101
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Peterson AM, Pilz-Allen C, Möhwald H, Shchukin DG. Evaluation of the role of polyelectrolyte deposition conditions in growth factor release. J Mater Chem B 2014; 2:2680-2687. [DOI: 10.1039/c3tb21757d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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102
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Sulkowski M, Kim YJ, Serpe M. Postsynaptic glutamate receptors regulate local BMP signaling at the Drosophila neuromuscular junction. Development 2013; 141:436-47. [PMID: 24353060 DOI: 10.1242/dev.097758] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Effective communication between pre- and postsynaptic compartments is required for proper synapse development and function. At the Drosophila neuromuscular junction (NMJ), a retrograde BMP signal functions to promote synapse growth, stability and homeostasis and coordinates the growth of synaptic structures. Retrograde BMP signaling triggers accumulation of the pathway effector pMad in motoneuron nuclei and at synaptic termini. Nuclear pMad, in conjunction with transcription factors, modulates the expression of target genes and instructs synaptic growth; a role for synaptic pMad remains to be determined. Here, we report that pMad signals are selectively lost at NMJ synapses with reduced postsynaptic sensitivities. Despite this loss of synaptic pMad, nuclear pMad persisted in motoneuron nuclei, and expression of BMP target genes was unaffected, indicating a specific impairment in pMad production/maintenance at synaptic termini. During development, synaptic pMad accumulation followed the arrival and clustering of ionotropic glutamate receptors (iGluRs) at NMJ synapses. Synaptic pMad was lost at NMJ synapses developing at suboptimal levels of iGluRs and Neto, an auxiliary subunit required for functional iGluRs. Genetic manipulations of non-essential iGluR subunits revealed that synaptic pMad signals specifically correlated with the postsynaptic type-A glutamate receptors. Altering type-A receptor activities via protein kinase A (PKA) revealed that synaptic pMad depends on the activity and not the net levels of postsynaptic type-A receptors. Thus, synaptic pMad functions as a local sensor for NMJ synapse activity and has the potential to coordinate synaptic activity with a BMP retrograde signal required for synapse growth and homeostasis.
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Affiliation(s)
- Mikolaj Sulkowski
- Program in Cellular Regulation and Metabolism, NICHD, NIH, Bethesda, MD 20892, USA
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103
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Panfilio K, Roth S. Development: Getting into the Groove, or Evolving off the Rails? Curr Biol 2013; 23:R1101-3. [DOI: 10.1016/j.cub.2013.10.073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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104
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Mannervik M. Control of Drosophila embryo patterning by transcriptional co-regulators. Exp Cell Res 2013; 321:47-57. [PMID: 24157250 DOI: 10.1016/j.yexcr.2013.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 10/10/2013] [Accepted: 10/14/2013] [Indexed: 12/29/2022]
Abstract
A combination of broadly expressed transcriptional activators and spatially restricted repressors are used to pattern embryos into cells of different fate. Transcriptional co-regulators are essential mediators of transcription factor function, and contribute to selective transcriptional responses in embryo development. A two step mechanism of transcriptional regulation is discussed, where remodeling of chromatin is initially required, followed by stimulation of recruitment or release of RNA polymerase from the promoter. Transcriptional co-regulators are essential for both of these steps. In particular, most co-activators are associated with histone acetylation and co-repressors with histone deacetylation. In the early Drosophila embryo, genome-wide studies have shown that the CBP co-activator has a preference for associating with some transcription factors and regulatory regions. The Groucho, CtBP, Ebi, Atrophin and Brakeless co-repressors are selectively used to limit zygotic gene expression. New findings are summarized which show that different co-repressors are often utilized by a single repressor, that the context in which a co-repressor is recruited to DNA can affect its activity, and that co-regulators may switch from co-repressors to co-activators and vice versa. The possibility that co-regulator activity is regulated and plays an instructive role in development is discussed as well. This review highlights how findings in Drosophila embryos have contributed to the understanding of transcriptional regulation in eukaryotes as well as to mechanisms of animal embryo patterning.
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Affiliation(s)
- Mattias Mannervik
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Arrheniuslaboratories E3, SE-106 91 Stockholm, Sweden.
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105
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Buchta T, Özüak O, Stappert D, Roth S, Lynch JA. Patterning the dorsal–ventral axis of the wasp Nasonia vitripennis. Dev Biol 2013; 381:189-202. [DOI: 10.1016/j.ydbio.2013.05.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 05/14/2013] [Accepted: 05/24/2013] [Indexed: 10/26/2022]
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106
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Scaling of dorsal-ventral patterning by embryo size-dependent degradation of Spemann's organizer signals. Cell 2013; 153:1296-311. [PMID: 23746842 DOI: 10.1016/j.cell.2013.05.004] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 02/15/2013] [Accepted: 05/01/2013] [Indexed: 11/24/2022]
Abstract
Spemann's organizer plays a key role in dorsal-ventral (DV) patterning in the amphibian embryo by secreting diffusible proteins such as Chordin, an antagonist to ventralizing bone morphogenetic proteins (BMPs). The DV patterning is so robust that an amphibian embryo with its ventral half surgically removed can develop into a smaller but proportionally patterned larva. Here, we show that this robust patterning depends on facilitated Chordin degradation and requires the expression of the Chordin-proteinase inhibitor Sizzled on the opposite side. Sizzled, which is stable and diffuses widely along the DV axis, stabilizes Chordin and expands its distribution in the ventral direction. This expanded Chordin distribution, in turn, limits BMP-dependent Sizzled production, forming an axis-wide feedback loop for shaping Chordin's activity. Using bisection assays, we demonstrate that Chordin degradation is dynamically controlled by embryo-size-coupled Sizzled accumulation. We propose a scaling model that enables the DV pattern to adjust proportionally to embryonic axis size.
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107
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The Drosophila COMPASS-like Cmi-Trr coactivator complex regulates dpp/BMP signaling in pattern formation. Dev Biol 2013; 380:185-98. [DOI: 10.1016/j.ydbio.2013.05.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 05/01/2013] [Accepted: 05/13/2013] [Indexed: 01/01/2023]
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108
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Saunders A, Core LJ, Sutcliffe C, Lis JT, Ashe HL. Extensive polymerase pausing during Drosophila axis patterning enables high-level and pliable transcription. Genes Dev 2013; 27:1146-58. [PMID: 23699410 DOI: 10.1101/gad.215459.113] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Cascades of zygotic gene expression pattern the anterior-posterior (AP) and dorsal-ventral (DV) axes of the early Drosophila embryo. Here, we used the global run-on sequencing assay (GRO-seq) to map the genome-wide RNA polymerase distribution during early Drosophila embryogenesis, thus providing insights into how genes are regulated. We identify widespread promoter-proximal pausing yet show that the presence of paused polymerase does not necessarily equate to direct regulation through pause release to productive elongation. Our data reveal that a subset of early Zelda-activated genes is regulated at the level of polymerase recruitment, whereas other Zelda target and axis patterning genes are predominantly regulated through pause release. In contrast to other signaling pathways, we found that bone morphogenetic protein (BMP) target genes are collectively more highly paused than BMP pathway components and show that BMP target gene expression requires the pause-inducing negative elongation factor (NELF) complex. Our data also suggest that polymerase pausing allows plasticity in gene activation throughout embryogenesis, as transiently repressed and transcriptionally silenced genes maintain and lose promoter polymerases, respectively. Finally, we provide evidence that the major effect of pausing is on the levels, rather than timing, of transcription. These data are discussed in terms of the efficiency of transcriptional activation required across cell populations during developmental time constraints.
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Affiliation(s)
- Abbie Saunders
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
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109
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Tian C, Liu J. Repulsive guidance molecules (RGMs) and neogenin in bone morphogenetic protein (BMP) signaling. Mol Reprod Dev 2013; 80:700-17. [PMID: 23740870 DOI: 10.1002/mrd.22199] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 05/28/2013] [Indexed: 02/06/2023]
Abstract
Bone morphogenetic proteins (BMPs) belong to the transforming growth factor-beta (TGFβ) superfamily. BMPs mediate a highly conserved signal transduction cascade through the type-I and type-II serine/threonine kinase receptors and intracellular Smad proteins, which regulate multiple developmental and homeostatic processes. Mutations in this pathway can cause various diseases in humans, such as skeletal disorders, cardiovascular diseases, and various cancers. Multiple levels of regulation, including extracellular regulation, help to ensure proper spatiotemporal control of BMP signaling in the right cellular context. The family of repulsive guidance molecules (RGMs) and the type-I transmembrane protein neogenin, a paralog of DCC (Deleted in Colorectal Cancer), have been implicated in modulating the BMP pathway. In this review, we discuss the properties and functions of RGM proteins and neogenin, focusing on their roles in the modulation of BMP signal transduction.
