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Bileckyj C, Blotz B, Cripps RM. Drosophila as a Model to Understand Second Heart Field Development. J Cardiovasc Dev Dis 2023; 10:494. [PMID: 38132661 PMCID: PMC10744189 DOI: 10.3390/jcdd10120494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/06/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023] Open
Abstract
The genetic model system Drosophila has contributed fundamentally to our understanding of mammalian heart specification, development, and congenital heart disease. The relatively simple Drosophila heart is a linear muscular tube that is specified and develops in the embryo and persists throughout the life of the animal. It functions at all stages to circulate hemolymph within the open circulatory system of the body. During Drosophila metamorphosis, the cardiac tube is remodeled, and a new layer of muscle fibers spreads over the ventral surface of the heart to form the ventral longitudinal muscles. The formation of these fibers depends critically upon genes known to be necessary for mammalian second heart field (SHF) formation. Here, we review the prior contributions of the Drosophila system to the understanding of heart development and disease, discuss the importance of the SHF to mammalian heart development and disease, and then discuss how the ventral longitudinal adult cardiac muscles can serve as a novel model for understanding SHF development and disease.
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Affiliation(s)
| | | | - Richard M. Cripps
- Department of Biology, San Diego State University, San Diego, CA 92182, USA
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2
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Lei Y, Huang Y, Yang K, Cao X, Song Y, Martín-Blanco E, Pastor-Pareja JC. FGF signaling promotes spreading of fat body precursors necessary for adult adipogenesis in Drosophila. PLoS Biol 2023; 21:e3002050. [PMID: 36947563 PMCID: PMC10069774 DOI: 10.1371/journal.pbio.3002050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 04/03/2023] [Accepted: 02/24/2023] [Indexed: 03/23/2023] Open
Abstract
Knowledge of adipogenetic mechanisms is essential to understand and treat conditions affecting organismal metabolism and adipose tissue health. In Drosophila, mature adipose tissue (fat body) exists in larvae and adults. In contrast to the well-known development of the larval fat body from the embryonic mesoderm, adult adipogenesis has remained mysterious. Furthermore, conclusive proof of its physiological significance is lacking. Here, we show that the adult fat body originates from a pool of undifferentiated mesodermal precursors that migrate from the thorax into the abdomen during metamorphosis. Through in vivo imaging, we found that these precursors spread from the ventral midline and cover the inner surface of the abdomen in a process strikingly reminiscent of embryonic mesoderm migration, requiring fibroblast growth factor (FGF) signaling as well. FGF signaling guides migration dorsally and regulates adhesion to the substrate. After spreading is complete, precursor differentiation involves fat accumulation and cell fusion that produces mature binucleate and tetranucleate adipocytes. Finally, we show that flies where adult adipogenesis is impaired by knock down of FGF receptor Heartless or transcription factor Serpent display ectopic fat accumulation in oenocytes and decreased resistance to starvation. Our results reveal that adult adipogenesis occurs de novo during metamorphosis and demonstrate its crucial physiological role.
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Affiliation(s)
- Yuting Lei
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuwei Huang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Ke Yang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Xueya Cao
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuzhao Song
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Enrique Martín-Blanco
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Parc Científic de Barcelona, Barcelona, Spain
| | - José Carlos Pastor-Pareja
- School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
- Institute of Neurosciences, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, San Juan de Alicante, Spain
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3
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Abbas Kadhim Hamzah, Forat Abd Al-Hamzah. Effect of Laser Radiation on the Phenotypic Mutations of Drosophila melanogaster (Diptera:Drosophilidae). JOURNAL OF ADVANCED ZOOLOGY 2022; 43:104-110. [DOI: 10.17762/jaz.v43i1.141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
This study was conducted to find out the effect of 5 periods of exposure to laser rays (0,15,10,5,20) minutes on the phenotypic mutations of Drosophila melanogaster, as well as calculating the percentage of mortality and the percentage of larval failure. The results showed that laser beams had significant effects in causing mutations, especially in the 15-minute period, which amounted to 0.33 and thus formed significant differences compared to the control group. The periods of exposure to laser rays also caused clear effects in the rate of larval mortality, as the death rate was 100% for the period of 20 minutes, while this rate decreased to 27% and 34% for the periods 5 and 10 minutes, respectively, while the lowest failure rate was 0% at the period 20, which led to the death of all the larvae.
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4
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Secchia S, Forneris M, Heinen T, Stegle O, Furlong EEM. Simultaneous cellular and molecular phenotyping of embryonic mutants using single-cell regulatory trajectories. Dev Cell 2022; 57:496-511.e8. [PMID: 35176234 PMCID: PMC8893321 DOI: 10.1016/j.devcel.2022.01.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/04/2021] [Accepted: 01/26/2022] [Indexed: 11/09/2022]
Abstract
Developmental progression and cellular diversity are largely driven by transcription factors (TFs); yet, characterizing their loss-of-function phenotypes remains challenging and often disconnected from their underlying molecular mechanisms. Here, we combine single-cell regulatory genomics with loss-of-function mutants to jointly assess both cellular and molecular phenotypes. Performing sci-ATAC-seq at eight overlapping time points during Drosophila mesoderm development could reconstruct the developmental trajectories of all major muscle types and reveal the TFs and enhancers involved. To systematically assess mutant phenotypes, we developed a single-nucleus genotyping strategy to process embryo pools of mixed genotypes. Applying this to four TF mutants could identify and quantify their characterized phenotypes de novo and discover new ones, while simultaneously revealing their regulatory input and mode of action. Our approach is a general framework to dissect the functional input of TFs in a systematic, unbiased manner, identifying both cellular and molecular phenotypes at a scale and resolution that has not been feasible before. scATAC time course constructs regulatory trajectories of Drosophila muscle lineages Combining a wild-type trajectory with mutants identifies and quantifies phenotypes de novo Digital nuclear genotyping enables the processing of pooled embryos of mixed genotypes This framework simultaneously uncovers cellular and molecular phenotypes in embryos
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Affiliation(s)
- Stefano Secchia
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Baden-Württemberg, Germany; Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, Baden-Württemberg, Germany
| | - Mattia Forneris
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Baden-Württemberg, Germany
| | - Tobias Heinen
- Division of Computational Genomics and Systems Genetics, German Cancer Research Center (DKFZ), 69120 Heidelberg, Baden-Württemberg, Germany; Heidelberg University, Faculty of Mathematics and Computer Science, 69120 Heidelberg, Baden-Württemberg, Germany
| | - Oliver Stegle
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Baden-Württemberg, Germany; Division of Computational Genomics and Systems Genetics, German Cancer Research Center (DKFZ), 69120 Heidelberg, Baden-Württemberg, Germany
| | - Eileen E M Furlong
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Baden-Württemberg, Germany.
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5
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A Large Scale Systemic RNAi Screen in the Red Flour Beetle Tribolium castaneum Identifies Novel Genes Involved in Insect Muscle Development. G3-GENES GENOMES GENETICS 2019; 9:1009-1026. [PMID: 30733381 PMCID: PMC6469426 DOI: 10.1534/g3.118.200995] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Although muscle development has been widely studied in Drosophila melanogaster there are still many gaps in our knowledge, and it is not known to which extent this knowledge can be transferred to other insects. To help in closing these gaps we participated in a large-scale RNAi screen that used the red flour beetle, Tribolium castaneum, as a screening platform. The effects of systemic RNAi were screened upon double-stranded RNA injections into appropriate muscle-EGFP tester strains. Injections into pupae were followed by the analysis of the late embryonic/early larval muscle patterns, and injections into larvae by the analysis of the adult thoracic muscle patterns. Herein we describe the results of the first-pass screens with pupal and larval injections, which covered ∼8,500 and ∼5,000 genes, respectively, of a total of ∼16,500 genes of the Tribolium genome. Apart from many genes known from Drosophila as regulators of muscle development, a collection of genes previously unconnected to muscle development yielded phenotypes in larval body wall and leg muscles as well as in indirect flight muscles. We then present the main candidates from the pupal injection screen that remained after being processed through a series of verification and selection steps. Further, we discuss why distinct though overlapping sets of genes are revealed by the Drosophila and Tribolium screening approaches.
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Banerjee U, Girard JR, Goins LM, Spratford CM. Drosophila as a Genetic Model for Hematopoiesis. Genetics 2019; 211:367-417. [PMID: 30733377 PMCID: PMC6366919 DOI: 10.1534/genetics.118.300223] [Citation(s) in RCA: 142] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/05/2018] [Indexed: 12/17/2022] Open
Abstract
In this FlyBook chapter, we present a survey of the current literature on the development of the hematopoietic system in Drosophila The Drosophila blood system consists entirely of cells that function in innate immunity, tissue integrity, wound healing, and various forms of stress response, and are therefore functionally similar to myeloid cells in mammals. The primary cell types are specialized for phagocytic, melanization, and encapsulation functions. As in mammalian systems, multiple sites of hematopoiesis are evident in Drosophila and the mechanisms involved in this process employ many of the same molecular strategies that exemplify blood development in humans. Drosophila blood progenitors respond to internal and external stress by coopting developmental pathways that involve both local and systemic signals. An important goal of these Drosophila studies is to develop the tools and mechanisms critical to further our understanding of human hematopoiesis during homeostasis and dysfunction.
