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Geisbrecht ER, Sawant K, Su Y, Liu ZC, Silver DL, Burtscher A, Wang X, Zhu AJ, McDonald JA. Genetic interaction screens identify a role for hedgehog signaling in Drosophila border cell migration. Dev Dyn 2013; 242:414-31. [PMID: 23335293 DOI: 10.1002/dvdy.23926] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 12/22/2012] [Accepted: 12/28/2012] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Cell motility is essential for embryonic development and physiological processes such as the immune response, but also contributes to pathological conditions such as tumor progression and inflammation. However, our understanding of the mechanisms underlying migratory processes is incomplete. Drosophila border cells provide a powerful genetic model to identify the roles of genes that contribute to cell migration. RESULTS Members of the Hedgehog signaling pathway were uncovered in two independent screens for interactions with the small GTPase Rac and the polarity protein Par-1 in border cell migration. Consistent with a role in migration, multiple Hh signaling components were enriched in the migratory border cells. Interference with Hh signaling by several different methods resulted in incomplete cell migration. Moreover, the polarized distribution of E-Cadherin and a marker of tyrosine kinase activity were altered when Hh signaling was disrupted. Conservation of Hh-Rac and Hh-Par-1 signaling was illustrated in the wing, in which Hh-dependent phenotypes were enhanced by loss of Rac or par-1. CONCLUSIONS We identified a pathway by which Hh signaling connects to Rac and Par-1 in cell migration. These results further highlight the importance of modifier screens in the identification of new genes that function in developmental pathways.
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Affiliation(s)
- Erika R Geisbrecht
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, Missouri 64110, USA
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52
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Lim RSM, Osato M, Kai T. Isolation of undifferentiated female germline cells from adult Drosophila ovaries. ACTA ACUST UNITED AC 2013; Chapter 2:Unit2E.3. [PMID: 22872426 DOI: 10.1002/9780470151808.sc02e03s22] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This unit describes a method for isolating undifferentiated, stem cell-like germline cells from adult Drosophila ovaries. Here, we demonstrate that this population of cells can be effectively purified from hand-dissected ovaries in considerably large quantities. Tumor ovaries with expanded populations of undifferentiated germline cells are first removed from fly abdomens and dissociated into a cell suspension with the aid of protease treatment. The target cells, which express Vasa-green fluorescent protein (GFP) fusion protein under the control of the germline-specific vasa promoter, are specifically selected from the suspension via fluorescence-activated cell sorting (FACS). These protocols can be adapted to isolate other cell types from fly ovaries, such as somatic follicle cells or escort cells, by driving GFP expression in the respective target cells.
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Affiliation(s)
- Robyn Su May Lim
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore
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53
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Marmion RA, Jevtic M, Springhorn A, Pyrowolakis G, Yakoby N. The Drosophila BMPRII, wishful thinking, is required for eggshell patterning. Dev Biol 2012; 375:45-53. [PMID: 23274688 DOI: 10.1016/j.ydbio.2012.12.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 10/13/2012] [Accepted: 12/13/2012] [Indexed: 10/27/2022]
Abstract
The Drosophila eggshell is an elaborate structure that is derived from a monolayer of follicular epithelium surrounding the developing oocyte within the female ovary. The bone morphogenetic protein (BMP) signaling pathway is essential for controlling the patterning and morphogenesis of the eggshell. During oogenesis, the roles of patterning and morphogenesis by the BMP type I receptor thickveins (tkv) have been studied extensively. However, signaling through this pathway requires both type I and II receptors, and the latter has yet to be established in oogenesis. We focus on wishful thinking (wit), the Drosophila homolog to the mammalian BMP type II receptor, BMPRII. We found that wit is expressed dynamically in the FCs of D. melanogaster in an evolutionary conserved pattern. The expression patterns are highly correlated with the dynamics of the BMP signaling, which is consistent with our finding that wit is a target of BMP signaling. Furthermore, we established that WIT is necessary for BMP signaling, and loss of WIT is associated with cell autonomous loss of BMP responses. Of importance, we demonstrated that perturbations in WIT led to changes in eggshell morphologies in domains that are patterned by BMP signaling. Previous studies have shown a role for WIT in BMP signaling during neurogenesis; however, our results reveal a role for WIT in epithelial cells' development.
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Affiliation(s)
- Robert A Marmion
- Department of Biology and Center for Computational and Integrative Biology, Rutgers, The State University of NJ, Camden, NJ, USA
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54
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Group choreography: mechanisms orchestrating the collective movement of border cells. Nat Rev Mol Cell Biol 2012; 13:631-45. [PMID: 23000794 DOI: 10.1038/nrm3433] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cell movements are essential for animal development and homeostasis but also contribute to disease. Moving cells typically extend protrusions towards a chemoattractant, adhere to the substrate, contract and detach at the rear. It is less clear how cells that migrate in interconnected groups in vivo coordinate their behaviour and navigate through natural environments. The border cells of the Drosophila melanogaster ovary have emerged as an excellent model for the study of collective cell movement, aided by innovative genetic, live imaging, and photomanipulation techniques. Here we provide an overview of the molecular choreography of border cells and its more general implications.
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55
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On the role of PDZ domain-encoding genes in Drosophila border cell migration. G3-GENES GENOMES GENETICS 2012; 2:1379-91. [PMID: 23173089 PMCID: PMC3484668 DOI: 10.1534/g3.112.004093] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 09/10/2012] [Indexed: 12/31/2022]
Abstract
Cells often move as collective groups during normal embryonic development and wound healing, although the mechanisms governing this type of migration are poorly understood. The Drosophila melanogaster border cells migrate as a cluster during late oogenesis and serve as a powerful in vivo genetic model for collective cell migration. To discover new genes that participate in border cell migration, 64 out of 66 genes that encode PDZ domain-containing proteins were systematically targeted by in vivo RNAi knockdown. The PDZ domain is one of the largest families of protein-protein interaction domains found in eukaryotes. Proteins that contain PDZ domains participate in a variety of biological processes, including signal transduction and establishment of epithelial apical-basal polarity. Targeting PDZ proteins effectively assesses a larger number of genes via the protein complexes and pathways through which these proteins function. par-6, a known regulator of border cell migration, was a positive hit and thus validated the approach. Knockdown of 14 PDZ domain genes disrupted migration with multiple RNAi lines. The candidate genes have diverse predicted cellular functions and are anticipated to provide new insights into the mechanisms that control border cell movement. As a test of this concept, two genes that disrupted migration were characterized in more detail: big bang and the Dlg5 homolog CG6509. We present evidence that Big bang regulates JAK/STAT signaling, whereas Dlg5/CG6509 maintains cluster cohesion. Moreover, these results demonstrate that targeting a selected class of genes by RNAi can uncover novel regulators of collective cell migration.
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56
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Dornier E, Coumailleau F, Ottavi JF, Moretti J, Boucheix C, Mauduit P, Schweisguth F, Rubinstein E. TspanC8 tetraspanins regulate ADAM10/Kuzbanian trafficking and promote Notch activation in flies and mammals. ACTA ACUST UNITED AC 2012; 199:481-96. [PMID: 23091066 PMCID: PMC3483123 DOI: 10.1083/jcb.201201133] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
TspanC8 tetraspanins have a conserved function in the regulation of ADAM10 trafficking and activity, thereby positively regulating Notch activation. The metalloprotease ADAM10/Kuzbanian catalyzes the ligand-dependent ectodomain shedding of Notch receptors and activates Notch. Here, we show that the human tetraspanins of the evolutionary conserved TspanC8 subfamily (Tspan5, Tspan10, Tspan14, Tspan15, Tspan17, and Tspan33) directly interact with ADAM10, regulate its exit from the endoplasmic reticulum, and that four of them regulate ADAM10 surface expression levels. In an independent RNAi screen in Drosophila, two TspanC8 genes were identified as Notch regulators. Functional analysis of the three Drosophila TspanC8 genes (Tsp3A, Tsp86D, and Tsp26D) indicated that these genes act redundantly to promote Notch signaling. During oogenesis, TspanC8 genes were up-regulated in border cells and regulated Kuzbanian distribution, Notch activity, and cell migration. Furthermore, the human TspanC8 tetraspanins Tspan5 and Tspan14 positively regulated ligand-induced ADAM10-dependent Notch1 signaling. We conclude that TspanC8 tetraspanins have a conserved function in the regulation of ADAM10 trafficking and activity, thereby positively regulating Notch receptor activation.
