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Auswahl der wissenschaftlichen Literatur zum Thema „Head mesoderm“
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Zeitschriftenartikel zum Thema "Head mesoderm"
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Yin, Z., X. L. Xu und M. Frasch. „Regulation of the twist target gene tinman by modular cis-regulatory elements during early mesoderm development“. Development 124, Nr. 24 (15.12.1997): 4971–82. http://dx.doi.org/10.1242/dev.124.24.4971.
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The Drosophila tinman homeobox gene has a major role in early mesoderm patterning and determines the formation of visceral mesoderm, heart progenitors, specific somatic muscle precursors and glia-like mesodermal cells. These functions of tinman are reflected in its dynamic pattern of expression, which is characterized by initial widespread expression in the trunk mesoderm, then refinement to a broad dorsal mesodermal domain, and finally restricted expression in heart progenitors. Here we show that each of these phases of expression is driven by a discrete enhancer element, the first being active in the early mesoderm, the second in the dorsal mesoderm and the third in cardioblasts. We provide evidence that the early-active enhancer element is a direct target of twist, a gene encoding a basic helix-loop-helix (bHLH) protein, which is necessary for tinman activation. This 180 bp enhancer includes three E-box sequences which bind Twist protein in vitro and are essential for enhancer activity in vivo. Ectodermal misexpression of twist causes ectopic activation of this enhancer in ectodermal cells, indicating that twist is the only mesoderm-specific activator of early tinman expression. We further show that the 180 bp enhancer also includes negatively acting sequences. Binding of Even-skipped to these sequences appears to reduce twist-dependent activation in a periodic fashion, thus producing a striped tinman pattern in the early mesoderm. In addition, these sequences prevent activation of tinman by twist in a defined portion of the head mesoderm that gives rise to hemocytes. We find that this repression requires the function of buttonhead, a head-patterning gene, and that buttonhead is necessary for normal activation of the hematopoietic differentiation gene serpent in the same area. Together, our results show that tinman is controlled by an array of discrete enhancer elements that are activated successively by differential genetic inputs, as well as by closely linked activator and repressor binding sites within an early-acting enhancer, which restrict twist activity to specific areas within the twist expression domain.
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Noden, Drew M. „Interactions and fates of avian craniofacial mesenchyme“. Development 103, Supplement (01.09.1988): 121–40. http://dx.doi.org/10.1242/dev.103.supplement.121.
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Craniofacial mesenchyme is composed of three mesodermal populations – prechordal plate, lateral mesoderm and paraxial mesoderm, which includes the segmented occipital somites and the incompletely segmented somitomeres – and the neural crest. This paper outlines the fates of each of these, as determined using quail–chick chimaeras, and presents similarities and differences between these cephalic populations and their counterparts in the trunk. Prechordal and paraxial mesodermal populations are the sources of all voluntary muscles of the head. The latter also provides most of the connective precursors of the calvaria, occipital, otic–parietal and basisphenoid tissues. Lateral mesoderm is the source of peripharyngeal connective tissues; the most rostral skeletal tissues it forms are the laryngeal and tracheal cartilages. When migrating neural crest cells encounter segmented paraxial mesoderm (occipital and trunk somites), most move into the region between the dermamyotome and sclerotome in the cranial half of each somite. In contrast, most cephalic crest cells migrate superficial to somitomeres. There is, however, a small subpopulation of the head crest that invades somitomeric mesoderm. These cells subsequently segregate presumptive myogenic precursors of visceral arch voluntary muscles from underlying mesenchyme. In the neurula-stage avian embryo, all paraxial and lateral mesodermal populations contain precursors of vascular endothelial cells, which can be detected in chimaeric embryos using anti-quail endothelial antibodies. Some of these angioblasts differentiate in situ, contributing directly to pre-existing vessels or forming isolated, nonpatent, cords that subsequently vesiculate and fuse with nearby vessels. Many angioblasts migrate in all directions, invading embryonic mesenchymal and epithelial tissues and participating in new blood vessel formation in distant sites. The interactions leading to proper spatial patterning of craniofacial skeletal, muscular, vascular and peripheral neural tissues has been studied by performing heterotopic transplants of each of these mesodermal and neural crest populations. The results consistently indicate that connective tissue precursors, regardless of their origin, contain spatial information used by the precursors of muscles and blood vessels and by outgrowing peripheral nerves. Some of these connective tissue precursors (e.g. the neural crest, paraxial mesoderm) acquire their spatial programming while in association with the central nervous system or developing sensory epithelia (e.g. otic, optic, nasal epithelia).
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Kusch, T., und R. Reuter. „Functions for Drosophila brachyenteron and forkhead in mesoderm specification and cell signalling“. Development 126, Nr. 18 (15.09.1999): 3991–4003. http://dx.doi.org/10.1242/dev.126.18.3991.
