, we use antibodies that specifically recognize Schlank, a schlank mRNA probe and an endogenous schlank promoter driven LacZ reporter line to reveal the expression pattern of Schlank throughout embryogenesis. We found that Schlank is expressed in all embryonic epithelia during embryogenesis including the developing epidermis and the gastrointestinal tract. In addition, Schlank is upregulated in the developing central (CNS) and peripheral nervous system (PNS). Co-staining experiments with neuronal and glial markers revealed specific expression of Schlank in glial and neuronal cells of the CNS and PNS.
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21
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Nakamura Y, Tsiairis CD, Özbek S, Holstein TW. Autoregulatory and repressive inputs localize Hydra Wnt3 to the head organizer. Proc Natl Acad Sci U S A 2011; 108:9137-42. [PMID: 21576458 PMCID: PMC3107325 DOI: 10.1073/pnas.1018109108] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polarized Wnt signaling along the primary body axis is a conserved property of axial patterning in bilaterians and prebilaterians, and depends on localized sources of Wnt ligands. However, the mechanisms governing the localized Wnt expression that emerged early in evolution are poorly understood. Here we find in the cnidarian Hydra that two functionally distinct cis-regulatory elements control the head organizer-associated Hydra Wnt3 (HyWnt3). An autoregulatory element, which mediates direct inputs of Wnt/β-catenin signaling, highly activates HyWnt3 transcription in the head region. In contrast, a repressor element is necessary and sufficient to restrict the activity of the autoregulatory element, thereby allowing the organizer-specific expression. Our results reveal that a combination of autoregulation and repression is crucial for establishing a Wnt-expressing organizing center in a basal metazoan. We suggest that this transcriptional control is an evolutionarily old strategy in the formation of Wnt signaling centers and metazoan axial patterning.
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Affiliation(s)
- Yukio Nakamura
- Department of Molecular Evolution and Genomics, Heidelberg Institute of Zoology, University of Heidelberg, D-69120 Heidelberg, Germany
| | - Charisios D. Tsiairis
- Department of Molecular Evolution and Genomics, Heidelberg Institute of Zoology, University of Heidelberg, D-69120 Heidelberg, Germany
| | - Suat Özbek
- Department of Molecular Evolution and Genomics, Heidelberg Institute of Zoology, University of Heidelberg, D-69120 Heidelberg, Germany
| | - Thomas W. Holstein
- Department of Molecular Evolution and Genomics, Heidelberg Institute of Zoology, University of Heidelberg, D-69120 Heidelberg, Germany
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22
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Boyle MJ, Seaver EC. Expression of FoxA and GATA transcription factors correlates with regionalized gut development in two lophotrochozoan marine worms: Chaetopterus (Annelida) and Themiste lageniformis (Sipuncula). EvoDevo 2010; 1:2. [PMID: 20849645 PMCID: PMC2938726 DOI: 10.1186/2041-9139-1-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2009] [Accepted: 07/05/2010] [Indexed: 12/04/2022] Open
Abstract
Background A through gut is present in almost all metazoans, and most likely represents an ancient innovation that enabled bilaterian animals to exploit a wide range of habitats. Molecular developmental studies indicate that Fox and GATA regulatory genes specify tissue regions along the gut tube in a broad diversity of taxa, although little is known about gut regionalization within the Lophotrochozoa. In this study, we isolated FoxA and GATA456 orthologs and used whole mount in situ hybridization during larval gut formation in two marine worms: the segmented, polychaete annelid Chaetopterus, which develops a planktotrophic larva with a tripartite gut, and the non-segmented sipunculan Themiste lageniformis, which develops a lecithotrophic larva with a U-shaped gut. Results FoxA and GATA456 transcripts are predominantly restricted to gut tissue, and together show regional expression spanning most of the alimentary canal in each of these lophotrochozoans, although neither FoxA nor GATA456 is expressed in the posterior intestine of Chaetopterus. In both species, FoxA is expressed at the blastula stage, transiently in presumptive endoderm before formation of a definitive gut tube, and throughout early larval development in discrete foregut and hindgut domains. GATA456 genes are expressed during endoderm formation, and in endoderm and mesoderm associated with the midgut in each species. Several species-specific differences were detected, including an overlap of FoxA and GATA456 expression in the intestinal system of Themiste, which is instead complimentary in Chaetopterus. Other differences include additional discrete expression domains of FoxA in ectodermal trunk cells in Themiste but not Chaetopterus, and expression of GATA456 in anterior ectoderm and midgut cells unique to Chaetopterus. Conclusions This study of gene expression in a sipunculan contributes new comparative developmental insights from lophotrochozoans, and shows that FoxA and GATA456 transcription factors are part of an ancient patterning mechanism that was deployed during early evolution of the metazoan through gut. The common utilization of FoxA and GATA456 throughout gut formation by species with contrasting life history modes indicates that both genes are core components of a gut-specific gene regulatory network in spiralians. Despite a highly conserved pattern of early development, and probably similar ontogenic origins of gut tissue, there are molecular differences in gut regionalization between lophotrochozoan species.
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Affiliation(s)
- Michael J Boyle
- Kewalo Marine Laboratory, Pacific Biosciences Research Center, University of Hawaii, Honolulu, HI 96813, USA.
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23
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Kim MS, Kim JR, Cho KH. Dynamic network rewiring determines temporal regulatory functions in Drosophilamelanogaster development processes. Bioessays 2010; 32:505-13. [PMID: 20486137 DOI: 10.1002/bies.200900169] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Man-Sun Kim
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
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Navet S, Andouche A, Baratte S, Bonnaud L. Shh and Pax6 have unconventional expression patterns in embryonic morphogenesis in Sepia officinalis (Cephalopoda). Gene Expr Patterns 2009; 9:461-7. [PMID: 19683074 DOI: 10.1016/j.gep.2009.08.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 08/05/2009] [Accepted: 08/07/2009] [Indexed: 10/20/2022]
Abstract
Cephalopods show a very complex nervous system, particularly derived when compared to other molluscs. In vertebrates, the setting up of the nervous system depends on genes such as Shh and Pax6. In this paper we assess Shh and Pax6 expression patterns during Sepia officinalis development by whole-mount in situ hybridization. In vertebrates, Shh has been shown to indirectly inhibit Pax6. This seems to be the case in cephalopods as the expression patterns of these genes do not overlap during S. officinalis development. Pax6 is expressed in the optic region and brain and Shh in gut structures, as already seen in vertebrates and Drosophila. Thus, both genes show expression in analogous structures in vertebrates. Surprisingly, they also exhibit unconventional expressions such as in gills for Pax6 and ganglia borders for Shh. They are also expressed in many cephalopods' derived characters among molluscs as in arm suckers for Pax6 and beak producing tissues, nuchal organ and neural cord of the arms for Shh. This new data supports the fact that molecular control patterns have evolved with the appearance of morphological novelties in cephalopods as shown in this new model, S. officinalis.