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Affiliation(s)
- Emmanuel Dornier
- Institut National de la Santé et de la Recherche Médicale, U1004, F-94807 Villejuif, France
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57
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Niepielko MG, Ip K, Kanodia JS, Lun DS, Yakoby N. Evolution of BMP signaling in Drosophila oogenesis: a receptor-based mechanism. Biophys J 2012; 102:1722-30. [PMID: 22768927 DOI: 10.1016/j.bpj.2012.03.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 03/06/2012] [Accepted: 03/12/2012] [Indexed: 01/22/2023] Open
Abstract
The bone morphogenetic protein (BMP) signaling pathway is a conserved regulator of cellular and developmental processes in animals. The mechanisms underlying BMP signaling activation differ among tissues and mostly reflect changes in the expression of pathway components. BMP signaling is one of the major pathways responsible for the patterning of the Drosophila eggshell, a complex structure derived from a layer of follicle cells (FCs) surrounding the developing oocyte. Activation of BMP signaling in the FCs is dynamic. Initially, signaling is along the anterior-posterior (A/P) axis; later, signaling acquires dorsal-ventral (D/V) polarity. These dynamics are regulated by changes in the expression pattern of the type I BMP receptor thickveins (tkv). We recently found that signaling dynamics and TKV patterning are highly correlated in the FCs of multiple Drosophila species. In addition, we showed that signaling patterns are spatially different among species. Here, we use a mathematical model to simulate the dynamics and differences of BMP signaling in numerous species. This model predicts that qualitative and quantitative changes in receptor expression can lead to differences in the spatial pattern of BMP signaling. We tested these predications experimentally in three different Drosophila species and through genetic perturbations of BMP signaling in D. melanogaster. On the basis of our results, we concluded that changes in tkv patterning can account for the experimentally observed differences in the patterns of BMP signaling in multiple Drosophila species.
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58
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Functional transcriptomics of a migrating cell in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2012; 109:16246-51. [PMID: 22991463 DOI: 10.1073/pnas.1203045109] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In both metazoan development and metastatic cancer, migrating cells must carry out a detailed, complex program of sensing cues, binding substrates, and moving their cytoskeletons. The linker cell in Caenorhabditis elegans males undergoes a stereotyped migration that guides gonad organogenesis, occurs with precise timing, and requires the nuclear hormone receptor NHR-67. To better understand how this occurs, we performed RNA-seq of individually staged and dissected linker cells, comparing transcriptomes from linker cells of third-stage (L3) larvae, fourth-stage (L4) larvae, and nhr-67-RNAi-treated L4 larvae. We observed expression of 8,000-10,000 genes in the linker cell, 22-25% of which were up- or down-regulated 20-fold during development by NHR-67. Of genes that we tested by RNAi, 22% (45 of 204) were required for normal shape and migration, suggesting that many NHR-67-dependent, linker cell-enriched genes play roles in this migration. One unexpected class of genes up-regulated by NHR-67 was tandem pore potassium channels, which are required for normal linker-cell migration. We also found phenotypes for genes with human orthologs but no previously described migratory function. Our results provide an extensive catalog of genes that act in a migrating cell, identify unique molecular functions involved in nematode cell migration, and suggest similar functions in humans.
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59
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Hoffmann AA, Blacket MJ, McKechnie SW, Rako L, Schiffer M, Rane RV, Good RT, Robin C, Lee SF. A proline repeat polymorphism of the Frost gene of Drosophila melanogaster showing clinal variation but not associated with cold resistance. INSECT MOLECULAR BIOLOGY 2012; 21:437-445. [PMID: 22708613 DOI: 10.1111/j.1365-2583.2012.01149.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Genetic polymorphisms underlying adaptive shifts in thermal responses are poorly known even though studies are providing a detailed understanding of these responses at the cellular and physiological levels. The Frost gene of Drosophila melanogaster is a prime candidate for thermal adaptation; it is up-regulated under cold stress and knockdown of this gene influences cold resistance. Here we describe an amino-acid INDEL polymorphism in proline repeat number in the structural component of this gene. The two main repeats, accounting for more than 90% of alleles in eastern Australia, show a strong clinal pattern; the 6P allele was at a high frequency in tropical locations, and the 10P allele was common in temperate populations. However, the frequency of these alleles was not associated with three different assays of cold resistance. Adult transcription level of Frost was also unrelated to cold resistance as measured through post chill coma mobility. The functional significance of the proline repeat polymorphism therefore remains unclear despite its clinal pattern. The data also demonstrate the feasibility of using Roche/454 sequencing for establishing clinal patterns.
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Affiliation(s)
- A A Hoffmann
- Department of Genetics, Bio21 Institute, The University of Melbourne, Melbourne, Victoria, Australia School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
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60
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Yang N, Inaki M, Cliffe A, Rørth P. Microtubules and Lis-1/NudE/dynein regulate invasive cell-on-cell migration in Drosophila. PLoS One 2012; 7:e40632. [PMID: 22808215 PMCID: PMC3396602 DOI: 10.1371/journal.pone.0040632] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 06/11/2012] [Indexed: 11/24/2022] Open
Abstract
The environment through which cells migrate in vivo differs considerably from the in vitro environment where cell migration is often studied. In vivo many cells migrate in crowded and complex 3-dimensional tissues and may use other cells as the substratum on which they move. This includes neurons, glia and their progenitors in the brain. Here we use a Drosophila model of invasive, collective migration in a cellular environment to investigate the roles of microtubules and microtubule regulators in this type of cell movement. Border cells are of epithelial origin and have no visible microtubule organizing center (MTOC). Interestingly, microtubule plus-end growth was biased away from the leading edge. General perturbation of the microtubule cytoskeleton and analysis by live imaging showed that microtubules in both the migrating cells and the substrate cells affect movement. Also, whole-tissue and cell autonomous deletion of the microtubule regulator Stathmin had distinct effects. A screen of 67 genes encoding microtubule interacting proteins uncovered cell autonomous requirements for Lis-1, NudE and Dynein in border cell migration. Net cluster migration was decreased, with initiation of migration and formation of dominant front cell protrusion being most dramatically affected. Organization of cells within the cluster and localization of cell-cell adhesion molecules were also abnormal. Given the established role of Lis-1 in migrating neurons, this could indicate a general role of Lis-1/NudE, Dynein and microtubules, in cell-on-cell migration. Spatial regulation of cell-cell adhesion may be a common theme, consistent with observing both cell autonomous and non-autonomous requirements in both systems.
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Affiliation(s)
- Nachen Yang
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Department of Biological Sciences, The National University of Singapore, Singapore, Singapore
| | - Mikiko Inaki
- Institute of Molecular and Cell Biology, Singapore, Singapore
| | - Adam Cliffe
- Institute of Molecular and Cell Biology, Singapore, Singapore
| | - Pernille Rørth
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Department of Biological Sciences, The National University of Singapore, Singapore, Singapore
- * E-mail:
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61
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Banerjee D, Shimaoka M. Lentiviral gene transfer method to study integrin function in T lymphocytes. Methods Mol Biol 2012; 757:47-54. [PMID: 21909905 DOI: 10.1007/978-1-61779-166-6_4] [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: 05/31/2023]
Abstract
Integrins play critical roles in adhesion and migration of T cells during an immune response and inflammation. It is of great importance to understand the molecular pathways that regulate integrin function in T cells. Lentiviral vector-based gene transfer method has emerged in the past decade as an efficient means of transferring genes into both resting and activated hard-to-transfect cells, including T cells to knockdown gene expression. Therefore, this technology could be utilized effectively to study different aspects of integrin function or even to perform genome-wide RNAi screens to look globally for regulators of integrin function in T cells. In this chapter, we provide the simplest protocol to infect activated CD4(+) human T cells with high efficiency.
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Affiliation(s)
- Daliya Banerjee
- Immune Disease Institute, Program in Cellular and Molecular Medicine, Children's Hospital Boston, Boston, MA, USA.
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62
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Analysis of a Drosophila amplicon in follicle cells highlights the diversity of metazoan replication origins. Proc Natl Acad Sci U S A 2011; 108:16681-6. [PMID: 21933960 DOI: 10.1073/pnas.1114209108] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
To investigate the properties of metazoan replication origins, recent studies in cell culture have adopted the strategy of identifying origins using genome-wide approaches and assessing correlations with such features as transcription and histone modifications. Drosophila amplicon in follicle cells (DAFCs), genomic regions that undergo repeated rounds of DNA replication to increase DNA copy number, serve as powerful in vivo model replicons. Because there are six DAFCs, compared with thousands of origins activated in the typical S phase, close molecular characterization of all DAFCs is possible. To determine the extent to which the six DAFCs are different or similar, we investigated the developmental and replication properties of the newly identified DAFC-34B. DAFC-34B contains two genes expressed in follicle cells, although the timing and spatial patterns of expression suggest that amplification is not a strategy to promote high expression at this locus. Like the previously characterized DAFC-62D, DAFC-34B displays origin activation at two separate stages of development. However, unlike DAFC-62D, amplification at the later stage is not transcription-dependent. We mapped the DAFC-34B amplification origin to 1 kb by nascent strand analysis and delineated cis requirements for origin activation, finding that a 6-kb region, but not the 1-kb origin alone, is sufficient for amplification. We analyzed the developmental localization of the origin recognition complex (ORC) and the minichromosome maintenance (MCM)2-7 complex, the replicative helicase. Intriguingly, the final round of origin activation at DAFC-34B occurs in the absence of detectable ORC, although MCMs are present, suggesting a new amplification initiation mechanism.