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Affiliation(s)
- Chenxi Tian
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York
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110
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Xu J, Wang AH, Oses-Prieto J, Makhijani K, Katsuno Y, Pei M, Yan L, Zheng YG, Burlingame A, Brückner K, Derynck R. Arginine Methylation Initiates BMP-Induced Smad Signaling. Mol Cell 2013; 51:5-19. [PMID: 23747011 PMCID: PMC3951972 DOI: 10.1016/j.molcel.2013.05.004] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 10/12/2012] [Accepted: 05/02/2013] [Indexed: 11/15/2022]
Abstract
Kinase activation and substrate phosphorylation commonly form the backbone of signaling cascades. Bone morphogenetic proteins (BMPs), a subclass of TGF-β family ligands, induce activation of their signaling effectors, the Smads, through C-terminal phosphorylation by transmembrane receptor kinases. However, the slow kinetics of Smad activation in response to BMP suggests a preceding step in the initiation of BMP signaling. We now show that arginine methylation, which is known to regulate gene expression, yet also modifies some signaling mediators, initiates BMP-induced Smad signaling. BMP-induced receptor complex formation promotes interaction of the methyltransferase PRMT1 with the inhibitory Smad6, resulting in Smad6 methylation and relocalization at the receptor, leading to activation of effector Smads through phosphorylation. PRMT1 is required for BMP-induced biological responses across species, as evidenced by the role of its ortholog Dart1 in BMP signaling during Drosophila wing development. Activation of signaling by arginine methylation may also apply to other signaling pathways.
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Affiliation(s)
- Jian Xu
- Departments of Cell and Tissue Biology, and Anatomy, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, San Francisco, California 94143-0512. USA
| | - A. Hongjun Wang
- Departments of Cell and Tissue Biology, and Anatomy, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, San Francisco, California 94143-0512. USA
| | - Juan Oses-Prieto
- Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California 94143-0512. USA
| | - Kalpana Makhijani
- Departments of Cell and Tissue Biology, and Anatomy, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, San Francisco, California 94143-0512. USA
| | - Yoko Katsuno
- Departments of Cell and Tissue Biology, and Anatomy, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, San Francisco, California 94143-0512. USA
| | - Ming Pei
- Departments of Cell and Tissue Biology, and Anatomy, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, San Francisco, California 94143-0512. USA
| | - Leilei Yan
- Department of Chemistry, Georgia State University, Atlanta, GA30302-4098
| | - Y. George Zheng
- Department of Chemistry, Georgia State University, Atlanta, GA30302-4098
| | - Alma Burlingame
- Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, California 94143-0512. USA
| | - Katja Brückner
- Departments of Cell and Tissue Biology, and Anatomy, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, San Francisco, California 94143-0512. USA
| | - Rik Derynck
- Departments of Cell and Tissue Biology, and Anatomy, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California at San Francisco, San Francisco, California 94143-0512. USA
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111
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Tremmel DM, Resad S, Little CJ, Wesley CS. Notch and PKC are involved in formation of the lateral region of the dorso-ventral axis in Drosophila embryos. PLoS One 2013; 8:e67789. [PMID: 23861806 PMCID: PMC3701627 DOI: 10.1371/journal.pone.0067789] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 05/23/2013] [Indexed: 01/04/2023] Open
Abstract
The Notch gene encodes an evolutionarily conserved cell surface receptor that generates regulatory signals based on interactions between neighboring cells. In Drosophila embryos it is normally expressed at a low level due to strong negative regulation. When this negative regulation is abrogated neurogenesis in the ventral region is suppressed, the development of lateral epidermis is severely disrupted, and the dorsal aminoserosa is expanded. Of these phenotypes only the anti-neurogenic phenotype could be linked to excess canonical Notch signaling. The other phenotypes were linked to high levels of Notch protein expression at the surface of cells in the lateral regions indicating that a non-canonical Notch signaling activity normally functions in these regions. Results of our studies reported here provide evidence. They show that Notch activities are inextricably linked to that of Pkc98E, the homolog of mammalian PKCδ. Notch and Pkc98E up-regulate the levels of the phosphorylated form of IκBCactus, a negative regulator of Toll signaling, and Mothers against dpp (MAD), an effector of Dpp signaling. Our data suggest that in the lateral regions of the Drosophila embryos Notch activity, in conjunction with Pkc98E activity, is used to form the slopes of the opposing gradients of Toll and Dpp signaling that specify cell fates along the dorso-ventral axis.
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Affiliation(s)
- Daniel M. Tremmel
- Departments of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Sedat Resad
- Departments of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Christopher J. Little
- Departments of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Cedric S. Wesley
- Departments of Genetics and Medical Genetics, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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112
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Humphreys GB, Jud MC, Monroe KM, Kimball SS, Higley M, Shipley D, Vrablik MC, Bates KL, Letsou A. Mummy, A UDP-N-acetylglucosamine pyrophosphorylase, modulates DPP signaling in the embryonic epidermis of Drosophila. Dev Biol 2013; 381:434-45. [PMID: 23796903 DOI: 10.1016/j.ydbio.2013.06.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 06/06/2013] [Indexed: 12/29/2022]
Abstract
The evolutionarily conserved JNK/AP-1 (Jun N-terminal kinase/activator protein 1) and BMP (Bone Morphogenetic Protein) signaling cascades are deployed hierarchically to regulate dorsal closure in the fruit fly Drosophila melanogaster. In this developmental context, the JNK/AP-1 signaling cascade transcriptionally activates BMP signaling in leading edge epidermal cells. Here we show that the mummy (mmy) gene product, which is required for dorsal closure, functions as a BMP signaling antagonist. Genetic and biochemical tests of Mmy's role as a BMP-antagonist indicate that its function is independent of AP-1, the transcriptional trigger of BMP signal transduction in leading edge cells. pMAD (phosphorylated Mothers Against Dpp) activity data show the mmy gene product to be a new type of epidermal BMP regulator - one which transforms a BMP ligand from a long- to a short-range signal. mmy codes for the single UDP-N-acetylglucosamine pyrophosphorylase in Drosophila, and its requirement for attenuating epidermal BMP signaling during dorsal closure points to a new role for glycosylation in defining a highly restricted BMP activity field in the fly. These findings add a new dimension to our understanding of mechanisms modulating the BMP signaling gradient.
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Affiliation(s)
- Gregory B Humphreys
- Department of Human Genetics, Eccles Institute of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
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113
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Ramel MC, Hill CS. The ventral to dorsal BMP activity gradient in the early zebrafish embryo is determined by graded expression of BMP ligands. Dev Biol 2013; 378:170-82. [PMID: 23499658 PMCID: PMC3899928 DOI: 10.1016/j.ydbio.2013.03.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/26/2013] [Accepted: 03/04/2013] [Indexed: 12/26/2022]
Abstract
In the early zebrafish embryo, a ventral to dorsal gradient of bone morphogenetic protein (BMP) activity is established, which is essential for the specification of cell fates along this axis. To visualise and mechanistically determine how this BMP activity gradient forms, we have used a transgenic zebrafish line that expresses monomeric red fluorescent protein (mRFP) under the control of well-characterised BMP responsive elements. We demonstrate that mRFP expression in this line faithfully reports BMP and GDF signalling at both early and late stages of development. Taking advantage of the unstable nature of mRFP transcripts, we use in situ hybridisation to reveal the dynamic spatio-temporal pattern of BMP activity and establish the timing and sequence of events that lead to the formation of the BMP activity gradient. We show that the BMP transcriptional activity gradient is established between 30% and 40% epiboly stages and that it is preceded by graded mRNA expression of the BMP ligands. Both Dharma and FGF signalling contribute to graded bmp transcription during these early stages and it is subsequently maintained through autocrine BMP signalling. We show that BMP2B protein is also expressed in a gradient as early as blastula stages, but do not find any evidence of diffusion of this BMP to generate the BMP transcriptional activity gradient. Thus, in contrast to diffusion/transport-based models of BMP gradient formation in Drosophila, our results indicate that the establishment of the BMP activity gradient in early zebrafish embryos is determined by graded expression of the BMP ligands.
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Affiliation(s)
| | - Caroline S. Hill
- Laboratory of Developmental Signalling, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3LY, United Kingdom
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114
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Fine-tuned shuttles for bone morphogenetic proteins. Curr Opin Genet Dev 2013; 23:374-84. [PMID: 23735641 DOI: 10.1016/j.gde.2013.04.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 04/15/2013] [Accepted: 04/16/2013] [Indexed: 01/27/2023]
Abstract
Bone morphogenetic proteins (BMPs) are potent secreted signaling factors that trigger phosphorylation of Smad transcriptional regulators through receptor complex binding at the cell-surface. Resulting changes in target gene expression impact critical cellular responses during development and tissue homeostasis. BMP activity is tightly regulated in time and space by secreted modulators that control BMP extracellular distribution and availability for receptor binding. Such extracellular regulation is key for BMPs to function as morphogens and/or in the formation of morphogen activity gradients. Here, we review shuttling systems utilized to control the distribution of BMP ligands in tissue of various geometries, developing under different temporal constraints. We discuss the biological advantages for employing specific strategies for BMP shuttling and roles of varied ligand forms.