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Affiliation(s)
- Utpal Banerjee
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095
- Molecular Biology Institute, University of California, Los Angeles, California 90095
- Department of Biological Chemistry, University of California, Los Angeles, California 90095
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, California 90095
| | - Juliet R Girard
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095
| | - Lauren M Goins
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095
| | - Carrie M Spratford
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095
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7
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Clark E. Dynamic patterning by the Drosophila pair-rule network reconciles long-germ and short-germ segmentation. PLoS Biol 2017; 15:e2002439. [PMID: 28953896 PMCID: PMC5633203 DOI: 10.1371/journal.pbio.2002439] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 10/09/2017] [Accepted: 09/07/2017] [Indexed: 02/07/2023] Open
Abstract
Drosophila segmentation is a well-established paradigm for developmental pattern formation. However, the later stages of segment patterning, regulated by the "pair-rule" genes, are still not well understood at the system level. Building on established genetic interactions, I construct a logical model of the Drosophila pair-rule system that takes into account the demonstrated stage-specific architecture of the pair-rule gene network. Simulation of this model can accurately recapitulate the observed spatiotemporal expression of the pair-rule genes, but only when the system is provided with dynamic "gap" inputs. This result suggests that dynamic shifts of pair-rule stripes are essential for segment patterning in the trunk and provides a functional role for observed posterior-to-anterior gap domain shifts that occur during cellularisation. The model also suggests revised patterning mechanisms for the parasegment boundaries and explains the aetiology of the even-skipped null mutant phenotype. Strikingly, a slightly modified version of the model is able to pattern segments in either simultaneous or sequential modes, depending only on initial conditions. This suggests that fundamentally similar mechanisms may underlie segmentation in short-germ and long-germ arthropods.
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Affiliation(s)
- Erik Clark
- Laboratory for Development and Evolution, Department of Zoology, University of Cambridge, Cambridge, United Kingdom
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8
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Mendoza-García P, Hugosson F, Fallah M, Higgins ML, Iwasaki Y, Pfeifer K, Wolfstetter G, Varshney G, Popichenko D, Gergen JP, Hens K, Deplancke B, Palmer RH. The Zic family homologue Odd-paired regulates Alk expression in Drosophila. PLoS Genet 2017; 13:e1006617. [PMID: 28369060 PMCID: PMC5393633 DOI: 10.1371/journal.pgen.1006617] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 04/17/2017] [Accepted: 02/07/2017] [Indexed: 01/30/2023] Open
Abstract
The Anaplastic Lymphoma Kinase (Alk) receptor tyrosine kinase (RTK) plays a critical role in the specification of founder cells (FCs) in the Drosophila visceral mesoderm (VM) during embryogenesis. Reporter gene and CRISPR/Cas9 deletion analysis reveals enhancer regions in and upstream of the Alk locus that influence tissue-specific expression in the amnioserosa (AS), the VM and the epidermis. By performing high throughput yeast one-hybrid screens (Y1H) with a library of Drosophila transcription factors (TFs) we identify Odd-paired (Opa), the Drosophila homologue of the vertebrate Zic family of TFs, as a novel regulator of embryonic Alk expression. Further characterization identifies evolutionarily conserved Opa-binding cis-regulatory motifs in one of the Alk associated enhancer elements. Employing Alk reporter lines as well as CRISPR/Cas9-mediated removal of regulatory elements in the Alk locus, we show modulation of Alk expression by Opa in the embryonic AS, epidermis and VM. In addition, we identify enhancer elements that integrate input from additional TFs, such as Binou (Bin) and Bagpipe (Bap), to regulate VM expression of Alk in a combinatorial manner. Taken together, our data show that the Opa zinc finger TF is a novel regulator of embryonic Alk expression. The Alk receptor tyrosine kinase is employed repeatedly during Drosophila development to drive signaling events in a variety of tissues. The spatial and temporal expression pattern of the Alk gene is tightly regulated. Identifying factors that influence the expression of Alk is important to better understand how Alk signaling is controlled. In this paper we characterize cis-regulatory sequences in the Alk locus and the transcription factors that bind them to govern Alk expression in the Drosophila embryo. Using a robotic protein-DNA interaction assay, we identified the Zic family transcription factor Odd-paired as a factor that binds to regulatory elements in the Alk locus. Binding of Odd-paired to Alkcis-regulatory elements varies spatially, revealing a requirement for additional transcription factors such as the NK3 and FoxF orthologues Bagpipe and Biniou in a subset of Alk-expressing tissues. Our findings provide new insight into the dynamics underlying temporal and spatial regulation of the Alk receptor during embryogenesis.
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Affiliation(s)
- Patricia Mendoza-García
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Fredrik Hugosson
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Mahsa Fallah
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Michael L. Higgins
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Yasuno Iwasaki
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Kathrin Pfeifer
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Georg Wolfstetter
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Gaurav Varshney
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | | | - J. Peter Gergen
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Korneel Hens
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
| | - Bart Deplancke
- Laboratory of Systems Biology and Genetics, Lausanne, Switzerland
| | - Ruth H. Palmer
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- * E-mail:
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9
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10
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Qualitative Dynamical Modelling Can Formally Explain Mesoderm Specification and Predict Novel Developmental Phenotypes. PLoS Comput Biol 2016; 12:e1005073. [PMID: 27599298 PMCID: PMC5012701 DOI: 10.1371/journal.pcbi.1005073] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 07/22/2016] [Indexed: 12/21/2022] Open
Abstract
Given the complexity of developmental networks, it is often difficult to predict the effect of genetic perturbations, even within coding genes. Regulatory factors generally have pleiotropic effects, exhibit partially redundant roles, and regulate highly interconnected pathways with ample cross-talk. Here, we delineate a logical model encompassing 48 components and 82 regulatory interactions involved in mesoderm specification during Drosophila development, thereby providing a formal integration of all available genetic information from the literature. The four main tissues derived from mesoderm correspond to alternative stable states. We demonstrate that the model can predict known mutant phenotypes and use it to systematically predict the effects of over 300 new, often non-intuitive, loss- and gain-of-function mutations, and combinations thereof. We further validated several novel predictions experimentally, thereby demonstrating the robustness of model. Logical modelling can thus contribute to formally explain and predict regulatory outcomes underlying cell fate decisions.
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11
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Clark E, Akam M. Odd-paired controls frequency doubling in Drosophila segmentation by altering the pair-rule gene regulatory network. eLife 2016; 5:e18215. [PMID: 27525481 PMCID: PMC5035143 DOI: 10.7554/elife.18215] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 08/14/2016] [Indexed: 01/08/2023] Open
Abstract
The Drosophila embryo transiently exhibits a double-segment periodicity, defined by the expression of seven 'pair-rule' genes, each in a pattern of seven stripes. At gastrulation, interactions between the pair-rule genes lead to frequency doubling and the patterning of 14 parasegment boundaries. In contrast to earlier stages of Drosophila anteroposterior patterning, this transition is not well understood. By carefully analysing the spatiotemporal dynamics of pair-rule gene expression, we demonstrate that frequency-doubling is precipitated by multiple coordinated changes to the network of regulatory interactions between the pair-rule genes. We identify the broadly expressed but temporally patterned transcription factor, Odd-paired (Opa/Zic), as the cause of these changes, and show that the patterning of the even-numbered parasegment boundaries relies on Opa-dependent regulatory interactions. Our findings indicate that the pair-rule gene regulatory network has a temporally modulated topology, permitting the pair-rule genes to play stage-specific patterning roles.
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Affiliation(s)
- Erik Clark
- Laboratory for Development and Evolution, Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Michael Akam
- Laboratory for Development and Evolution, Department of Zoology, University of Cambridge, Cambridge, United Kingdom
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12
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Dobi KC, Schulman VK, Baylies MK. Specification of the somatic musculature in Drosophila. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2015; 4:357-75. [PMID: 25728002 PMCID: PMC4456285 DOI: 10.1002/wdev.182] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 01/16/2015] [Accepted: 02/04/2015] [Indexed: 11/09/2022]
Abstract
The somatic muscle system formed during Drosophila embryogenesis is required for larvae to hatch, feed, and crawl. This system is replaced in the pupa by a new adult muscle set, responsible for activities such as feeding, walking, and flight. Both the larval and adult muscle systems are comprised of distinct muscle fibers to serve these specific motor functions. In this way, the Drosophila musculature is a valuable model for patterning within a single tissue: while all muscle cells share properties such as the contractile apparatus, properties such as size, position, and number of nuclei are unique for a particular muscle. In the embryo, diversification of muscle fibers relies first on signaling cascades that pattern the mesoderm. Subsequently, the combinatorial expression of specific transcription factors leads muscle fibers to adopt particular sizes, shapes, and orientations. Adult muscle precursors (AMPs), set aside during embryonic development, proliferate during the larval phases and seed the formation of the abdominal, leg, and flight muscles in the adult fly. Adult muscle fibers may either be formed de novo from the fusion of the AMPs, or are created by the binding of AMPs to an existing larval muscle. While less is known about adult muscle specification compared to the larva, expression of specific transcription factors is also important for its diversification. Increasingly, the mechanisms required for the diversification of fly muscle have found parallels in vertebrate systems and mark Drosophila as a robust model system to examine questions about how diverse cell types are generated within an organism.