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63
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miRNA-mediated feedback inhibition of JAK/STAT morphogen signalling establishes a cell fate threshold. Nat Cell Biol 2011; 13:1062-9. [PMID: 21857668 PMCID: PMC3167036 DOI: 10.1038/ncb2316] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 06/24/2011] [Indexed: 12/20/2022]
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64
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Parachoniak CA, Luo Y, Abella JV, Keen JH, Park M. GGA3 functions as a switch to promote Met receptor recycling, essential for sustained ERK and cell migration. Dev Cell 2011; 20:751-63. [PMID: 21664574 DOI: 10.1016/j.devcel.2011.05.007] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 02/08/2011] [Accepted: 05/09/2011] [Indexed: 12/21/2022]
Abstract
Cells are dependent on correct sorting of activated receptor tyrosine kinases (RTKs) for the outcome of growth factor signaling. Upon activation, RTKs are coupled through the endocytic machinery for degradation or recycled to the cell surface. However, the molecular mechanisms governing RTK recycling are poorly understood. Here, we show that Golgi-localized gamma ear-containing Arf-binding protein 3 (GGA3) interacts selectively with the Met/hepatocyte growth factor RTK when stimulated, to sort it for recycling in association with "gyrating" clathrin. GGA3 loss abrogates Met recycling from a Rab4 endosomal subdomain, resulting in pronounced trafficking of Met toward degradation. Decreased Met recycling attenuates ERK activation and cell migration. Met recycling, sustained ERK activation, and migration require interaction of GGA3 with Arf6 and an unexpected association with the Crk adaptor. The data show that GGA3 defines an active recycling pathway and support a broader role for GGA3-mediated cargo selection in targeting receptors destined for recycling.
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65
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Niepielko MG, Hernáiz-Hernández Y, Yakoby N. BMP signaling dynamics in the follicle cells of multiple Drosophila species. Dev Biol 2011; 354:151-9. [PMID: 21402065 DOI: 10.1016/j.ydbio.2011.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 02/13/2011] [Accepted: 03/04/2011] [Indexed: 11/18/2022]
Abstract
The dorsal anterior region of the follicle cells (FCs) in the developing Drosophila egg gives rise to the respiratory eggshell appendages. These tubular structures display a wide range of qualitative and quantitative variations across Drosophila species, providing a remarkable example of a rapidly evolving morphology. In D. melanogaster, the bone morphogenetic protein (BMP) signaling pathway is an important regulator of FCs patterning and dorsal appendages morphology. To explore the mechanisms underlying the diversification of eggshell patterning, we analyzed BMP signaling in the FCs of 16 Drosophila species that span 45 million years of evolution. We found that the spatial patterns of BMP signaling in the FCs are dynamic and exhibit a range of interspecies' variations. In most of the species examined, the dynamics of BMP signaling correlate with the expression of the type I BMP receptor thickveins (tkv). This correlation suggests that interspecies' variations of tkv expression are responsible for the diversification of BMP signaling during oogenesis. This model was supported by genetic manipulations of tkv expression in the FCs of D. melanogaster that successfully recapitulated the signaling diversities found in the other species. Our results suggest that regulation of receptor expression mediates spatial diversification of BMP signaling in Drosophila oogenesis, and they provide insight into a mechanism underlying the evolution of eggshell patterning.
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Affiliation(s)
- Matthew G Niepielko
- Biology Department and Center for Computational and Integrative Biology, Science Building, 315 Penn Street, Rutgers, The State University of New Jersey, Camden, NJ 08102, USA
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66
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Kim JH, Cho A, Yin H, Schafer DA, Mouneimne G, Simpson KJ, Nguyen KV, Brugge JS, Montell DJ. Psidin, a conserved protein that regulates protrusion dynamics and cell migration. Genes Dev 2011; 25:730-41. [PMID: 21406550 DOI: 10.1101/gad.2028611] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Dynamic assembly and disassembly of actin filaments is a major driving force for cell movements. Border cells in the Drosophila ovary provide a simple and genetically tractable model to study the mechanisms regulating cell migration. To identify new genes that regulate cell movement in vivo, we screened lethal mutations on chromosome 3R for defects in border cell migration and identified two alleles of the gene psidin (psid). In vitro, purified Psid protein bound F-actin and inhibited the interaction of tropomyosin with F-actin. In vivo, psid mutations exhibited genetic interactions with the genes encoding tropomyosin and cofilin. Border cells overexpressing Psid together with GFP-actin exhibited altered protrusion/retraction dynamics. Psid knockdown in cultured S2 cells reduced, and Psid overexpression enhanced, lamellipodial dynamics. Knockdown of the human homolog of Psid reduced the speed and directionality of migration in wounded MCF10A breast epithelial monolayers, whereas overexpression of the protein increased migration speed and altered protrusion dynamics in EGF-stimulated cells. These results indicate that Psid is an actin regulatory protein that plays a conserved role in protrusion dynamics and cell migration.
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Affiliation(s)
- Ji Hoon Kim
- Department of Biological Chemistry, Center for Cell Dynamics, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
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67
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Prasad M, Wang X, He L, Montell DJ. Border cell migration: a model system for live imaging and genetic analysis of collective cell movement. Methods Mol Biol 2011; 769:277-286. [PMID: 21748683 PMCID: PMC4006199 DOI: 10.1007/978-1-61779-207-6_19] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Border cell migration in the Drosophila ovary has emerged as a genetically tractable model for studying collective cell movement. Over many years border cell migration was exclusively studied in fixed samples due to the inability to culture stage 9 egg chambers in vitro. Although culturing late stage egg chambers was long feasible, stage 9 egg chambers survived only briefly outside the female body. We identified culture conditions that support stage 9 egg chamber development and sustain complete migration of border cells ex vivo. This protocol enables one to compare the dynamics of egg chamber development in wild type and mutant egg chambers using time-lapse microscopy and taking advantage of a multiposition microscope with a motorized imaging stage. In addition, this protocol has been successfully used in combination with fluorescence resonance energy transfer biosensors, photo-activatable proteins, and pharmacological agents and can be used with widefield or confocal microscopes in either an upright or inverted configuration.
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Affiliation(s)
- Mohit Prasad
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, 855 N. Wolfe St, Rangos 456, Baltimore, MD 21205, USA
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68
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Polesello C, Roch F, Gobert V, Haenlin M, Waltzer L. Modeling cancers in Drosophila. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 100:51-82. [PMID: 21377624 DOI: 10.1016/b978-0-12-384878-9.00002-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The basic cellular processes deregulated during carcinogenesis and the vast majority of the genes implicated in cancer appear conserved from humans to flies. This conservation, together with an ever-expanding fly genetic toolbox, has made of Drosophila melanogaster a remarkably profitable model to study many fundamental aspects of carcinogenesis. In particular, Drosophila has played a major role in the identification of genes and pathways implicated in cancer and in disclosing novel functional relationships between cancer genes. It has also proved to be a genetically tractable system where to mimic cancer-like situations and characterize the mode of action of human oncogenes. Here, we outline some advances in the study of cancer, both at the basic and more translational levels, which have benefited from research carried out in flies.
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Affiliation(s)
- Cédric Polesello
- Université de Toulouse, UPS, CBD, Centre de Biologie du Développement, Bâtiment 4R3, 118 route de Narbonne, F-31062, CNRS, F-31062 Toulouse, France
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69
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Smolen GA, Zhang J, Zubrowski MJ, Edelman EJ, Luo B, Yu M, Ng LW, Scherber CM, Schott BJ, Ramaswamy S, Irimia D, Root DE, Haber DA. A genome-wide RNAi screen identifies multiple RSK-dependent regulators of cell migration. Genes Dev 2010; 24:2654-65. [PMID: 21062900 DOI: 10.1101/gad.1989110] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
To define the functional pathways regulating epithelial cell migration, we performed a genome-wide RNAi screen using 55,000 pooled lentiviral shRNAs targeting ∼11,000 genes, selecting for transduced cells with increased motility. A stringent validation protocol generated a set of 31 genes representing diverse pathways whose knockdown dramatically enhances cellular migration. Some of these pathways share features of epithelial-to-mesenchymal transition (EMT), and together they implicate key regulators of transcription, cellular signaling, and metabolism, as well as novel modulators of cellular trafficking, such as DLG5. In delineating downstream pathways mediating these migration phenotypes, we observed universal activation of ERKs and a profound dependence on their RSK effectors. Pharmacological inhibition of RSK dramatically suppresses epithelial cell migration induced by knockdown of all 31 genes, suggesting that convergence of diverse migratory pathways on this kinase may provide a therapeutic opportunity in disorders of cell migration, including cancer metastasis.
