During gastrulation, the Drosophila mesoderm invaginates and forms a single cell layer in close juxtaposition to the overlying ectoderm. Subsequently, particular cell types within the mesoderm are specified along the anteroposterior and dorsoventral axes. The exact developmental pathways that guide the specification of different cell types within the mesoderm are not well understood. We have analyzed the developmental relationship between two mesodermal tissues in the Drosophila embryo, the gonadal mesoderm and the fat body. Both tissues arise from lateral mesoderm within the eve domain. Whereas in the eve domain of parasegments 10-12 gonadal mesoderm develops from dorsolateral mesoderm and fat body from ventrolateral mesoderm, in parasegments 4-9 only fat body is specified. Our results demonstrate that the cell fate decision between gonadal mesoderm and fat body identity within dorsolateral mesoderm along the anteroposterior axis is determined by the combined actions of genes including abdA, ...
Head and trunk muscles have discrete embryological origins and are governed by distinct regulatory programmes. Whereas the developmental route of trunk muscles from mesoderm is well studied, that of head muscles is ill defined. Here, we show that, unlike the myogenic trunk paraxial mesoderm, head mesoderm development is independent of the T/Tbx6 network in mouse. We reveal that, in contrast to Wnt and FGF-driven trunk mesoderm, dual inhibition of Wnt/β-catenin and Nodal specifies head mesoderm. Remarkably, the progenitors derived from embryonic stem cells by dual inhibition efficiently differentiate into cardiac and skeletal muscle cells. This twin potential is the defining feature of cardiopharyngeal mesoderm: the head subtype giving rise to heart and branchiomeric head muscles. Therefore, our findings provide compelling evidence that dual inhibition specifies head mesoderm and unravel the mechanism that diversifies head and trunk muscle programmes during early mesoderm fate commitment. ...
Gastrulation is the process in which the three germ layers (ectoderm, mesoderm and endoderm) are formed by successive waves of epiblast cells migrating through the primitive streak. Formation of the primitive streak, on day 15, marks the first event of gastrulation. Cells from the epiblast migrate into the interior of the embryo, via the primitive streak, in a process termed ingression, which involves a cellular epithelial-to-mesenchymal transition (EMT). The initial wave of migrating cells (day 16) streams through the primitive streak, displacing the hypoblast cells to become definitive endoderm, which ultimately produces the future gut derivatives and gut linings.. The second wave of migrating cells (also on day 16) populate a layer between the epiblast and the definitive endoderm, thereby forming the mesoderm layer. The intraembryonic mesoderm cells later give rise to five subpopulations of cells: paraxial mesoderm, intermediate mesoderm, lateral plate mesoderm, cardiogenic mesoderm and a ...
The lateral mesoderm extends on periphery of embryo, it is divisible into extra embryonic and embryonic mesoderms. This lateral mesoderm will split into two layers. The upper layer is called somatic mesoderm and inner layer is called splanchnic mesoderm. Ectoderm and somatic mesoderm will be called somatopleure. The splanchnic layer and endoderm will be called splanchnopleure. In between the two layers of mesoderm the space is called coelome ...
Many mesodermal cell types, including pharynx and body muscle cells, are derived from a single cell, the MS blastomere, in Caenorhabditis elegans. Mesoderm specification involves the activation of the T-box factor gene tbx-35; tbx-35 mutation results in a severe decrease in MS-derived tissue. On p. 2735, Morris Maduro and co-workers now identify the NK-2 homeobox gene ceh-51 as a novel regulator of mesoderm development. The researchers report that ceh-51 is expressed in mesoderm cells and is a direct target of TBX-35. Its overexpression causes embryonic arrest and promotes MS-derived tissue specification, whereas a null mutation results in larval arrest and pharyngeal defects. Embryos with loss-of-function mutations in both ceh-51 and tbx-35 have a more severe phenotype than do single mutants, indicating that the functions of TBX-35 and CEH-51 in mesoderm development partially overlap. Given that T-box and NK-2 factors are also crucial for heart development in flies and vertebrates, their role ...
