251
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Mallik M, Lakhotia SC. Modifiers and mechanisms of multi-system polyglutamine neurodegenerative disorders: lessons from fly models. J Genet 2010; 89:497-526. [DOI: 10.1007/s12041-010-0072-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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252
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Fox DT, Gall JG, Spradling AC. Error-prone polyploid mitosis during normal Drosophila development. Genes Dev 2010; 24:2294-302. [PMID: 20952538 DOI: 10.1101/gad.1952710] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Endopolyploidy arises during normal development in many species when cells undergo endocycles-variant cell cycles in which DNA replicates but daughter cells do not form. Normally, polyploid cells do not divide mitotically after initiating endocycles; hence, little is known about their mitotic competence. However, polyploid cells are found in many tumors, and the enhanced chromosomal instability of polyploid cells in culture suggests that such cells contribute to tumor aneuploidy. Here, we describe a novel polyploid Drosophila cell type that undergoes normal mitotic cycles as part of a remodeling process that forms the adult rectal papillae. Similar polyploid mitotic divisions, but not depolyploidizing divisions, were observed during adult ileum development in the mosquito Culex pipiens. Extended anaphases, chromosome bridges, and lagging chromosomes were frequent during these polyploid divisions, despite normal expression of cell cycle regulators. Our results show that the switch to endocycles during development is not irreversible, but argue that the polyploid mitotic cycle is inherently error-prone, and that polyploid mitoses may help destabilize the cancer genome.
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Affiliation(s)
- Donald T Fox
- Howard Hughes Medical Institute Research Laboratories, Carnegie Institution for Science, Baltimore, Maryland 21218, USA
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253
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Posnien N, Schinko JB, Kittelmann S, Bucher G. Genetics, development and composition of the insect head--a beetle's view. ARTHROPOD STRUCTURE & DEVELOPMENT 2010; 39:399-410. [PMID: 20800703 DOI: 10.1016/j.asd.2010.08.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 08/08/2010] [Accepted: 08/15/2010] [Indexed: 05/29/2023]
Abstract
Many questions regarding evolution and ontogeny of the insect head remain open. Likewise, the genetic basis of insect head development is poorly understood. Recently, the investigation of gene expression data and the analysis of patterning gene function have revived interest in insect head development. Here, we argue that the red flour beetle Tribolium castaneum is a well suited model organism to spearhead research with respect to the genetic control of insect head development. We review recent molecular data and discuss its bearing on early development and morphogenesis of the head. We present a novel hypothesis on the ontogenetic origin of insect head sutures and review recent insights into the question on the origin of the labrum. Further, we argue that the study of developmental genes may identify the elusive anterior non-segmental region and present some evidence in favor of its existence. With respect to the question of evolution of patterning we show that the head Anlagen of the fruit fly Drosophila melanogaster and Tribolium differ considerably and we review profound differences of their genetic regulation. Finally, we discuss which insect model species might help us to answer the open questions concerning the genetic regulation of head development and its evolution.
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Affiliation(s)
- Nico Posnien
- Institute for Population Genetics, University of Veterinary Medicine Vienna, Veterinärplatz 1, Vienna, Austria
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254
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Lam VK, Tokusumi T, Cerabona D, Schulz RA. Specific cell ablation in Drosophila using the toxic viral protein M2(H37A). Fly (Austin) 2010; 4:338-43. [PMID: 20798602 DOI: 10.4161/fly.4.4.13114] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The expression of toxic viral proteins for the purpose of eliminating distinct populations of cells, while leaving the rest of an organism unaffected, is a valuable method for analyzing development. Using the Gal4-UAS system, we employed the M2(H37A) toxic ion channel of the influenza-A virus to selectively ablate the Drosophila eye-antennal imaginal discs, hemocytes, dorsal vessel and nervous tissue, and comparatively monitored the effects of expressing the apoptosis-promoting protein Reaper in identical cell populations. In this report, we demonstrate the effectiveness of M2(H37A)-mediated ablation as a new means to selectively eliminate cells of interest during Drosophila development.
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Affiliation(s)
- Victoria K Lam
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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255
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Melicharek DJ, Ramirez LC, Singh S, Thompson R, Marenda DR. Kismet/CHD7 regulates axon morphology, memory and locomotion in a Drosophila model of CHARGE syndrome. Hum Mol Genet 2010; 19:4253-64. [PMID: 20716578 DOI: 10.1093/hmg/ddq348] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
CHARGE syndrome (CS, OMIM #214800) is a rare, autosomal dominant disorder, two-thirds of which are caused by haplo-insufficiency in the Chd7 gene. Here, we show that the Drosophila homolog of Chd7, kismet, is required for proper axonal pruning, guidance and extension in the developing fly's central nervous system. In addition to defects in neuroanatomy, flies with reduced kismet expression show defects in memory and motor function, phenotypes consistent with symptoms observed in CS patients. We suggest that the analysis of this disease model can complement and expand upon the existing studies for this disease, allowing a better understanding of the role of kismet in neural developmental, and Chd7 in CS pathogenesis.