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Affiliation(s)
- Sandra Navet
- Muséum National d'Histoire Naturelle, Département Milieux et Peuplements Aquatiques, Laboratoire Biologie des ORganismes et Ecosystèmes Aquatiques, UMR MNHN USM 401, CNRS 7208, IRD 207, UPMC, Paris, France.
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25
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The Hedgehog gene family of the cnidarian, Nematostella vectensis, and implications for understanding metazoan Hedgehog pathway evolution. Dev Biol 2007; 313:501-18. [PMID: 18068698 DOI: 10.1016/j.ydbio.2007.09.032] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2007] [Revised: 09/10/2007] [Accepted: 09/10/2007] [Indexed: 11/24/2022]
Abstract
Hedgehog signaling is an important component of cell-cell communication during bilaterian development, and abnormal Hedgehog signaling contributes to disease and birth defects. Hedgehog genes are composed of a ligand ("hedge") domain and an autocatalytic intein ("hog") domain. Hedgehog (hh) ligands bind to a conserved set of receptors and activate downstream signal transduction pathways terminating with Gli/Ci transcription factors. We have identified five intein-containing genes in the anthozoan cnidarian Nematostella vectensis, two of which (NvHh1 and NvHh2) contain definitive hedgehog ligand domains, suggesting that to date, cnidarians are the earliest branching metazoan phylum to possess definitive Hh orthologs. Expression analysis of NvHh1 and NvHh2, the receptor NvPatched, and a downstream transcription factor NvGli (a Gli3/Ci ortholog) indicate that these genes may have conserved roles in planar and trans-epithelial signaling during gut and germline development, while the three remaining intein-containing genes (NvHint1,2,3) are expressed in a cell-type-specific manner in putative neural precursors. Metazoan intein-containing genes that lack a hh ligand domain have previously only been identified within nematodes. However, we have identified intein-containing genes from both Nematostella and in two newly annotated lophotrochozoan genomes. Phylogenetic analyses suggest that while nematode inteins may be derived from an ancestral true hedgehog gene, the newly identified cnidarian and lophotrochozoan inteins may be orthologous, suggesting that both true hedgehog and hint genes may have been present in the cnidarian-bilaterian ancestor. Genomic surveys of N. vectensis suggest that most of the components of both protostome and deuterostome Hh signaling pathways are present in anthozoans and that some appear to have been lost in ecdysozoan lineages. Cnidarians possess many bilaterian cell-cell signaling pathways (Wnt, TGFbeta, FGF, and Hh) that appear to act in concert to pattern tissues along the oral-aboral axis of the polyp. Cnidarians represent a diverse group of animals with a predominantly epithelial body plan, and perhaps selective pressures to pattern epithelia resulted in the ontogeny of the hedgehog pathway in the common ancestor of the Cnidaria and Bilateria.
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Lechner H, Josten F, Fuss B, Bauer R, Hoch M. Cross regulation of intercellular gap junction communication and paracrine signaling pathways during organogenesis in Drosophila. Dev Biol 2007; 310:23-34. [PMID: 17707365 DOI: 10.1016/j.ydbio.2007.07.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Revised: 06/22/2007] [Accepted: 07/12/2007] [Indexed: 01/09/2023]
Abstract
The spatial and temporal coordination of patterning and morphogenesis is often achieved by paracrine morphogen signals or by the direct coupling of cells via gap junctions. How paracrine signals and gap junction communication cooperate to control the coordinated behavior of cells and tissues is mostly unknown. We found that hedgehog signaling is required for the expression of wingless and of Delta/Notch target genes in a single row of boundary cells in the foregut-associated proventriculus organ of the Drosophila embryo. These cells coordinate the movement and folding of proventricular cells to generate a multilayered organ. hedgehog and wingless regulate gap junction communication by transcriptionally activating the innexin2 gene, which encodes a member of the innexin family of gap junction proteins. In innexin2 mutants, gap junction-mediated cell-to-cell communication is strongly reduced and the proventricular cell layers fail to fold and invaginate, similarly as in hedgehog or wingless mutants. We further found that innexin2 is required in a feedback loop for the transcriptional activation of the hedgehog and wingless morphogens and of Delta in the proventriculus primordium. We propose that the transcriptional cross regulation of paracrine and gap junction-mediated signaling is essential for organogenesis in Drosophila.
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Affiliation(s)
- Hildegard Lechner
- LIMES Institute, Laboratory of Molecular Developmental Biology, University of Bonn, Meckenheimer Allee 169, Poppelsdorfer Schloss, D-53115 Bonn, Germany
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27
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Liu G, Moro A, Zhang JJR, Cheng W, Qiu W, Kim PCW. The role of Shh transcription activator Gli2 in chick cloacal development. Dev Biol 2006; 303:448-60. [PMID: 17239843 DOI: 10.1016/j.ydbio.2006.10.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 09/19/2006] [Accepted: 10/27/2006] [Indexed: 12/25/2022]
Abstract
Patterning and differentiation along the dorsal-ventral (D-V) axis lead to cloacal partitioning into ventral urinary and dorsal alimentary tracts in most mammals, but not birds and fish. We previously reported that the major activator of Sonic hedgehog (Shh) signaling transcription factor Gli2 plays an essential role in cloacal partitioning along the D-V axis in a mouse model. Here, we report that chick cloacal patterning and differentiation is along the anterior-posterior axis. During chick cloacal formation, Shh is expressed strongly in hindgut endoderm; Gli2 is very weakly detected in the surrounding hindgut mesoderm. In the mesoderm of the cloacal region, the over-expression of the constitutively active form of mouse Gli2 has been shown to: not induce cloacal partitioning along the D-V axis; induce expression of Ptch1, Gli2, bmp4, wnt5a, and hoxd-13, which have been previously shown to play a role in hindgut patterning; increase cell proliferation; and reduce apoptosis. Interestingly, p63 expression in the cloacal endoderm is also up-regulated, suggesting an interaction between the Shh and p63 pathways. In conclusion, Gli2 alone is insufficient to induce partitioning along the D-V axis in the chick embryo. However, Gli2 regulates both epithelial and mesenchymal cell proliferation and apoptosis during cloacal development.