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The visceral musculature of the larval midgut of Drosophila has a lattice-type structure and consists of an inner stratum of circular fibers and an outer stratum of longitudinal fibers. The longitudinal fibers originate from the posterior tip of the mesoderm anlage, which has been termed the caudal visceral mesoderm (CVM). In this study, we investigate the specification of the CVM and particularly the role of the Drosophila Brachyury-homologue brachyenteron. Supported by fork head, brachyenteron mediates the early specification of the CVM along with zinc-finger homeodomain protein-1. This is the first function described for brachyenteron or fork head in the mesoderm of Drosophila. The mode of cooperation resembles the interaction of the Xenopus homologues Xbra and Pintallavis. Another function of brachyenteron is to establish the surface properties of the CVM cells, which are essential for their orderly migration along the trunk-derived visceral mesoderm. During this movement, the CVM cells, under the control of brachyenteron, induce the formation of one muscle/pericardial precursor cell in each parasegment. We propose that the functions of brachyenteron in mesodermal development of Drosophila are comparable to the roles of the vertebrate Brachyury genes during gastrulation.
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Yamamoto, A., S. L. Amacher, S. H. Kim, D. Geissert, C. B. Kimmel und E. M. De Robertis. „Zebrafish paraxial protocadherin is a downstream target of spadetail involved in morphogenesis of gastrula mesoderm“. Development 125, Nr. 17 (01.09.1998): 3389–97. http://dx.doi.org/10.1242/dev.125.17.3389.
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Zebrafish paraxial protocadherin (papc) encodes a transmembrane cell adhesion molecule (PAPC) expressed in trunk mesoderm undergoing morphogenesis. Microinjection studies with a dominant-negative secreted construct suggest that papc is required for proper dorsal convergence movements during gastrulation. Genetic studies show that papc is a close downstream target of spadetail, gene encoding a transcription factor required for mesodermal morphogenetic movements. Further, we show that the floating head homeobox gene is required in axial mesoderm to repress the expression of both spadetail and papc, promoting notochord and blocking differentiation of paraxial mesoderm. The PAPC structural cell-surface protein may provide a link between regulatory transcription factors and the actual cell biological behaviors that execute morphogenesis during gastrulation.
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Kofron, M., T. Demel, J. Xanthos, J. Lohr, B. Sun, H. Sive, S. Osada, C. Wright, C. Wylie und J. Heasman. „Mesoderm induction in Xenopus is a zygotic event regulated by maternal VegT via TGFbeta growth factors“. Development 126, Nr. 24 (15.12.1999): 5759–70. http://dx.doi.org/10.1242/dev.126.24.5759.
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The maternal transcription factor VegT is important for establishing the primary germ layers in Xenopus. In previous work, we showed that the vegetal masses of embryos lacking maternal VegT do not produce mesoderm-inducing signals and that mesoderm formation in these embryos occurred ectopically, from the vegetal area rather than the equatorial zone of the blastula. Here we have increased the efficiency of the depletion of maternal VegT mRNA and have studied the effects on mesoderm formation. We find that maternal VegT is required for the formation of 90% of mesodermal tissue, as measured by the expression of mesodermal markers MyoD, cardiac actin, Xbra, Xwnt8 and alphaT4 globin. Furthermore, the transcription of FGFs and TGFbetas, Xnr1, Xnr2, Xnr4 and derriere does not occur in VegT-depleted embryos. We test whether these growth factors may be endogenous factors in mesoderm induction, by studying their ability to rescue the phenotype of VegT-depleted embryos, when their expression is restricted to the vegetal mass. We find that Xnr1, Xnr2, Xnr4 and derriere mRNA all rescue mesoderm formation, as well as the formation of blastopores and the wild-type body axis. Derriere rescues trunk and tail while nr1, nr2 and nr4 rescue head, trunk and tail. We conclude that mesoderm induction in Xenopus depends on a maternal transcription factor regulating these zygotic growth factors.
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Halpern, M. E., C. Thisse, R. K. Ho, B. Thisse, B. Riggleman, B. Trevarrow, E. S. Weinberg, J. H. Postlethwait und C. B. Kimmel. „Cell-autonomous shift from axial to paraxial mesodermal development in zebrafish floating head mutants“. Development 121, Nr. 12 (01.12.1995): 4257–64. http://dx.doi.org/10.1242/dev.121.12.4257.
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Zebrafish floating head mutant embryos lack notochord and develop somitic muscle in its place. This may result from incorrect specification of the notochord domain at gastrulation, or from respecification of notochord progenitors to form muscle. In genetic mosaics, floating head acts cell autonomously. Transplanted wild-type cells differentiate into notochord in mutant hosts; however, cells from floating head mutant donors produce muscle rather than notochord in wild-type hosts. Consistent with respecification, markers of axial mesoderm are initially expressed in floating head mutant gastrulas, but expression does not persist. Axial cells also inappropriately express markers of paraxial mesoderm. Thus, single cells in the mutant midline transiently co-express genes that are normally specific to either axial or paraxial mesoderm. Since floating head mutants produce some floor plate in the ventral neural tube, midline mesoderm may also retain early signaling capabilities. Our results suggest that wild-type floating head provides an essential step in maintaining, rather than initiating, development of notochord-forming axial mesoderm.
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Bodmer, R., L. Y. Jan und Y. N. Jan. „A new homeobox-containing gene, msh-2, is transiently expressed early during mesoderm formation of Drosophila“. Development 110, Nr. 3 (01.11.1990): 661–69. http://dx.doi.org/10.1242/dev.110.3.661.