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115
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Matsuda S, Yoshiyama N, Künnapuu-Vulli J, Hatakeyama M, Shimmi O. Dpp/BMP transport mechanism is required for wing venation in the sawfly Athalia rosae. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 43:466-473. [PMID: 23499566 DOI: 10.1016/j.ibmb.2013.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/21/2013] [Accepted: 02/27/2013] [Indexed: 06/01/2023]
Abstract
The pattern of wing venation varies considerably among different groups of insects and has been used as a means of species-specific identification. However, little is known about how wing venation is established and diversified among insects. The decapentaplegic (Dpp)/bone morphogenetic protein (BMP) signaling pathway plays a critical role in wing vein formation during the pupal stages in Drosophila melanogaster. A key mechanism is BMP transport from the longitudinal veins (LVs) to the posterior crossvein (PCV) by the BMP-binding proteins, short gastrulation (Sog) and twisted gastrulation2/crossveinless (Tsg2/Cv). To investigate whether the BMP transport mechanism is utilized to specify insect wing vein patterns in other than Drosophila, we used the sawfly Athalia rosae as a model, which has distinct venation patterns in the fore- and hindwings. Here, we show that Ar-dpp is ubiquitously expressed in both the fore- and hindwings, but is required for localized BMP signaling that reflects distinct wing vein patterns between the fore- and hindwings. By isolating Ar-tsg/cv in the sawfly, we found that Ar-Tsg/Cv is also required for BMP signaling in wing vein formation and retains the ability to transport Dpp. These data suggest that the BMP transport system is widely used to redistribute Dpp to specify wing venation and may be a basal mechanism underlying diversified wing vein patterns among insects.
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Affiliation(s)
- Shinya Matsuda
- Institute of Biotechnology, University of Helsinki, P.O. Box 65-Viikinkaari 1, 00014 Helsinki, Finland
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116
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Abstract
Bone morphogenetic proteins (BMPs) play key roles in development. In Drosophila melanogaster, there are three BMP-encoding genes: decapentaplegic (dpp), glass bottom boat (gbb) and screw (scw). dpp and gbb are found in all groups of insects. In contrast, the origin of scw via duplication of an ancestral gbb homologue is more recent, with new evidence placing it within the Diptera. Recent studies show that scw appeared basal to the Schizophora, since scw orthologues exist in aschizan cyclorrhaphan flies. In order to further localise the origin of scw, we have utilised new genomic resources for the nematoceran moth midge Clogmia albipunctata (Psychodidae). We identified the BMP subclass members dpp and gbb from an early embryonic transcriptome and show that their expression patterns in the blastoderm differ considerably from those seen in cyclorrhaphan flies. Further searches of the genome of C. albipunctata were unable to identify a scw-like gbb duplicate, but confirm the presence of dpp and gbb. Our phylogenetic analysis shows these to be clear orthologues of dpp and gbb from other non-cyclorrhaphan insects, with C. albipunctata gbb branching ancestrally to the cyclorrhaphan gbb/scw split. Furthermore, our analysis suggests that scw is absent from all Nematocera, including the Bibionomorpha. We conclude that the gbb/scw duplication occurred between the separation of the lineage leading to Brachycera and the origin of cyclorrhaphan flies 200–150 Ma ago.
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117
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Shaping organs by a wingless-int/Notch/nonmuscle myosin module which orients feather bud elongation. Proc Natl Acad Sci U S A 2013; 110:E1452-61. [PMID: 23576731 DOI: 10.1073/pnas.1219813110] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
How organs are shaped to specific forms is a fundamental issue in developmental biology. To address this question, we used the repetitive, periodic pattern of feather morphogenesis on chicken skin as a model. Avian feathers within a single tract extend from dome-shaped primordia to thin conical structures with a common axis of orientation. From a systems biology perspective, the process is precise and robust. Using tissue transplantation assays, we demonstrate that a "zone of polarizing activity," localized in the posterior feather bud, is necessary and sufficient to mediate the directional elongation. This region contains a spatially well-defined nuclear β-catenin zone, which is induced by wingless-int (Wnt)7a protein diffusing in from posterior bud epithelium. Misexpressing nuclear β-catenin randomizes feather polarity. This dermal nuclear β-catenin zone, surrounded by Notch1 positive dermal cells, induces Jagged1. Inhibition of Notch signaling disrupts the spatial configuration of the nuclear β-catenin zone and leads to randomized feather polarity. Mathematical modeling predicts that lateral inhibition, mediated by Notch signaling, functions to reduce Wnt7a gradient variations and fluctuations to form the sharp boundary observed for the dermal β-catenin zone. This zone is also enriched for nonmuscle myosin IIB. Suppressing nonmuscle myosin IIB disrupts directional cell rearrangements and abolishes feather bud elongation. These data suggest that a unique molecular module involving chemical-mechanical coupling converts a pliable chemical gradient to a precise domain, ready for subsequent mechanical action, thus defining the position, boundary, and duration of localized morphogenetic activity that molds the shape of growing organs.
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118
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Matsuda S, Blanco J, Shimmi O. A feed-forward loop coupling extracellular BMP transport and morphogenesis in Drosophila wing. PLoS Genet 2013; 9:e1003403. [PMID: 23555308 PMCID: PMC3605110 DOI: 10.1371/journal.pgen.1003403] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 02/06/2013] [Indexed: 11/18/2022] Open
Abstract
A variety of extracellular factors regulate morphogenesis during development. However, coordination between extracellular signaling and dynamic morphogenesis is largely unexplored. We address the fundamental question by studying posterior crossvein (PCV) development in Drosophila as a model, in which long-range BMP transport from the longitudinal veins plays a critical role during the pupal stages. Here, we show that RhoGAP Crossveinless-C (Cv-C) is induced at the PCV primordial cells by BMP signaling and mediates PCV morphogenesis cell-autonomously by inactivating members of the Rho-type small GTPases. Intriguingly, we find that Cv-C is also required non-cell-autonomously for BMP transport into the PCV region, while a long-range BMP transport is guided toward ectopic wing vein regions by loss of the Rho-type small GTPases. We present evidence that low level of ß-integrin accumulation at the basal side of PCV epithelial cells regulated by Cv-C provides an optimal extracellular environment for guiding BMP transport. These data suggest that BMP transport and PCV morphogenesis are tightly coupled. Our study reveals a feed-forward mechanism that coordinates the spatial distribution of extracellular instructive cues and morphogenesis. The coupling mechanism may be widely utilized to achieve precise morphogenesis during development and homeostasis. It has been extensively studied how tissue morphogenesis is regulated by a variety of extracellular cues. Given that dynamic morphogenesis coincides with arrival of extracellular factors, there must be also mechanisms that coordinate extracellular signaling and intracellular morphogenesis. However, the coordination is largely unknown, due to the complexity of morphogenesis in vivo. We addressed the fundamental question by studying posterior crossvein (PCV) development in Drosophila as a model, in which a long-range transport of bone morphogenetic protein (BMP) type ligands from adjacent longitudinal veins plays a critical role during the pupal stages. Here, we first showed that RhoGAP Crossveinless-C (Cv-C) is induced at the PCV region by BMP signal and mediates PCV morphogenesis. By modulating wing vein morphogenesis, we then found that PCV morphogenesis is required for BMP transport, while ectopic wing vein morphogenesis sufficiently guides a long-range BMP transport. These data suggest a feed-forward mechanism that coordinates the spatial distribution of extracellular instructive cues and morphogenesis. The coupling mechanism may be widely utilized to achieve precise tissue morphogenesis and tissue homeostasis.
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Affiliation(s)
- Shinya Matsuda
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Jorge Blanco
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Osamu Shimmi
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
- * E-mail:
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119
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Abstract
Development, regeneration, and even day-to-day physiology require plant and animal cells to make decisions based on their locations. The principles by which cells may do this are deceptively straightforward. But when reliability needs to be high--as often occurs during development--successful strategies tend to be anything but simple. Increasingly, the challenge facing biologists is to relate the diverse diffusible molecules, control circuits, and gene regulatory networks that help cells know where they are to the varied, sometimes stringent, constraints imposed by the need for real-world precision and accuracy.
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Affiliation(s)
- Arthur D Lander
- Department of Developmental and Cell Biology, and Center for Complex Biological Systems, University of California Irvine, Irvine, CA 92697, USA.
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120
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Shilo BZ, Haskel-Ittah M, Ben-Zvi D, Schejter ED, Barkai N. Creating gradients by morphogen shuttling. Trends Genet 2013; 29:339-47. [PMID: 23369355 DOI: 10.1016/j.tig.2013.01.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 11/22/2012] [Accepted: 01/03/2013] [Indexed: 11/28/2022]
Abstract
Morphogen gradients are used to pattern a field of cells according to variations in the concentration of a signaling molecule. Typically, the morphogen emanates from a confined group of cells. During early embryogenesis, however, the ability to define a restricted source for morphogen production is limited. Thus, various early patterning systems rely on a broadly expressed morphogen that generates an activation gradient within its expression domain. Computational and experimental work has shed light on how a sharp and robust gradient can be established under those situations, leading to a mechanism termed 'morphogen shuttling'. This mechanism relies on an extracellular shuttling molecule that forms an inert, highly diffusible complex with the morphogen. Morphogen release from the complex following cleavage of the shuttling molecule by an extracellular protease leads to the accumulation of free ligand at the center of its expression domain and a graded activation of the developmental pathway that decreases significantly even within the morphogen-expression domain.