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Affiliation(s)
- Guodong Liu
- Department of Surgery, Programs of Infection, Immunity, Injury and Repair, The Hospital for Sick Children, 555 University Ave, Suite 1526, Toronto, Ontario, Canada M5G 1X8
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Maeda R, Hozumi S, Taniguchi K, Sasamura T, Murakami R, Matsuno K. Roles of single-minded in the left-right asymmetric development of the Drosophila embryonic gut. Mech Dev 2006; 124:204-17. [PMID: 17241775 DOI: 10.1016/j.mod.2006.12.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2006] [Revised: 11/14/2006] [Accepted: 12/08/2006] [Indexed: 11/20/2022]
Abstract
Many animals have genetically determined left-right (LR) asymmetry of their internal organs. The midline structure of vertebrate embryos has important roles in LR asymmetric development both as the signaling center for LR asymmetry and as a barrier to inappropriate LR signaling across the midline. However, in invertebrates, the functions of the midline in LR asymmetric development are unknown. To elucidate these roles, we studied the involvement of single-minded (sim) in the LR asymmetry of the Drosophila embryonic gut, which develops in a stereotypic, asymmetric manner. sim encodes a bHLH/PAS transcription factor that is required for the development of the ventral midline structure. Here we report that sim was expressed in the midline of the foregut and hindgut primordia. The handedness of the embryonic gut was affected in sim mutant embryos and in embryos overexpressing sim. However, midline-derived events, which involve Slit/Robo and EGFr signaling and direct the development of the tissues adjacent to the midline, did not affect the laterality of this organ, suggesting a crucial role for the midline itself in LR asymmetry. In the sim mutants, the midline structures of the embryonic anal pad were deformed. The mis-expression of sim in the anal-pad primordium induced LR defects. We also found that different portions of the embryonic gut require sim functions at different times for normal LR asymmetry. Our results suggest that the midline structures are involved in the LR asymmetric development of the Drosophila embryonic gut.
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Affiliation(s)
- Reo Maeda
- Department of Biological Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
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Shinmyo Y, Mito T, Uda T, Nakamura T, Miyawaki K, Ohuchi H, Noji S. brachyenteron is necessary for morphogenesis of the posterior gut but not for anteroposterior axial elongation from the posterior growth zone in the intermediate-germband cricket Gryllus bimaculatus. Development 2006; 133:4539-47. [PMID: 17050622 DOI: 10.1242/dev.02646] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the long-germband insect Drosophila, all body segments and posterior terminal structures, including the posterior gut and anal pads, are specified at the blastoderm stage. In short- and intermediate-germband insects, however, posterior segments are sequentially produced from the posterior growth zone, a process resembling somitogenesis in vertebrates, and invagination of the posterior gut starts after anteroposterior (AP) axial elongation from the growth zone. The mechanisms underlying posterior segmentation and terminal patterning in these insects are poorly understood. In order to elucidate these mechanisms, we have investigated the roles of the Brachyury/brachyenteron (Bra/byn) homolog in the intermediate-germband cricket Gryllus bimaculatus. Loss-of-function analysis by RNA interference (RNAi) revealed that Gryllus byn (Gb'byn) is not required for AP axial elongation or normal segment formation, but is required for specification of the posterior gut. We also analyzed Gryllus caudal (Gb'cad) RNAi embryos using in situ hybridization with a Gb'byn probe, and found that Gb'cad is required for internalization of the posterior gut primordium, in addition to AP axial elongation. These results suggest that the functions of byn and cad in posterior terminal patterning are highly conserved in Gryllus and Drosophila despite their divergent posterior patterning. Moreover, because it is thought that the progressive growth of the AP axis from the growth zone, controlled by a genetic program involving Cdx/cad and Bra/byn, might be ancestral to bilaterians, our data suggest that the function of Bra/byn in this process might have been lost in insects.
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Affiliation(s)
- Yohei Shinmyo
- Department of Biological Science and Technology, Faculty of Engineering, The University of Tokushima, 2-1 Minami-Josanjima-cho, Tokushima City 770-8506, Japan
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30
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de Velasco B, Erclik T, Shy D, Sclafani J, Lipshitz H, McInnes R, Hartenstein V. Specification and development of the pars intercerebralis and pars lateralis, neuroendocrine command centers in the Drosophila brain. Dev Biol 2006; 302:309-23. [PMID: 17070515 DOI: 10.1016/j.ydbio.2006.09.035] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Revised: 09/19/2006] [Accepted: 09/20/2006] [Indexed: 11/16/2022]
Abstract
The central neuroendocrine system in the Drosophila brain includes two centers, the pars intercerebralis (PI) and pars lateralis (PL). The PI and PL contain neurosecretory cells (NSCs) which project their axons to the ring gland, a complex of peripheral endocrine glands flanking the aorta. We present here a developmental and genetic study of the PI and PL. The PI and PL are derived from adjacent neurectodermal placodes in the dorso-medial head. The placodes invaginate during late embryogenesis and become attached to the brain primordium. The PI placode and its derivatives express the homeobox gene Dchx1 and can be followed until the late pupal stage. NSCs labeled by the expression of Drosophila insulin-like peptide (Dilp), FMRF, and myomodulin form part of the Dchx1 expressing PI domain. NSCs of the PL can be followed throughout development by their expression of the adhesion molecule FasII. Decapentaplegic (Dpp), secreted along the dorsal midline of the early embryo, inhibits the formation of the PI and PL placodes; loss of the signal results in an unpaired, enlarged placodeal ectoderm. The other early activated signaling pathway, EGFR, is positively required for the maintenance of the PI placode. Of the dorso-medially expressed head gap genes, only tailless (tll) is required for the specification of the PI. Absence of the corpora cardiaca, the endocrine gland innervated by neurosecretory cells of the PI and PL, does not affect the formation of the PI/PL, indicating that inductive stimuli from their target tissue are not essential for early PI/PL development.