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Affiliation(s)
- Gromoslaw A Smolen
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, 02129, USA
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70
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Yan H, Venkatesan K, Beaver JE, Klitgord N, Yildirim MA, Hao T, Hill DE, Cusick ME, Perrimon N, Roth FP, Vidal M. A genome-wide gene function prediction resource for Drosophila melanogaster. PLoS One 2010; 5:e12139. [PMID: 20711346 PMCID: PMC2920829 DOI: 10.1371/journal.pone.0012139] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Accepted: 07/14/2010] [Indexed: 11/19/2022] Open
Abstract
Predicting gene functions by integrating large-scale biological data remains a challenge for systems biology. Here we present a resource for Drosophila melanogaster gene function predictions. We trained function-specific classifiers to optimize the influence of different biological datasets for each functional category. Our model predicted GO terms and KEGG pathway memberships for Drosophila melanogaster genes with high accuracy, as affirmed by cross-validation, supporting literature evidence, and large-scale RNAi screens. The resulting resource of prioritized associations between Drosophila genes and their potential functions offers a guide for experimental investigations.
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Affiliation(s)
- Han Yan
- Department of Cancer Biology, Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Kavitha Venkatesan
- Department of Cancer Biology, Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - John E. Beaver
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Niels Klitgord
- Department of Cancer Biology, Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Muhammed A. Yildirim
- Department of Cancer Biology, Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- Applied Physics Program, Division of Engineering and Applied Sciences, Graduate School of Arts and Sciences, Harvard University, Cambridge, Massachusetts, United States of America
| | - Tong Hao
- Department of Cancer Biology, Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - David E. Hill
- Department of Cancer Biology, Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Michael E. Cusick
- Department of Cancer Biology, Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Frederick P. Roth
- Department of Cancer Biology, Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (FPR); (MV)
| | - Marc Vidal
- Department of Cancer Biology, Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (FPR); (MV)
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71
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Boyle MJ, French RL, Cosand KA, Dorman JB, Kiehart DP, Berg CA. Division of labor: subsets of dorsal-appendage-forming cells control the shape of the entire tube. Dev Biol 2010; 346:68-79. [PMID: 20659448 DOI: 10.1016/j.ydbio.2010.07.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 06/30/2010] [Accepted: 07/16/2010] [Indexed: 11/19/2022]
Abstract
The function of an organ relies on its form, which in turn depends on the individual shapes of the cells that create it and the interactions between them. Despite remarkable progress in the field of developmental biology, how cells collaborate to make a tissue remains an unsolved mystery. To investigate the mechanisms that determine organ structure, we are studying the cells that form the dorsal appendages (DAs) of the Drosophila melanogaster eggshell. These cells consist of two differentially patterned subtypes: roof cells, which form the outward-facing roof of the lumen, and floor cells, which dive underneath the roof cells to seal off the floor of the tube. In this paper, we present three lines of evidence that reveal a further stratification of the DA-forming epithelium. Laser ablation of only a few cells in the anterior of the region causes a disproportionately severe shortening of the appendage. Genetic alteration through the twin peaks allele of tramtrack69 (ttk(twk)), a female-sterile mutation that leads to severely shortened DAs, causes no such shortening when removed from a majority of the DA-forming cells, but rather, produces short appendages only when removed from cells in the very anterior of the tube-forming tissue. Additionally we show that heterotrimeric G-protein function is required for DA morphogenesis. Like TTK69, Gbeta 13F is not required in all DA-forming follicle cells but only in the floor and leading roof cells. The different phenotypes that result from removal of Gbeta 13F from each region demonstrate a striking division of function between different DA-forming cells. Gbeta mutant floor cells are unable to control the width of the appendage while Gbeta mutant leading roof cells fail to direct the elongation of the appendage and the convergent-extension of the roof-cell population.
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Affiliation(s)
- Michael J Boyle
- Department of Genome Sciences, University of Washington, Seattle, WA 98195-5065, USA
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72
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Levine B, Hackney JF, Bergen A, Dobens L, Truesdale A, Dobens L. Opposing interactions between Drosophila cut and the C/EBP encoded by slow border cells direct apical constriction and epithelial invagination. Dev Biol 2010; 344:196-209. [PMID: 20450903 DOI: 10.1016/j.ydbio.2010.04.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Revised: 04/26/2010] [Accepted: 04/27/2010] [Indexed: 12/29/2022]
Abstract
Stage 10 of Drosophila oogenesis can be subdivided into stages 10A and 10B based on a change in the morphology of the centripetal follicle cells (FC) from a columnar to an apically constricted shape. This coordinated cell shape change drives epithelial cell sheet involution between the oocyte and nurse cell complex which patterns the operculum structure of the mature eggshell. We have shown previously that proper centripetal FC migration requires transient expression of the C/EBP encoded by slow border cells (slbo) at 10A, due in part to Notch activation followed by slbo autorepression (Levine et al., 2007). Here we show that decreased slbo expression in the centripetal FC coincides with increased expression of the transcription factor Cut, a Cut/Cux/CDP family member, at 10B. The 10A/10B temporal switch from Slbo to Cut expression is refined by both cross repression between Slbo and Cut, Slbo auto repression and Cut auto activation. High Cut levels are necessary and sufficient to direct polarized, supracellular accumulation of Actin, DE-cadherin and Armadillo associated with apical constriction of the centripetal FC. Separately, Slbo in the border cell rosette and Cut in the pole cells have antagonistic interactions to restrict Fas2 accumulation to the pole cells, which is important for proper border cell migration. The opposing effects of Cut and Slbo in these two tissues reflect the opposing interactions between their respective mammalian homologs CAAT Displacement Protein (CDP; now CUX1) and CAAT Enhancer Binding Protein (C/EBP) in tissue culture.
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Affiliation(s)
- Benjamin Levine
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA
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73
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Akiyama-Oda Y, Oda H. Cell migration that orients the dorsoventral axis is coordinated with anteroposterior patterning mediated by Hedgehog signaling in the early spider embryo. Development 2010; 137:1263-73. [PMID: 20332148 DOI: 10.1242/dev.045625] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The early embryo of the spider Achaearanea tepidariorum is emerging as a model for the simultaneous study of cell migration and pattern formation. A cell cluster internalized at the center of the radially symmetric germ disc expresses the evolutionarily conserved dorsal signal Decapentaplegic. This cell cluster migrates away from the germ disc center along the basal side of the epithelium to the germ disc rim. This cell migration is thought to be the symmetry-breaking event that establishes the orientation of the dorsoventral axis. In this study, knockdown of a patched homolog, At-ptc, that encodes a putative negative regulator of Hedgehog (Hh) signaling, prevented initiation of the symmetry-breaking cell migration. Knockdown of a smoothened homolog, At-smo, showed that Hh signaling inactivation also arrested the cells at the germ disc center, whereas moderate inactivation resulted in sporadic failure of cell migration termination at the germ disc rim. hh transcript expression patterns indicated that the rim and outside of the germ disc were the source of the Hh ligand. Analyses of patterning events suggested that in the germ disc, short-range Hh signal promotes anterior specification and long-range Hh signal represses caudal specification. Moreover, negative regulation of Hh signaling by At-ptc appears to be required for progressive derepression of caudal specification from the germ disc center. Cell migration defects caused by At-ptc and At-smo knockdown correlated with patterning defects in the germ disc epithelium. We propose that the cell migration crucial for dorsoventral axis orientation in Achaearanea is coordinated with anteroposterior patterning mediated by Hh signaling.
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74
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Chung MI, Nascone-Yoder NM, Grover SA, Drysdale TA, Wallingford JB. Direct activation of Shroom3 transcription by Pitx proteins drives epithelial morphogenesis in the developing gut. Development 2010; 137:1339-49. [PMID: 20332151 DOI: 10.1242/dev.044610] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Individual cell shape changes are essential for epithelial morphogenesis. A transcriptional network for epithelial cell shape change is emerging in Drosophila, but this area remains largely unexplored in vertebrates. The distinction is important as so far, key downstream effectors of cell shape change in Drosophila appear not to be conserved. Rather, Shroom3 has emerged as a central effector of epithelial morphogenesis in vertebrates, driving both actin- and microtubule-based cell shape changes. To date, the morphogenetic role of Shroom3 has been explored only in the neural epithelium, so the broad expression of this gene raises two important questions: what are the requirements for Shroom3 in non-neural tissues and what factors control Shroom3 transcription? Here, we show in Xenopus that Shroom3 is essential for cell shape changes and morphogenesis in the developing vertebrate gut and that Shroom3 transcription in the gut requires the Pitx1 transcription factor. Moreover, we show that Pitx proteins directly activate Shroom3 transcription, and we identify Pitx-responsive regulatory elements in the genomic DNA upstream of Shroom3. Finally, we show that ectopic expression of Pitx proteins is sufficient to induce Shroom3-dependent cytoskeletal reorganization and epithelial cell shape change. These data demonstrate new breadth to the requirements for Shroom3 in morphogenesis, and they also provide a cell-biological basis for the role of Pitx transcription factors in morphogenesis. More generally, these results provide a foundation for deciphering the transcriptional network that underlies epithelial cell shape change in developing vertebrates.