Historically the three germ layer of the body: endoderm, ectoderm, and mesoderm, were considered to diverge early in development with the derivatives of each to progress along differentiation routes independent of one another. However, it is now known that neuromesodermal progenitors (NMPs) are present during axial elongation, after the basic formation of the three germ layers during gastrulation. These bipotent cells generate neurectodermal tissue in the form of the neural tube, giving rise to the central nervous system, and mesoderm in the formation of somites. NMPs are located within the anterior of the primitive streak, in the node streak border and the adjacent caudal lateral epiblast in the E8.5 mouse embryo. As axial elongation continues they are found in the chordoneural hinge within the tailbud until E13.5. Another progenitor population, denoted lateral and paraxial mesoderm progenitors (LPMPs) are found within the posterior of the primitive streak and the adjacent caudal lateral ...
Definition of Lateral mesoderm in the Financial Dictionary - by Free online English dictionary and encyclopedia. What is Lateral mesoderm? Meaning of Lateral mesoderm as a finance term. What does Lateral mesoderm mean in finance?
In the gastrulating chick embryo, the mesoderm cells arise from the epiblast layer by ingression through the linear accumulation of cells called the primitive streak. The mesoderm cells emerge from the streak with a fibroblastic morphology and proceed to move away from the mid-line of the embryo using, as a substratum, the basement membrane of the overlying epiblast and the extracellular matrix. We have investigated the roles of fibronectin and laminin as putative substrata for mesoderm cells using complementary in vivo and in vitro methods. We have microinjected agents into the tissue space adjacent to the primitive streak of living embryos and, after further incubation, we have examined the embryos for perturbation of the mesoderm tissue. These agents were: cell-binding regions from fibronectin (RGDS) and laminin (YIGSR), antibodies to these glycoproteins, and a Fab fragment of the antibody to fibronectin. We find that RGDS, antibody to fibronectin, and the Fab fragment cause a decrease in ...
FGF signaling is very important to the forming of mesoderm in vertebrates, so when it really is perturbed in manifestation furthermore to its well-characterized part in maintaining manifestation. 1996; Horb and Thomsen, 1997; Zhang et al., 1998; Clements et al., 1999; Kofron et al., 1999; Xanthos et al., 2001). Many studies show that these indicators are essential for mesoderm development in Xenopus. Dominant unfavorable Activin receptors or inhibitory mRNA inhibit mesoderm development (Hemmati-Brivanlou and Melton, 1992; Chang et al., 1997; Bhushan et al., 1998; Casellas and Brivanlou, 1998). Likewise, inhibition of TGF ligands with non-cleavable precursors or by manifestation of nodal antagonists also prevent mesoderm development (Sunlight et al., 1999; Agius et al., 2000; Cheng et al., 2000; Tanegashima et al., 2000; Eimon and Harland, 2002; White et al., 2002). While nodal signaling is vital, FGF signaling also takes on a crucial GW 5074 part GW 5074 in mesoderm development, and an FGF ...
In amphibians, certain growth factor antagonists are secreted by the most dorsal cells (i.e., Chordin, Noggin, Follistatin, Frzb). Mesoderm cells at different dorsal-ventral positions are committed to become different types of mesoderm based on their exposure to different levels of the dorsal-promoting Chordin, Noggin, Follistatin and Frzb proteins, which function by antagonizing the ventral-promoting growth factors BMPs and Wnts.. The most dorsal tissue (axial mesoderm, or notochord) forms from cells exposed to the highest levels of Chordin, Noggin, Follistatin and Frzb (and thus lowest effective levels of BMPs and Wnts) while the most ventral tissue (heart, which develops from lateral mesoderm) forms from mesoderm cells exposed to the lowest levels of Chordin, Noggin and Follistatin and hence the highest effective levels of BMPs and Wnts.. ...
STRIP1, a core component of STRIPAK complexes, is essential for normal mesoderm migration in the mouse embryo[4] Regulated mesoderm migration is necessary for the proper morphogenesis and organ formation during embryonic development. Cell migration and its dependence on the cytoskeleton and signaling machines have been studied extensively in cultured cells; in contrast, remarkably little is known about the mechanisms that regulate mesoderm cell migration in vivo. Here, we report the identification and characterization of a mouse mutation in striatin-interacting protein 1 (Strip1) that disrupts migration of the mesoderm after the gastrulation epithelial-to-mesenchymal transition (EMT). STRIP1 is a core component of the biochemically defined mammalian striatin-interacting phosphatases and kinase (STRIPAK) complexes that appear to act through regulation of protein phosphatase 2A (PP2A), but their functions in mammals in vivo have not been examined. Strip1-null mutants arrest development at ...