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Affiliation(s)
- Begona de Velasco
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
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31
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Seaver EC, Kaneshige LM. Expression of 'segmentation' genes during larval and juvenile development in the polychaetes Capitella sp. I and H. elegans. Dev Biol 2005; 289:179-94. [PMID: 16330020 DOI: 10.1016/j.ydbio.2005.10.025] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Revised: 10/14/2005] [Accepted: 10/18/2005] [Indexed: 11/16/2022]
Abstract
Polychaete annelids and arthropods are both segmented protostome invertebrates. To investigate whether the segmented body plan of these two phyla share a common molecular ground pattern, we report the developmental expression of orthologues of the arthropod segment polarity genes engrailed (en), hedgehog (hh), and wingless (wg/Wnt1) in larval and juvenile stages of the polychaete annelid Capitella sp. I and en in a second polychaete, Hydroides elegans. Temporally, neither Wnt1 nor hh are detected in the segmented region of the larval body until after morphological segmentation is apparent. Expression of CapI-Wnt1 is limited to a ring of ectoderm marking the future anus during larval segmentation. CapI-hh is expressed in a ring of the hindgut internal to that of CapI-Wnt1, as well as in a subset of ventral nerve cord neurons, anterior gut tissue, and mesoderm. In both H. elegans and Capitella sp. I, en is expressed in a spatially and temporally dynamic manner in segmentally iterated structures as well as a population of cells that migrate internally from ectoderm to mesoderm, possibly representing a population of ecto-mesodermal precursors. Significantly, the expression patterns we report for wg, en, and hh orthologues in Capitella sp. I and for en in larval development of H. elegans are not comparable to the highly conserved ectodermal segment polarity pattern observed in arthropods at any life history stage, consistent with distinct origins of segmentation between annelids and arthropods.
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Affiliation(s)
- Elaine C Seaver
- Kewalo Marine Lab, PBRC/University of Hawaii, Honolulu, 96813, USA.
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32
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Fritzenwanker JH, Saina M, Technau U. Analysis of forkhead and snail expression reveals epithelial-mesenchymal transitions during embryonic and larval development of Nematostella vectensis. Dev Biol 2005; 275:389-402. [PMID: 15501226 DOI: 10.1016/j.ydbio.2004.08.014] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Revised: 08/10/2004] [Accepted: 08/12/2004] [Indexed: 01/15/2023]
Abstract
The winged helix transcription factor Forkhead and the zinc finger transcription factor Snail are crucially involved in germ layer formation in Bilateria. Here, we isolated and characterized a homolog of forkhead/HNF3 (FoxA/group 1) and of snail from a diploblast, the sea anemone Nematostella vectensis. We show that Nematostella forkhead expression starts during late Blastula stage in a ring of cells that demarcate the blastopore margin during early gastrulation, thereby marking the boundary between ectodermal and endodermal tissue. snail, by contrast, is expressed in a complementary pattern in the center of forkhead-expressing cells marking the presumptive endodermal cells fated to ingress during gastrulation. In a significant portion of early gastrulating embryos, forkhead is expressed asymmetrically around the blastopore. While snail-expressing cells form the endodermal cell mass, forkhead marks the pharynx anlage throughout embryonic and larval development. In the primary polyp, forkhead remains expressed in the pharynx. The detailed analysis of forkhead and snail expression during Nematostella embryonic and larval development further suggests that endoderm formation results from epithelial invagination, mesenchymal immigration, and reorganization of the endodermal epithelial layer, that is, by epithelial-mesenchymal transitions (EMT) in combination with extensive morphogenetic movements. snail also governs EMT at different processes during embryonic development in Bilateria. Our data indicate that the function of snail in Diploblasts is to regulate motility and cell adhesion, supporting that the triggering of changes in cell behavior is the ancestral role of snail in Metazoa.
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Affiliation(s)
- Jens H Fritzenwanker
- Molecular Cell Biology, Institute for Zoology, Darmstadt University of Technology, 64287 Darmstadt, Germany
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33
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Phelan P. Innexins: members of an evolutionarily conserved family of gap-junction proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2004; 1711:225-45. [PMID: 15921654 DOI: 10.1016/j.bbamem.2004.10.004] [Citation(s) in RCA: 177] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Revised: 10/12/2004] [Accepted: 10/14/2004] [Indexed: 11/20/2022]
Abstract
Gap junctions are clusters of intercellular channels that provide cells, in all metazoan organisms, with a means of communicating directly with their neighbours. Surprisingly, two gene families have evolved to fulfil this fundamental, and highly conserved, function. In vertebrates, gap junctions are assembled from a large family of connexin proteins. Innexins were originally characterized as the structural components of gap junctions in Drosophila, an arthropod, and the nematode Caenorhabditis elegans. Since then, innexin homologues have been identified in representatives of the other major invertebrate phyla and in insect-associated viruses. Intriguingly, functional innexin homologues have also been found in vertebrate genomes. These studies have informed our understanding of the molecular evolution of gap junctions and have greatly expanded the numbers of model systems available for functional studies. Genetic manipulation of innexin function in relatively simple cellular systems should speed progress not only in defining the importance of gap junctions in a variety of biological processes but also in elucidating the mechanisms by which they act.
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Affiliation(s)
- Pauline Phelan
- Department of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, UK.