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Affiliation(s)
- Krista C. Dobi
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY, USA
| | - Victoria K. Schulman
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY, USA
- Cell and Developmental Biology, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, NY, USA
| | - Mary K. Baylies
- Program in Developmental Biology, Sloan Kettering Institute, New York, NY, USA
- Cell and Developmental Biology, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, NY, USA
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13
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Schäfer G, Narasimha M, Vogelsang E, Leptin M. Cadherin switching during the formation and differentiation of the Drosophila mesoderm - implications for epithelial-to-mesenchymal transitions. J Cell Sci 2014; 127:1511-22. [PMID: 24496448 DOI: 10.1242/jcs.139485] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Epithelial-to-mesenchymal transition (EMT) is typically accompanied by downregulation of epithelial (E-) cadherin, and is often additionally accompanied by upregulation of a mesenchymal or neuronal (N-) cadherin. Snail represses transcription of the E-cadherin gene both during normal development and during tumour spreading. The formation of the mesodermal germ layer in Drosophila, considered a paradigm of a developmental EMT, is associated with Snail-mediated repression of E-cadherin and the upregulation of N-cadherin. By using genetic manipulation to remove or overexpress the cadherins, we show here that the complementarity of cadherin expression is not necessary for the segregation or the dispersal of the mesodermal germ layer in Drosophila. However, we discover different effects of E- and N-cadherin on the differentiation of subsets of mesodermal derivatives, which depend on Wingless signalling from the ectoderm, indicating differing abilities of E- and N-cadherin to bind to and sequester the common junctional and signalling effector β-catenin. These results suggest that the downregulation of E-cadherin in the mesoderm might be required to facilitate optimal levels of Wingless signalling.
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Affiliation(s)
- Gritt Schäfer
- Institute of Genetics, University of Cologne, Zülpicher Strasse 47a, 50674 Cologne, Germany
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14
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The Iroquois complex is required in the dorsal mesoderm to ensure normal heart development in Drosophila. PLoS One 2013; 8:e76498. [PMID: 24086746 PMCID: PMC3781054 DOI: 10.1371/journal.pone.0076498] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 08/27/2013] [Indexed: 12/23/2022] Open
Abstract
Drosophila heart development is an invaluable system to study the orchestrated action of numerous factors that govern cardiogenesis. Cardiac progenitors arise within specific dorsal mesodermal regions that are under the influence of temporally coordinated actions of multiple signaling pathways. The Drosophila Iroquois complex (Iro-C) consists of the three homeobox transcription factors araucan (ara), caupolican (caup) and mirror (mirr). The Iro-C has been shown to be involved in tissue patterning leading to the differentiation of specific structures, such as the lateral notum and dorsal head structures and in establishing the dorsal-ventral border of the eye. A function for Iro-C in cardiogenesis has not been investigated yet. Our data demonstrate that loss of the whole Iro complex, as well as loss of either ara/caup or mirr only, affect heart development in Drosophila. Furthermore, the data indicate that the GATA factor Pannier requires the presence of Iro-C to function in cardiogenesis. Furthermore, a detailed expression pattern analysis of the members of the Iro-C revealed the presence of a possibly novel subpopulation of Even-skipped expressing pericardial cells and seven pairs of heart-associated cells that have not been described before. Taken together, this work introduces Iro-C as a new set of transcription factors that are required for normal development of the heart. As the members of the Iro-C may function, at least partly, as competence factors in the dorsal mesoderm, our results are fundamental for future studies aiming to decipher the regulatory interactions between factors that determine different cell fates in the dorsal mesoderm.
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15
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Green J, Akam M. Evolution of the pair rule gene network: Insights from a centipede. Dev Biol 2013; 382:235-45. [PMID: 23810931 PMCID: PMC3807789 DOI: 10.1016/j.ydbio.2013.06.017] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 06/05/2013] [Accepted: 06/12/2013] [Indexed: 11/29/2022]
Abstract
Comparative studies have examined the expression and function of homologues of the Drosophila melanogaster pair rule and segment polarity genes in a range of arthropods. The segment polarity gene homologues have a conserved role in the specification of the parasegment boundary, but the degree of conservation of the upstream patterning genes has proved more variable. Using genomic resources we identify a complete set of pair rule gene homologues from the centipede Strigamia maritima, and document a detailed time series of expression during trunk segmentation. We find supportive evidence for a conserved hierarchical organisation of the pair rule genes, with a division into early- and late-activated genes which parallels the functional division into primary and secondary pair rule genes described in insects. We confirm that the relative expression of sloppy-paired and paired with respect to wingless and engrailed at the parasegment boundary is conserved between myriapods and insects; suggesting that functional interactions between these genes might be an ancient feature of arthropod segment patterning. However, we find that the relative expression of a number of the primary pair rule genes is divergent between myriapods and insects. This corroborates suggestions that the evolution of upper tiers in the segmentation gene network is more flexible. Finally, we find that the expression of the Strigamia pair rule genes in periodic patterns is restricted to the ectoderm. This suggests that any direct role of these genes in segmentation is restricted to this germ layer, and that mesoderm segmentation is either dependent on the ectoderm, or occurs through an independent mechanism.
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Affiliation(s)
- Jack Green
- Laboratory for Development and Evolution, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB23EJ, UK.
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16
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Schaub C, Frasch M. Org-1 is required for the diversification of circular visceral muscle founder cells and normal midgut morphogenesis. Dev Biol 2013; 376:245-59. [PMID: 23380635 DOI: 10.1016/j.ydbio.2013.01.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 01/23/2013] [Indexed: 02/08/2023]
Abstract
The T-Box family of transcription factors plays fundamental roles in the generation of appropriate spatial and temporal gene expression profiles during cellular differentiation and organogenesis in animals. In this study we report that the Drosophila Tbx1 orthologue optomotor-blind-related-gene-1 (org-1) exerts a pivotal function in the diversification of circular visceral muscle founder cell identities in Drosophila. In embryos mutant for org-1, the specification of the midgut musculature per se is not affected, but the differentiating midgut fails to form the anterior and central midgut constrictions and lacks the gastric caeca. We demonstrate that this phenotype results from the nearly complete loss of the founder cell specific expression domains of several genes known to regulate midgut morphogenesis, including odd-paired (opa), teashirt (tsh), Ultrabithorax (Ubx), decapentaplegic (dpp) and wingless (wg). To address the mechanisms that mediate the regulatory inputs from org-1 towards Ubx, dpp, and wg in these founder cells we genetically dissected known visceral mesoderm specific cis-regulatory-modules (CRMs) of these genes. The analyses revealed that the activities of the dpp and wg CRMs depend on org-1, the CRMs are bound by Org-1 in vivo and their T-Box binding sites are essential for their activation in the visceral muscle founder cells. We conclude that Org-1 acts within a well-defined signaling and transcriptional network of the trunk visceral mesoderm as a crucial founder cell-specific competence factor, in concert with the general visceral mesodermal factor Biniou. As such, it directly regulates several key genes involved in the establishment of morphogenetic centers along the anteroposterior axis of the visceral mesoderm, which subsequently organize the formation of midgut constrictions and gastric caeca and thereby determine the morphology of the midgut.
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Affiliation(s)
- Christoph Schaub
- Department of Biology, Division of Developmental Biology, Friedrich-Alexander University of Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany
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17
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Fujioka M, Gebelein B, Cofer ZC, Mann RS, Jaynes JB. Engrailed cooperates directly with Extradenticle and Homothorax on a distinct class of homeodomain binding sites to repress sloppy paired. Dev Biol 2012; 366:382-92. [PMID: 22537495 DOI: 10.1016/j.ydbio.2012.04.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 03/25/2012] [Accepted: 04/07/2012] [Indexed: 10/28/2022]
Abstract
Even skipped (Eve) and Engrailed (En) are homeodomain-containing transcriptional repressors with similar DNA binding specificities that are sequentially expressed in Drosophila embryos. The sloppy-paired (slp) locus is a target of repression by both Eve and En. At blastoderm, Eve is expressed in 7 stripes that restrict the posterior border of slp stripes, allowing engrailed (en) gene expression to be initiated in odd-numbered parasegments. En, in turn, prevents expansion of slp stripes after Eve is turned off. Prior studies showed that the two tandem slp transcription units are regulated by cis-regulatory modules (CRMs) with activities that overlap in space and time. An array of CRMs that generate 7 stripes at blastoderm, and later 14 stripes, surround slp1 (Fujioka and Jaynes, 2012). Surprisingly given their similarity in DNA binding specificity and function, responsiveness to ectopic Eve and En indicates that most of their direct target sites are either in distinct CRMs, or in different parts of coregulated CRMs. We localized cooperative binding sites for En, with the homeodomain-containing Hox cofactors Extradenticle (Exd) and Homothorax (Hth), within two CRMs that drive similar expression patterns. Functional analysis revealed two distinct, redundant sites within one CRM. The other CRM contains a single cooperative site that is both necessary and sufficient for repression in the en domain. Correlating in vivo and in vitro analysis suggests that cooperativity with Exd and Hth is a key ingredient in the mechanism of En-dependent repression, and that apparent affinity in vitro is an unreliable predictor of in vivo function.
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Affiliation(s)
- Miki Fujioka
- Department of Biochemistry and Molecular Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
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18
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Abstract
Cell-cell signaling and adhesion are critical for establishing tissue architecture during development and for maintaining tissue architecture and function in the adult. Defects in adhesion and signaling can result in mislocalization of cells, uncontrolled proliferation and improper differentiation, leading to tissue overgrowth, tumor formation, and cancer metastasis. An important example is found in the germline. Germ cells that are not incorporated into the gonad exhibit a greater propensity for forming germ cell tumors, and defects in germline development can reduce fertility. While much attention is given to germ cells, their development into functional gametes depends upon somatic gonadal cells. The study of model organisms has provided great insights into how somatic gonadal cells are specified, the molecular mechanisms that regulate gonad morphogenesis, and the role of germline-soma communication in the establishment and maintenance of the germline stem cell niche. This work will be discussed in the context of Drosophila melanogaster.