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Affiliation(s)
- Ben-Zion Shilo
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
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121
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Dahal GR, Rawson J, Gassaway B, Kwok B, Tong Y, Ptácek LJ, Bates E. An inwardly rectifying K+ channel is required for patterning. Development 2012; 139:3653-64. [PMID: 22949619 DOI: 10.1242/dev.078592] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mutations that disrupt function of the human inwardly rectifying potassium channel KIR2.1 are associated with the craniofacial and digital defects of Andersen-Tawil Syndrome, but the contribution of Kir channels to development is undefined. Deletion of mouse Kir2.1 also causes cleft palate and digital defects. These defects are strikingly similar to phenotypes that result from disrupted TGFβ/BMP signaling. We use Drosophila melanogaster to show that a Kir2.1 homolog, Irk2, affects development by disrupting BMP signaling. Phenotypes of irk2 deficient lines, a mutant irk2 allele, irk2 siRNA and expression of a dominant-negative Irk2 subunit (Irk2DN) all demonstrate that Irk2 function is necessary for development of the adult wing. Compromised Irk2 function causes wing-patterning defects similar to those found when signaling through a Drosophila BMP homolog, Decapentaplegic (Dpp), is disrupted. To determine whether Irk2 plays a role in the Dpp pathway, we generated flies in which both Irk2 and Dpp functions are reduced. Irk2DN phenotypes are enhanced by decreased Dpp signaling. In wild-type flies, Dpp signaling can be detected in stripes along the anterior/posterior boundary of the larval imaginal wing disc. Reducing function of Irk2 with siRNA, an irk2 deletion, or expression of Irk2DN reduces the Dpp signal in the wing disc. As Irk channels contribute to Dpp signaling in flies, a similar role for Kir2.1 in BMP signaling may explain the morphological defects of Andersen-Tawil Syndrome and the Kir2.1 knockout mouse.
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Affiliation(s)
- Giri Raj Dahal
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA
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122
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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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123
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Rafiqi AM, Park CH, Kwan CW, Lemke S, Schmidt-Ott U. BMP-dependent serosa and amnion specification in the scuttle fly Megaselia abdita. Development 2012; 139:3373-82. [DOI: 10.1242/dev.083873] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Bone morphogenetic protein (BMP) signaling is an essential factor in dorsoventral patterning of animal embryos but how BMP signaling evolved with fundamental changes in dorsoventral tissue differentiation is unclear. Flies experienced an evolutionary reduction of extra-embryonic tissue types from two (amniotic and serosal tissue) to one (amnionserosal tissue). BMP-dependent amnioserosa specification has been studied in Drosophila melanogaster. However, the mechanisms of serosal and amniotic tissue specification in less diverged flies remain unknown. To better understand potential evolutionary links between BMP signaling and extra-embryonic tissue specification, we examined the activity profile and function of BMP signaling in serosa and amnion patterning of the scuttle fly Megaselia abdita (Phoridae) and compared the BMP activity profiles between M. abdita and D. melanogaster. In blastoderm embryos of both species, BMP activity peaked at the dorsal midline. However, at the beginning of gastrulation, peak BMP activity in M. abdita shifted towards prospective amnion tissue. This transition correlated with the first signs of amnion differentiation laterally adjacent to the serosa anlage. Marker-assisted analysis of six BMP signaling components (dpp, gbb, scw, tkv, sax, sog) by RNA interference revealed that both serosa and amnion specification of M. abdita are dependent on BMP activity. Conversely, BMP gain-of-function experiments caused sharpened expression boundaries of extra-embryonic target genes indicative of positive feedback. We propose that changes in the BMP activity profile at the beginning of gastrulation might have contributed to the reduction of extra-embryonic tissue types during the radiation of cyclorrhaphan flies.
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Affiliation(s)
- Ab. Matteen Rafiqi
- University of Chicago, Department of Organismal Biology and Anatomy, CLSC 1061C, 920 E. 58th Street, Chicago, IL 60637, USA
| | - Chee-Hyurng Park
- University of Chicago, Department of Organismal Biology and Anatomy, CLSC 1061C, 920 E. 58th Street, Chicago, IL 60637, USA
| | - Chun Wai Kwan
- University of Chicago, Department of Organismal Biology and Anatomy, CLSC 1061C, 920 E. 58th Street, Chicago, IL 60637, USA
| | - Steffen Lemke
- University of Chicago, Department of Organismal Biology and Anatomy, CLSC 1061C, 920 E. 58th Street, Chicago, IL 60637, USA
| | - Urs Schmidt-Ott
- University of Chicago, Department of Organismal Biology and Anatomy, CLSC 1061C, 920 E. 58th Street, Chicago, IL 60637, USA
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124
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Araujo H, Fontenele MR, da Fonseca RN. Position matters: variability in the spatial pattern of BMP modulators generates functional diversity. Genesis 2012; 49:698-718. [PMID: 21671348 DOI: 10.1002/dvg.20778] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Bone morphogenetic proteins (BMPs) perform a variety of functions during development. Considering a single BMP, what enables its multiple roles in tissues of varied sizes and shapes? What regulates the spatial distribution and activity patterns of the BMP in these different developmental contexts? Some BMP functions require controlling spread of the BMP morphogen, while others require formation of localized, high concentration peaks of BMP activity. Here we review work in Drosophila that describes spatial regulation of the BMP encoded by decapentaplegic (dpp) in different developmental contexts. We concentrate on extracellular modulation of BMP function and discuss the mechanisms that generate concentrated peaks of Dpp activity, subdivide territories of different activity levels or regulate spread of the Dpp morphogen from a point source. We compare these findings with data from vertebrates and non-model organisms to discuss how changes in the regulation of Dpp distribution by extracellular modulators may lead to variability in dpp function in different species.
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Affiliation(s)
- Helena Araujo
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, RJ, Brazil.
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125
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Yu B, Zhao X, Yang C, Crane J, Xian L, Lu W, Wan M, Cao X. Parathyroid hormone induces differentiation of mesenchymal stromal/stem cells by enhancing bone morphogenetic protein signaling. J Bone Miner Res 2012; 27:2001-14. [PMID: 22589223 PMCID: PMC3423493 DOI: 10.1002/jbmr.1663] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Parathyroid hormone (PTH) stimulates bone remodeling and induces differentiation of bone marrow mesenchymal stromal/stem cells (MSCs) by orchestrating activities of local factors such as bone morphogenetic proteins (BMPs). The activity and specificity of different BMP ligands are controlled by various extracellular antagonists that prevent binding of BMPs to their receptors. Low-density lipoprotein receptor-related protein 6 (LRP6) has been shown to interact with both the PTH and BMP extracellular signaling pathways by forming a complex with parathyroid hormone 1 receptor (PTH1R) and sharing common antagonists with BMPs. We hypothesized that PTH-enhanced differentiation of MSCs into the osteoblast lineage through enhancement of BMP signaling occurs by modifying the extracellular antagonist network via LRP6. In vitro studies using multiple cell lines, including Sca-1(+) CD45(-) CD11b(-) MSCs, showed that a single injection of PTH enhanced phosphorylation of Smad1 and could also antagonize the inhibitory effect of noggin. PTH treatment induced endocytosis of a PTH1R/LRP6 complex and resulted in enhancement of phosphorylation of Smad1 that was abrogated by deletion of PTH1R, β-arrestin, or chlorpromazine. Deletion of LRP6 alone led to enhancement of pSmad1 levels that could not be further increased with PTH treatment. Finally, knockdown of LRP6 increased the exposure of endogenous cell-surface BMP receptor type II (BMPRII) significantly in C2C12 cells, and PTH treatment significantly enhanced cell-surface binding of (125) I-BMP2 in a dose- and time-dependent manner, implying that LRP6 organizes an extracellular network of BMP antagonists that prevent access of BMPs to BMP receptors. In vivo studies in C57BL/6J mice and of transplanted green fluorescent protein (GFP)-labeled Sca-1(+) CD45(-) CD11b(-) MSCs into the bone marrow cavity of Rag2(-/-) immunodeficient mice showed that PTH enhanced phosphorylation of Smad1 and increased commitment of MSCs to osteoblast lineage, respectively. These data demonstrate that PTH enhancement of MSC differentiation to the osteoblast lineage occurs through a PTH- and LRP6-dependent pathway by endocytosis of the PTH1R/LRp6 complex, allowing enhancement of BMP signaling.
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Affiliation(s)
- Bing Yu
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xiaoli Zhao
- Department of Orthopaedics and Traumatology, University of Hong Kong, Hong Kong, China
| | - Chaozhe Yang
- Center for Clinical and Community Research, Children’s National Medical Center, Washington, DC, USA
| | - Janet Crane
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lingling Xian
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - William Lu
- Department of Orthopaedics and Traumatology, University of Hong Kong, Hong Kong, China
| | - Mei Wan
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xu Cao
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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126
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Fischer S, Bayersdorfer F, Harant E, Reng R, Arndt S, Bosserhoff AK, Schneuwly S. fussel (fuss)--A negative regulator of BMP signaling in Drosophila melanogaster. PLoS One 2012; 7:e42349. [PMID: 22879948 PMCID: PMC3413677 DOI: 10.1371/journal.pone.0042349] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 07/04/2012] [Indexed: 11/29/2022] Open
Abstract
The TGF-β/BMP signaling cascades control a wide range of developmental and physiological functions in vertebrates and invertebrates. In Drosophila melanogaster, members of this pathway can be divided into a Bone Morphogenic Protein (BMP) and an Activin-ß (Act-ß) branch, where Decapentaplegic (Dpp), a member of the BMP family has been most intensively studied. They differ in ligands, receptors and transmitting proteins, but also share some components, such as the Co-Smad Medea (Med). The essential role of Med is to form a complex with one of the two activating Smads, mothers against decapentaplegic (Mad) or dSmad, and to translocate together to the nucleus where they can function as transcriptional regulators of downstream target genes. This signaling cascade underlies different mechanisms of negative regulation, which can be exerted by inhibitory Smads, such as daughters against decapentaplegic (dad), but also by the Ski-Sno family. In this work we identified and functionally analyzed a new member of the Ski/Sno-family, fussel (fuss), the Drosophila homolog of the human functional suppressing element 15 (fussel-15). fuss codes for two differentially spliced transcripts with a neuronal expression pattern. The proteins are characterized by a Ski-Sno and a SAND homology domain. Overexpression studies and genetic interaction experiments clearly reveal an interaction of fuss with members of the BMP pathway, leading to a strong repression of BMP-signaling. The protein interacts directly with Medea and seems to reprogram the Smad pathway through its influence upon the formation of functional Mad/Medea complexes. This leads amongst others to a repression of downstream target genes of the Dpp pathway, such as optomotor blind (omb). Taken together we could show that fuss exerts a pivotal role as an antagonist of BMP signaling in Drosophila melanogaster.