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Simonnet F, Deutsch J, Quéinnec E. hedgehog is a segment polarity gene in a crustacean and a chelicerate. Dev Genes Evol 2004; 214:537-45. [PMID: 15365834 DOI: 10.1007/s00427-004-0435-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Accepted: 08/16/2004] [Indexed: 10/26/2022]
Abstract
The evolution of arthropod segmentation has been studied by comparing expression patterns of pair-rule and segment polarity genes in various species. In Drosophila, the formation and maintenance of the parasegmental boundaries depend on the interactions between the wingless (wg), engrailed (en) and hedgehog (hh) genes. Until now, the expression pattern of hh has not been analysed to such a great extent as en or wg. We report the cloning and expression analysis of hh genes from Euscorpius flavicaudis, a chelicerate, and Artemia franciscana, a branchiopod crustacean. Our data provide evidence that hh, being expressed in the posterior part of every segment, is a segment polarity gene in both organisms. Additional hh expression sites were observed in the rostrum and appendages of Euscorpius and in the gut of Artemia. From the available data on hh expression in various bilaterians, we review the various hypotheses on the evolution of hh function and we suggest an ancestral role of hh in proctodeum specification and gut formation.
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Affiliation(s)
- Franck Simonnet
- Evolution et Développement UMR 7138--Systématique, Adaptation et Evolution, Université Pierre et Marie Curie (Paris 6), 9 quai Saint-Bernard, Case 5, 75252 Paris 05, France
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Johansen KA, Green RB, Iwaki DD, Hernandez JB, Lengyel JA. The Drm-Bowl-Lin relief-of-repression hierarchy controls fore- and hindgut patterning and morphogenesis. Mech Dev 2004; 120:1139-51. [PMID: 14568103 DOI: 10.1016/j.mod.2003.08.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The elucidation of pathways linking patterning to morphogenesis is a problem of great interest. We show here that, in addition to their roles in patterning and morphogenesis of the hindgut, the Drosophila genes drumstick (drm) and bowl are required in the foregut for spatially localized gene expression and the morphogenetic processes that form the proventriculus. drm and bowl belong to a family of genes encoding C(2)H(2) zinc finger proteins; the other two members of this family are odd-skipped (odd) and sob. In both the fore- and hindgut, drm acts upstream of lines (lin), which encodes a putative transcriptional regulator, and relieves its repressive function. In spite of its phenotypic similarities with drm, bowl was found in both foregut and hindgut to act downstream, rather than upstream, of lin. These results support a hierarchy in which Drm relieves the repressive effect of Lin on Bowl, and Bowl then acts to promote spatially localized expression of genes (particularly the JAK/STAT pathway ligand encoded by upd) that control fore- and hindgut morphogenesis. Since the odd-family and lin are conserved in mosquito, mouse, and humans, we propose that the odd-family genes and lin may also interact to control patterning and morphogenesis in other insects and in vertebrates.
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Affiliation(s)
- Katherine A Johansen
- Department of Molecular, Cell, and Developmental Biology, University of California, Box 160606, Los Angeles, CA 90095-1606, USA
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36
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Janssen R, Prpic NM, Damen WGM. Gene expression suggests decoupled dorsal and ventral segmentation in the millipede Glomeris marginata (Myriapoda: Diplopoda). Dev Biol 2004; 268:89-104. [PMID: 15031107 DOI: 10.1016/j.ydbio.2003.12.021] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Revised: 12/11/2003] [Accepted: 12/13/2003] [Indexed: 11/19/2022]
Abstract
Diplopods (millipedes) are known for their irregular body segmentation. Most importantly, the number of dorsal segmental cuticular plates (tergites) does not match the number of ventral structures (e.g., sternites). Controversial theories exist to explain the origin of this so-called diplosegmentation. We have studied the embryology of a representative diplopod, Glomeris marginata, and have analyzed the segmentation genes engrailed (en), hedgehog (hh), cubitus-interruptus (ci), and wingless (wg). We show that dorsal segments can be distinguished from ventral segments. They differ not only in number and developmental history, but also in gene expression patterns. engrailed, hedgehog, and cubitus-interruptus are expressed in both ventral and dorsal segments, but at different intrasegmental locations, whereas wingless is expressed only in the ventral segments, but not in the dorsal segments. Ventrally, the patterns are similar to what has been described from Drosophila and other arthropods, consistent with a conserved role of these genes in establishing parasegment boundaries. On the dorsal side, however, the gene expression patterns are different and inconsistent with a role in boundary formation between segments, but they suggest that these genes might function to establish the tergite borders. Our data suggest a profound and rather complete decoupling of dorsal and ventral segmentation leading to the dorsoventral discrepancies in the number of segmental elements. Based on gene expression, we propose a model that may resolve the hitherto controversial issue of the correlation between dorsal tergites and ventral leg pairs in basal diplopods (e.g., Glomeris) and is suggestive also for derived, ring-forming diplopods (e.g., Juliformia).
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Affiliation(s)
- Ralf Janssen
- Department for Evolutionary Genetics, Institute for Genetics, University of Cologne, D-50931 Köln, Germany
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Kang D, Huang F, Li D, Shankland M, Gaffield W, Weisblat DA. A hedgehog homolog regulates gut formation in leech (Helobdella). Development 2003; 130:1645-57. [PMID: 12620988 DOI: 10.1242/dev.00395] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Signaling by the hedgehog (hh)-class gene pathway is essential for embryogenesis in organisms ranging from Drosophila to human. We have isolated a hh homolog (Hro-hh) from a lophotrochozoan species, the glossiphoniid leech, Helobdella robusta, and examined its expression by reverse transcription polymerase chain reaction (RT-PCR) and whole-mount in situ hybridization. The peak of Hro-hh expression occurs during organogenesis (stages 10-11). No patterned expression was detected within the segmented portion of the germinal plate during the early stages of segmentation. In stage 10-11 embryos, Hro-hh is expressed in body wall, foregut, anterior and posterior midgut, reproductive organs and in a subset of ganglionic neurons. Evidence that Hro-hh regulates gut formation was obtained using the steroidal alkaloid cyclopamine, which specifically blocks HH signaling. Cyclopamine induced malformation of both foregut and anterior midgut in Helobdella embryos, and no morphologically recognizable gonads were seen. In contrast, no gross abnormalities were observed in the posterior midgut. Segmental ectoderm developed normally, as did body wall musculature and some other mesodermal derivatives, but the mesenchymal cells that normally come to fill most of the coelomic cavities failed to develop. Taken with data from Drosophila and vertebrates, our data suggest that the role of hh-class genes in gut formation and/or neural differentiation is ancestral to the bilaterians, whereas their role in segmentation evolved secondarily within the Ecdysozoa.