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Affiliation(s)
- Jennifer C Jemc
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA.
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19
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de Joussineau C, Bataillé L, Jagla T, Jagla K. Diversification of muscle types in Drosophila: upstream and downstream of identity genes. Curr Top Dev Biol 2012; 98:277-301. [PMID: 22305167 DOI: 10.1016/b978-0-12-386499-4.00011-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Understanding gene regulatory pathways underlying diversification of cell types during development is one of the major challenges in developmental biology. Progressive specification of mesodermal lineages that are at the origin of body wall muscles in Drosophila embryos has been extensively studied during past years, providing an attractive framework for dissecting cell type diversification processes. In particular, it has been found that muscle founder cells that are at the origin of individual muscles display specific expression of transcription factors that control diversification of muscle types. These factors, encoded by genes collectively called muscle identity genes, are activated in discrete subsets of muscle founders. As a result, each founder cell is thought to carry a unique combinatorial code of identity gene expression. Considering this, to define temporally and spatially restricted expression of identity genes, a set of coordinated upstream regulatory inputs is required. But also, to realize the identity program and to form specific muscle types with distinct properties, an efficient battery of downstream identity gene targets needs to be activated. Here we review how the specificity of expression and action of muscle identity genes is acquired.
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Affiliation(s)
- Cyrille de Joussineau
- GReD INSERM UMR1103, CNRS UMR6293, University of Clermont-Ferrand, Clermont-Ferrand, France
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20
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Belu M, Mizutani CM. Variation in mesoderm specification across Drosophilids is compensated by different rates of myoblast fusion during body wall musculature development. PLoS One 2011; 6:e28970. [PMID: 22194964 PMCID: PMC3237579 DOI: 10.1371/journal.pone.0028970] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 11/18/2011] [Indexed: 11/20/2022] Open
Abstract
Background It has been shown that species separated by relatively short evolutionary distances may have extreme variations in egg size and shape. Those variations are expected to modify the polarized morphogenetic gradients that pattern the dorso-ventral axis of embryos. Currently, little is known about the effects of scaling over the embryonic architecture of organisms. We began examining this problem by asking if changes in embryo size in closely related species of Drosophila modify all three dorso-ventral germ layers or only particular layers, and whether or not tissue patterning would be affected at later stages. Principal Findings Here we report that changes in scale affect predominantly the mesodermal layer at early stages, while the neuroectoderm remains constant across the species studied. Next, we examined the fate of somatic myoblast precursor cells that derive from the mesoderm to test whether the assembly of the larval body wall musculature would be affected by the variation in mesoderm specification. Our results show that in all four species analyzed, the stereotyped organization of the body wall musculature is not disrupted and remains the same as in D. melanogaster. Instead, the excess or shortage of myoblast precursors is compensated by the formation of individual muscle fibers containing more or less fused myoblasts. Conclusions Our data suggest that changes in embryonic scaling often lead to expansions or retractions of the mesodermal domain across Drosophila species. At later stages, two compensatory cellular mechanisms assure the formation of a highly stereotyped larval somatic musculature: an invariable selection of 30 muscle founder cells per hemisegment, which seed the formation of a complete array of muscle fibers, and a variable rate in myoblast fusion that modifies the number of myoblasts that fuse to individual muscle fibers.
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Affiliation(s)
- Mirela Belu
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Claudia M. Mizutani
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Genetics, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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21
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Weyers JJ, Milutinovich AB, Takeda Y, Jemc JC, Van Doren M. A genetic screen for mutations affecting gonad formation in Drosophila reveals a role for the slit/robo pathway. Dev Biol 2011; 353:217-28. [PMID: 21377458 PMCID: PMC3635084 DOI: 10.1016/j.ydbio.2011.02.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 02/24/2011] [Accepted: 02/24/2011] [Indexed: 12/19/2022]
Abstract
Organogenesis is a complex process requiring multiple cell types to associate with one another through correct cell contacts and in the correct location to achieve proper organ morphology and function. To better understand the mechanisms underlying gonad formation, we performed a mutagenesis screen in Drosophila and identified twenty-four genes required for gonadogenesis. These genes affect all different aspects of gonad formation and provide a framework for understanding the molecular mechanisms that control these processes. We find that gonad formation is regulated by multiple, independent pathways; some of these regulate the key cell adhesion molecule DE-cadherin, while others act through distinct mechanisms. In addition, we discover that the Slit/Roundabout pathway, best known for its role in regulating axonal guidance, is essential for proper gonad formation. Our findings shed light on the complexities of gonadogenesis and the genetic regulation required for proper organ formation.
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Affiliation(s)
- Jill J Weyers
- Department of Biology, Johns Hopkins University, 3400 N Charles St., Baltimore, MD, USA.
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22
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Grigorian M, Mandal L, Hakimi M, Ortiz I, Hartenstein V. The convergence of Notch and MAPK signaling specifies the blood progenitor fate in the Drosophila mesoderm. Dev Biol 2011; 353:105-18. [PMID: 21382367 PMCID: PMC3312814 DOI: 10.1016/j.ydbio.2011.02.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 02/26/2011] [Accepted: 02/26/2011] [Indexed: 11/25/2022]
Abstract
Blood progenitors arise from a pool of pluripotential cells ("hemangioblasts") within the Drosophila embryonic mesoderm. The fact that the cardiogenic mesoderm consists of only a small number of highly stereotypically patterned cells that can be queried individually regarding their gene expression in normal and mutant embryos is one of the significant advantages that Drosophila offers to dissect the mechanism specifying the fate of these cells. We show in this paper that the expression of the Notch ligand Delta (Dl) reveals segmentally reiterated mesodermal clusters ("cardiogenic clusters") that constitute the cardiogenic mesoderm. These clusters give rise to cardioblasts, blood progenitors and nephrocytes. Cardioblasts emerging from the cardiogenic clusters accumulate high levels of Dl, which is required to prevent more cells from adopting the cardioblast fate. In embryos lacking Dl function, all cells of the cardiogenic clusters become cardioblasts, and blood progenitors are lacking. Concomitant activation of the Mitogen Activated Protein Kinase (MAPK) pathway by Epidermal Growth Factor Receptor (EGFR) and Fibroblast Growth Factor Receptor (FGFR) is required for the specification and maintenance of the cardiogenic mesoderm; in addition, the spatially restricted localization of some of the FGFR ligands may be instrumental in controlling the spatial restriction of the Dl ligand to presumptive cardioblasts.
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Affiliation(s)
- Melina Grigorian
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA.
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23
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Dobi KC, Metzger T, Baylies MK. Characterization of early steps in muscle morphogenesis in a Drosophila primary culture system. Fly (Austin) 2011; 5:68-75. [PMID: 21339707 DOI: 10.4161/fly.5.2.15031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Myogenesis in Drosophila embryos requires fusion between Founder cells (FCs) and Fusion Competent myoblasts (FCMs) to form multinucleate myotubes. Myoblast fusion is well characterized in embryos, and many factors required for this process have been identified; however, a number of questions pertaining to the mechanisms of fusion remain and are challenging to answer in the embryo. We have developed a modified primary cell culture protocol to address these questions in vitro. Using this system, we determined the optimal time for examining fusion in culture and confirmed that known fusion proteins are expressed and localized as in embryos. Importantly, we disrupted the actin and microtubule networks with the drugs latrunculin B and nocodazole, respectively, confirming that actin is required for myoblast fusion and showing for the first time that microtubules are also required for this process in Drosophila. Finally, we show that myotubes in culture adopt and maintain specific muscle identities.
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Affiliation(s)
- Krista C Dobi
- Memorial Sloan-Kettering Cancer Center; New York, NY, USA
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24
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Tixier V, Bataillé L, Jagla K. Diversification of muscle types: recent insights from Drosophila. Exp Cell Res 2010; 316:3019-27. [PMID: 20673829 DOI: 10.1016/j.yexcr.2010.07.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 07/20/2010] [Accepted: 07/21/2010] [Indexed: 11/28/2022]
Abstract
Myogenesis is a highly conserved process ending up by the formation of contracting muscles. In Drosophila embryos, myogenesis gives rise to a segmentally repeated array of thirty distinct fibres, each of which represents an individual muscle. Since Drosophila offers a large range of genetic tools for easily testing gene functions, it has become one of the most studied and consequently best-described model organisms for muscle development. Over the last two decades, the Drosophila model system has enabled major advances in our understanding of how the initially equivalent mesodermal cells become competent for entering myogenic differentiation and how each distinct type of muscle is specified. Here we present an overview of Drosophila muscle development with a special focus on the diversification of muscle types and the genes that control acquisition of distinct muscle properties.
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Affiliation(s)
- Vanessa Tixier
- GReD, INSERM U931, CNRS UMR6247, Clermont University, Faculty of Medicine, 28 place Henri Dunant, Clermont-Ferrand, France
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25
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Ciglar L, Furlong EEM. Conservation and divergence in developmental networks: a view from Drosophila myogenesis. Curr Opin Cell Biol 2009; 21:754-60. [PMID: 19896355 DOI: 10.1016/j.ceb.2009.10.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Revised: 09/20/2009] [Accepted: 10/06/2009] [Indexed: 01/07/2023]
Abstract
Understanding developmental networks has recently been enhanced through the identification of a large number of conserved essential regulators. Interspecies comparisons of the transcriptional networks regulated by these factors are still at a rather early stage, with limited global data available. Here we use the accumulating phenotypic information from multiple species to provide initial insights into the wiring and rewiring of developmental networks, with particular emphasis on myogenesis, a highly conserved developmental process. This review highlights the most recent findings on the transcriptional program driving Drosophila myogenesis and compares this with vertebrates, revealing emerging themes that may be applicable to other developmental contexts.