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Many homeobox-containing genes of Drosophila regulate pathways of differentiation. These proteins probably function as promoter- or enhancer-selective transcription factors. We have isolated a new homeobox-containing gene, msh-2, by means of the polymerase chain reactions (PCR) using redundant primers. msh-2 is specifically expressed in mesodermal primordia during a short time period early in development. It first appears at blastoderm stage just before the ventral invagination of the mesoderm and shortly after twist, a gene required for mesoderm formation, is expressed. During germband elongation all the mesodermal cells in the segmented part of the embryo express msh-2, but soon afterwards msh-2 becomes restricted to the dorsal mesoderm, which includes the primordia for the visceral musculature and the heart. Prior to muscle differentiation, msh-2 expression ceases, except for two rows of cells that will be included in the dorsal vessel. Embryos that are deficient for the chromosomal region, 93C-F, which includes the msh-2 gene, show normal mesoderm invagination and dorsal spreading. However, later in development no visceral muscle and dorsal vessel differentiation can be detected, but some skeletal muscles do form, albeit abnormally. msh-2 expression, except for a patch in the head, is dependent on twist function. On the other hand, snail, another mesoderm determinant, does not appear to be required for msh-2 initiation, but is necessary for the maintenance of msh-2 expression after germband elongation. H2.0, a homeo-box-containing gene specifically expressed in visceral mesoderm, is not transcribed in the mesoderm in 93C-F deficiency embryos.(ABSTRACT TRUNCATED AT 250 WORDS)
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Kessler, D. S., und D. A. Melton. „Induction of dorsal mesoderm by soluble, mature Vg1 protein“. Development 121, Nr. 7 (01.07.1995): 2155–64. http://dx.doi.org/10.1242/dev.121.7.2155.
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Mesoderm induction during Xenopus development has been extensively studied, and two members of the transforming growth factor-beta family, activin beta B and Vg1, have emerged as candidates for a natural inducer of dorsal mesoderm. Heretofore, analysis of Vg1 activity has relied on injection of hybrid Vg1 mRNAs, which have not been shown to direct efficient secretion of ligand and, therefore, the mechanism of mesoderm induction by processed Vg1 protein is unclear. This report describes injection of Xenopus oocytes with a chimeric activin-Vg1 mRNA, encoding the pro-region of activin beta B fused to the mature region of Vg1, resulting in the processing and secretion of mature Vg1. Treatment of animal pole explants with mature Vg1 protein resulted in differentiation of dorsal, but not ventral, mesodermal tissues and dose-dependent activation of both dorsal and ventrolateral mesodermal markers. At high doses, mature Vg1 induced formation of ‘embryoids’ with a rudimentary axial pattern, head structures including eyes and a functional neuromuscular system. Furthermore, truncated forms of the activin and FGF receptors, which block mesoderm induction in the intact embryo, fully inhibited mature Vg1 activity. To examine the mechanism of inhibition, we have performed receptor-binding assays with radiolabeled Vg1. Finally, follistatin, a specific inhibitor of activin beta B which is shown not to block endogenous dorsal mesoderm induction, failed to inhibit Vg1. The results support a role for endogenous Vg1 in dorsal mesoderm induction during Xenopus development.
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Amaya, E., P. A. Stein, T. J. Musci und M. W. Kirschner. „FGF signalling in the early specification of mesoderm in Xenopus“. Development 118, Nr. 2 (01.06.1993): 477–87. http://dx.doi.org/10.1242/dev.118.2.477.
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We have examined the role of FGF signalling in the development of muscle and notochord and in the expression of early mesodermal markers in Xenopus embryos. Disruption of the FGF signalling pathway by expression of a dominant negative construct of the FGF receptor (XFD) generally results in gastrulation defects that are later evident in the formation of the trunk and tail, though head structures are formed nearly normally. These defects are reflected in the loss of notochord and muscle. Even in embryos that show mild defects and gastrulate properly, muscle formation is impaired, suggesting that morphogenesis and tissue differentiation each depend on FGF. The XFD protein inhibits the expression of the immediate early gene brachyury throughout the marginal zone, including the dorsal side; it does not, however, inhibit the dorsal lip marker goosecoid, which is expressed in the first involuting mesoderm at the dorsal side that will underlie the head. The XFD protein also inhibits Xpo expression, an immediate early marker of ventral and lateral mesoderm. These results suggest that FGF is involved in the earliest events of most mesoderm induction that occur before gastrulation and that the early dorsal mesoderm is already composed of two cell populations that differ in their requirements for FGF.
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Sun, B. I., S. M. Bush, L. A. Collins-Racie, E. R. LaVallie, E. A. DiBlasio-Smith, N. M. Wolfman, J. M. McCoy und H. L. Sive. „derriere: a TGF-beta family member required for posterior development in Xenopus“. Development 126, Nr. 7 (01.04.1999): 1467–82. http://dx.doi.org/10.1242/dev.126.7.1467.