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256
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Ngo KT, Wang J, Junker M, Kriz S, Vo G, Asem B, Olson JM, Banerjee U, Hartenstein V. Concomitant requirement for Notch and Jak/Stat signaling during neuro-epithelial differentiation in the Drosophila optic lobe. Dev Biol 2010; 346:284-95. [PMID: 20692248 DOI: 10.1016/j.ydbio.2010.07.036] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Revised: 07/12/2010] [Accepted: 07/30/2010] [Indexed: 11/28/2022]
Abstract
The optic lobe forms a prominent compartment of the Drosophila adult brain that processes visual input from the compound eye. Neurons of the optic lobe are produced during the larval period from two neuroepithelial layers called the outer and inner optic anlage (OOA, IOA). In the early larva, the optic anlagen grow as epithelia by symmetric cell division. Subsequently, neuroepithelial cells (NE) convert into neuroblasts (NB) in a tightly regulated spatio-temporal progression that starts at the edges of the epithelia and gradually move towards its centers. Neuroblasts divide at a much faster pace in an asymmetric mode, producing lineages of neurons that populate the different parts of the optic lobe. In this paper we have reconstructed the complex morphogenesis of the optic lobe during the larval period, and established a role for the Notch and Jak/Stat signaling pathways during the NE-NB conversion. After an early phase of complete overlap in the OOA, signaling activities sort out such that Jak/Stat is active in the lateral OOA which gives rise to the lamina, and Notch remains in the medial cells that form the medulla. During the third instar, a wave front of enhanced Notch activity progressing over the OOA from medial to lateral controls the gradual NE-NB conversion. Neuroepithelial cells at the medial edge of the OOA, shortly prior to becoming neuroblasts, express high levels of Delta, which activates the Notch pathway and thereby maintains the OOA in an epithelial state. Loss of Notch signaling, as well as Jak/Stat signaling, results in a premature NE-NB conversion of the OOA, which in turn has severe effects on optic lobe patterning. Our findings present the Drosophila optic lobe as a useful model to analyze the key signaling mechanisms controlling transitions of progenitor cells from symmetric (growth) to asymmetric (differentiative) divisions.
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Affiliation(s)
- Kathy T Ngo
- Department of Molecular, Cell, and Developmental Biology, UC Los Angeles, Los Angeles, CA 90095-1606, USA
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257
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The 2010 Genetics Society of America Elizabeth W. Jones Award for Excellence in Education: Utpal Banerjee. Genetics 2010. [DOI: 10.1534/genetics.110.114868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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258
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Clark IE, Romero-Calderón R, Olson JM, Jaworski L, Lopatto D, Banerjee U. "Deconstructing" scientific research: a practical and scalable pedagogical tool to provide evidence-based science instruction. PLoS Biol 2009; 7:e1000264. [PMID: 20041028 PMCID: PMC2796859 DOI: 10.1371/journal.pbio.1000264] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Focused analysis of current research projects provides an effective platform for teaching early-stage undergraduates the logic of scientific inquiry.
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Affiliation(s)
- Ira E. Clark
- Department of Molecular, Cell, and Developmental Biology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Rafael Romero-Calderón
- Department of Molecular, Cell, and Developmental Biology, University of California Los Angeles, Los Angeles, California, United States of America
| | - John M. Olson
- Department of Molecular, Cell, and Developmental Biology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Leslie Jaworski
- Department of Psychology, Grinnell College, Grinnell, Iowa, United States of America
| | - David Lopatto
- Department of Psychology, Grinnell College, Grinnell, Iowa, United States of America
| | - Utpal Banerjee
- Department of Molecular, Cell, and Developmental Biology, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Biological Chemistry; Molecular Biology Institute; Broad Stem Cell Research Center, University of California Los Angeles, Los Angeles, California, United States of America
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259
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Kao CF, Lee T. Birth time/order-dependent neuron type specification. Curr Opin Neurobiol 2009; 20:14-21. [PMID: 19944594 DOI: 10.1016/j.conb.2009.10.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 10/26/2009] [Accepted: 10/28/2009] [Indexed: 11/18/2022]
Abstract
Neurons derived from the same progenitor may acquire different fates according to their birth timing/order. To reveal temporally guided cell fates, we must determine neuron types as well as their lineage relationships and times of birth. Recent advances in genetic lineage analysis and fate mapping are facilitating such studies. For example, high-resolution lineage analysis can identify each sequentially derived neuron of a lineage and has revealed abrupt temporal identity changes in diverse Drosophila neuronal lineages. In addition, fate mapping of mouse neurons made from the same pool of precursors shows production of specific neuron types in specific temporal patterns. The tools used in these analyses are helping to further our understanding of the genetics of neuronal temporal identity.
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Affiliation(s)
- Chih-Fei Kao
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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260
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