DOWNLOAD PDF DETERMINATION OF PREPLACODAL ECTODERM AND SENSORY PLACODES SALLY A. MOODY

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1 Chapter 1 : Olfactory epithelium - Wikipedia The sensory organs of the vertebrate head derive from two embryological structures, the neural crest and the ectodermal placodes. Although quite a lot is known about the secreted and transcription. Artikel bewerten Providing expert coverage of all major events in early embryogenesis and the organogenesis of specific systems, and supplemented with representative clinical syndromes, Principles of Developmental Genetics, Second Edition discusses the processes of normal development in embryonic and prenatal animals, including humans. The new edition of this classic work supports clinical researchers developing future therapies with its all-new coverage of systems biology, stem cell biology, new technologies, and clinical disorders. A crystal-clear layout, exceptional full-color design, and bulleted summaries of major takeaways and clinical pathways assist comprehension and readability of the highly complex content. Prior to this appointment she was on the faculty of the Anatomy and Cell Biology Department, the Department of Neuroscience, and the Developmental Biology program at the University of Virginia. She has also served on many National Institute of Health advisory committees dealing with issues in developmental biology and developmental neurobiology, and served on the Board of Trustees of the Society for Developmental Biology. Emerging Technologies and Systems Biology 1. Untangling the Gordian knot: Cell signaling events that instruct development 2. RNA-seq and deep sequencing 3. Using mutagenesis in mice and zebrafish for developmental gene discovery 4. Chemical approaches to control stem cell fate 5. BMP signaling and stem cell self-renewal in the Drosophila ovary 6. Genomic Analyses of Neural Stem Cells 7. Chordate origins, stem cells and regeneration Section II: Early Embryology and Morphogenesis 8. Dorsal-ventral axis patterning in insects 9. Anterior-Posterior patterning in mammals Early development of epidermis and neural tissue Taking the middle road: Lateral line migration Section III: Neural cell fate determination Neural crest determination Determination of preplacodal ectoderm and sensory placodes Inner ear development Molecular genetics of tooth development Induction of the cardiac lineages Blood vessel formation Blood induction and embryonic formation Development of the genital system Formation of vertebrate limbs Patterning the embryonic endoderm into presumptive organ domains Selected Clinical Problems Diaphragmatic embryogenesis and human congenital diaphragmatic defects Genetic and developmental basis of congenital cardiovascular malformations Multiple Roles of T-box genes DeGeorge and related syndromes Neural tube defects Verlagsort. Page 1

2 Chapter 2 : Sally Moody The George Washington University - blog.quintoapp.com 27 DETERMINATION OF PREPLACODAL ECTODERM AND Department of Anatomy and Cell Biology, The George Washington University. Moody and a team of world-renowned experts provide a groundbreaking view of developmental genetics that will influence scientific approaches in embryology, comparative biology, as well as the newly emerging fields of stem cell biology and regenerative medicine. Principles of Developmental Genetics highlights the intersection of developmental biology with new revolutionary genomic technologies, and details how these advances have accelerated our understanding of the molecular genetic processes that regulates development. This definitive resource provides researchers with the opportunity to gain important insights into the clinical applicability of emerging new technologies and animal model data. This book is a must-have for all researchers in genetics, developmental biology, regenerative medicine, and stem cell biology. Audience Advanced molecular, cell, developmental biologists and developmental geneticists, and clinical geneticists Contents I. Untangling the Gordian knot: Chesnut and Mahendra S. Early Embryology, Fate Determination and Patterning 8. Ratnaparkhi and Albert J. Formation of the Embryonic Mesoderm Lisa L. Chang and Daniel S. Multiple roles of T-box genes L. Naiche and Virginia E. Morphogenetic and Cell Movements Regulation of tissue separation in the amphibian embryo Herbert Steinbeisser Branching Morphogenesis of Mammalian epithelia Jamie Davies Sansom and Frederick J. Pathfinding and Patterning of Axonal Connections S. Krull 25 Retinal Development Kathryn B. Moore and Monica L. Neural Crest Determination Roberto Mayor The Inner Ear Donna F. Fekete and Ulrike J. Craniofacial Formation and Congenital Defects S. Induction of the Cardiac Lineage Andrew S. Warkman and Paul A. Topics in Vertebrate Kidney Formation: A Comparative Perspective Thomas M. Ackerman and David R. Formation of Vertebrate Limbs Yingzi Yang Skeletal Development Peter G. Boyce, and Rocky S. Moore-Scott and James M. Kormish and Kenneth S. Page 2