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TGF-beta signaling plays a key role in induction of the Xenopus mesoderm and endoderm. Using a yeast-based selection scheme, we isolated derriere, a novel TGF-beta family member that is closely related to Vg1 and that is required for normal mesodermal patterning, particularly in posterior regions of the embryo. Unlike Vg1, derriere is expressed zygotically, with RNA localized to the future endoderm and mesoderm by late blastula, and to the posterior mesoderm by mid-gastrula. The derriere expression pattern appears to be identical to the zygotic expression domain of VegT (Xombi, Brat, Antipodean), and can be activated by VegT as well as fibroblast growth factor (FGF). In turn, derriere activates expression of itself, VegT and eFGF, suggesting that a regulatory loop exists between these genes. derriere is a potent mesoderm and endoderm inducer, acting in a dose-dependent fashion. When misexpressed ventrally, derriere induces a secondary axis lacking a head, an effect that is due to dorsalization of the ventral marginal zone. When misexpressed dorsally, derriere suppresses head formation. derriere can also posteriorize neurectoderm, but appears to do so indirectly. Together, these data suggest that derriere expression is compatible only with posterior fates. In order to assess the in vivo function of derriere, we constructed a dominant interfering Derriere protein (Cm-Derriere), which preferentially blocks Derriere activity relative to that of other TGFbeta family members. Cm-derriere expression in embryos leads to posterior truncation, including defects in blastopore lip formation, gastrulation and neural tube closure. Normal expression of anterior and hindbrain markers is observed; however, paraxial mesodermal gene expression is ablated. This phenotype can be rescued by wild-type derriere and by VegT. Our findings indicate that derriere plays a crucial role in mesodermal patterning and development of posterior regions in Xenopus.
Dissertationen zum Thema "Head mesoderm"
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Velasco, Begona de. „The development of the neuroendocrine system and head mesoderm in Drosophila“. Diss., Restricted to subscribing institutions, 2006. http://proquest.umi.com/pqdweb?did=1188872391&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Jullian, Estelle. „Myogenic fate choice in the cardiopharyngeal mesoderm“. Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0363.
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Le mésoderme cardiopharyngé (CPM) est localisé au niveau crânial de l’embryon de souris, et contribue aux muscles de la tête et du cou, dérivés des arcs pharyngés, et aux cellules progénitrices du second champ cardiaque qui donne naissance au muscle cardiaque. L’étude du CPM permet de comprendre les malformations congénitales cardiaques et crâniofaciales, comme celles observées chez les patients atteints du syndrome de microdélétion 22q11.2. Chez la souris, une analyse de clonale rétrospective a établi qu’il existe une relation clonale entre certaines parties du cœur, dérivant du second champ cardiaque et certains muscles branchiomériques. Bien que, chez le protochordé Ciona, une cellule progénitrice du CPM a été identifiée, capable de contribuer au cœur et aux muscles squelettiques pharyngés, les cellules progénitrices communes entre le cœur et les muscles de la tête n’ont pas été localisées dans l’embryon de souris. L’objectif de ma thèse consiste à étudier le destin du cœur contre celui des muscles de la tête dans le CPM. Le premier chapitre des résultats adresse la localisation spatiotemporelle des potentielles cellules progénitrices bipotentes du cœur et des muscles de la tête dans le CPM murin et comment elles sont régulées. Les résultats démontrent que bien que les composants conservés soient présents, leur régulation diffère entre la souris et Ciona. Le second et le troisième chapitres de résultats présentent une analyse de l’hétérogénéité à l’intérieur du CPM et entre les arcs pharyngés. Des domains ont été déterminés dans les arcs, et le destin cellulaire reste à explorerCardiopharyngeal mesoderm is localized at the cranial level of the mouse embryo, and contributes to head and neck muscles, derived from pharyngeal arches, and cardiac muscle. Study cardiopharyngeal mesoderm allows to understand some congenital abnormalities, which have cardiac and craniofacial defects, like DiGeorge syndrome. In mouse, retrospective clonal analysis allows to determinate a relationship between second heart field and specific branchiomeric muscles. Each pharyngeal arch gives rise to a specific branchiomeric muscles group which is linked to a part of the heart. Indeed, it has been showed in Chordates, a progenitor cell which is able to contribute to the heart and head muscles. My thesis objective is to investigate heart versus head muscles fate in cardiopharyngeal mesoderm. I wanted to understand the mechanism underlying heart and head muscles specification. The first part of the thesis will undercover the localization and the timeline of the potential bipotent myogenic progenitor cells present in cardiopharyngeal mesoderm and how they are regulated. The results showed that the conserved components are present but the regulation between each component seemed to be different in the mouse compared to Ciona. The second part and the three part of the thesis will undercover the heterogeneity intra- and inter-pharyngeal arches. Domains through the core of the arches could be observed and the fate of each domain needs to be explored
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Sefton, Elizabeth Marie. „Evolution of the Amphibian Head and Neck: Fate and Patterning of Cranial Mesoderm in the Axolotl (Ambystoma Mexicanum)“. Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:26718769.