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Affiliation(s)
- Mei-I Chung
- Section of Molecular Cell and Developmental Biology, University of Texas at Austin, Austin, TX 78712, USA
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75
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Aman A, Piotrowski T. Cell migration during morphogenesis. Dev Biol 2009; 341:20-33. [PMID: 19914236 DOI: 10.1016/j.ydbio.2009.11.014] [Citation(s) in RCA: 184] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2009] [Revised: 11/04/2009] [Accepted: 11/08/2009] [Indexed: 12/15/2022]
Abstract
During development, functional structures must form with the correct three-dimensional geometry composed of the correct cell types. In many cases cell types are specified at locations distant to where they will ultimately reside for normal biological function. Although cell migration is crucial for normal development and morphogenesis of animal body plans and organ systems, abnormal cell migration during adult life underlies pathological states such as invasion and metastasis of cancer. In both contexts cells migrate either individually, as loosely associated sheets or as clusters of cells. In this review, we summarize, compare and integrate knowledge gained from several in vivo model systems that have yielded insights into the regulation of morphogenic cell migration, such as the zebrafish lateral line primordium and primordial germ cells, Drosophila border cell clusters, vertebrate neural crest migration and angiogenic sprouts in the post-natal mouse retina. Because of its broad multicontextual and multiphylletic distribution, understanding cell migration in its various manifestations in vivo is likely to provide new insights into both the function and malfunction of key embryonic and postembryonic events. In this review, we will provide a succinct phenotypic description of the many model systems utilized to study cell migration in vivo. More importantly, we will highlight, compare and integrate recent advances in our understanding of how cell migration is regulated in these varied model systems with special emphasis on individual and collective cell movements.
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Affiliation(s)
- Andy Aman
- University of Utah, Department Neurobiology and Anatomy, 20N Medical Drive, MREB 401, Salt Lake City, UT 84132, USA
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76
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Yew JY, Wang Y, Barteneva N, Dikler S, Kutz-Naber KK, Li L, Kravitz EA. Analysis of neuropeptide expression and localization in adult drosophila melanogaster central nervous system by affinity cell-capture mass spectrometry. J Proteome Res 2009; 8:1271-84. [PMID: 19199706 DOI: 10.1021/pr800601x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A combined approach using mass spectrometry, a novel neuron affinity capture technique, and Drosophila melanogaster genetic manipulation has been developed to characterize the expression and localization of neuropeptides in the adult D. melanogaster brain. In extract from the whole adult brain, 42 neuropeptides from 18 peptide families were sequenced. Neuropeptide profiling also was performed on targeted populations of cells which were enriched with immunoaffinity purification using a genetically expressed marker.
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Affiliation(s)
- Joanne Y Yew
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA.
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77
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Gates J, Nowotarski SH, Yin H, Mahaffey JP, Bridges T, Herrera C, Homem CCF, Janody F, Montell DJ, Peifer M. Enabled and Capping protein play important roles in shaping cell behavior during Drosophila oogenesis. Dev Biol 2009; 333:90-107. [PMID: 19576200 DOI: 10.1016/j.ydbio.2009.06.030] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 06/20/2009] [Accepted: 06/22/2009] [Indexed: 12/29/2022]
Abstract
During development, cells craft an impressive array of actin-based structures, mediating events as diverse as cytokinesis, apical constriction, and cell migration. One challenge is to determine how cells regulate actin assembly and disassembly to carry out these cell behaviors. During Drosophila oogenesis diverse cell behaviors are seen in the soma and germline. We used oogenesis to explore developmental roles of two important actin regulators: Enabled/VASP proteins and Capping protein. We found that Enabled plays an important role in cortical integrity of nurse cells, formation of robust bundled actin filaments in late nurse cells that facilitate nurse cell dumping, and migration of somatic border cells. During nurse cell dumping, Enabled localizes to barbed ends of the nurse cell actin filaments, suggesting its mechanism of action. We further pursued this mechanism using mutant Enabled proteins, each affecting one of its protein domains. These data suggest critical roles for the EVH2 domain and its tetramerization subdomain, while the EVH1 domain appears less critical. Enabled appears to be negatively regulated during oogenesis by Abelson kinase. We also explored the function of Capping protein. This revealed important roles in oocyte determination, nurse cell cortical integrity and nurse cell dumping, and support the idea that Capping protein and Enabled act antagonistically during dumping. Together these data reveal places that these actin regulators shape oogenesis.
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Affiliation(s)
- Julie Gates
- Lineberger Comprehensive Cancer Center and Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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78
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Di Fiore PP. Endocytosis, signaling and cancer, much more than meets the eye. Preface. Mol Oncol 2009; 3:273-9. [PMID: 19628439 DOI: 10.1016/j.molonc.2009.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Accepted: 06/12/2009] [Indexed: 11/24/2022] Open
Affiliation(s)
- Pier Paolo Di Fiore
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare at IFOM-IEO Campus, 20139 Milan, Italy.
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79
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Jang ACC, Chang YC, Bai J, Montell D. Border-cell migration requires integration of spatial and temporal signals by the BTB protein Abrupt. Nat Cell Biol 2009; 11:569-79. [PMID: 19350016 PMCID: PMC2675665 DOI: 10.1038/ncb1863] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Accepted: 01/26/2009] [Indexed: 12/30/2022]
Abstract
During development, elaborate patterns of cell differentiation and movement must occur in the correct locations and at the proper times. Developmental timing has been studied less than spatial pattern formation, and the mechanisms integrating the two are poorly understood. Border-cell migration in the Drosophila ovary occurs specifically at stage 9. Timing of the migration is regulated by the steroid hormone ecdysone, whereas spatial patterning of the migratory population requires localized activity of the JAK-STAT pathway. Ecdysone signalling is patterned spatially as well as temporally, although the mechanisms are not well understood. In stage 9 egg chambers, ecdysone signalling is highest in anterior follicle cells including the border cells. We identify the gene abrupt as a repressor of ecdysone signalling and border-cell migration. Abrupt protein is normally lost from border-cell nuclei during stage 9, in response to JAK-STAT activity. This contributes to the spatial pattern of the ecdysone response. Abrupt attenuates ecdysone signalling by means of a direct interaction with the basic helix-loop-helix (bHLH) domain of the P160 ecdysone receptor coactivator Taiman (Tai). Taken together, these findings provide a molecular mechanism by which spatial and temporal cues are integrated.
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Affiliation(s)
- Anna C-C Jang
- Department of Biological Chemistry, Johns Hopkins School of Medicine, 725 North Wolfe Street, Baltimore, Maryland 21205-2185, USA
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80
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Identification of genes that regulate epithelial cell migration using an siRNA screening approach. Nat Cell Biol 2009; 10:1027-38. [PMID: 19160483 DOI: 10.1038/ncb1762] [Citation(s) in RCA: 327] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
To provide a systematic analysis of genes that regulate epithelial cell migration, we performed a high throughput wound healing screen with MCF-10A breast epithelial cells, using siRNAs targeting 1,081 human genes encoding phosphatases, kinases and proteins predicted to influence cell migration and adhesion. The primary screen identified three categories of hits: those that accelerate, those that inhibit and those that impair migration with associated effects on cell proliferation or metabolism. Extensive validation of all the hits yielded 66 high confidence genes that, when downregulated, either accelerated or impaired migration; 42 of these high confidence genes have not been previously associated with motility or adhesion. Time-lapse video microscopy revealed a broad spectrum of phenotypic changes involving alterations in the extent and nature of disruption of cell-cell adhesion, directionality of motility, cell polarity and shape, and protrusion dynamics. Informatics analysis highlighted three major signalling nodes, beta-catenin, beta1-integrin and actin, and a large proportion of the genes that accelerated migration impaired cell-cell adhesion.