3 Chapter 3 : Faculty Directory The School of Medicine & Health Sciences The George Washington Univer Cranial sensory placodes arise from a common precursor field, the pre-placodal ectoderm (PPE), which surrounds the anterior neural plate just lateral to the neural crest. Tammy Awtry, Science Educator Dr. Moore, Professor, University of Utah Dr. You can view the article here. You can view the entire publication here. Science and Technology Dorsal axis-inducing activity can be activated by an activin-like signal and by localized polyadenylation between the 8- and cell stages. Ventrally localized Wnt8b signaling antagonizes this dorsal-axis activity. Noggin signaling from animal blastomeres promotes a neural fate in vegetal equatorial cells. We identified 40 unique mrnas that are enriched in the animal blastomeres using a microarray approach. We are functionally characterizing a number of these to discover whether they bias cells towards a neural fate. Recently in collaboration with Dr. Peter Nemes GWU Chemistry we used Mass Spectrometry to identified metabolites and proteins that are unique to specific blastomeres of different fates. Angewandte Chemie International Edition Nemes Single-cell mass spectrometry with multi-solvent extraction identified metabolic differences between left and right blastomeres in the 8-cell frog Xenopus embryo. Moody Neural transcription factors bias cleavage stage blastomeres to give rise to neural ectoderm. Nemes Single-cell mass spectrometry reveals small molecules that affect cell fates in the cell embryo. Novel animal pole-enriched maternal mrnas are preferentially expressed in neural ectoderm. Moody Blastomere explants to test for cell fate commitment during embryonic development. Journal of Visualized Experiments 71 e, doi: Noggin signaling from Xenopus animal blastomere lineages promotes a neural fate in neighboring vegetal blastomere lineages. Moody Multiple maternal influences on dorsal-ventral fate in Xenopus animal blastomeres. Moody An activin-like signal activates a dorsal-specifying RNA between the 8- and cell stages of Xenopus. Link We cloned two maternal genes foxd5, flotillin1 and are studying their functions in establishing neural fate in dorsal, animal lineages. For a description of FoxD5, please see: A gene regulatory network involved in neural plate development. Flotillin1 is a member of a family of membrane-associated proteins of unknown function that are highly expressed in the nervous system. These proteins are highly enriched in growing axons. There are three Xenopus alleles flotillin 1a, 1b, 1c that have very similar expression profiles. Flotillin1 is expressed during oogenesis and transcripts become enriched in the animal hemisphere precursors of the embryonic ectoderm. Zygotic transcripts are expressed in the presumptive neural plate, with lower levels in the non-neural ectoderm. At neural tube closure, Flotillin1 is expressed in the entire telencephalon, dorsal domains of the rest of the neural tube and dorsal paraxial mesoderm. Primary sensory neurons Rohon-Beard cells express Flotillin1 at particularly high levels. At tail bud stages, placodal and branchial arch structures additionally express Flotillin1. While flotillin1 has been implicated in axon regeneration, its function during early development is not known. FoxD5 also known as foxd4l1 is expressed maternally during oogenesis, and maternal transcripts are confined to the animal hemisphere precursors of the embryonic ectoderm. In over-expression and animal cap assays, it activates dorsal axis genes, both neural and muscle, and induces a secondary axis. It is induced strongly by Siamois and Cerberus, but only weakly by neural inducers Noggin, Chordin. Its expression is down-regulated as the neural tube closes and differentiation begins. We demonstrated that foxd5 acts upstream of numerous co-expressed neural plate genes, some of which stabilize a neural ectodermal fate and some of which initiate neural differentiation. Together these genes define a regulatory network that establishes the neural ectoderm and controls the onset of neural differentiation. Conserved structural domains in FoxD4L1, a neural forkhead box transcription factor, are required to repress or activate target genes. Link Specification of Cranial Placode Ectoderm Placodes are ectodermal specializations in the vertebrate head that contribute to each of the sensory systems olfactory epithelium, lens, vestibular-acoustic organs and ganglia, cranial ganglia and lateral line. We cloned a member of the Six gene family Six1 that is expressed in the embryonic precursor of the placodes, the pre-placodal ectoderm PPE. This gene is highly expressed in all neurogenic cranial placodes and lateral line Page 3