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The vertebrate head is a complex structure derived from all three embryonic germ layers. Cranial mesoderm forms most of the neurocranium, cardiovascular tissues and voluntary muscles required for intake of food and oxygenated fluid. Despite its essential role in shaping cranial and neck anatomy, long-term fate maps of cranial mesoderm are known only from the mouse and chicken, as effective labeling techniques for use in other species have been developed only recently. Data from additional species are needed to determine the embryonic origin of features absent in amniotes but present in other vertebrates and to evaluate the extent of conservation in the development of homologous structures. This dissertation examines the role of cranial mesoderm as well as its interactions with neural crest in shaping the tetrapod craniofacial and neck region, focusing on the skull and head muscles in the axolotl, Ambystoma mexicanum. I demonstrate a dual embryonic origin of the pharyngeal skeleton, including derivation of basibranchial 2 from mesoderm closely associated with the second heart field. Additionally, heterotopic transplantation experiments reveal lineage restriction of mesodermal cells that contribute to pharyngeal cartilage. The entire parietal bone is derived from mesoderm. Several structures arise from both mesoderm and cranial neural crest, including the squamosal, parasphenoid and stapes. The mesodermal contribution to the dorsal portion of the squamosal bone supports the homology of the corresponding dorsal ossification center, which fuses to the ventral center early in development, to the supratemporal, a bone lost repeatedly in tetrapods. I locate the posterior limit of myogenic cranial mesoderm, extending the head-trunk boundary to the axial level of the third somite. Using fate mapping, gene expression and comparative anatomy, I provide evidence that the cucullaris muscle, a homologue of the mammalian trapezius, is a cranial muscle allied with the gill levators of anamniotes. Finally, I generate two novel transgenic lines of Xenopus tropicalis that will be used to fate map neural crest and mesoderm. Taken together, these results add to our understanding of cranial homologies and point to a larger role for cranial mesoderm in the evolution of a mobile neck.Biology, Organismic and Evolutionary
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Gibert, Yann. „Zebrafish as a vertebrate model to study retinoic acid signalling in head mesoderm and pectoral fin development and to investigate non-ion channel epilepsies“. [S.l. : s.n.], 2004. http://nbn-resolving.de/urn:nbn:de:bsz:352-opus-18235.
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Meister, Blanco Lydvina. „La somitogénèse chez les chordés et l’apparition de la tête chez les vertébrés“. Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS144.
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Une question centrale dans l'histoire de l'évolution des vertébrés est de comprendre l'origine de leur tête complexe. L'apparition de nouvelles structures de la tête, telles que les cellules de la crête neurale, a déjà été longuement étudiée. Cependant, comment le mésoderme non segmenté de la tête chez les vertébrés a émergé à partir d’un mésoderme entièrement segmenté reste une question non résolue. En raison de leur position phylogénétique, de leurs caractéristiques morphologiques, développementales et génomiques, les céphalochordés (c'est-à-dire les amphioxus) représentent le meilleur proxy existant de l'ancêtre des chordés. De plus, l'amphioxus possède un mésoderme paraxial entièrement segmenté tout le long du corps, caractéristique proposée comme ancestrale. Comparer la somitogenèse entre amphioxus et vertébrés pourrait résoudre la question de savoir comment le mésoderme non segmenté de la tête des vertébrés a évolué. Les travaux réalisés dans notre laboratoire ont montré le rôle central du signal FGF, via la voie MAPK, dans la formation des somites les plus antérieurs chez l'amphioxus. L'inhibition de cette voie de signalisation au cours de la gastrulation induit une perte spécifique de ces structures. Afin de comprendre le destin du mésoderme paraxial antérieur présomptif après inhibition de la signalisation FGF, j’ai analysé l’expression de différents gènes marqueurs, j’ai réalisé un traçage des cellules de ce territoire et, enfin, j’ai mis en œuvre des analyses morphologiques. Nous avons conclu que ce territoire acquiert un destin axial dorsal antérieur au cours de la gastrulation lorsque le signal FGF est inhibé et que les cellules correspondantes intègrent ensuite la notochorde. L'étude morphologique de la notochorde chez ces embryons traités nous permet de proposer une hypothèse quant à l'apparition de la plaque préchordale. Pour la deuxième partie de mon doctorat, des études avaient préalablement montré que la formation des somites antérieurs et postérieurs repose sur la fonction de facteurs de transcription (Six1/2 et Pax3/7) orthologues d’acteurs majeurs de la formation des muscles du tronc chez les vertébrés. De plus, les gènes principalement impliqués dans la formation du mésoderme de la tête et du mésoderme latéral chez les vertébrés sont exprimés dans la partie ventrale des somites d'amphioxus. A partir de ces données, il a été proposé l'hypothèse que le mésoderme de la tête des vertébrés soit homologue à la partie ventrale des somites d’amphioxus. D’une part, j’ai analysé chez l'amphioxus l’expression de gènes connus comme jouant un rôle dans le développement des dérivés du mésoderme latéral chez les vertébrés. D’autre part, j’ai montré que les séquences cis-régulatrices de certains gènes d'amphioxus exprimés dans les somites ventraux dirigent l’expression dans les dérivés du mésoderme de la tête et latéral chez le poisson zèbre, un vertébré. En conclusion, ces résultats permettent d'améliorer la robustesse de notre hypothèse proposant l'homologie entre le mésoderme latéral/de la tête des vertébrés et la partie ventrale des somites d’amphioxusA central question in the evolutionary history of vertebrates is to understand the origin of their complex head. The emergence of new head structures, such as neural crest cells, has already been extensively studied. However, how the unsegmented mesoderm of the head in vertebrates emerged from a fully segmented mesoderm remains an unresolved question. Because of their phylogenetic position, morphological, developmental, and genomic characteristics, cephalochordates (i.e., amphioxus) represent the best existing proxy for the ancestor of chordates. Furthermore, amphioxus has a fully segmented paraxial mesoderm, a feature proposed as ancestral. Comparing somitogenesis between amphioxus and vertebrates could resolve the question of how the unsegmented mesoderm of the vertebrate head evolved. Work in our laboratory has shown the central role of FGF signaling, via the MAPK pathway, in the formation of the most anterior somites in amphioxus. Inhibition of this signaling pathway during gastrulation induces a specific loss of these structures. In order to understand the fate of the presumptive anterior paraxial mesoderm after inhibition of FGF signaling, I analyzed the expression of different marker genes, performed cell tracing of this territory, and finally implemented morphological analyses. We concluded that this territory acquires an anterior dorsal axial fate during gastrulation when the FGF signal is inhibited and that the corresponding cells subsequently integrate the notochord. The morphological study of the notochord in these treated embryos allows us to propose a hypothesis for the appearance of the prechordal plate. For the second part of my PhD, studies had previously shown that the formation of the anterior and posterior somites relies on the function of transcription factors (Six1/2 and Pax3/7) orthologous to major players in the formation of trunk muscles in vertebrates. In addition, genes primarily involved in the formation of head mesoderm and lateral mesoderm in vertebrates are expressed in the ventral part of amphioxus somites. Based on these data, it was proposed that the vertebrate head mesoderm is homologous to the ventral part of amphioxus somites. On the one hand, I analyzed in amphioxus the expression of genes known to play a role in the development of lateral mesoderm derivatives in vertebrates. On the other hand, I showed that cis-regulatory sequences of some amphioxus genes expressed in ventral somites direct the expression of a reporter gene in the head and in lateral mesoderm derivatives in the vertebrate zebrafish. In conclusion, these results improve the robustness of our hypothesis proposing homology between vertebrate lateral/head mesoderm and the ventral region of amphioxus somites
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Grimaldi, Alexandre. „Fondements régulatoires de la diversité des muscles faciaux : origines développementales de la résilience musculaire“. Electronic Thesis or Diss., Sorbonne université, 2020. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2020SORUS244.pdf.