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Affiliation(s)
- Susanne Fischer
- Institute of Zoology, University of Regensburg, Regensburg, Germany
| | | | - Eva Harant
- Institute of Zoology, University of Regensburg, Regensburg, Germany
| | - Renate Reng
- Institute of Zoology, University of Regensburg, Regensburg, Germany
| | - Stephanie Arndt
- Institute of Pathology, University of Regensburg, Regensburg, Germany
| | | | - Stephan Schneuwly
- Institute of Zoology, University of Regensburg, Regensburg, Germany
- * E-mail:
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127
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Butchar JP, Cain D, Manivannan SN, McCue AD, Bonanno L, Halula S, Truesdell S, Austin CL, Jacobsen TL, Simcox A. New negative feedback regulators of Egfr signaling in Drosophila. Genetics 2012; 191:1213-26. [PMID: 22595244 PMCID: PMC3416002 DOI: 10.1534/genetics.112.141093] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 05/07/2012] [Indexed: 12/18/2022] Open
Abstract
The highly conserved epidermal growth factor receptor (Egfr) pathway is required in all animals for normal development and homeostasis; consequently, aberrant Egfr signaling is implicated in a number of diseases. Genetic analysis of Drosophila melanogaster Egfr has contributed significantly to understanding this conserved pathway and led to the discovery of new components and targets. Here we used microarray analysis of third instar wing discs, in which Egfr signaling was perturbed, to identify new Egfr-responsive genes. Upregulated transcripts included five known targets, suggesting the approach was valid. We investigated the function of 29 previously uncharacterized genes, which had pronounced responses. The Egfr pathway is important for wing-vein patterning and using reverse genetic analysis we identified five genes that showed venation defects. Three of these genes are expressed in vein primordia and all showed transcriptional changes in response to altered Egfr activity consistent with being targets of the pathway. Genetic interactions with Egfr further linked two of the genes, Sulfated (Sulf1), an endosulfatase gene, and CG4096, an A Disintegrin And Metalloproteinase with ThromboSpondin motifs (ADAMTS) gene, to the pathway. Sulf1 showed a strong genetic interaction with the neuregulin-like ligand vein (vn) and may influence binding of Vn to heparan-sulfated proteoglycans (HSPGs). How Drosophila Egfr activity is modulated by CG4096 is unknown, but interestingly vertebrate EGF ligands are regulated by a related ADAMTS protein. We suggest Sulf1 and CG4096 are negative feedback regulators of Egfr signaling that function in the extracellular space to influence ligand activity.
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Affiliation(s)
- Jonathan P. Butchar
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210
| | - Donna Cain
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210
| | | | - Andrea D. McCue
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210
| | - Liana Bonanno
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210
| | - Sarah Halula
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210
| | - Sharon Truesdell
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210
| | - Christina L. Austin
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210
| | - Thomas L. Jacobsen
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210
| | - Amanda Simcox
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210
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128
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Efficient reverse-engineering of a developmental gene regulatory network. PLoS Comput Biol 2012; 8:e1002589. [PMID: 22807664 PMCID: PMC3395622 DOI: 10.1371/journal.pcbi.1002589] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 04/27/2012] [Indexed: 11/19/2022] Open
Abstract
Understanding the complex regulatory networks underlying development and evolution of multi-cellular organisms is a major problem in biology. Computational models can be used as tools to extract the regulatory structure and dynamics of such networks from gene expression data. This approach is called reverse engineering. It has been successfully applied to many gene networks in various biological systems. However, to reconstitute the structure and non-linear dynamics of a developmental gene network in its spatial context remains a considerable challenge. Here, we address this challenge using a case study: the gap gene network involved in segment determination during early development of Drosophila melanogaster. A major problem for reverse-engineering pattern-forming networks is the significant amount of time and effort required to acquire and quantify spatial gene expression data. We have developed a simplified data processing pipeline that considerably increases the throughput of the method, but results in data of reduced accuracy compared to those previously used for gap gene network inference. We demonstrate that we can infer the correct network structure using our reduced data set, and investigate minimal data requirements for successful reverse engineering. Our results show that timing and position of expression domain boundaries are the crucial features for determining regulatory network structure from data, while it is less important to precisely measure expression levels. Based on this, we define minimal data requirements for gap gene network inference. Our results demonstrate the feasibility of reverse-engineering with much reduced experimental effort. This enables more widespread use of the method in different developmental contexts and organisms. Such systematic application of data-driven models to real-world networks has enormous potential. Only the quantitative investigation of a large number of developmental gene regulatory networks will allow us to discover whether there are rules or regularities governing development and evolution of complex multi-cellular organisms.
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129
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Pi X, Schmitt CE, Xie L, Portbury AL, Wu Y, Lockyer P, Dyer LA, Moser M, Bu G, Flynn EJ, Jin SW, Patterson C. LRP1-dependent endocytic mechanism governs the signaling output of the bmp system in endothelial cells and in angiogenesis. Circ Res 2012; 111:564-74. [PMID: 22777006 DOI: 10.1161/circresaha.112.274597] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
RATIONALE Among the extracellular modulators of Bmp (bone morphogenetic protein) signaling, Bmper (Bmp endothelial cell precursor-derived regulator) both enhances and inhibits Bmp signaling. Recently we found that Bmper modulates Bmp4 activity via a concentration-dependent, endocytic trap-and-sink mechanism. OBJECTIVE To investigate the molecular mechanisms required for endocytosis of the Bmper/Bmp4 and signaling complex and determine the mechanism of Bmper's differential effects on Bmp4 signaling. METHODS AND RESULTS Using an array of biochemical and cell biology techniques, we report that LRP1 (LDL receptor-related protein 1), a member of the LDL receptor family, acts as an endocytic receptor for Bmper and a coreceptor of Bmp4 to mediate the endocytosis of the Bmper/Bmp4 signaling complex. Furthermore, we demonstrate that LRP1-dependent Bmper/Bmp4 endocytosis is essential for Bmp4 signaling, as evidenced by the phenotype of lrp1-deficient zebrafish, which have abnormal cardiovascular development and decreased Smad1/5/8 activity in key vasculogenic structures. CONCLUSIONS Together, these data reveal a novel role for LRP1 in the regulation of Bmp4 signaling by regulating receptor complex endocytosis. In addition, these data introduce LRP1 as a critical regulator of vascular development. These observations demonstrate Bmper's ability to fine-tune Bmp4 signaling at the single-cell level, unlike the spatial regulatory mechanisms applied by other Bmp modulators.
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Affiliation(s)
- Xinchun Pi
- Health Care Entrepreneurship, UNC Center for Heart and Vascular Care, Division of Cardiology, 8200 Medical Biomolecular Research Building, Chapel Hill, NC 27599-7126, USA.
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130
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Ramel MC, Hill CS. Spatial regulation of BMP activity. FEBS Lett 2012; 586:1929-41. [PMID: 22710177 DOI: 10.1016/j.febslet.2012.02.035] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 02/21/2012] [Accepted: 02/22/2012] [Indexed: 12/14/2022]
Abstract
The bone morphogenetic protein (BMP) signalling pathway is critical for embryonic development and tissue homeostasis, and impaired BMP signalling has been implicated in multiple diseases. Molecular tools have been developed to visualise BMP activity in vivo and these have allowed a better understanding of the intricate ways in which BMP activity is regulated spatially. In particular, generation and interpretation of BMP activity gradients during development result from the complex interplay between core BMP signalling components and specific regulators. In this essay we discuss the mechanisms by which spatial regulation of BMP activity is achieved and its functional consequences.
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Affiliation(s)
- Marie-Christine Ramel
- Laboratory of Developmental Signalling, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, United Kingdom
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131
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Multistep molecular mechanism for bone morphogenetic protein extracellular transport in the Drosophila embryo. Proc Natl Acad Sci U S A 2012; 109:11222-7. [PMID: 22733779 DOI: 10.1073/pnas.1202781109] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
In the Drosophila embryo, formation of a bone morphogenetic protein (BMP) morphogen gradient requires transport of a heterodimer of the BMPs Decapentaplegic (Dpp) and Screw (Scw) in a protein shuttling complex. Although the core components of the shuttling complex--Short Gastrulation (Sog) and Twisted Gastrulation (Tsg)--have been identified, key aspects of this shuttling system remain mechanistically unresolved. Recently, we discovered that the extracellular matrix protein collagen IV is important for BMP gradient formation. Here, we formulate a molecular mechanism of BMP shuttling that is catalyzed by collagen IV. We show that Dpp is the only BMP ligand in Drosophila that binds collagen IV. A collagen IV binding-deficient Dpp mutant signals at longer range in vivo, indicating that collagen IV functions to immobilize free Dpp in the embryo. We also provide in vivo evidence that collagen IV functions as a scaffold to promote shuttling complex assembly in a multistep process. After binding of Dpp/Scw and Sog to collagen IV, protein interactions are remodeled, generating an intermediate complex in which Dpp/Scw-Sog is poised for release by Tsg through specific disruption of a collagen IV-Sog interaction. Because all components are evolutionarily conserved, we propose that regulation of BMP shuttling and immobilization through extracellular matrix interactions is widely used, both during development and in tissue homeostasis, to achieve a precise extracellular BMP distribution.