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Affiliation(s)
- Lucia Ciglar
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
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26
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Soler C, Taylor MV. The Him gene inhibits the development of Drosophila flight muscles during metamorphosis. Mech Dev 2009; 126:595-603. [DOI: 10.1016/j.mod.2009.03.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 03/10/2009] [Accepted: 03/11/2009] [Indexed: 01/25/2023]
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27
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Stöbe P, Stein SMA, Habring-Müller A, Bezdan D, Fuchs AL, Hueber SD, Wu H, Lohmann I. Multifactorial regulation of a hox target gene. PLoS Genet 2009; 5:e1000412. [PMID: 19282966 PMCID: PMC2646128 DOI: 10.1371/journal.pgen.1000412] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Accepted: 02/09/2009] [Indexed: 01/27/2023] Open
Abstract
Hox proteins play fundamental roles in controlling morphogenetic diversity along the anterior-posterior body axis of animals by regulating distinct sets of target genes. Within their rather broad expression domains, individual Hox proteins control cell diversification and pattern formation and consequently target gene expression in a highly localized manner, sometimes even only in a single cell. To achieve this high-regulatory specificity, it has been postulated that Hox proteins co-operate with other transcription factors to activate or repress their target genes in a highly context-specific manner in vivo. However, only a few of these factors have been identified. Here, we analyze the regulation of the cell death gene reaper (rpr) by the Hox protein Deformed (Dfd) and suggest that local activation of rpr expression in the anterior part of the maxillary segment is achieved through a combinatorial interaction of Dfd with at least eight functionally diverse transcriptional regulators on a minimal enhancer. It follows that context-dependent combinations of Hox proteins and other transcription factors on small, modular Hox response elements (HREs) could be responsible for the proper spatio-temporal expression of Hox targets. Thus, a large number of transcription factors are likely to be directly involved in Hox target gene regulation in vivo.
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Affiliation(s)
- Petra Stöbe
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Sokrates M. A. Stein
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Anette Habring-Müller
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Daniela Bezdan
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Aurelia L. Fuchs
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
- BIOQUANT Center, Heidelberg, Germany
| | - Stefanie D. Hueber
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Haijia Wu
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Ingrid Lohmann
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
- BIOQUANT Center, Heidelberg, Germany
- * E-mail:
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28
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Sellin J, Drechsler M, Nguyen HT, Paululat A. Antagonistic function of Lmd and Zfh1 fine tunes cell fate decisions in the Twi and Tin positive mesoderm of Drosophila melanogaster. Dev Biol 2008; 326:444-55. [PMID: 19028484 DOI: 10.1016/j.ydbio.2008.10.041] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Revised: 09/30/2008] [Accepted: 10/29/2008] [Indexed: 10/21/2022]
Abstract
In this study we show that cell fate decisions in the dorsal and lateral mesoderm of Drosophila melanogaster depend on the antagonistic action of the Gli-like transcription factor Lame duck (Lmd) and the zinc finger homeodomain factor Zfh1. Lmd expression leads to the reduction of Zfh1 positive cell types, thereby restricting the number of Odd-skipped (Odd) positive and Tinman (Tin) positive pericardial cells in the dorsal mesoderm. In more lateral regions, ectopic activation of Zfh1 or loss of Lmd leads to an excess of adult muscle precursor (AMP) like cells. We also observed that Lmd is co-expressed with Tin in the early dorsal mesoderm and leads to a reduction of Tin expression in cells destined to become dorsal fusion competent myoblasts (FCMs). In the absence of Lmd function, these cells remain Tin positive and develop as Tin positive pericardial cells although they do not express Zfh1. We show further that Tin repression and pericardial restriction in the dorsal mesoderm facilitated by Lmd is instructed by a late Decapentaplegic (Dpp) signal that is abolished in embryos carrying the disk region mutation dpp(d6).
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Affiliation(s)
- Julia Sellin
- Universität Osnabrück, Fachbereich Biologie/Chemie - Zoologie/Entwicklungsbiologie, Osnabrück, Germany
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29
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Bryantsev AL, Cripps RM. Cardiac gene regulatory networks in Drosophila. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2008; 1789:343-53. [PMID: 18849017 DOI: 10.1016/j.bbagrm.2008.09.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Revised: 08/09/2008] [Accepted: 09/09/2008] [Indexed: 11/29/2022]
Abstract
The Drosophila system has proven a powerful tool to help unlock the regulatory processes that occur during specification and differentiation of the embryonic heart. In this review, we focus upon a temporal analysis of the molecular events that result in heart formation in Drosophila, with a particular emphasis upon how genomic and other cutting-edge approaches are being brought to bear upon the subject. We anticipate that systems-level approaches will contribute greatly to our comprehension of heart development and disease in the animal kingdom.
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Affiliation(s)
- Anton L Bryantsev
- Department of Biology, University of New Mexico, Albuquerque, NM 87131-0001, USA
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30
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Thompson EC, Travers AA. A Drosophila Smyd4 homologue is a muscle-specific transcriptional modulator involved in development. PLoS One 2008; 3:e3008. [PMID: 18714374 PMCID: PMC2500188 DOI: 10.1371/journal.pone.0003008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Accepted: 07/28/2008] [Indexed: 12/22/2022] Open
Abstract
Background SET and MYND domain (Smyd) proteins are involved in the transcriptional regulation of cellular proliferation and development in vertebrates. However, the in vivo functions and mechanisms by which these proteins act are poorly understood. Methodology/Principal Findings We have used biochemical and genetic approaches to study the role of a Smyd protein in Drosophila. We identified eleven Drosophila genes that encode Smyd proteins. CG14122 encodes a Smyd4 homologue that we have named dSmyd4. dSmyd4 repressed transcription and recruited class I histone deacetylases (HDACs). A region of dSmyd4 including the MYND domain interacted directly with ∼150 amino acids at the N-termini of dHDAC1 and dHDAC3. dSmyd4 interacts selectively with Ebi, a component of the dHDAC3/SMRTER co-repressor complex. During embryogenesis dSmyd4 was expressed throughout the mesoderm, with highest levels in the somatic musculature. Muscle-specific RNAi against dSmyd4 resulted in depletion of the protein and lead to severe lethality. Eclosion is the final moulting stage of Drosophila development when adult flies escape from the pupal case. 80% of dSmyd4 knockdown flies were not able to eclose, resulting in late pupal lethality. However, many aspects of eclosion were still able to occur normally, indicating that dSmyd4 is likely to be involved in the development or function of adult muscle. Conclusions/Significance Repression of transcription by dSmyd4 and the involvement of this protein in development suggests that aspects of Smyd protein function are conserved between vertebrates and invertebrates.
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31
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Genetic control of muscle development: learning from Drosophila. J Muscle Res Cell Motil 2008; 28:397-407. [PMID: 18347920 DOI: 10.1007/s10974-008-9133-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Accepted: 03/04/2008] [Indexed: 01/06/2023]
Abstract
Muscle development involves a complex sequence of time and spatially regulated cellular events leading to the formation of highly specialised syncytial muscle cells displaying a common feature, the capacity of contraction. Analyses of mechanisms controlling muscle development reveals that the main steps of muscle formation including myogenic determination, diversification of muscle precursors, myoblast fusion and terminal differentiation involve the actions of evolutionarily conserved genes. Thus dissecting the genetic control of muscle development in simple model organisms appears to be an attractive way to get insights into core genetic cascade that orchestrate myogenesis. In this respect, particularly insightful have been data generated using Drosophila as a model system. Notably, the interplay between intrinsic and extrinsic cues that determine the early myogenic decisions leading to the specification of muscle progenitors and those controlling myoblasts fusion are much better characterised in Drosophila than in vertebrate species. Also, adult Drosophila myogenesis, which leads to the formation of vertebrate-like multi-fibre muscles, emerges as a particularly well-adapted system to study normal and aberrant muscle development.
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32
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Long persistence of importin-β explains extended survival of cells and zygotes that lack the encoding gene. Mech Dev 2008; 125:196-206. [DOI: 10.1016/j.mod.2007.12.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Accepted: 12/05/2007] [Indexed: 11/23/2022]
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Figeac N, Daczewska M, Marcelle C, Jagla K. Muscle stem cells and model systems for their investigation. Dev Dyn 2008; 236:3332-42. [PMID: 17948301 DOI: 10.1002/dvdy.21345] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Stem cells are characterized by their clonal ability both to generate differentiated progeny and to undergo self-renewal. Studies of adult mammalian organs have revealed stem cells in practically every tissue. In the adult skeletal muscle, satellite cells are the primary muscle stem cells, responsible for postnatal muscle growth, hypertrophy, and regeneration. In the past decade, several molecular markers have been found that identify satellite cells in quiescent and activated states. However, despite their prime importance, surprisingly little is known about the biology of satellite cells, as their analysis was for a long time hampered by a lack of genetically amenable experimental models where their properties can be dissected. Here, we review how the embryonic origin of satellite cells was discovered using chick and mouse model systems and discuss how cells from other sources can contribute to muscle regeneration. We present evidence for evolutionarily conserved properties of muscle stem cells and their identification in lower vertebrates and in the fruit fly. In Drosophila, muscle stem cells called adult muscle precursors (AMP) can be identified in embryos and in larvae by persistent expression of a myogenic basic helix-loop-helix factor Twist. AMP cells play a crucial role in the Drosophila life cycle, allowing de novo formation and regeneration of adult musculature during metamorphosis. Based on the premise that AMPs represent satellite-like cells of the fruit fly, important insight into the biology of vertebrate muscle stem cells can be gained from genetic analysis in Drosophila.