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Affiliation(s)
- Dongmin Kang
- Department of Molecular and Cell Biology, 385 LSA, University of California, Berkeley, CA 94720-3200, USA
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38
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Bauer R, Lehmann C, Hoch M. Gastrointestinal development in the Drosophila embryo requires the activity of innexin gap junction channel proteins. CELL COMMUNICATION & ADHESION 2003; 8:307-10. [PMID: 12064608 DOI: 10.3109/15419060109080743] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cell to cell communication plays an essential role during pattern formation and morphogenesis of the diverse tissues and organs of the body. In invertebrates, such as the fruitfly Drosophila, the direct communication of closely apposed cells is mediated by gap junctions which are composed of oligomers of the innexin family of transmembrane channel proteins. Few data exist about the developmental role of the eight innexin genes which have been found in the Drosophila genome. We have investigated the role of the innexin 2 and ogre genes during gastrointestinal development of the fly embryo. Our findings suggest that innexins are involved in the formation of the proventriculus, an organ that develops at the foregut/midgut boundary by migration of primordial cells and subsequent infolding of epithelial tissue layers.
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Affiliation(s)
- R Bauer
- Institut für Zoophysiologie der Universität Bonn, Abt. für Entwicklungsbiologie, Germany
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Abstract
Recent studies in zebrafish have contributed to our understanding of early endoderm formation in vertebrates. Specifically, they have illustrated the importance of Nodal signaling as well as three transcription factors, Faust/Gata5, Bonnie and Clyde, and Casanova, in this process. Ongoing genetic and embryological studies in zebrafish are also contributing to our understanding of later aspects of endoderm development, including the formation of the gut and its associated organs, the liver and pancreas. The generation of transgenic lines expressing GFP in these organs promises to be particularly helpful in such studies.
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Affiliation(s)
- Elke A Ober
- Department of Biochemistry and Biophysics, Programs in Developmental Biology, Genetics and Human Genetics, University of California, San Francisco, CA 94143-0448, USA
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Johansen KA, Iwaki DD, Lengyel JA. Localized JAK/STAT signaling is required for oriented cell rearrangement in a tubular epithelium. Development 2003; 130:135-45. [PMID: 12441298 DOI: 10.1242/dev.00202] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Rearrangement of cells constrained within an epithelium is a key process that contributes to tubular morphogenesis. We show that activation in a gradient of the highly conserved JAK/STAT pathway is essential for orienting the cell rearrangement that drives elongation of a genetically tractable model. Using loss-of-function and gain-of-function experiments, we show that the components of the pathway from ligand to the activated transcriptional regulator STAT are required for cell rearrangement in the Drosophila embryonic hindgut. The difference in effect between localized expression of ligand (Unpaired) and dominant active JAK (Hopscotch) demonstrates that the ligand plays a cell non-autonomous role in hindgut cell rearrangement. Taken together with the appearance of STAT92E in a gradient in the hindgut epithelium, these results support a model in which an anteroposterior gradient of ligand results in a gradient of activated STAT. These results provide the first example in which JAK/STAT signaling plays a required role in orienting cell rearrangement that elongates an epithelium.
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Affiliation(s)
- Katherine A Johansen
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095-1606, USA
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Maurange C, Paro R. A cellular memory module conveys epigenetic inheritance of hedgehog expression during Drosophila wing imaginal disc development. Genes Dev 2002; 16:2672-83. [PMID: 12381666 PMCID: PMC187463 DOI: 10.1101/gad.242702] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In Drosophila, the Trithorax-group (trxG) and Polycomb-group (PcG) proteins interact with chromosomal elements, termed Cellular Memory Modules (CMMs). By modifying chromatin, this ensures a stable heritable maintenance of the transcriptional state of developmental regulators, like the homeotic genes, that is defined embryonically. We asked whether such CMMs could also control expression of genes involved in patterning imaginal discs during larval development. Our results demonstrate that expression of the hedgehog gene, once activated, is maintained by a CMM. In addition, our experiments indicate that the switching of such CMMs to an active state during larval stages, in contrast to embryonic stages, may require specific trans-activators. Our results suggest that the patterning of cells in particular developmental fields in the imaginal discs does not only rely on external cues from morphogens, but also depends on the previous history of the cells, as the control by CMMs ensures a preformatted gene expression pattern.
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Affiliation(s)
- Cédric Maurange
- Zentrum für Molekulare Biologie Heidelberg (ZMBH), University of Heidelberg, D-69120 Heidelberg, Germany
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42
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Cuschieri A. Anorectal anomalies associated with or as part of other anomalies. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 110:122-30. [PMID: 12116249 DOI: 10.1002/ajmg.10371] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Anorectal anomalies occurring with other anomalies or as part of syndromes were analyzed to determine how their epidemiological characteristics differed from those of isolated anal anomalies. Almost 15% of cases were chromosomal, monogenic or teratogenic syndromes, whereas the rest were of unknown cause including sequences (9.3%), VACTERL associations (15.4%) and multiple congenital anomalies (MCA) (60.2%). Almost half of babies with MCA had one or two VACTERL anomalies with distribution frequencies that did not differ significantly from those in babies with the full VACTERL association. There were considerable differences in the frequency of the VACTERL association among babies with different types of anorectal anomaly. Babies with anal anomalies occurring with sequences, VACTERL or MCA showed the same sex differences as babies with isolated anal anomalies, namely male predominance in anal atresia without fistula or cloaca, no sex difference in anal atresia with fistula, and female predominance in ectopic anus and congenital anal fistula. These anomalies, however, were associated with significantly lower mean gestational lengths and birth weights, and higher frequencies of fetal death and pregnancy termination than babies with isolated anal anomalies. Twins were more frequent in sequences, VACTERL and MCA than in isolated anomalies, monogenic syndromes or chromosome anomalies. Five cases were conjoined twins, representing 15% of all cases of twin pregnancies with an anal anomaly. Indeterminate sex was more frequent in babies with anal atresias without fistula than in those with fistula. Anal anomalies are defects of blastogenesis attributable to disorders in expression of pattern determining genes. The differential sex involvement in different types of anal anomaly may be manifestations of expression of the HY/SRY genes during blastogenesis or of X-linkage.