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132
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Le VQ, Wharton KA. Hyperactive BMP signaling induced by ALK2(R206H) requires type II receptor function in a Drosophila model for classic fibrodysplasia ossificans progressiva. Dev Dyn 2012; 241:200-14. [PMID: 22174087 DOI: 10.1002/dvdy.22779] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Fibrodysplasia Ossificans Progressiva (FOP) is an autosomal dominant disorder characterized by episodic deposition of heterotopic bone in place of soft connective tissue. All FOP-associated mutations map to the BMP type I receptor, ALK2, with the ALK2(R206H) mutant form found in the vast majority of patients. The mechanism(s) regulating the expressivity of hyperactive ALK2(R206H) signaling throughout a patient's life is not well understood. RESULTS In Drosophila, human ALK2(R206H) receptor induces hyperactive BMP signaling. As in vertebrates, elevated signaling associated with ALK2(R206H) in Drosophila is ligand-independent. We found that a key determinant for ALK2(R206H) hyperactivity is a functional type II receptor. Furthermore, our results indicate that like its Drosophila ortholog, Saxophone (Sax), wild-type ALK2 can antagonize, as well as promote, BMP signaling. CONCLUSIONS The dual function of ALK2 is of particular interest given the heterozygous nature of FOP, as the normal interplay between such disparate behaviors could be shifted by the presence of ALK2(R206H) receptors. Our studies provide a compelling example for Drosophila as a model organism to study the molecular underpinnings of complex human syndromes such as FOP.
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Affiliation(s)
- Viet Q Le
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02912, USA
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133
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Matsuda S, Shimmi O. Directional transport and active retention of Dpp/BMP create wing vein patterns in Drosophila. Dev Biol 2012; 366:153-62. [PMID: 22542596 DOI: 10.1016/j.ydbio.2012.04.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 03/30/2012] [Accepted: 04/02/2012] [Indexed: 11/19/2022]
Abstract
The bone morphogenetic protein (BMP) family ligand decapentaplegic (Dpp) plays critical roles in wing vein development during pupal stages in Drosophila. However, how the diffusible Dpp specifies elaborate wing vein patterns remains unknown. Here, we visualized Dpp distribution in the pupal wing and found that it tightly reflects the wing vein patterns. We show that Dpp is directionally transported from the longitudinal veins (LVs) into the posterior crossvein (PCV) primordial region by the extracellular BMP-binding proteins, short gastrulation (Sog) and crossveinless (Cv). Another BMP-type ligand, glass bottom boat (Gbb), also moves into the PCV region and is required for Dpp distribution, presumably as a Dpp-Gbb heterodimer. In contrast, we found that most of the Dpp is actively retained in the LVs by the BMP type I receptor thickveins (Tkv) and a positive feedback mechanism. We provide evidence that the directionality of Dpp transport is manifested by sog transcription that prepatterns the PCV position in a Dpp signal-independent manner. Taken together, our data suggest that spatial distribution of Dpp is tightly regulated at the extracellular level by combination of long-range facilitated transport toward the PCV and short-range signaling by active retention in the LVs, thereby allowing diffusible ligands to form elaborate wing vein patterns.
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Affiliation(s)
- Shinya Matsuda
- Institute of Biotechnology, University of Helsinki, PO Box 65 (Viikinkaari 1), 00014 Helsinki, Finland
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134
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Guo J, Wu G. The signaling and functions of heterodimeric bone morphogenetic proteins. Cytokine Growth Factor Rev 2012; 23:61-7. [PMID: 22421241 DOI: 10.1016/j.cytogfr.2012.02.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 02/01/2012] [Accepted: 02/16/2012] [Indexed: 02/07/2023]
Abstract
Heterodimeric bone morphogenetic proteins (BMPs) consist of disulfide-linked dimeric monomers derived from different BMP members. Owing to this specific constitution pattern, they bear high affinity to both type I and type II BMP receptors simultaneously. Meanwhile, the antagonism efficiency of extracellular antagonists to heterodimeric BMPs is also significantly lower than that to homodimeric ones. All these specific properties confer heterodimeric BMPs with distinct signaling and bio-functions that are characterized by more speediness, lower concentration/dose threshold and higher efficiency than homodimeric BMPs. Consequently, heterodimeric BMPs bear promising application potential in inducing osteogenesis. In addition, they may play indispensible roles in organogenesis. In this review, we summarize the current knowledge of heterodimeric BMPs in their signaling pathways and bio-functions.
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Affiliation(s)
- Jing Guo
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Research Institute MOVE, VU University and University of Amsterdam, Amsterdam, The Netherlands.
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135
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Promiscuity and specificity in BMP receptor activation. FEBS Lett 2012; 586:1846-59. [PMID: 22710174 DOI: 10.1016/j.febslet.2012.02.043] [Citation(s) in RCA: 219] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 02/28/2012] [Accepted: 02/29/2012] [Indexed: 02/03/2023]
Abstract
Bone Morphogenetic Proteins (BMPs), together with Transforming Growth Factor (TGF)-β and Activins/Inhibins constitute the TGF-β superfamily of ligands. This superfamily is formed by more than 30 structurally related secreted proteins. Since TGF-β members act as morphogens, either a strict relation between a particular ligand to a distinct cellular receptor and/or temporospatial expression patterns of ligands and receptors is expected. Instead, only a limited number of receptors exist implicating promiscuous interactions of ligands and receptors. Furthermore, in complex tissues a multitude of different ligands can be found, which signal via overlapping subsets of receptors. This raises the intriguing question how concerted interactions of different ligands and receptors generate highly specific cellular signals, which are required during development and tissue homeostasis.
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136
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Kanodia JS, Liang HL, Kim Y, Lim B, Zhan M, Lu H, Rushlow CA, Shvartsman SY. Pattern formation by graded and uniform signals in the early Drosophila embryo. Biophys J 2012; 102:427-33. [PMID: 22325264 DOI: 10.1016/j.bpj.2011.12.042] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 12/06/2011] [Accepted: 12/07/2011] [Indexed: 12/24/2022] Open
Abstract
The early Drosophila embryo is patterned by graded distributions of maternal transcription factors. Recent studies revealed that pattern formation by these graded signals depends on uniformly expressed transcriptional activators, such as Zelda. Removal of Zelda influences both the timing and the spatial expression domains for most of the genes controlled by maternal gradients. We demonstrate that some of these patterning defects, which range from temporal delay to loss of expression, can be rationalized with the use of a mathematical model based on cooperative binding of graded and uniform factors. This model makes a number of predictions, which we confirm experimentally by analyzing the expression of short gastrulation (sog), a gene that is controlled by a combination of the Dorsal morphogen gradient and Zelda. The proposed model suggests a general mechanism for the formation of nested gene expression domains, which is a hallmark of tissue patterning by morphogen gradients. According to this mechanism, the differential effects of a morphogen on its target genes can depend on their differential sensitivity to uniform factors.
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Affiliation(s)
- Jitendra S Kanodia
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, USA
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137
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Izawa T, Ogasawara JE, Sakurai T, Nomura S, Kizaki T, Ohno H. Recent advances in the adaptations of adipose tissue to physical activity: Morphology and adipose tissue cellularity. THE JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE 2012. [DOI: 10.7600/jpfsm.1.381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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138
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El-Sherif E, Lynch JA, Brown SJ. Comparisons of the embryonic development of Drosophila, Nasonia, and Tribolium. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2012; 1:16-39. [PMID: 23801665 PMCID: PMC5323069 DOI: 10.1002/wdev.3] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Studying the embryogenesis of diverse insect species is crucial to understanding insect evolution. Here, we review current advances in understanding the development of two emerging model organisms: the wasp Nasonia vitripennis and the beetle Tribolium castaneum in comparison with the well-studied fruit fly Drosophila melanogaster. Although Nasonia represents the most basally branching order of holometabolous insects, it employs a derived long germband mode of embryogenesis, more like that of Drosophila, whereas Tribolium undergoes an intermediate germband mode of embryogenesis, which is more similar to the ancestral mechanism. Comparing the embryonic development and genetic regulation of early patterning events in these three insects has given invaluable insights into insect evolution. The similar mode of embryogenesis of Drosophila and Nasonia is reflected in their reliance on maternal morphogenetic gradients. However, they employ different genes as maternal factors, reflecting the evolutionary distance separating them. Tribolium, on the other hand, relies heavily on self-regulatory mechanisms other than maternal cues, reflecting its sequential nature of segmentation and the need for reiterated patterning.