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34
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Jakobsen JS, Braun M, Astorga J, Gustafson EH, Sandmann T, Karzynski M, Carlsson P, Furlong EE. Temporal ChIP-on-chip reveals Biniou as a universal regulator of the visceral muscle transcriptional network. Genes Dev 2007; 21:2448-60. [PMID: 17908931 PMCID: PMC1993875 DOI: 10.1101/gad.437607] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Smooth muscle plays a prominent role in many fundamental processes and diseases, yet our understanding of the transcriptional network regulating its development is very limited. The FoxF transcription factors are essential for visceral smooth muscle development in diverse species, although their direct regulatory role remains elusive. We present a transcriptional map of Biniou (a FoxF transcription factor) and Bagpipe (an Nkx factor) activity, as a first step to deciphering the developmental program regulating Drosophila visceral muscle development. A time course of chromatin immunoprecipitatation followed by microarray analysis (ChIP-on-chip) experiments and expression profiling of mutant embryos reveal a dynamic map of in vivo bound enhancers and direct target genes. While Biniou is broadly expressed, it regulates enhancers driving temporally and spatially restricted expression. In vivo reporter assays indicate that the timing of Biniou binding is a key trigger for the time span of enhancer activity. Although bagpipe and biniou mutants phenocopy each other, their regulatory potential is quite different. This network architecture was not apparent from genetic studies, and highlights Biniou as a universal regulator in all visceral muscle, regardless of its developmental origin or subsequent function. The regulatory connection of a number of Biniou target genes is conserved in mice, suggesting an ancient wiring of this developmental program.
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Affiliation(s)
| | - Martina Braun
- European Molecular Biology Laboratory, D-69117 Heidelberg, Germany
| | - Jeanette Astorga
- Department of Cell and Molecular Biology, Goteborg University, SE-405 30 Goteborg, Sweden
| | | | - Thomas Sandmann
- European Molecular Biology Laboratory, D-69117 Heidelberg, Germany
| | - Michal Karzynski
- European Molecular Biology Laboratory, D-69117 Heidelberg, Germany
| | - Peter Carlsson
- Department of Cell and Molecular Biology, Goteborg University, SE-405 30 Goteborg, Sweden
| | - Eileen E.M. Furlong
- European Molecular Biology Laboratory, D-69117 Heidelberg, Germany
- Corresponding author.E-MAIL ; FAX 49-6221-387166
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Liu J, Qian L, Han Z, Wu X, Bodmer R. Spatial specificity of mesodermal even-skipped expression relies on multiple repressor sites. Dev Biol 2007; 313:876-86. [PMID: 18067885 DOI: 10.1016/j.ydbio.2007.10.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2007] [Revised: 10/11/2007] [Accepted: 10/18/2007] [Indexed: 01/26/2023]
Abstract
Individual cardiac progenitors emerge at defined positions within each segment in the trunk mesoderm. Their specification depends on segmental information from the pre-patterned ectoderm, which provides positional information to the underlying cardiac mesoderm via inductive signals. This pattern is further reinforced by repressive interactions between transcription factors that are expressed in neighboring sets of cardiac progenitors. For example, even-skipped (eve) and ladybird early (lbe) gene products mark adjacent cardiac cell clusters within a segment, and their antagonistic interaction results in mutually exclusive expression domains. Lbe acts directly on the eve mesodermal enhancer (eme) to participate in restricting its expression anteriorly. We hypothesized that additional repressive activities must regulate the precise pattern of eve expression in the cardiac mesoderm via this enhancer. In this study, we identified two additional repressor motifs: 4 copies of an "AT"-rich motif (M1a-d) and 2 copies of an "GC"-rich motif (M2 a,b), which when mutated cause expansion of eme-dependent reporter gene expression. We have also examined potential negative regulators of eve and found that their overexpression is sufficient to repress eve as well as the eme enhancer via these sites. Our data suggest that a combination of factors is likely to interact with multiple essential repressor sites to confer precise spatial specificity of eve expression in the cardiac mesoderm.
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Affiliation(s)
- Jiandong Liu
- Development and Aging Program, Center for Neuroscienes, Aging and Stem Cell Research, Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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Babu S, Ramachandra NB. Screen for new mutations on the 2nd chromosome involved in indirect flight muscle development in Drosophila melanogaster. Genome 2007; 50:343-50. [PMID: 17546092 DOI: 10.1139/g07-012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An extensive ethylmethanesulfonate mutagenesis of Drosophila melanogaster was undertaken to isolate the stronger alleles of 3 indirect flight-muscle mutations. We isolated 17 strong mutant lines, with nearly complete penetrance and expressivity, using direct screening under polarized light, from more than 1700 mutagenized chromosomes. On complementation, we found 11 of these 17 mutant lines to be alleles of 3 indirect flight-muscle mutations (Ifm(2)RU1, 3 noncomplementing lines; ifm(2)RU2, 6 alleles; ifm(2)RU3, 2 alleles) of the previously isolated 8 complementation groups (Ifm(2)RU1to ifm(2)RU8). In addition, we found 6 new complementation groups with strong defects in adult-muscle morphology; we named these ifm(2)RS1 to ifm(2)RS6. All mutant lines were mapped by meiotic recombination, and 5 of the 6 new complementation lines were mapped using chromosome deficiencies. ifm(2)RS1 maps to a region that harbors ifm(2)RU4 (a mutation that was isolated previously); however, theses are not alleles because each complements the other mutation, and the mutant-muscle phenotype is very different. We used direct screening under polarized light to find recessive mutations; although this method was labor intensive, it can be used to identify recessive genes involved in myogenesis, unlike screens for flightlessness or wing-position defects. This screen identifies regions on the second chromosome that harbor probable genes that are likely expressed in the mesoderm and are thought to be involved in myogenesis. This screen has generated valuable resources that will help us to understand the role of many molecular players involved in myogenesis.
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Affiliation(s)
- Sajesh Babu
- National Drosophila Stock Centre, Department of Studies in Zoology, University of Mysore, Manasagangothri, Mysore 570 006, India
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Hand is a direct target of the forkhead transcription factor Biniou during Drosophila visceral mesoderm differentiation. BMC DEVELOPMENTAL BIOLOGY 2007; 7:49. [PMID: 17511863 PMCID: PMC1891290 DOI: 10.1186/1471-213x-7-49] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Accepted: 05/18/2007] [Indexed: 11/10/2022]
Abstract
BACKGROUND The visceral trunk mesoderm in Drosophila melanogaster develops under inductive signals from the ectoderm. This leads to the activation of the key regulators Tinman, Bagpipe and Biniou that are crucial for specification of the circular visceral muscles. How further differentiation is regulated is widely unknown, therefore it seems to be essential to identify downstream target genes of the early key regulators. In our report we focus on the analysis of the transcriptional control of the highly conserved transcription factor Hand in circular visceral muscle cells, providing evidence that the hand gene is a direct target of Biniou. RESULTS Herein we describe the identification of a regulatory region in the hand gene essential and sufficient for the expression in the visceral mesoderm during embryogenesis. We found that hand expression in the circular visceral mesoderm is abolished in embryos mutant for the FoxF domain containing transcription factor Biniou. Furthermore we demonstrate that Biniou regulates hand expression by direct binding to a 300 bp sequence element, located within the 3rd intron of the hand gene. This regulatory element is highly conserved in different Drosophila species. In addition, we provide evidence that Hand is dispensable for the initial differentiation of the embryonic visceral mesoderm. CONCLUSION In the present report we show that cross species sequence comparison of non-coding sequences between orthologous genes is a powerful tool to identify conserved regulatory elements. Combining functional dissection experiments in vivo and protein/DNA binding studies we identified hand as a direct target of Biniou in the circular visceral muscles.
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Wohlfrom H, Schinko JB, Klingler M, Bucher G. Maintenance of segment and appendage primordia by the Tribolium gene knödel. Mech Dev 2006; 123:430-9. [PMID: 16806846 DOI: 10.1016/j.mod.2006.04.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Revised: 04/11/2006] [Accepted: 04/26/2006] [Indexed: 10/24/2022]
Abstract
For homeotic and segment-polarity genes in Drosophila, a switch in gene regulation has been described that distinguishes patterning and maintenance phases. Maintenance of segment and organ primordia involves secondary patterning and differentiation steps, as well as survival factors regulating proliferation and organ size. In a screen for embryonic lethal mutations in the flour beetle Tribolium castaneum, we have recovered two alleles of the knödel gene, which result in short, bag-like embryos. These embryos have severely reduced appendages and differentiate a cuticle that lacks most overt signs of segmentation. In addition, they lack bristles and display defects in the nervous system. Early patterning in knödel mutant embryos is normal up to the extended germ band stage, as indicated by the formation of regular even-skipped (Tc'eve) and wingless (Tc'wg) stripes. Afterwards, however, these patterns degenerate. Similarly, proximo-distal growth and patterning of limbs are nearly normal initially, but limb primordia shrink, and proximo-distal patterns degenerate, during subsequent stages. knödel could be a segment polarity gene required for segment border maintenance in both trunk and appendages. Alternatively, it may have a more general role in tissue or organ maintenance.