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Les muscles squelettiques sont présents dans tout le corps et présentent un niveau surprenant d'hétérogénéité, dans leur susceptibilité aux maladies, potentiel de régénération ou capacités métaboliques. Cette diversité est également retrouvée au cours du développement embryonnaire où les cellules myogéniques et non myogéniques établissent le système musculo-squelettique. La tête et le cou sont constitués d'une grande variété de muscles qui remplissent des fonctions essentielles, mais nous en savons peu sur la biologie des muscles craniofaciaux. Ces structures sont associées à l'émergence de cellules de la crête neurale (CCN) qui donnent naissance à la plupart des tissus non myogéniques crâniens et qui sont cruciales à la formation des muscles. Cependant, certains muscles crâniens sont privés de CCN, et nous ignorons comment les cellules myogéniques et non myogéniques contribuent à ces domaines. Cette thèse fournit des preuves démontrant que les progéniteurs en amont du muscle se détournent du programme myogénique pour donner naissance au tissu conjonctif. Nous avons utilisé une approche de single-cell RNAseq non biaisée et restreinte avec différentes lignées transgéniques de souris à des stades embryonnaires distincts, des marquages in situ et de nouvelles méthodes analytiques, et avons montré que les progéniteurs bipotents issus du mésoderme exprimant le gène de détermination musculaire Myf5 donnent naissance au muscle squelettique et au tissu conjonctif anatomiquement associé dans les muscles partiellement privés de CCN. Cette transition est caractérisée par une complémentarité de signalisation de récepteurs tyrosine kinase entre les cellules musculaires et non musculaires, ainsi que par des modules régulateurs distincts. Les muscles crâniens proviennent également de différentes lignées qui impliquent l'activité de cascades de régulation génique spécifiques. Ici, nous avons utilisé une approche non biaisée et large pour découvrir des modules de régulation spécifiques qui sous-tendent différentes populations de cellules myogéniques dans la tête et à travers plusieurs stades de développement. Certaines de ces « tâches de naissance génétiques » uniques sont des facteurs de transcription spécifiques et sont conservées dans les cellules souches musculaires adultes, ce qui indique que leur importance potentielle est de fournir les propriétés uniques qui ont été signalées pour différentes populations de cellules souches musculaires. Enfin, ces études utilisent des méthodes analytiques inédites qui bénéficient des dernières avancées algorithmiques et offrent de nouvelles perspectives pour la découverte de processus biologiques à partir de données à haut débitSkeletal muscles are found throughout the body and they display a surprising level of heterogeneity in properties and function. For example, some muscles are specifically susceptible to diseases, and some have better regenerative potential or different metabolic capacities. Diversity is also found during embryonic development where myogenic and non-myogenic cells establish the musculoskeletal system. The head and neck are comprised of a wide variety of muscles that perform essential functions such as feeding, breathing and vocalising, yet little is known about craniofacial muscle biology. Novel structures are associated with the emergence of neural crest cells (NCC) which give rise to most craniofacial connective tissue, cartilage and bone and are crucial for muscle morphogenesis. However, some cranial muscles are deprived of NCC, and it is unclear how myogenic and non-myogenic cells contribute to those domains. This thesis provides evidence demonstrating that upstream progenitors redirect from the myogenic program to give rise to the muscle-associated connective tissue that supports the formation of muscular structures. We employed unbiased and lineage-restricted single-cell RNAseq using different mouse transgenic lines at distinct embryonic stages, in situ labelling, and new analytical methods, and show that bipotent progenitors expressing the muscle determination gene Myf5 give rise to skeletal muscle and anatomically associated connective tissue in distinct muscle groups spatiotemporally. Notably, this property was restricted to muscles with only partial contribution from NCCs suggesting that in their absence, the balance of myogenic and connective tissue cells is undertaken by somite-derived or cranial-derived mesoderm. This transition is characterised by a complementarity of tyrosine kinase receptor signalling between muscle and non-muscle cells, as well as distinct regulatory modules. Cranial muscles also originate from different lineages that involve the activity of specific gene regulatory cascades. Here, we used an all-inclusive unbiased approach to uncover specific regulatory modules that underlie different myogenic cell populations in the head and across multiple developmental stages. Some of these unique “genetic birthmarks” are specific transcription factors, and are retained in adult muscle stem cells pointing to their potential importance is delivering the unique properties that have been reported for different muscle stem cell populations. Finally, these studies employ novel computational methods that benefit from the latest algorithmic advancements and they provide prospects for the discovery of new biological processes from high throughput data
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Gibert, Yann [Verfasser]. „Zebrafish as a vertebrate model to study retinoic acid signaling in head mesoderm and pectoral fin development and to investigate non-ion channel epilepsies / vorgelegt von Yann Gibert“. 2006. http://d-nb.info/980418585/34.