4 primordia from neurula to tadpole stages. We used markers of the PPE to show that low concentrations of neural inducers e. Over-expression of Six1 expands the PPE at the expense of neural crest and epidermis, whereas knock-down of Six1 protein results in reduction of the PPE domain and expansion of the neural plate, neural crest and epidermis. Using activator and repressor constructs of Six1 or co-expression of wild-type six1 with activating eya1 or repressing groucho co-factors, we demonstrated that Six1 inhibits neural crest and epidermis genes via transcriptional repression and enhances PPE genes via transcriptional activation. Ectopic expression of neural plate, neural crest and epidermal genes in the PPE demonstrates that these factors mutually influence each other to establish the appropriate boundaries between these ectodermal domains. We are continuing to examine the upstream regulators of Six1 expression and the down-stream target genes. In collaboration with Gerhart Schlosser and Mike Klymkowski, we studied whether Six1 plays a role in controlling cell proliferation and differentiation during later placode development. Six1 is expressed in both superficial and sensorial layers of the neurogenic placodes beginning at mid-gastrula stages, but the neuronal derivatives turn off six1 expression as they migrate away from the placodal region. We showed that both Six1 and Eya1 are required for neural differentiation in all neurogenic placodes. At high levels of expression, Six1 and Eya1 expand the expression of SoxB1 genes, maintain cells in proliferative state and block expression of neuronal differentiation genes. At lower levels, they promote neuronal diferentiation. The transcriptional activity of Six proteins can be modified by co-factor proteins, the best characterized being Eya and Groucho proteins. We searched the Xenopus genome for orthologues of Drosphila co-factor proteins that interact with the fly six-related factor SO. We identified 33 Xenopus genes with high sequence identity to 20 fly proteins and demonstrate that a large number of these are expressed in cranofacial tissues that express Six1. Moody Microarray identification of novel genes downstream of Six1, a critical factor in cranial placode, somite and kidney development. Principles of Developmental Genetics. Second edition, pp Eya1 and Six1 promote neurogenesis in the cranial placodes in a SoxB1? Determination of pre-placodal ectoderm and sensory placodes. Principles in Developmental Genetics. Induction and specification of the vertebrate ectodermal placodes: Six1 promotes a placodal fate within the lateral neurogenic ectoderm by functioning as both a transcriptional activator and repressor. Xenopus six1 gene is expressed in neurogenic cranial placodes and maintained in differentiating lateral lines. Mechanisms of Development Moody, are investigating the developmental causes of feeding and swallowing difficulties called pediatric dysphagia experienced by these patients. LaMantia A cellular and molecular mosaic establishes growth and differentiation states for cranial sensory neurons. Disease Models and Mechanisms 7: Link Specification of Retinal Stem Cells and Amacrine Cell Phenotypes The ability of embryonic cells to give rise to the retina is influenced by both maternal molecules and cell-cell interactions throughout development. We demonstrated that maternal asymmetries that set up the three embryonic germ layers ectoderm, mesoderm, endoderm influence whether an embryonic cell can give rise to retina. Vegetally localized factors that promote endo-mesoderm formation also antagonize neural and retinal fates involving the Derriere signaling pathway. Those blastomeres that do give rise to the retina are selected from the pool of competent blastomeres by residing in a region of the embryo where BMP signaling is highly repressed. The competence of Xenopus blastomeres to produce neural and retinal progeny is repressed by two endo-mesoderm promoting pathways. Animal-vegetal asymmetries influence the earliest steps in retinal fate commitment in Xenopus. Link During gastrulation retinal stem cells are selected from the pool of retina-competent precursors to form the definitive eye fields. Cells in the eye fields express several transcription factors that specify their retinal fate. We show that eye-specific transcription factors and ephrinb1-fgf signaling influence which embryonic cells are able to move into the eye field. We also showed that two of these factors, Rx1 and Pax6, differentially influence whether a cell maintains an immature retinal stem cell state or becomes a more restricted retinal progenitor cell. Alterations of rx1 and pax6 expression levels at neural plate stages differentially affect the production of retinal cell types and maintenance of retinal stem cell qualities. Dishevelled mediates ephrinb1 signaling in the eye field via the planar cell polarity pathway. Nature Cell Biology 8: Morphogenetic movements underlying eye field formation require Page 4