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Affiliation(s)
- Hilde Wohlfrom
- Institut für Biologie, Friedrich-Alexander-Universität Erlangen, Staudtstrasse 5, 91058 Erlangen, Germany
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Clark IBN, Boyd J, Hamilton G, Finnegan DJ, Jarman AP. D-six4 plays a key role in patterning cell identities deriving from the Drosophila mesoderm. Dev Biol 2006; 294:220-31. [PMID: 16595131 DOI: 10.1016/j.ydbio.2006.02.044] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Revised: 02/24/2006] [Accepted: 02/27/2006] [Indexed: 11/21/2022]
Abstract
Patterning of the Drosophila embryonic mesoderm requires the regulation of cell type-specific factors in response to dorsoventral and anteroposterior axis information. For the dorsoventral axis, the homeodomain gene, tinman, is a key patterning mediator for dorsal mesodermal fates like the heart. However, equivalent mediators for more ventral fates are unknown. We show that D-six4, which encodes a Six family transcription factor, is required for the appropriate development of most cell types deriving from the non-dorsal mesoderm - the fat body, somatic cells of the gonad, and a specific subset of somatic muscles. Misexpression analysis suggests that D-Six4 and its likely cofactor, Eyes absent, are sufficient to impose these fates on other mesodermal cells. At stage 10, the mesodermal expression patterns of D-six4 and tin are complementary, being restricted to the dorsal and non-dorsal regions respectively. Our data suggest that D-six4 is a key mesodermal patterning mediator at this stage that regulates a variety of cell-type-specific factors and hence plays an equivalent role to tin. At stage 9, however, D-six4 and tin are both expressed pan-mesodermally. At this stage, tin function is required for full D-six4 expression. This may explain the known requirement for tin in some non-dorsal cell types.
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Affiliation(s)
- Ivan B N Clark
- Centre for Integrative Physiology, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK
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40
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Sano H, Renault AD, Lehmann R. Control of lateral migration and germ cell elimination by the Drosophila melanogaster lipid phosphate phosphatases Wunen and Wunen 2. ACTA ACUST UNITED AC 2006; 171:675-83. [PMID: 16301333 PMCID: PMC2171572 DOI: 10.1083/jcb.200506038] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
In most organisms, primordial germ cells (PGCs) arise far from the region where somatic gonadal precursors (SGPs) are specified. Although PGCs in general originate as a single cluster of cells, the somatic parts of the gonad form on each site of the embryo. Thus, to reach the gonad, PGCs not only migrate from their site of origin but also split into two groups. Taking advantage of high-resolution real-time imaging, we show that in Drosophila melanogaster PGCs are polarized and migrate directionally toward the SGPs, avoiding the midline. Unexpectedly, neither PGC attractants synthesized in the SGPs nor known midline repellents for axon guidance were required to sort PGCs bilaterally. Repellent activity provided by wunen (wun) and wunen-2 (wun-2) expressed in the central nervous system, however, is essential in this migration process and controls PGC survival. Our results suggest that expression of wun/wun-2 repellents along the migratory paths provides faithful control over the sorting of PGCs into two gonads and eliminates PGCs left in the middle of the embryo.
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Affiliation(s)
- Hiroko Sano
- Department of Cell Biology, Developmental Genetics Program, Skirball Institute of Biomolecular Medicine and Howard Hughes Medical Institute, New York University Medical Center, New York, NY 10016
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de Velasco B, Mandal L, Mkrtchyan M, Hartenstein V. Subdivision and developmental fate of the head mesoderm in Drosophila melanogaster. Dev Genes Evol 2005; 216:39-51. [PMID: 16249873 DOI: 10.1007/s00427-005-0029-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Accepted: 09/04/2005] [Indexed: 10/25/2022]
Abstract
In this paper, we define temporal and spatial subdivisions of the embryonic head mesoderm and describe the fate of the main lineages derived from this tissue. During gastrulation, only a fraction of the head mesoderm (primary head mesoderm; PHM) invaginates as the anterior part of the ventral furrow. The PHM can be subdivided into four linearly arranged domains, based on the expression of different combinations of genetic markers (tinman, heartless, snail, serpent, mef-2, zfh-1). The anterior domain (PHMA) produces a variety of cell types, among them the neuroendocrine gland (corpus cardiacum). PHMB, forming much of the "T-bar" of the ventral furrow, migrates anteriorly and dorsally and gives rise to the dorsal pharyngeal musculature. PHMC is located behind the T-bar and forms part of the anterior endoderm, besides contributing to hemocytes. The most posterior domain, PHMD, belongs to the anterior gnathal segments and gives rise to a few somatic muscles, but also to hemocytes. The procephalic region flanking the ventral furrow also contributes to head mesoderm (secondary head mesoderm, SHM) that segregates from the surface after the ventral furrow has invaginated, indicating that gastrulation in the procephalon is much more protracted than in the trunk. We distinguish between an early SHM (eSHM) that is located on either side of the anterior endoderm and is the major source of hemocytes, including crystal cells. The eSHM is followed by the late SHM (lSHM), which consists of an anterior and posterior component (lSHMa, lSHMp). The lSHMa, flanking the stomodeum anteriorly and laterally, produces the visceral musculature of the esophagus, as well as a population of tinman-positive cells that we interpret as a rudimentary cephalic aorta ("cephalic vascular rudiment"). The lSHM contributes hemocytes, as well as the nephrocytes forming the subesophageal body, also called garland cells.
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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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42
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Vining MS, Bradley PL, Comeaux CA, Andrew DJ. Organ positioning in Drosophila requires complex tissue-tissue interactions. Dev Biol 2005; 287:19-34. [PMID: 16171793 DOI: 10.1016/j.ydbio.2005.08.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Revised: 08/05/2005] [Accepted: 08/09/2005] [Indexed: 12/25/2022]
Abstract
Positioning an organ with respect to other tissues is a complex process necessary for proper anatomical development and organ function. The local environment surrounding an organ can serve both as a substrate for migration and as a source of guidance cues that direct migration. Little is known about the factors guiding Drosophila salivary gland movement or about the contacts the glands establish along their migratory path. Here, we provide a detailed description of the spatial and temporal interactions between the salivary glands and surrounding tissues during embryogenesis. The glands directly contact five other tissues: the visceral mesoderm, gastric caecae, somatic mesoderm, fat body, and central nervous system. Mutational analysis reveals that all of the tissues tested in this study are important for normal salivary gland positioning; proper differentiation of the visceral and somatic mesoderm is necessary for the glands to attain their final correct position. We also provide evidence that the segment-polarity gene, gooseberry (gsb), controls expression of signals from the developing fat body that direct posterior migration of the glands. These data further the understanding of how organ morphology and position are determined by three-dimensional constraints and guidance cues provided by neighboring tissues.
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Affiliation(s)
- Melissa S Vining
- The Johns Hopkins University School of Medicine, Department of Cell Biology, Baltimore, MD 21205, USA
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43
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Pütz M, Kesper DA, Buttgereit D, Renkawitz-Pohl R. In Drosophila melanogaster, the rolling pebbles isoform 6 (Rols6) is essential for proper Malpighian tubule morphology. Mech Dev 2005; 122:1206-17. [PMID: 16169193 DOI: 10.1016/j.mod.2005.07.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Revised: 04/19/2005] [Accepted: 07/01/2005] [Indexed: 11/19/2022]
Abstract
During myoblast fusion, cell-cell recognition along with cell migration and adhesion are essential biological processes. The factors involved in these processes include members of the immunoglobulin superfamily like Sticks and stones (Sns), Dumbfounded (Duf) and Hibris (Hbs), SH3 domain-containing adaptor molecules like Myoblast city (Mbc) and multidomain proteins like Rolling pebbles (Rols). For rolling pebbles, two differentially expressed transcripts have been defined (rols7 and rols6). However, to date, only a muscle fusion phenotype has been described and assigned to the lack of the mesoderm-specific expressed rols7 transcript. Here, we show that a loss of the second rolling pebbles transcript, rols6, which is expressed from the early bud to later embryonic stages during Malpighian tubule (MpT) development, leads to an abnormal MpT morphology that is not due to defects in cell determination or proliferation but to aberrant morphogenesis. In addition, when Myoblast city or Rac are knocked out, a similar phenotype is observed. Myoblast city and Rac are essentially involved in the development of the somatic muscles and were proposed to be interaction partners of Rols7. Because of the predicted structural similarities of the Rols7 and Rols6 proteins, we argue that genetic interaction of rols6, mbc and rac might lead to proper MpT morphology. We also propose that these interactions result in stable cell connections due to rearrangement of the cytoskeleton.
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Affiliation(s)
- Michael Pütz
- Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, Karl-von-Frisch-Str. 8, 35043 Marburg, Germany
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Yamazaki K, Akiyama-Oda Y, Oda H. Expression patterns of a twist-related gene in embryos of the spider Achaearanea tepidariorum reveal divergent aspects of mesoderm development in the fly and spider. Zoolog Sci 2005; 22:177-85. [PMID: 15738638 DOI: 10.2108/zsj.22.177] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We cloned an Achaearanea tepidariorum (Chelicerata, Arachnida) gene related to Drosophila twist (twi), which encodes a basic helix-loop-helix transcription factor required to specify mesoderm fate in the Drosophila embryo. The cloned spider gene was designated At.twist (At.twi). We examined its expression by whole-mount in situ hybridization. At.twi transcripts were first detected in cells located at the polar and equatorial areas of the spherical embryo when the cumulus reached the equator. As the extra-embryonic area expanded, more cells expressed At.twi transcripts. The At.twi-expressing cells became distributed nearly uniformly in the embryonic area. At these stages, some At.twi-expressing cells were found in the surface epithelial cell layer, but other At.twi-expressing cells were at slightly deeper positions from the surface. When the embryo was transformed into a germ band, all At.twi-expressing cells were situated just beneath the surface ectoderm, where they became metamerically arranged. Although little expression was observed in the caudal lobe of the elongating germ band, new stripes of At.twi expression appeared beneath the ectoderm in accordance with the posterior growth. These observations suggested that the cells expressing At.twi were most likely mesoderm. We propose that At.twi can be used as a molecular marker for analyzing mesoderm development in the spider embryo. Moreover, comparison of the expression patterns of twi and At.twi revealed divergent aspects of mesoderm development in the fly and spider. In addition, we cloned an Achaearanea gene related to snail, which is another mesoderm-determining gene in Drosophila, and showed that its expression was restricted to the ectoderm with no indication for a role in mesoderm development.