Der volle Inhalt der QuelleBuchteile zum Thema "Head mesoderm"
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Seifert, Roswitha, Heinz Jürgen Jacob und Monika Jacob. „Differentiation Capabilities of the Avian Prechordal Head Mesoderm“. In Formation and Differentiation of Early Embryonic Mesoderm, 63–76. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4615-3458-7_6.
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Francis-West, P. H., L. Robson und Darell J. R. Evans. „Fate and Roles of the Neural Crest, Mesoderm, and Epithelium“. In Craniofacial Development The Tissue and Molecular Interactions That Control Development of the Head, 21–29. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-55570-1_3.
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Tickle, C., und M. Davey. „Laying Down The Vertebrate Body Plan“. In Patterning in Vertebrate Development, 10–23. Oxford University PressOxford, 2003. http://dx.doi.org/10.1093/oso/9780199638703.003.0002.
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Abstract How do different parts of the body arise in their proper positions in vertebrate embryos? In the first chapter, the principles of pattern formation were reviewed. This chapter outlines how the body plan is laid down, and provides the embryological background for the following chapters that deal in detail with patterning of mesoderm (Chapters 3 and 4), nervous system (Chapters 5, 6, 7, and 8), and limbs (Chapter 9) and the molecules involved. Laying down the body plan is essentially a matter of defining the main body axes: the anteroposterior axis (head to tail axis, sometimes known as rostral-caudal axis) and dorsoventral axis (back to front). Once these two axes have been set up, this also defines right and left (Fig. 1). In addition, the three main body layers—ectoderm, mesoderm, and endoderm—are formed and arranged so that endoderm comes to lie on the inside, ectoderm on the outside, and mesoderm in between. Establishment of these layers in their proper positions requires considerable cell rearrangements, which must be precisely choreographed.
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Patel, Shreyaskumar R., und Robert S. Benjamin. „Clinical Aspects and Management of Gastrointestinal Sarcomas: Management Options: Unresectable or Metastatic Gastrointestinal Sarcomas“. In Gastrointestinal Oncology, 834–38. Oxford University PressNew York, NY, 2003. http://dx.doi.org/10.1093/oso/9780195133721.003.0070.
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Abstract Sarcomas are malignancies of mesenchymal tissue, derived principally from the mesoderm with some contribution from the neuroectoderm. These tumors are rare and constitute less than 1% of all cancers. The annual incidence of soft tissue sarcomas, as estimated by the American Cancer Society, is 8300 new cases in the United States for the year 2002.1 Approximately 60% of these soft tissue sarcomas originate in the extremities, 30% in the trunk, and 10% in the head and neck region. About 40% of the soft tissue sarcomas of the trunk actually originate in the retroperitoneum.
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anderson, Douglas, jerry m. Rhee, und alan rawls. „Muscle and Somite Development“. In Inborn Errors Of Development, 150–61. Oxford University PressNew York, NY, 2008. http://dx.doi.org/10.1093/oso/9780195306910.003.0012.
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Abstract Vertebrate skeletal muscle is derived from paraxial and head mesoderm that appears on either side of the neural tube during gastrulation. A fundamental understanding of the cellular events associated with myogenesis has been well established through classic embryological studies in the chicken and mouse model systems. The 7rst appearance of myogenic cells is within individual somites derived from paraxial mesoderm. During embryonic development, these cells must undergo rapid expansion, migration, differentiation, and remodeling in order to generate the morphologically and functionally diverse perinatal muscles groups. Myogenic cells must also respond to spatial and temporal cues that lead to differences in cell fate along the anterior/posterior (A/P) and dorsal/ventral (D/V) axes. In addition, development of the skeletal muscle must be coordinated with the development of bone and cartilage, tendon, the peripheral nerves, and vasculature. During the past 15 years, gain-of-function and loss-of-function approaches have been used to reveal the complex genetic network that integrates these processes. In this chapter, we will review the embryonic development of somites and muscle and focus on our current understanding of the genetic regulation of somitogenesis and skeletal muscle development.
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Barresi, Michael J. F., und Scott F. Gilbert. „Ectodermal Placodes and the Epidermis“. In Developmental Biology. Oxford University Press, 2023. http://dx.doi.org/10.1093/hesc/9780197574591.003.0022.