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81
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A role for the chaperone Hsp70 in the regulation of border cell migration in the Drosophila ovary. Mech Dev 2008; 125:1048-58. [DOI: 10.1016/j.mod.2008.07.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Revised: 07/11/2008] [Accepted: 07/24/2008] [Indexed: 01/30/2023]
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82
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Yakoby N, Bristow CA, Gong D, Schafer X, Lembong J, Zartman JJ, Halfon MS, Schüpbach T, Shvartsman SY. A combinatorial code for pattern formation in Drosophila oogenesis. Dev Cell 2008; 15:725-37. [PMID: 19000837 PMCID: PMC2822874 DOI: 10.1016/j.devcel.2008.09.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Revised: 08/27/2008] [Accepted: 09/17/2008] [Indexed: 10/21/2022]
Abstract
Two-dimensional patterning of the follicular epithelium in Drosophila oogenesis is required for the formation of three-dimensional eggshell structures. Our analysis of a large number of published gene expression patterns in the follicle cells suggests that they follow a simple combinatorial code based on six spatial building blocks and the operations of union, difference, intersection, and addition. The building blocks are related to the distribution of inductive signals, provided by the highly conserved epidermal growth factor receptor and bone morphogenetic protein signaling pathways. We demonstrate the validity of the code by testing it against a set of patterns obtained in a large-scale transcriptional profiling experiment. Using the proposed code, we distinguish 36 distinct patterns for 81 genes expressed in the follicular epithelium and characterize their joint dynamics over four stages of oogenesis. The proposed combinatorial framework allows systematic analysis of the diversity and dynamics of two-dimensional transcriptional patterns and guides future studies of gene regulation.
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Affiliation(s)
- Nir Yakoby
- Lewis-Sigler Institute for Integrative Genomics and Department of Chemical Engineering, Princeton University, Princeton, NJ 08544, USA
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83
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PAR-1 kinase regulates epithelial detachment and directional protrusion of migrating border cells. Curr Biol 2008; 18:1659-67. [PMID: 18976916 DOI: 10.1016/j.cub.2008.09.041] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 09/15/2008] [Accepted: 09/16/2008] [Indexed: 01/02/2023]
Abstract
BACKGROUND Many cells that migrate during normal embryonic development or in metastatic cancer first detach from an epithelium. However, this step is often difficult to observe directly in vivo, and the mechanisms controlling the ability of cells to leave the epithelium are poorly understood. In addition, once cells detach, they must assume a migratory phenotype, involving changes in cytoskeletal and signaling dynamics. Drosophila border cells provide a model system in which a combination of forward genetics and live-cell imaging can allow researchers to investigate the cellular and molecular mechanisms of epithelial cell detachment and migration in vivo. RESULTS We identified the Drosophila homolog of the serine/threonine kinase PAR-1 (MARK/Kin1) in a screen for mutations that disrupt border cell migration. Previous studies identified two proteins, Apontic and Notch, that indirectly affect border cell detachment by regulating transcription of downstream targets. In contrast, PAR-1 directly modulates apical-basal polarity between border cells and epithelial cells to promote detachment. Furthermore, PAR-1, but not the apical polarity complex protein PAR-3, promotes the directionality of transient cell protrusions, which border cells require for sensing the chemoattractant gradient. CONCLUSIONS We conclude that PAR-1-dependent apical-basal polarity is required for proper detachment of migratory border cells from neighboring epithelial cells. Moreover, polarity controlled by PAR-1 influences the ability of migratory cells to sense direction, a critical feature of migration. Thus, this work reveals new insights into two distinct, but essential, steps of epithelial cell migration.
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84
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Zartman JJ, Kanodia JS, Yakoby N, Schafer X, Watson C, Schlichting K, Dahmann C, Shvartsman SY. Expression patterns of cadherin genes in Drosophila oogenesis. Gene Expr Patterns 2008; 9:31-6. [PMID: 18817893 DOI: 10.1016/j.gep.2008.09.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 08/28/2008] [Accepted: 09/03/2008] [Indexed: 01/31/2023]
Abstract
In Drosophila oogenesis, the follicular epithelium that envelops the oocyte is patterned by a small set of inductive signals and gives rise to an elaborate three-dimensional eggshell. Several eggshell structures provide sensitive readouts of the patterning signals, but the formation of these structures is still poorly understood. In other systems, epithelial morphogenesis is guided by the spatial patterning of cell adhesion and cytoskeleton genes. As a step towards developing a comprehensive description of patterning events leading to eggshell morphogenesis, we report the expression of Drosophila cadherins, calcium-dependent adhesion molecules that are repeatedly used throughout development. We found that 9/17 of Drosophila cadherins are expressed in the follicular epithelium in dynamic patterns during oogenesis. In late oogenesis, the expression patterns of cadherin genes in the main body follicle cells is summarized using a compact set of simple geometric shapes, reflecting the integration of the EGFR and DPP inductive signals. The multi-layered composite patterning of the cadherins is hypothesized to play a key role in the formation of the eggshell. Of particular note is the complex patterning of the region of the follicular epithelium that gives rise to the dorsal appendages, which are tubular structures that serve as respiratory organs for the developing embryo.
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Affiliation(s)
- Jeremiah J Zartman
- Lewis Sigler Institute, Department of Chemical Engineering, Princeton University, Princeton, NJ 08544, USA
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85
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Sigismund S, Argenzio E, Tosoni D, Cavallaro E, Polo S, Di Fiore PP. Clathrin-mediated internalization is essential for sustained EGFR signaling but dispensable for degradation. Dev Cell 2008; 15:209-19. [PMID: 18694561 DOI: 10.1016/j.devcel.2008.06.012] [Citation(s) in RCA: 489] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2008] [Revised: 06/11/2008] [Accepted: 06/20/2008] [Indexed: 12/31/2022]
Abstract
Clathrin-mediated endocytosis (CME) is the major pathway of epidermal growth factor receptor (EGFR) internalization. It is commonly believed that CME mediates long-term attenuation of EGFR signaling by targeting the receptor for degradation. However, the EGFR can also be internalized through (a) clathrin-independent pathway(s), and it remains unclear why distinct mechanisms of internalization have evolved. Here, we report that EGFRs internalized via CME are not targeted for degradation, but instead are recycled to the cell surface. By contrast, clathrin-independent internalization preferentially commits the receptor to degradation. This finding has profound implications for signaling, as by skewing EGFR fate toward recycling rather than degradation, CME prolongs the duration of signaling. Our data show that CME determines the longevity of some EGFR-activated signaling pathways and that EGF-dependent biological responses, such as DNA synthesis, absolutely require CME. Thus, CME of the EGFR unexpectedly has a greater impact on receptor signaling than on receptor degradation.
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Affiliation(s)
- Sara Sigismund
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
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86
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Abstract
From the signaling point of view, endocytosis has long been regarded as a major mechanism of attenuation, through the degradation of signaling receptors and, in some cases, of their ligands. This outlook has changed, over the past decade, as it has become clear that signaling persists in the endocytic route, and that intracellular endocytic stations (the 'signaling endosomes') actually contribute to the sorting of signals in space and time. Endocytosis-mediated recycling of receptors and of signaling molecules to specific regions of the plasma membrane is also coming into focus as a major mechanism in the execution of spatially restricted functions, such as cell motility. In addition, emerging evidence connects endocytosis as a whole, or individual endocytic proteins, to complex cellular programs, such as the control of the cell cycle, mitosis, apoptosis and cell fate determination. Thus, endocytosis seems to be deeply ingrained into the cell regulation blueprint and its subversion is predicted to play an important role in human diseases: first and foremost, cancer.
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Affiliation(s)
- Letizia Lanzetti
- Dipartimento di Scienze Oncologiche, Università degli Studi di Torino, Istituto per la Ricerca e la Cura del Cancro, Candiolo, Turin, Italy
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87
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Zartman JJ, Yakoby N, Bristow CA, Zhou X, Schlichting K, Dahmann C, Shvartsman SY. Cad74A is regulated by BR and is required for robust dorsal appendage formation in Drosophila oogenesis. Dev Biol 2008; 322:289-301. [PMID: 18708045 DOI: 10.1016/j.ydbio.2008.07.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2008] [Revised: 07/17/2008] [Accepted: 07/18/2008] [Indexed: 11/27/2022]
Abstract
Drosophila egg development is an established model for studying epithelial patterning and morphogenesis, but the connection between signaling pathways and egg morphology is still incompletely understood. We have identified a non-classical cadherin, Cad74A, as a putative adhesion gene that bridges epithelial patterning and morphogenesis in the follicle cells. Starting in mid-oogenesis, Cad74A is expressed in the follicle cells that contact the oocyte, including the border cells and most of the columnar follicle cells. However, Cad74A is repressed in two dorsolateral patches of follicle cells, which participate in the formation of tubular respiratory appendages. We show genetically that Cad74A is downstream of the EGFR and BMP signaling pathways and is repressed by the Zn-finger transcription factor Broad. The correlation of Cad74A repression in the cells that bend out of the plane of the follicular epithelium is preserved across Drosophila species and mutant backgrounds exhibiting a range of eggshell phenotypes. Complete removal of Cad74A from the follicle cells causes defects in dorsal appendage formation. Ectopic expression of Cad74A in the roof cells results in shortened, flattened appendages due to the hindered migration of the roof cells. Based on these results, we propose that Cad74A is part of the adhesive machinery that enables robust dorsal appendage formation, and as such provides a link between the patterning of the follicle cells and eggshell morphogenesis.