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Abstract
I review how both the parasegmental and segmental frames are used in constructing the body plan of the arthropods. The parasegment is the primary genetic unit, as shown by Hox gene expression, and the parasegmental design is maintained in the nerve cord. It is, however, not maintained in the epidermis, where the cuticle grooves are segmental, and in the musculature, which is segmental in organisation. This frame shift is reflected in the sensory and motor nerve connections between the ganglia and the periphery. I suggest that the need for movement in an organism equipped with a hard exoskeleton was the functional constraint that shaped this apparently complex mode of development.
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Affiliation(s)
- Jean S Deutsch
- Equipe Evolution et Développement, CNRS et Universite P et M Curie, 9 quai St-Bernard, case 24, 75252 Paris cedex 05.
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46
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Lee HH, Frasch M. Survey of forkhead domain encoding genes in the Drosophila genome: Classification and embryonic expression patterns. Dev Dyn 2004; 229:357-66. [PMID: 14745961 DOI: 10.1002/dvdy.10443] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Genetic approaches in Drosophila led to the identification of Forkhead, the prototype of forkhead domain transcription factors that are now known to comprise an evolutionarily conserved family of proteins with essential roles in development and differentiation. Sequence analysis of the recently published genomic scaffold sequence from Drosophila melanogaster has allowed us to determine the presumably full complement of forkhead domain encoding genes in this species. We show herein that the Drosophila genome contains 17 forkhead domain encoding genes; 13 of these genes have orthologs in chordate species, and their products can be assigned to 10 of the 17 forkhead domain subclasses known from chordates. One Drosophila forkhead domain gene only has a Caenorhabditis elegans ortholog and may represent a subclass that is absent in chordates, while the remaining three cannot be classified. We present the mRNA expression patterns of seven previously uncharacterized members of this gene family and show that they are expressed in tissues from all three germ layers, including central and peripheral nervous system, epidermis, salivary gland primordia, endoderm, somatic mesoderm, and hemocyte progenitors. Furthermore, the expression patterns of two of these genes, fd19B and fd102C, suggest a role for them as gap genes during early embryonic head segmentation.
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Affiliation(s)
- Hsiu-Hsiang Lee
- Mount Sinai School of Medicine, Brookdale Department of Molecular, Cell and Developmental Biology, New York, New York, USA
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47
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Jaynes JB, Fujioka M. Drawing lines in the sand: even skipped et al. and parasegment boundaries. Dev Biol 2004; 269:609-22. [PMID: 15110723 PMCID: PMC2709281 DOI: 10.1016/j.ydbio.2004.03.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2004] [Accepted: 03/05/2004] [Indexed: 11/17/2022]
Abstract
The pair-rule segmentation gene even skipped (eve) is required to activate engrailed stripes and to organize odd-numbered parasegments (PSs). The protein product Eve has been shown to be an active repressor of transcription, and recent models for Eve function suggest that activation of engrailed is indirect, but these models have not been fully tested. Here we identify the forkhead domain transcription factor Sloppy-paired as the key intermediate in the initial activation of engrailed by Eve in odd-numbered parasegments. We also analyze the roles of the transcription factors Runt and Odd-skipped in this process. Detailed analysis of engrailed and pair-rule gene expression in various mutant combinations shows how eve activates engrailed by repressing these engrailed repressors, and further indicates that mutual repression among pair-rule genes plays an important role in establishing parasegment boundaries. We present a new model of pair-rule gene function that explains the response of these boundaries to the relative levels of Eve and Fushi Tarazu.
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Affiliation(s)
- James B Jaynes
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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48
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Lee HH, Norris A, Weiss JB, Frasch M. Jelly belly protein activates the receptor tyrosine kinase Alk to specify visceral muscle pioneers. Nature 2003; 425:507-12. [PMID: 14523446 DOI: 10.1038/nature01916] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2003] [Accepted: 07/14/2003] [Indexed: 11/08/2022]
Abstract
The secreted protein Jelly belly (Jeb) is required for an essential signalling event in Drosophila muscle development. In the absence of functional Jeb, visceral muscle precursors are normally specified but fail to migrate and differentiate. The structure and distribution of Jeb protein implies that Jeb functions as a signal to organize the development of visceral muscles. Here we show that the Jeb receptor is the Drosophila homologue of anaplastic lymphoma kinase (Alk), a receptor tyrosine kinase of the insulin receptor superfamily. Human ALK was originally identified as a proto-oncogene, but its normal function in mammals is not known. In Drosophila, localized Jeb activates Alk and the downstream Ras/mitogen-activated protein kinase cascade to specify a select group of visceral muscle precursors as muscle-patterning pioneers. Jeb/Alk signalling induces the myoblast fusion gene dumbfounded (duf; also known as kirre) as well as org-1, a Drosophila homologue of mammalian TBX1, in these cells.
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Affiliation(s)
- Hsiu-Hsiang Lee
- Brookdale Department of Molecular, Cell and Developmental Biology, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1020, New York, New York 10029, USA
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49
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Avaron F, Thaëron-Antono C, Beck CW, Borday-Birraux V, Géraudie J, Casane D, Laurenti P. Comparison of even-skipped related gene expression pattern in vertebrates shows an association between expression domain loss and modification of selective constraints on sequences. Evol Dev 2003; 5:145-56. [PMID: 12622731 DOI: 10.1046/j.1525-142x.2003.03021.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The even-skipped related genes (evx) encode homeodomain-containing transcription factors that play key roles in body patterning and neurogenesis in a wide array of Eumetazoa species. It is thought that the genome of the last common ancestor of Chordata contained a unique evx gene linked to a unique ancestral Hox complex. During subsequent evolution, two rounds of whole genome duplication followed by individual gene losses gave rise to three paralogs: evx1, evx2, and eve1. Then, eve1 was maintained in Actinopterygii lineage but not in Tetrapoda. To explain this discrepancy, we examined the expression patterns of the evx1 homologue, Xhox3, in Xenopus laevis and that of evx1 and eve1 in Danio rerio. We show here that Xhox3 is expressed in a manner that closely reflects the inferred expression pattern of the evx1 gene in the last common ancestor of Vertebrata (i.e., in gastrula, the central nervous system, the posterior gut, and the tip of the growing tail). Zebrafish evx1 and Xenopus Xhox3 are expressed in homologous cell lineages of the central nervous system and of the posterior gut, but evx1 was undetectable in the gastrula and the tail bud. Strikingly, eve1 is the only evx gene of zebrafish to be expressed in these two latter regions. Thus, the ancestral expression pattern of evx1 in vertebrates appears to have been distributed between evx1 and eve1 in zebrafish. We propose that evx1 and eve1 underwent a complementary loss of expression domain in zebrafish that allowed the maintenance of the two paralogs in accordance with the duplication-degeneration-complementation model. It is important to note that, in zebrafish, Evx1 and Eve1 have lost most of the protein domain upstream of the homeodomain. In addition, Eve1 has accumulated substitutions in positions that are highly conserved in all other Evx proteins. Thus, the reduction of the expression domain of both evx1 and eve1 in zebrafish appears to be associated with the modification of constraints on the protein sequences, allowing the shortening of both genes and an accelerated substitution rate in eve1.
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Affiliation(s)
- Fabien Avaron
- Laboratoire de Biologie du Développement, Université de Paris 7, case courrier 7077, 2 place Jussieu, 75251 Paris cedex 5, France
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Wheeler JC, VanderZwan C, Xu X, Swantek D, Tracey WD, Gergen JP. Distinct in vivo requirements for establishment versus maintenance of transcriptional repression. Nat Genet 2002; 32:206-10. [PMID: 12145660 DOI: 10.1038/ng942] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Low-level ectopic expression of the Runt transcription factor blocks activation of the Drosophila melanogaster segmentation gene engrailed (en) in odd-numbered parasegments and is associated with a lethal phenotype. Here we show, by using a genetic screen for maternal factors that contribute in a dose-dependent fashion to Runt-mediated repression, that there are two distinct steps in the repression of en by Runt. The initial establishment of repression is sensitive to the dosage of the zinc-finger transcription factor Tramtrack. By contrast, the co-repressor proteins Groucho and dCtBP, and the histone deacetylase Rpd3, do not affect establishment but instead maintain repression after the blastoderm stage. The distinction between establishment and maintenance is confirmed by experiments with Runt derivatives that are impaired specifically for either co-repressor interaction or DNA binding. Other transcription factors can also establish repression in Rpd3-deficient embryos, which indicates that the distinction between establishment and maintenance may be a general feature of eukaryotic transcriptional repression.
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Affiliation(s)
- John C Wheeler
- Department of Biochemistry and Cell Biology and the Center for Developmental Genetics, Stony Brook University, Stony Brook, New York 11794-5140, USA
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