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Affiliation(s)
- Ezzat El-Sherif
- Program of Genetics, Kansas State University, Manhattan, Kansas
| | - Jeremy A Lynch
- Institute for Developmental Biology, University of Cologne, Cologne, Germany
| | - Susan J Brown
- Division of Biology, Kansas State University, Manhattan, Kansas
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139
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Fritsch C, Sawala A, Harris R, Maartens A, Sutcliffe C, Ashe HL, Ray RP. Different requirements for proteolytic processing of bone morphogenetic protein 5/6/7/8 ligands in Drosophila melanogaster. J Biol Chem 2011; 287:5942-53. [PMID: 22199351 PMCID: PMC3285362 DOI: 10.1074/jbc.m111.316745] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Bone morphogenetic proteins (BMPs) are synthesized as proproteins that undergo proteolytic processing by furin/subtilisin proprotein convertases to release the active ligand. Here we study processing of BMP5/6/7/8 proteins, including the Drosophila orthologs Glass Bottom Boat (Gbb) and Screw (Scw) and human BMP7. Gbb and Scw have three functional furin/subtilisin proprotein convertase cleavage sites; two between the prodomain and ligand domain, which we call the Main and Shadow sites, and one within the prodomain, which we call the Pro site. In Gbb each site can be cleaved independently, although efficient cleavage at the Shadow site requires cleavage at the Main site, and remarkably, none of the sites is essential for Gbb function. Rather, Gbb must be processed at either the Pro or Main site to produce a functional ligand. Like Gbb, the Pro and Main sites in Scw can be cleaved independently, but cleavage at the Shadow site is dependent on cleavage at the Main site. However, both Pro and Main sites are essential for Scw function. Thus, Gbb and Scw have different processing requirements. The BMP7 ligand rescues gbb mutants in Drosophila, but full-length BMP7 cannot, showing that functional differences in the prodomain limit the BMP7 activity in flies. Furthermore, unlike Gbb, cleavage-resistant BMP7, although non-functional in rescue assays, activates the downstream signaling cascade and thus retains some functionality. Our data show that cleavage requirements evolve rapidly, supporting the notion that changes in post-translational processing are used to create functional diversity between BMPs within and between species.
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Affiliation(s)
- Cornelia Fritsch
- School of Life Sciences, University of Sussex, Falmer Brighton BN1 9QG, United Kingdom
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140
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Abstract
Patterning of the dorsoventral axis by graded BMP signaling is conserved in the evolution of animals. However, this system has also proven to be highly adaptable, as is now highlighted by its short-range function in the leech Helobdella.
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141
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Roth S. Mathematics and biology: a Kantian view on the history of pattern formation theory. Dev Genes Evol 2011; 221:255-79. [PMID: 22086125 PMCID: PMC3234355 DOI: 10.1007/s00427-011-0378-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Accepted: 10/19/2011] [Indexed: 12/20/2022]
Abstract
Driesch's statement, made around 1900, that the physics and chemistry of his day were unable to explain self-regulation during embryogenesis was correct and could be extended until the year 1972. The emergence of theories of self-organisation required progress in several areas including chemistry, physics, computing and cybernetics. Two parallel lines of development can be distinguished which both culminated in the early 1970s. Firstly, physicochemical theories of self-organisation arose from theoretical (Lotka 1910-1920) and experimental work (Bray 1920; Belousov 1951) on chemical oscillations. However, this research area gained broader acceptance only after thermodynamics was extended to systems far from equilibrium (1922-1967) and the mechanism of the prime example for a chemical oscillator, the Belousov-Zhabotinski reaction, was deciphered in the early 1970s. Secondly, biological theories of self-organisation were rooted in the intellectual environment of artificial intelligence and cybernetics. Turing wrote his The chemical basis of morphogenesis (1952) after working on the construction of one of the first electronic computers. Likewise, Gierer and Meinhardt's theory of local activation and lateral inhibition (1972) was influenced by ideas from cybernetics. The Gierer-Meinhardt theory provided an explanation for the first time of both spontaneous formation of spatial order and of self-regulation that proved to be extremely successful in elucidating a wide range of patterning processes. With the advent of developmental genetics in the 1980s, detailed molecular and functional data became available for complex developmental processes, allowing a new generation of data-driven theoretical approaches. Three examples of such approaches will be discussed. The successes and limitations of mathematical pattern formation theory throughout its history suggest a picture of the organism, which has structural similarity to views of the organic world held by the philosopher Immanuel Kant at the end of the eighteenth century.
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Affiliation(s)
- Siegfried Roth
- Institute of Developmental Biology, University of Cologne, Biowissenschaftliches Zentrum, Zülpicher Strasse 47b, 50674 Cologne, Germany.
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142
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143
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Kanodia JS, Kim Y, Tomer R, Khan Z, Chung K, Storey JD, Lu H, Keller PJ, Shvartsman SY. A computational statistics approach for estimating the spatial range of morphogen gradients. Development 2011; 138:4867-74. [PMID: 22007136 DOI: 10.1242/dev.071571] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A crucial issue in studies of morphogen gradients relates to their range: the distance over which they can act as direct regulators of cell signaling, gene expression and cell differentiation. To address this, we present a straightforward statistical framework that can be used in multiple developmental systems. We illustrate the developed approach by providing a point estimate and confidence interval for the spatial range of the graded distribution of nuclear Dorsal, a transcription factor that controls the dorsoventral pattern of the Drosophila embryo.
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Affiliation(s)
- Jitendra S Kanodia
- Department of Chemical and Biological Engineering and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
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144
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Clark RI, Woodcock KJ, Geissmann F, Trouillet C, Dionne MS. Multiple TGF-β superfamily signals modulate the adult Drosophila immune response. Curr Biol 2011; 21:1672-7. [PMID: 21962711 PMCID: PMC3191266 DOI: 10.1016/j.cub.2011.08.048] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 08/02/2011] [Accepted: 08/19/2011] [Indexed: 12/29/2022]
Abstract
TGF-β superfamily signals play complex roles in regulation of tissue repair and inflammation in mammals [1]. Drosophila melanogaster is a well-established model for the study of innate immune function [2, 3] and wound healing [4–7]. Here, we explore the role and regulation of two TGF-β superfamily members, dawdle and decapentaplegic (dpp), in response to wounding and infection in adult Drosophila. We find that both TGF-β signals exhibit complex regulation in response to wounding and infection, each is expressed in a subset of phagocytes, and each inhibits a specific arm of the immune response. dpp is rapidly activated by wounds and represses the production of antimicrobial peptides; flies lacking dpp function display persistent, strong antimicrobial peptide expression after even a small wound. dawdle, in contrast, is activated by Gram-positive bacterial infection but repressed by Gram-negative infection or wounding; its role is to limit infection-induced melanization. Flies lacking dawdle function exhibit melanization even when uninfected. Together, these data imply a model in which the bone morphogenetic protein (BMP) dpp is an important inhibitor of inflammation following sterile injury whereas the activin-like dawdle determines the nature of the induced immune response.
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Affiliation(s)
- Rebecca I Clark
- Centre for the Molecular and Cellular Biology of Inflammation and Peter Gorer Department of Immunobiology, King's College London School of Medicine, London SE1 1UL, UK
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145
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Expansion-repression mechanism for scaling the Dpp activation gradient in Drosophila wing imaginal discs. Curr Biol 2011; 21:1391-6. [PMID: 21835621 DOI: 10.1016/j.cub.2011.07.015] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 06/20/2011] [Accepted: 07/12/2011] [Indexed: 12/20/2022]
Abstract
Maintaining a proportionate body plan requires the adjustment or scaling of organ pattern with organ size. Scaling is a general property of developmental systems, yet little is known about its underlying molecular mechanisms. Using theoretical modeling, we examine how the Dpp activation gradient in the Drosophila wing imaginal disc scales with disc size. We predict that scaling is achieved through an expansion-repression mechanism [1] whose mediator is the widely diffusible protein Pentagone (Pent). Central to this mechanism is the repression of pent expression by Dpp signaling, which provides an effective size measurement, and the Pent-dependent expansion of the Dpp gradient, which adjusts the gradient with tissue size. We validate this mechanism experimentally by demonstrating that scaling requires Pent and further, that scaling is abolished when pent is ubiquitously expressed. The expansion-repression circuit can be readily implemented by a variety of molecular interactions, suggesting its general utilization for scaling morphogen gradients during development.
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146
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Kuo DH, Weisblat DA. A new molecular logic for BMP-mediated dorsoventral patterning in the leech Helobdella. Curr Biol 2011; 21:1282-8. [PMID: 21782437 PMCID: PMC3152669 DOI: 10.1016/j.cub.2011.06.024] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 06/08/2011] [Accepted: 06/09/2011] [Indexed: 11/26/2022]
Abstract
Bone morphogenetic protein (BMP) signaling is broadly implicated in dorsoventral (DV) patterning of bilaterally symmetric animals [1-3], and its role in axial patterning apparently predates the birth of Bilateria [4-7]. In fly and vertebrate embryos, BMPs and their antagonists (primarily Sog/chordin) diffuse and interact to generate signaling gradients that pattern fields of cells [8-10]. Work in other species reveals diversity in essential facets of this ancient patterning process, however. Here, we report that BMP signaling patterns the DV axis of segmental ectoderm in the leech Helobdella, a clitellate annelid (superphylum Lophotrochozoa) featuring stereotyped developmental cell lineages, but the detailed mechanisms of DV patterning in Helobdella differ markedly from fly and vertebrates. In Helobdella, BMP2/4s are expressed broadly, rather than in dorsal territory, whereas a dorsally expressed BMP5-8 specifies dorsal fate by short-range signaling. A BMP antagonist, gremlin, is upregulated by BMP5-8 in dorsolateral, rather than ventral territory, and yet the BMP-antagonizing activity of gremlin is required for normal ventral cell fates. Gremlin promotes ventral fates without disrupting dorsal fates by selectively inhibiting BMP2/4s, not BMP5-8. Thus, DV patterning in the development of the leech revealed unexpected evolutionary plasticity of the conserved BMP patterning system, presumably reflecting its adaptation to different modes of embryogenesis.