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This chapter focuses on ectodermal placodes, which are areas of columnar-shaped cells. It illustrates how cranial placodes in the head contribute to the sense organs forming the olfactory epithelium, the inner ear, and the lens of the eye, and to the cranial sensory ganglia. It also explains how the pre-placodal region separates into individual placodes, a process controlled by local signals from the neural tube and underlying mesoderm or endoderm. The chapter discusses eye development and shows how it starts with the specification of the eye field in the ventral diencephalon. The chapter also shows the major role Pax6 plays in eye formation. It mentions the enamel knot, which is the signaling center for tooth shape and development.
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Atkinson, Martin E. „Embryology of the head and neck“. In Anatomy for Dental Students. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199234462.003.0030.
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Embryology and development have been covered after the main anatomical descriptions in the previous sections, but it is going to precede them in this section. The reason for this departure is that the embryonic development of the head and neck explains much of the mature anatomy which can seem illogical without its developmental history. The development of the head, face, and neck is an area of embryology where significant strides in our understanding have been made in the last few years. The development of the head is intimately related to the development of the brain outlined in Chapter 19 and its effects on shaping the head will be described in Chapters 32 and 33. The major thrust of this chapter is the description of the formation of structures called the pharyngeal (or branchial) arches and the fate of the tissues that contribute to them. All four embryonic germ layers contribute to the pharyngeal arches and their derivatives, hence to further development of the head and neck. Figure 21.1 is a cross section through the neck region of a 3-week old embryo after neurulation and folding described in Chapter 8. It shows the structures and tissues that contribute to the formation of the head and neck: • The neural tube situated posteriorly and the ectomesenchymal neural crest cells that arise as the tube closes; • The paraxial mesoderm anterolateral to the neural tube; • The endodermal foregut tube anteriorly; • The investing layer of ectoderm. The development of all these tissues is intimately interrelated. The pharyngeal arches are very ancient structures in the evolutionary history of vertebrates. The arches and their individual components have undergone many modifications during their long history. In ancestral aquatic vertebrates, as in modern fishes, water was drawn in through the mouth and expelled through a series of gill slits (or branchiae, hence the term ‘branchial arch’) in the sides of the pharynx. Oxygen was extracted as the water was passed over a gill apparatus supported by a branchial arch skeleton moved by branchial muscles controlled by branchial nerves. Although ventilation and respiration is now a function of the lungs in land vertebrates, the pharyngeal arches persist during vertebrate development.
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Gorlin, Robert J., M. Michael Cohen und Raoul C. M. Hennekam. „Syndromes of the Eye“. In Syndromes of the Head and Neck, 1181–214. Oxford University PressNew York, NY, 2001. http://dx.doi.org/10.1093/oso/9780195118612.003.0030.
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Abstract Rieger syndrome (hypodontia and primary mesodermal dysgenesis of the iris) Hypodontia in combination with malformation of part of the anterior chamber of the eye was described as early as 1883 by Vossius (43). However, the condition was not recognized as a heritable syndrome until the report of Rieger (34), in 1935. The syndrome has been expanded to include absent maxillary incisor teeth, malformations of the anterior chamber of the eye (Rieger anomaly), and umbilical anomalies (11,22,38). Its frequency has been estimated as 1/200,000 population (2).
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Chipman, Ariel D. „Vertebrate characteristics“. In Organismic Animal Biology, 175–80. Oxford University PressOxford, 2024. http://dx.doi.org/10.1093/oso/9780192893581.003.0029.
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Abstract Vertebrata includes some of the most familiar and best-loved animal species. The generally larger size of vertebrates makes them dominant animals in most environments. Vertebrates are distinguished from other chordates by the presence of bone, which forms the vertebral column and to other skeletal structures. Vertebrates also have a large distinct head with a skull and an enlarged brain. Many of the novel structures of vertebrates are derived from a vertebrate-specific group of embryonic cells, the neural crest. There are two types of bones in vertebrates: endochondral bone, which is derived from ossification of cartilage, and dermal bone, which is derived from ossification of the mesodermal layer of the integument. The brain of vertebrates is composed of three embryonic regions that differentiate to give rise to a complex, multi-regional adult brain. A series of acute sense organs are linked to the brain, to give a high level of sensory processing.
Konferenzberichte zum Thema "Head mesoderm"
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Varner, Victor D., Dmitry A. Voronov und Larry A. Taber. „Mechanics of Embryonic Head Fold Morphogenesis“. In ASME 2008 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2008. http://dx.doi.org/10.1115/sbc2008-193032.
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Head fold morphogenesis constitutes the first discernible epithelial folding event in the embryonic development of the chick. It arises at Hamburger and Hamilton (HH) stage 6 (approximately 24 hours into a 21-day incubation period) and establishes the anterior extent of the embryo [1]. At this stage, the embryonic blastoderm is composed of three germ layers (endoderm, mesoderm, and ectoderm), which are organized into a flat layered sheet that overlies the fibrous vitelline membrane (VM). Within this blastodermal sheet, a crescent-shaped head fold develops just anterior to the elongating notochord, spanning across the embryonic midline at the rostral end of neural plate. At the crest of this fold, the bilateral precardiac plates fuse in a cranial to caudal direction and give rise to the primitive heart tube and foregut [2, 3]. An understanding of head fold morphogenesis may thus offer insight into how embryonic tissues are arranged to make ready for proper cardiac formation.