5 interactions between the FGF and ephrinb1 signaling pathways. Transcription factors of the anterior neural plate alter cell movements of epidermal progenitors to specify a retinal fate. Link Using cell lineage analyses, neurotransmitter-specific immunocytochemistry, and confocal microscopy, we determined the cell lineage origin of different neurotransmitter subtypes of amacrine neurons. Using single cell transplantation and gene mis-expression techniques, we demonstrated some of the interactions and transcription factors necessary to produce these specific phenotypes. Methods in Molecular Biology: Changes in Rx1 and Pax6 activity at eye field stages differentially alter the production of amacrine neurotransmitter subtypes in Xenopus. Intrinsic bias and lineage restriction in the phenotype determination of dopamine and neuropeptide Y amacrine cells. Dual expression of GABA or serotonin and dopamine in Xenopus amacrine cells is transient and may be regulated by laminar cues. Three types of serotonin-containing amacrine cells in the tadpole retina have distinct clonal origins. Asymmetrical blastomere origin and spatial domains of dopamine and Neuropeptide Y amacrine cells in Xenopus tadpole retina. The retinal fate of Xenopus cleavage stage progenitors is dependent upon blastomere position and competence: Studies of normal and regulated clones. Therefore, this gene is likely to be regulated by proteins that establish neuronal cell fate. We cloned the upstream sequences of this gene in rat and analyzed in silico which regions are likely to be involved in neuron-specific expression. The promoter region of the rat neuron-specific Class III beta-tubulin gene contains several proximal elements that may regulate neuron specific expression. Developmental expression of neuron-specific beta-tubulin in frog Xenopus laevis ; a marker for growing axons during the embryonic period. Page 5

6 Chapter 4 : Development of the Pre-Placodal Ectoderm and Cranial Sensory Placodes â NYU Scholars This zone subsequently gives rise to two distinct precursor populations of the peripheral nervous system: the neural crest and the preplacodal ectoderm (PPE). The PPE is a common field from which all cranial sensory placodes arise (adenohypophyseal, olfactory, lens, trigeminal, epibranchial, otic). Brush cells Olfactory sensory neurons[ edit ] The olfactory sensory neurons of the olfactory epithelium are bipolar neurons. The apical poles of these neurons express odorant receptors on non-motile cilia at the ends of the dendritic knob, which extend out into the airspace to interact with odorants. Odorant receptors bind odorants in the airspace, which are made soluble by the serous secretions from olfactory glands located in the lamina propria of the mucosa. Once the axons pass through the cribriform plate, they terminate and synapse with the dendrites of mitral cells in the glomeruli of the olfactory bulb. Supporting cells[ edit ] Analogous to neural glial cells, the supporting cells are non-neural cells in the olfactory epithelium that are located in the apical layer of the pseudostratified ciliated columnar epithelium. There are two types of supporting cells in the olfactory epithelium: The sustentacular cells function as metabolic and physical support for the olfactory epithelium. Microvillar cells are another class of supporting cells that are morphologically and biochemically distinct from the sustentacular cells, and arise from a basal cell population that expresses c-kit. While some of these basal cells divide rapidly, a significant proportion remain relatively quiescent and replenish olfactory epithelial cells as needed. This leads to the olfactory epithelium being replaced every 6â 8 weeks. These glands deliver a proteinaceous secretion via ducts onto the surface of the mucosa. The role of the secretions are to trap and dissolve odiferous substances for the bipolar neurons. Constant flow from the olfactory glands allows old odors to be constantly washed away. Placodes are transient, focal aggregations of ectoderm located in the developmental region of future vertebrate head, and give rise to sensory organs. The axons of OSNs expressing the same odorant receptors converge onto the same glomerulus at the olfactory bulb, allowing for the organization of olfactory information. Olfaction results from the proper development and interaction of the two components of the primary olfactory pathway: In order for olfactory sensory neurons to function properly, they must express odorant receptors and the proper transduction proteins on non-motile cilia that extend from the dendritic knob in addition to projecting their axons to the olfactory bulb. Once the olfactory sensory neurons differentiate, they express odorant receptors, which transduce odorant information from the environment to the central nervous system and aids in the development of the odorant map. The organization and subsequent processing of odorant information is possible due to the convergence of olfactory sensory neuron axons expressing the same odorant receptors onto the same glomerulus at the olfactory bulb. Because of its regenerative capacity, damage to the olfactory epithelium can be temporary but in extreme cases, injury can be permanent, leading to anosmia. Composition of the Olfactory receptor neuron captions in German olfactory epithelium pig. Chapter 5 : PRINCIPLES OF DEVELOPMENTAL GENETICS - blog.quintoapp.com Moody, S.A. and J.-P. Saint-Jeannet () "Determination of pre-placodal ectoderm and sensory placodes" In: Principles of Developmental Genetics. Elsevier, NY. Second edition, pp Page 6