STRIP1, a core component of STRIPAK complexes, is essential for normal mesoderm migration in the mouse embryo[4] Regulated mesoderm migration is necessary for the proper morphogenesis and organ formation during embryonic development. Cell migration and its dependence on the cytoskeleton and signaling machines have been studied extensively in cultured cells; in contrast, remarkably little is known about the mechanisms that regulate mesoderm cell migration in vivo. Here, we report the identification and characterization of a mouse mutation in striatin-interacting protein 1 (Strip1) that disrupts migration of the mesoderm after the gastrulation epithelial-to-mesenchymal transition (EMT). STRIP1 is a core component of the biochemically defined mammalian striatin-interacting phosphatases and kinase (STRIPAK) complexes that appear to act through regulation of protein phosphatase 2A (PP2A), but their functions in mammals in vivo have not been examined. Strip1-null mutants arrest development at ...
TY - JOUR. T1 - Fibroblast growth factor signalling controls successive cell behaviours during mesoderm layer formation in Drosophila. AU - Clark, Ivan B. N.. AU - Muha, Villo. AU - Klingseisen, Anna. AU - Leptin, Maria. AU - Muller, Hans-Arno J.. PY - 2011/7/1. Y1 - 2011/7/1. N2 - Fibroblast growth factor (FGF)-dependent epithelial-mesenchymal transitions and cell migration contribute to the establishment of germ layers in vertebrates and other animals, but a comprehensive demonstration of the cellular activities that FGF controls to mediate these events has not been provided for any system. The establishment of the Drosophila mesoderm layer from an epithelial primordium involves a transition to a mesenchymal state and the dispersal of cells away from the site of internalisation in a FGF-dependent fashion. We show here that FGF plays multiple roles at successive stages of mesoderm morphogenesis in Drosophila. It is first required for the mesoderm primordium to lose its epithelial polarity. An ...
The mesoderm arises from pluripotent epiblasts and differentiates into multiple lineages; however, the underlying molecular mechanisms are unclear. Tbx6 is enriched in the paraxial mesoderm and is implicated in somite formation, but its function in other mesoderms remains elusive. Here, using direct …
etv5a expression was analyzed by whole-mount in situ hybridization and quantitative real-time PCR of zebrafish embryos at developmental stages ranging from one-cell stage to 48 hours post fertilization (hpf). A strong and ubiquitous signal was detected from one-cell to the oblong stage, which indicated that etv5a was expressed as a maternal mRNA (Fig. 1A-C). Ubiquitous expression was observed throughout the whole embryo before gastrulation (Fig. 1D,E). During early gastrulation (75% epiboly), expression localized to the ventral mesoderm (arrowhead in Fig. 1F,G). At later stages, etv5a expression became confined to the lateral mesoderm as demonstrated by the presence of two longitudinal stripes at the six-somite stage (Fig. 1H-J). A previous study showed that cells present in this region are multipotent progenitors that give rise to hematopoietic, endothelial and pronephric derivatives (Gering et al., 1998). etv5a expression was maintained in the posterior lateral mesoderm (Fig. 1K-N) during ...
Antibodies for proteins involved in paraxial mesodermal cell fate commitment pathways, according to their Panther/Gene Ontology Classification
BACKGROUND: The Brachyury (T) gene is required for the formation of posterior mesoderm and for axial development in both mouse and zebrafish embryos. In these species, and in Xenopus, the gene is expressed transiently throughout the presumptive mesoderm, and transcripts then persiste in notochord and posterior tissues. In Xenopus embryos, expression of the Xenopus homologue of Brachyury, Xbra, can be induced in presumptive ectoderm by basic fibroblast growth factor (FGF) and activin; in the absence of functional FGF or activin signalling pathways, expression of the gene is severely reduced. Ectopic expression of Xbra in presumptive ectoderm causes mesoderm to be formed. As Brachyury and its homologues encode sequence-specific DNA-binding proteins, it is likely that each functions by directly activating downstream mesoderm-specific genes. RESULTS: We show that expression in Xenopus embryos of RNA encoding a dominant-negative FGF receptor inhibits the mesoderm-inducing activity of Xbra. We ...