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Affiliation(s)
- Jeremiah J Zartman
- Lewis Sigler Institute and Department of Chemical Engineering, Carl Icahn Laboratory, Princeton University, Princeton, NJ 08544, USA
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88
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Oti M, van Reeuwijk J, Huynen MA, Brunner HG. Conserved co-expression for candidate disease gene prioritization. BMC Bioinformatics 2008; 9:208. [PMID: 18433471 PMCID: PMC2383918 DOI: 10.1186/1471-2105-9-208] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Accepted: 04/23/2008] [Indexed: 11/16/2022] Open
Abstract
Background Genes that are co-expressed tend to be involved in the same biological process. However, co-expression is not a very reliable predictor of functional links between genes. The evolutionary conservation of co-expression between species can be used to predict protein function more reliably than co-expression in a single species. Here we examine whether co-expression across multiple species is also a better prioritizer of disease genes than is co-expression between human genes alone. Results We use co-expression data from yeast (S. cerevisiae), nematode worm (C. elegans), fruit fly (D. melanogaster), mouse and human and find that the use of evolutionary conservation can indeed improve the predictive value of co-expression. The effect that genes causing the same disease have higher co-expression than do other genes from their associated disease loci, is significantly enhanced when co-expression data are combined across evolutionarily distant species. We also find that performance can vary significantly depending on the co-expression datasets used, and just using more data does not necessarily lead to better prioritization. Instead, we find that dataset quality is more important than quantity, and using a consistent microarray platform per species leads to better performance than using more inclusive datasets pooled from various platforms. Conclusion We find that evolutionarily conserved gene co-expression prioritizes disease candidate genes better than human gene co-expression alone, and provide the integrated data as a new resource for disease gene prioritization tools.
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Affiliation(s)
- Martin Oti
- Centre for Molecular and Biomolecular Informatics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Geert Grooteplein 26-28, 6525 GA, Nijmegen, The Netherlands.
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89
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Scita G, Confalonieri S, Lappalainen P, Suetsugu S. IRSp53: crossing the road of membrane and actin dynamics in the formation of membrane protrusions. Trends Cell Biol 2008; 18:52-60. [DOI: 10.1016/j.tcb.2007.12.002] [Citation(s) in RCA: 208] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 12/04/2007] [Accepted: 12/04/2007] [Indexed: 11/16/2022]
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90
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Drosophila follicle cells: morphogenesis in an eggshell. Semin Cell Dev Biol 2008; 19:271-82. [PMID: 18304845 DOI: 10.1016/j.semcdb.2008.01.004] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Accepted: 01/16/2008] [Indexed: 01/15/2023]
Abstract
Epithelial morphogenesis is important for organogenesis and pivotal for carcinogenesis, but mechanisms that control it are poorly understood. The Drosophila follicular epithelium is a genetically tractable model to understand these mechanisms in vivo. This epithelium of follicle cells encases germline cells to create an egg. In this review, we summarize progress toward understanding mechanisms that maintain the epithelium or permit migrations essential for oogenesis. Cell-cell communication is important, but the same signals are used repeatedly to control distinct events. Understanding intrinsic mechanisms that alter responses to developmental signals will be important to understand regulation of cell shape and organization.
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91
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Yakoby N, Lembong J, Schüpbach T, Shvartsman SY. Drosophila eggshell is patterned by sequential action of feedforward and feedback loops. Development 2007; 135:343-51. [PMID: 18077592 DOI: 10.1242/dev.008920] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During Drosophila oogenesis, patterning activities of the EGFR and Dpp pathways specify several subpopulations of the follicle cells that give rise to dorsal eggshell structures. The roof of dorsal eggshell appendages is formed by the follicle cells that express Broad (Br), a zinc-finger transcription factor regulated by both pathways. EGFR induces Br in the dorsal follicle cells. This inductive signal is overridden in the dorsal midline cells, which are exposed to high levels of EGFR activation, and in the anterior cells, by Dpp signaling. We show that the resulting changes in the Br pattern affect the expression of Dpp receptor thickveins (tkv), which is essential for Dpp signaling. By controlling tkv, Br controls Dpp signaling in late stages of oogenesis and, as a result, regulates its own repression in a negative-feedback loop. We synthesize these observations into a model, whereby the dynamics of Br expression are driven by the sequential action of feedforward and feedback loops. The feedforward loop controls the spatial pattern of Br expression, while the feedback loop modulates this pattern in time. This mechanism demonstrates how complex patterns of gene expression can emerge from simple inputs, through the interaction of regulatory network motifs.
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Affiliation(s)
- Nir Yakoby
- Department of Chemical Engineering and Lewis-Sigler Institute for Integrative Genomics, Princeton University, NJ 08544, USA
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92
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Wilkins SJ, Yoong S, Verkade H, Mizoguchi T, Plowman SJ, Hancock JF, Kikuchi Y, Heath JK, Perkins AC. Mtx2 directs zebrafish morphogenetic movements during epiboly by regulating microfilament formation. Dev Biol 2007; 314:12-22. [PMID: 18154948 DOI: 10.1016/j.ydbio.2007.10.050] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Revised: 10/17/2007] [Accepted: 10/19/2007] [Indexed: 11/16/2022]
Abstract
The homeobox transcription factor Mtx2 is essential for epiboly, the first morphogenetic movement of gastrulation in zebrafish. Morpholino knockdown of Mtx2 results in stalling of epiboly and lysis due to yolk rupture. However, the mechanism of Mtx2 action is unknown. The role of mtx2 is surprising as most mix/bix family genes are thought to have roles in mesendoderm specification. Using a transgenic sox17-promoter driven EGFP line, we show that Mtx2 is not required for endoderm specification but is required for correct morphogenetic movements of endoderm and axial mesoderm. During normal zebrafish development, mtx2 is expressed at both the blastoderm margin and in the zebrafish equivalent of visceral endoderm, the extra-embryonic yolk syncytial layer (YSL). We show that formation of the YSL is not Mtx2 dependent, but that Mtx2 directs spatial arrangement of YSL nuclei. Furthermore, we demonstrate that Mtx2 knockdown results in loss of the YSL F-actin ring, a microfilament structure previously shown to be necessary for epiboly progression. In summary, we propose that Mtx2 acts within the YSL to regulate morphogenetic movements of both embryonic and extra-embryonic tissues, independently of cell fate specification.
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Affiliation(s)
- Simon J Wilkins
- Institute for Molecular Bioscience, University of Queensland, Brisbane, 4072, Australia
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93
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Ogienko AA, Fedorova SA, Baricheva EM. Basic aspects of ovarian development in Drosophila melanogaster. RUSS J GENET+ 2007. [DOI: 10.1134/s1022795407100055] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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94
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Abstract
Cell motility makes essential contributions to normal embryonic development and homeostasis. It is also thought to contribute in important ways to tumor metastasis. Because of this dual importance, cell migration has been extensively studied. The fruit fly Drosophila melanogaster has served as an important model organism for genetic analysis of many aspects of developmental biology, including cell migration. Here we describe the various types of cell movements that have been studied in detail, which represent models for epithelial-to-mesenchymal transition, transepithelial migration, inflammation, wound healing and invasion. We summarize what has been learned about the molecular control of cell migration from genetic studies in the fly. In addition, we describe recent efforts to model tumor metastasis directly in Drosophila by expressing oncogenes and/or mutating tumor suppressor genes. Together these studies suggest that Drosophila has much to offer as a model for varied aspects of tumor metastasis.
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Affiliation(s)
- Anna C-C Jang
- Department of Biological Chemistry, Johns Hopkins School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205-2185, USA
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95
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Chanut-Delalande H, Jung AC, Lin L, Baer MM, Bilstein A, Cabernard C, Leptin M, Affolter M. A genetic mosaic analysis with a repressible cell marker screen to identify genes involved in tracheal cell migration during Drosophila air sac morphogenesis. Genetics 2007; 176:2177-87. [PMID: 17603108 PMCID: PMC1950623 DOI: 10.1534/genetics.107.073890] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Branching morphogenesis of the Drosophila tracheal system relies on the fibroblast growth factor receptor (FGFR) signaling pathway. The Drosophila FGF ligand Branchless (Bnl) and the FGFR Breathless (Btl/FGFR) are required for cell migration during the establishment of the interconnected network of tracheal tubes. However, due to an important maternal contribution of members of the FGFR pathway in the oocyte, a thorough genetic dissection of the role of components of the FGFR signaling cascade in tracheal cell migration is impossible in the embryo. To bypass this shortcoming, we studied tracheal cell migration in the dorsal air sac primordium, a structure that forms during late larval development. Using a mosaic analysis with a repressible cell marker (MARCM) clone approach in mosaic animals, combined with an ethyl methanesulfonate (EMS)-mutagenesis screen of the left arm of the second chromosome, we identified novel genes implicated in cell migration. We screened 1123 mutagenized lines and identified 47 lines displaying tracheal cell migration defects in the air sac primordium. Using complementation analyses based on lethality, mutations in 20 of these lines were genetically mapped to specific genomic areas. Three of the mutants were mapped to either the Mhc or the stam complementation groups. Further experiments confirmed that these genes are required for cell migration in the tracheal air sac primordium.