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Iwaki DD, Lengyel JA. A Delta-Notch signaling border regulated by Engrailed/Invected repression specifies boundary cells in the Drosophila hindgut. Mech Dev 2002; 114:71-84. [PMID: 12175491 DOI: 10.1016/s0925-4773(02)00061-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The Drosophila hindgut develops three morphologically distinct regions along its anteroposterior axis: small intestine, large intestine and rectum. Single-cell rings of 'boundary cells' delimit the large intestine from the small intestine at the anterior, and the rectum at the posterior. The large intestine also forms distinct dorsal and ventral regions; these are separated by two single-cell rows of boundary cells. Boundary cells are distinguished by their elongated morphology, high level of both apical and cytoplasmic Crb protein, and gene expression program. During embryogenesis, the boundary cell rows arise at the juxtaposition of a domain of Engrailed (En)- plus Invected (Inv)-expressing cells with a domain of Delta (Dl)-expressing cells. Analysis of loss-of-function and ectopic expression phenotypes shows that the domain of Dl-expressing cells is defined by En/Inv repression. Further, Notch pathway signaling, specifically the juxtaposition of Dl-expressing and Dl-non-expressing cells, is required to specify the rows of boundary cells. This Notch-induced cell specification is distinguished by the fact that it does not appear to utilize the ligand Serrate and the modulator Fringe.
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Affiliation(s)
- D David Iwaki
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, CA 90095-1606, USA
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Abstract
The Drosophila hindgut is fruitful territory for investigation of events common to many types of organogenesis. The development of the Drosophila hindgut provides, in microcosm, a genetic model system for studying processes such as establishment (patterning) of an epithelial primordium, its internalization by gastrulation, development of left--right asymmetric looping, patterning in both the anteroposterior and dorsoventral axes, innervation, investment of an epithelium with mesoderm, reciprocal epitheliomesenchymal interactions, cell shape change, and cell rearrangement. We review the genetic control of these processes during development of the Drosophila hindgut, and compare these to related processes in other bilaterians, particularly vertebrates. We propose that caudal/Cdx, brachyenteron/Brachyury, fork head/HNF-3, and wingless/Wnt constitute a conserved "cassette" of genes expressed in the blastopore and later in the gut, involved in posterior patterning, cell rearrangement, and gut maintenance. Elongation of the internalized Drosophila hindgut primordium is similar to elongation of the archenteron and also of the entire embryonic axis (both during and after gastrulation), as well as of various tubules (e.g., nephric ducts, Malpighian tubules), as it is driven by cell rearrangement. The genes drumstick, bowl, and lines (which encode putative transcriptional regulators) are required for this cell rearrangement, as well as for spatially localized gene expression required to establish the three morphologically distinct subregions of the hindgut. Expression of signaling molecules regulated by drumstick, bowl, and lines, in particular of the JAK/STAT activator Unpaired at the hindgut anterior, may play a role in controlling hindgut cell rearrangement. Other cell signaling molecules expressed in the hindgut epithelium are required to establish its normal size (Dpp and Hh), and to establish and maintain the hindgut visceral mesoderm (Wg and Hh). Both maternal gene activity and zygotic gene activity are required for asymmetric left--right looping of the hindgut. Some of the same genes (caudal and brachyenteron) required for embryonic hindgut development also act during pupation to construct a new hindgut from imaginal cells. Application of the plethora of genetic techniques available in Drosophila, including forward genetic screens, should identify additional genes controlling hindgut development and thus shed light on a variety of common morphogenetic processes.
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Affiliation(s)
- Judith A Lengyel
- Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, California 90095-1606, USA.
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Fuss B, Hoch M. Notch signaling controls cell fate specification along the dorsoventral axis of the Drosophila gut. Curr Biol 2002; 12:171-9. [PMID: 11839268 DOI: 10.1016/s0960-9822(02)00653-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Gut formation is a key event during animal development. Recent genetic analysis in chick, mice, and Drosophila has identified Hedgehog and TGFbeta signals as essential players for the development of the primitive gut tube along its anterior-posterior (AP) axis. However, the genetic programs that control gut patterning along its dorsoventral (DV) axis have remained largely elusive. RESULTS We demonstrate that the activation of the Notch receptor occurs in a single row of boundary cells which separates dorsal from ventral cells in the Drosophila hindgut. rhomboid, which encodes a transmembrane protein, and knirps/knirps-related, which encode nuclear steroid receptors, are Notch target genes required for the expression of crumbs, which encodes a transmembrane protein involved in organizing apical-basal polarity. Notch receptor activation depends on the expression of its ligand Delta in ventral cells, and localizing the Notch receptor to the apical domain of the boundary cells may be required for proper signaling. The analysis of gene expression mediated by a Notch response element suggests that boundary cell-specific expression can be obtained by cooperation of Suppressor of Hairless and the transcription factor Grainyhead or a related factor. CONCLUSIONS Our results demonstrate that Notch signaling plays a pivotal role in determining cell fates along the DV axis of the Drosophila hindgut. The finding that Notch signaling results in the expression of an apical polarity organizer which may be required, in turn, for apical Notch receptor localization suggests a simple mechanism by which the specification of a single cell row might be controlled.
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Affiliation(s)
- Bernhard Fuss
- Universität Bonn, Institut für Zoophysiologie, Abteilung Entwicklungsbiologie, Poppelsdorfer Schloss, D-53115 Bonn, Germany
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Inoue Y, Niwa N, Mito T, Ohuchi H, Yoshioka H, Noji S. Expression patterns of hedgehog, wingless, and decapentaplegic during gut formation of Gryllus bimaculatus (cricket). Mech Dev 2002; 110:245-8. [PMID: 11744392 DOI: 10.1016/s0925-4773(01)00584-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We observed expression patterns of hedgehog (hh), wingless (wg), and decapentaplegic (dpp) during gut development of Gryllus bimaculatus (the cricket), a typical hemimetabolous insect, and compared with those observed in Drosophila, a typical holometabolous insect. Gryllus hh(Gbhh) and Gbwg are expressed in both foregut and hindgut, while Gbdpp is expressed only in the hindgut: at the boundaries between the small and large intestine, and between the large intestine and rectum. Although the expression patterns of Gbhh and Gbwg are essentially comparable to those observed in Drosophila, the expression pattern of Gbdpp differs from those of the Drosophila dpp.