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Affiliation(s)
- Dian-Han Kuo
- Department of Molecular & Cell Biology, 385 LSA, University of California, Berkeley, Berkeley, CA 94720-3200, USA.
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147
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Vorwald-Denholtz PP, De Robertis EM. Temporal pattern of the posterior expression of Wingless in Drosophila blastoderm. Gene Expr Patterns 2011; 11:456-63. [PMID: 21821151 DOI: 10.1016/j.gep.2011.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 07/20/2011] [Accepted: 07/21/2011] [Indexed: 10/17/2022]
Abstract
In most animals, the antero-posterior (A-P) axis requires a gradient of Wnt signaling. Wnts are expressed posteriorly in many vertebrate and invertebrate embryos, forming a gradient of canonical Wnt/β-Catenin activity that is highest in the posterior and lowest in the anterior. One notable exception to this evolutionary conservation is in the Drosophila embryo, in which the A-P axis is established by early transcription factors of maternal origin. Despite this initial axial establishment, Drosophila still expresses Wingless (Wg), the main Drosophila Wnt homologue, in a strong posterior band early in embryogenesis. Since its discovery 30 years ago this posterior band of Wg has been largely ignored. In this study, we re-examined the onset of expression of the Wg posterior band in relation to the expression of Wg in other segments, and compared the timing of its expression to that of axial regulators such as gap and pair-rule genes. It was found that the posterior band of Wg is first detected in blastoderm at mid nuclear cycle 14, before the segment-polarity stripes of Wg are formed in other segments. The onset of the posterior band of Wg expression was preceded by that of the gap gene products Hunchback (hb) and Krüppel (Kr), and the pair-rule protein Even-skipped (Eve). Although the function of the posterior band of Wg was not analyzed in this study, we note that in temperature-sensitive Wg mutants, in which Wg is not properly secreted, the posterior band of Wg expression is diminished in strength, indicating a positive feedback loop required for Wg robust expression at the cellular blastoderm stage. We propose that this early posterior expression could play a role in the refinement of A-P patterning.
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Affiliation(s)
- Peggy P Vorwald-Denholtz
- Howard Hughes Medical Institute, Department of Biological Chemistry, University of California, Los Angeles, CA 90095-1662, United States
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148
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Liu Z, Matsuoka S, Enoki A, Yamamoto T, Furukawa K, Yamasaki Y, Nishida Y, Sugiyama S. Negative modulation of bone morphogenetic protein signaling by Dullard during wing vein formation in Drosophila. Dev Growth Differ 2011; 53:822-41. [PMID: 21790556 DOI: 10.1111/j.1440-169x.2011.01289.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Studies in Xenopus have shown that the C-terminal domain phosphatase-like domain (CPD) phosphatase Dullard is essential for proper neural development via inhibition of bone morphogenetic protein (BMP) signaling receptors. In contrast, the orthologous budding yeast Nem1 and human Dullard have been shown to dephosphorylate the phosphatidate phosphatases yeast Smp2/Pah1 and human Lipin, and the relationship between phospholipid metabolism and BMP signaling remain unsolved. Here we report evidence that the Dullard-Lipin phosphatase cascade in Drosophila can regulate BMP signaling, most likely by affecting the function of the nuclear envelope. Manipulating expression levels of either the Drosophila Dullard gene, d-dullard (ddd) or the Lipin gene, DmLpin affected wing vein formation in a manner suggesting a negative effect on BMP signaling. Furthermore, both genes exhibit genetic interaction with BMP signaling pathway components, and can affect the levels of phosphorylated-Mothers against dpp (p-Mad). Although changing ddd expression levels did not have an obvious effect on overall nuclear envelope morphology as has been shown for yeast nem1, the nuclear import machinery components Importin-β and RanGAP were mislocalized and membrane lipid staining was altered in cells overexpressing ddd. Considering the known genetic interaction between Nup84 complex nucleoporins and nem1 in yeast, and the recently reported requirement for components from the orthologous nucleoporin complex in the nuclear translocation of Drosophila Mad (Chen & Xu 2010), it is likely that the role of Drosophila Dullard in regulating membrane lipid homeostasis is conserved and is critical for normal BMP signaling.
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Affiliation(s)
- Ziguang Liu
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Japan
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149
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Moreno-Miralles I, Ren R, Moser M, Hartnett ME, Patterson C. Bone morphogenetic protein endothelial cell precursor-derived regulator regulates retinal angiogenesis in vivo in a mouse model of oxygen-induced retinopathy. Arterioscler Thromb Vasc Biol 2011; 31:2216-22. [PMID: 21737784 DOI: 10.1161/atvbaha.111.230235] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Bone morphogenetic proteins (BMPs) are potently proangiogenic; however, the mechanisms underlying the regulation of vessel development by BMPs are not fully understood. To assess the significance of BMP endothelial cell precursor-derived regulator (BMPER) in blood vessel formation in vivo, we investigated its role in retinal angiogenesis. METHODS AND RESULTS In a model of oxygen-induced retinopathy, Bmper mRNA expression and protein levels are downregulated, correlating with the initiation of Sma and Mad related protein phosphorylation in endothelial cells. Moreover, Bmper haploinsufficiency results in an increased rate of retinal revascularization, with retinas from Bmper+/- mice displaying increased numbers of branching points and angiogenic sprouts at the leading edge of the newly formed vasculature. Furthermore, although Bmper haploinsufficiency does not alter Bmp expression, it does lead to an increase in BMP signaling, as evidenced by increased phosphorylated Sma and Mad related protein levels in endothelial cells and increased expression of known BMP target genes. CONCLUSIONS These observations provide compelling evidence that BMPER is important in the regulation of BMP signaling and revascularization in the hypoxic retina. These bring forth the possibility of novel therapeutic approaches for pathological angiogenesis based on manipulation of BMP signaling.
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150
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Lemke S, Antonopoulos DA, Meyer F, Domanus MH, Schmidt-Ott U. BMP signaling components in embryonic transcriptomes of the hover fly Episyrphus balteatus (Syrphidae). BMC Genomics 2011; 12:278. [PMID: 21627820 PMCID: PMC3224130 DOI: 10.1186/1471-2164-12-278] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 05/31/2011] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND In animals, signaling of Bone Morphogenetic Proteins (BMPs) is essential for dorsoventral (DV) patterning of the embryo, but how BMP signaling evolved with changes in embryonic DV differentiation is largely unclear. Based on the extensive knowledge of BMP signaling in Drosophila melanogaster, the morphological diversity of extraembryonic tissues in different fly species provides a comparative system to address this question. The closest relatives of D. melanogaster with clearly distinct DV differentiation are hover flies (Diptera: Syrphidae). The syrphid Episyrphus balteatus is a commercial bio-agent against aphids and has been established as a model organism for developmental studies and chemical ecology. The dorsal blastoderm of E. balteatus gives rise to two extraembryonic tissues (serosa and amnion), whereas in D. melanogaster, the dorsal blastoderm differentiates into a single extraembryonic epithelium (amnioserosa). Recent studies indicate that several BMP signaling components of D. melanogaster, including the BMP ligand Screw (Scw) and other extracellular regulators, evolved in the dipteran lineage through gene duplication and functional divergence. These findings raise the question of whether the complement of BMP signaling components changed with the origin of the amnioserosa. RESULTS To search for BMP signaling components in E. balteatus, we generated and analyzed transcriptomes of freshly laid eggs (0-30 minutes) and late blastoderm to early germband extension stages (3-6 hours) using Roche/454 sequencing. We identified putative E. balteatus orthologues of 43% of all annotated D. melanogaster genes, including the genes of all BMP ligands and other BMP signaling components. CONCLUSION The diversification of several BMP signaling components in the dipteran linage of D. melanogaster preceded the origin of the amnioserosa.[Transcriptome sequence data from this study have been deposited at the NCBI Sequence Read Archive (SRP005289); individually assembled sequences have been deposited at GenBank (JN006969-JN006986).].
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Affiliation(s)
- Steffen Lemke
- University of Chicago, Dept. of Organismal Biology and Anatomy, CLSC 921B, 920 E. 58th Street, Chicago, IL 60637, USA
- Current Address: University of Heidelberg, Centre for Organismal Studies, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Dionysios A Antonopoulos
- Argonne National Laboratory, Institute for Genomics & Systems Biology, 9700 S. Cass Avenue, Argonne, IL 60439, USA
| | - Folker Meyer
- Argonne National Laboratory, Institute for Genomics & Systems Biology, 9700 S. Cass Avenue, Argonne, IL 60439, USA
| | - Marc H Domanus
- Argonne National Laboratory, Institute for Genomics & Systems Biology, 9700 S. Cass Avenue, Argonne, IL 60439, USA
| | - Urs Schmidt-Ott
- University of Chicago, Dept. of Organismal Biology and Anatomy, CLSC 921B, 920 E. 58th Street, Chicago, IL 60637, USA
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