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96
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Furriols M, Ventura G, Casanova J. Two distinct but convergent groups of cells trigger Torso receptor tyrosine kinase activation by independently expressing torso-like. Proc Natl Acad Sci U S A 2007; 104:11660-5. [PMID: 17595301 PMCID: PMC1913882 DOI: 10.1073/pnas.0700991104] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cell fate determination is often the outcome of specific interactions between adjacent cells. However, cells frequently change positions during development, and thus signaling molecules might be synthesized far from their final site of action. Here, we analyze the regulation of the torso-like gene, which is required to trigger Torso receptor tyrosine kinase activation in the Drosophila embryo. Whereas torso is present in the oocyte, torso-like is expressed in the egg chamber, at the posterior follicle cells and in two separated groups of anterior cells, the border cells and the centripetal cells. We find that JAK/STAT signaling regulates torso-like expression in the posterior follicle cells and border cells but not in the centripetal cells, where torso-like is regulated by a different enhancer. The border and centripetal cells, which are originally apart, converge at the anterior end of the oocyte, and we find that both groups contribute to trigger Torso activation. Our results illustrate how independently acquired expression of a signaling molecule can constitute a mechanism by which distinct groups of cells act together in the activation of a signaling pathway.
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Affiliation(s)
- Marc Furriols
- Institut de Biologia Molecular de Barcelona (Consejo Superior de Investigaciones Científicas), Institut de Recerca Biomèdica de Barcelona, C/Josep Samitier 1-5, 08028 Barcelona, Spain
- *To whom correspondence may be addressed. E-mail: or
| | - Gemma Ventura
- Institut de Biologia Molecular de Barcelona (Consejo Superior de Investigaciones Científicas), Institut de Recerca Biomèdica de Barcelona, C/Josep Samitier 1-5, 08028 Barcelona, Spain
| | - Jordi Casanova
- Institut de Biologia Molecular de Barcelona (Consejo Superior de Investigaciones Científicas), Institut de Recerca Biomèdica de Barcelona, C/Josep Samitier 1-5, 08028 Barcelona, Spain
- *To whom correspondence may be addressed. E-mail: or
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97
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Prasad M, Montell DJ. Cellular and Molecular Mechanisms of Border Cell Migration Analyzed Using Time-Lapse Live-Cell Imaging. Dev Cell 2007; 12:997-1005. [PMID: 17543870 DOI: 10.1016/j.devcel.2007.03.021] [Citation(s) in RCA: 181] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 03/13/2007] [Accepted: 03/30/2007] [Indexed: 10/23/2022]
Abstract
Border cells in the Drosophila ovary originate within an epithelium, detach from it, invade neighboring nurse cells, and migrate as a coherent cluster. This migration has served as a useful genetic model for understanding epithelial cell motility. The prevailing model of growth factor-mediated chemotaxis in general, and of border cells in particular, posits that receptor activation promotes cellular protrusion at the leading edge. Here we report the time-lapse video imaging of border cell migration, allowing us to test this model. Reducing the activities of the guidance receptors EGFR and PVR did not result in the expected inhibition of protrusion, but instead resulted in protrusion in all directions. In contrast, reduction in Notch activity resulted in failure of the cells to detach from the epithelium without affecting direction sensing. These observations provide new insight into the cellular dynamics and molecular mechanisms of cell migration in vivo.
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Affiliation(s)
- Mohit Prasad
- Department of Biological Chemistry, Center for Cell Dynamics, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
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98
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Mathieu J, Sung HH, Pugieux C, Soetaert J, Rorth P. A sensitized PiggyBac-based screen for regulators of border cell migration in Drosophila. Genetics 2007; 176:1579-90. [PMID: 17483425 PMCID: PMC1931525 DOI: 10.1534/genetics.107.071282] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Migration of border cells during Drosophila melanogaster oogenesis is a good model system for investigating the genetic requirements for cell migration in vivo. We present a sensitized loss-of-function screen used to identify new genes required in border cells for their migration. Chromosomes bearing FRTs on all four major autosomal arms were mutagenized by insertions of the transposable element PiggyBac, allowing multiple parallel clonal screens and easy identification of the mutated gene. For border cells, we analyzed homozygous mutant clones positively marked with lacZ and sensitized by expression of dominant-negative PVR, the guidance receptor. We identified new alleles of genes already known to be required for border cell migration, including aop/yan, DIAP1, and taiman as well as a conserved Slbo-regulated enhancer downstream of shg/DE-cadherin. Mutations in genes not previously described to be required in border cells were also uncovered: hrp48, vir, rme-8, kismet, and puckered. puckered was unique in that the migration defects were observed only when PVR signaling was reduced. We present evidence that an excess of JNK signaling is deleterious for migration in the absence of PVR activity at least in part through Fos transcriptional activity and possibly through antagonistic effects on DIAP1.
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99
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Levine B, Jean-Francois M, Bernardi F, Gargiulo G, Dobens L. Notch signaling links interactions between the C/EBP homolog slow border cells and the GILZ homolog bunched during cell migration. Dev Biol 2007; 305:217-31. [PMID: 17383627 DOI: 10.1016/j.ydbio.2007.02.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 01/11/2007] [Accepted: 02/09/2007] [Indexed: 10/23/2022]
Abstract
In the follicle cell (FC) epithelium that surrounds the Drosophila egg, a complex set of cell signals specifies two cell fates that pattern the eggshell: the anterior centripetal FC that produce the operculum and the posterior columnar FC that produce the main body eggshell structure. We have previously shown that the long-range morphogen DPP represses the expression of the bunched (bun) gene in the anterior-most centripetal FC. bun, which encodes a homolog of vertebrate TSC-22/GILZ, in turn represses anterior gene expression and antagonizes Notch signaling to restrict centripetal FC fates in posterior cells. From a screen for novel targets of bun repression we have identified the C/EBP homolog slow border cells (slbo). At stage 10A, slbo expression overlaps bun in anterior FC; by stage 10B they repress each other's expression to establish a sharp slbo/bun expression boundary. The precise position of the slbo/bun expression boundary is sensitive to Notch signaling, which is required for both slbo activation and bun repression. As centripetal migration proceeds from stages 10B-14, slbo represses its own expression and both slbo loss-of-function mutations and overexpression approaches reveal that slbo is required to coordinate centripetal migration with nurse cell dumping. We propose that in anterior FC exposed to a Dpp morphogen gradient, high and low levels of slbo and bun, respectively, are established by modulation of Notch signaling to direct threshold cell fates. Interactions among Notch, slbo and bun resemble a conserved signaling cassette that regulates mammalian adipocyte differentiation.
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Affiliation(s)
- Benjamin Levine
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA
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100
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Sun J, Deng WM. Hindsight mediates the role of notch in suppressing hedgehog signaling and cell proliferation. Dev Cell 2007; 12:431-42. [PMID: 17336908 PMCID: PMC1851662 DOI: 10.1016/j.devcel.2007.02.003] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2006] [Revised: 12/15/2006] [Accepted: 02/08/2007] [Indexed: 11/28/2022]
Abstract
Temporal and spatial regulation of proliferation and differentiation by signaling pathways is essential for animal development. Drosophila follicular epithelial cells provide an excellent model system for the study of temporal regulation of cell proliferation. In follicle cells, the Notch pathway stops proliferation and promotes a switch from the mitotic cycle to the endocycle. Here, we show that zinc-finger transcription factor Hindsight mediates the role of Notch in regulating cell differentiation and the switch of cell-cycle programs. Hindsight is required and sufficient to stop proliferation and induce the transition to the endocycle. To do so, it represses string, Cut, and Hedgehog signaling, which promote proliferation during early oogenesis. Hindsight, along with another zinc-finger protein, Tramtrack, downregulates Hedgehog signaling through transcriptional repression of cubitus interruptus. Our studies suggest that Hindsight bridges the two antagonistic pathways, Notch and Hedgehog, in the temporal regulation of follicle-cell proliferation and differentiation.
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