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Affiliation(s)
- Yoshiko Inoue
- Department of Biological Science and Technology, Faculty of Engineering, The University of Tokushima, 2-1 Minami-Jyosanjima-cho, Tokushima City, 770-8506, Japan
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Iwaki DD, Johansen KA, Singer JB, Lengyel JA. drumstick, bowl, and lines are required for patterning and cell rearrangement in the Drosophila embryonic hindgut. Dev Biol 2001; 240:611-26. [PMID: 11784087 DOI: 10.1006/dbio.2001.0483] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Drosophila embryonic hindgut is a robust system for the study of patterning and morphogenesis of epithelial organs. We show that, in a period of about 10 h, and in the absence of significant cell division or apoptosis, the hindgut epithelium undergoes morphogenesis by changes in cell shape and size and by cell rearrangement. The epithelium concomitantly becomes surrounded by visceral mesoderm and is characterized by distinct gene expression patterns that forecast the development of three morphological subdomains: small intestine, large intestine, and rectum. At least three genes encoding putative transcriptional regulators, drumstick (drm), bowl, and lines (lin), are required to establish normal hindgut morphology. We show that the defect in hindgut elongation in drm, bowl, and lin mutants is due, in large part, to the requirement of these genes in the process of cell rearrangement. Further, we show that drm, bowl, and lin are required for patterning of the hindgut, i.e., for correct expression in the prospective small intestine, large intestine, and rectum of genes encoding cell signals (wingless, hedgehog, unpaired, Serrate, dpp) and transcription factors (engrailed, dead ringer). The close association of both cell rearrangement and patterning defects in all three mutants suggest that proper patterning of the hindgut into small intestine and large intestine is likely required for its correct morphogenesis.
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Affiliation(s)
- D D Iwaki
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, California 90095-1606, USA
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Podos SD, Hanson KK, Wang YC, Ferguson EL. The DSmurf ubiquitin-protein ligase restricts BMP signaling spatially and temporally during Drosophila embryogenesis. Dev Cell 2001; 1:567-78. [PMID: 11703946 DOI: 10.1016/s1534-5807(01)00057-0] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We identified Drosophila Smurf (DSmurf) as a negative regulator of signaling by the BMP2/4 ortholog DPP during embryonic dorsal-ventral patterning. DSmurf encodes a HECT domain ubiquitin-protein ligase, homologous to vertebrate Smurf1 and Smurf2, that binds the Smad1/5 ortholog MAD and likely promotes its proteolysis. The essential function of DSmurf is restricted to its action on the DPP pathway. DSmurf has two distinct, possibly mechanistically separate, functions in controlling DPP signaling. Prior to gastrulation, DSmurf mutations cause a spatial increase in the DPP gradient, as evidenced by ventrolateral expansion in expression domains of target genes representing all known signaling thresholds. After gastrulation, DSmurf mutations cause a temporal delay in downregulation of earlier DPP signals, resulting in a lethal defect in hindgut organogenesis.
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Affiliation(s)
- S D Podos
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637, USA
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Shu W, Yang H, Zhang L, Lu MM, Morrisey EE. Characterization of a New Subfamily of Winged-helix/Forkhead (Fox) Genes That Are Expressed in the Lung and Act as Transcriptional Repressors. J Biol Chem 2001; 276:27488-97. [PMID: 11358962 DOI: 10.1074/jbc.m100636200] [Citation(s) in RCA: 247] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Epithelial gene expression in the lung is thought to be regulated by the coordinate activity of several different families of transcription factors including the Fox family of winged-helix/forkhead DNA-binding proteins. In this report, we have identified and characterized two members of this Fox gene family, Foxp1 and Foxp2, and show that they comprise a new subfamily of Fox genes expressed in the lung. Foxp1 and Foxp2 are expressed at high levels in the lung as early as E12.5 of mouse development with Foxp2 expression restricted to the airway epithelium. In addition, Foxp1 and Foxp2 are expressed at lower levels in neural, intestinal, and cardiovascular tissues during development. Upon differentiation of the airway epithelium along the proximal-distal axis, Foxp2 expression becomes restricted to the distal alveolar epithelium whereas Foxp1 expression is observed in the distal epithelium and mesenchyme. Foxp1 and Foxp2 can regulate epithelial lung gene transcription as was demonstrated by their ability to dramatically repress the mouse CC10 promoter and, to a lesser extent, the human surfactant protein C promoter. In addition, GAL4 fusion proteins encoding subdomains of Foxp1 and Foxp2 demonstrate that an independent and homologous transcriptional repression domain lies within the N-terminal end of the proteins. Together, these studies suggest that Foxp1 and Foxp2 are important regulators of lung epithelial gene transcription.
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Affiliation(s)
- W Shu
- Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Murakami R, Shiotsuki Y. Ultrastructure of the hindgut of Drosophila larvae, with special reference to the domains identified by specific gene expression patterns. J Morphol 2001; 248:144-50. [PMID: 11304745 DOI: 10.1002/jmor.1025] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The hindgut of Drosophila larvae consists of nine domains that have been distinguished by specific gene expression patterns. In the present study, we examined the ultrastructure of the hindgut of Drosophila larvae, with special reference to the domains, in order to determine whether or not the domains are morphologically distinct functional units. Each domain showed specific ultrastructural features that suggested specific corresponding functions. According to the morphological features, terms are proposed for each domain: the imaginal ring; the "pylorus," which has a thick cuticular layer and well-developed sphincter muscles; the "large intestine," which occupies a major middle portion of the hindgut and has a unique dorsal and ventral subdivision; "border cells," which delineate the anterior and posterior borders of the large intestine and the border between the dorsal and ventral domains of the large intestine; and the "rectum," which is situated at the posterior end of the hindgut and has a thick cuticular layer and sphincter muscles. The morphological features indicate that the large intestine has active absorptive activities. The domains, which have been distinguished by gene expressions, were demonstrated to be functional tissue units of the gut.
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Affiliation(s)
- R Murakami
- Department of Physics, Biology, and Informatics, Faculty of Sciences, Yamaguchi University, Japan.
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