Second heart field (SHF) progenitors perform essential functions during mammalian cardiogenesis. We recently identified a population of cardiac progenitor cells (CPCs) in zebrafish expressing latent TGF?-binding protein 3 (ltbp3) that exhibits several defining characteristics of the anterior SHF in mammals. However, ltbp3 transcripts are conspicuously absent in anterior lateral plate mesoderm (ALPM), where SHF progenitors are specified in higher vertebrates. Instead, ltbp3 expression initiates at the arterial pole of the developing heart tube. Because the mechanisms of cardiac development are conserved evolutionarily, we hypothesized that zebrafish SHF specification also occurs in the ALPM. To test this hypothesis, we Cre/loxP lineage traced gata4(+) and nkx2.5(+) ALPM populations predicted to contain SHF progenitors, based on evolutionary conservation of ALPM patterning. Traced cells were identified in SHF-derived distal ventricular myocardium and in three lineages in the outflow tract (OFT). ...
UNSPECIFIED. (1987) THE DEVELOPMENT OF ANIMAL CAP CELLS IN XENOPUS - A MEASURE OF THE START OF ANIMAL CAP COMPETENCE TO FORM MESODERM. DEVELOPMENT, 101 (3). pp. 557-563. ISSN 0950-1991 ...
Axial mesoderm: | |Axial mesoderm|, also known as |Chordamesoderm|, is a type of |mesoderm| that lies along... World Heritage Encyclopedia, the aggregation of the largest online encyclopedias available, and the most definitive collection ever assembled.
TY - JOUR. T1 - Ecsit is required for Bmp signaling and mesoderm formation during mouse embryogenesis. AU - Xiao, Changchun. AU - Shim, Jae Hyuck. AU - Klüppel, Michael. AU - Zhang, Samuel Shao Min. AU - Dong, Chen. AU - Flavell, Richard A.. AU - Fu, Xin Yuan. AU - Wrana, Jeffrey L.. AU - Hogan, Brigid L M. AU - Ghosh, Sankar. PY - 2003/12/1. Y1 - 2003/12/1. N2 - Bone morphogenetic proteins (Bmps) are members of the transforming growth factor β (TGFβ) superfamily that play critical roles during mouse embryogenesis. Signaling by Bmp receptors is mediated mainly by Smad proteins. In this study, we show that a targeted null mutation of Ecsit, encoding a signaling intermediate of the Toll pathway, leads to reduced cell proliferation, altered epiblast patterning, impairment of mesoderm formation, and embryonic lethality at embryonic day 7.5 (E7.5), phenotypes that mimic the Bmp receptor type1a (Bmpr1a) null mutant. In addition, specific Bmp target gene expression is abolished in the absence of ...
Somatic muscle is derived from a subset of embryonic mesoderm. In Drosophila, Twist (Twi), a basic helix-loop-helix transcription factor, is a candidate regulator of mesodermal differentiation and myogenesis. Altering amounts of Twist after gastrulation revealed that high levels of Twist are required for somatic myogenesis and block the formation of other mesodermal derivatives. Expression of twist in the ectoderm drives these cells into myogenesis. Thus, after an initial role in gastrulation, twist regulates mesodermal differentiation and propels a specific subset of mesodermal cells into somatic myogenesis. Vertebrate homologs of twist may also participate in the subdivision of mesoderm.. ...
Mesoderm: The mesoderm forms mesenchyme, mesothelium, non-epithelial blood cells, and coelomocytes. Mesothelium lines coeloms. Mesoderm forms the muscles in a process known as myogenesis, septa (cross-wise partitions), and mesenteries (length-wise partitions); and... Read more » ...
Mesoderm: The mesoderm forms mesenchyme, mesothelium, non-epithelial blood cells, and coelomocytes. Mesothelium lines coeloms. Mesoderm forms the muscles in a process known as myogenesis, septa (cross-wise partitions), and mesenteries (length-wise partitions); and... Read more » ...
The primary patterning event in early vertebrate development is the formation of the mesoderm and its subsequent induction of the neural tube. Classic experiments suggest that the vegetal region signals the animal hemisphere to diverge from the pathway of forming ectoderm to form mesoderm such as mu …
The spatial and temporal pattern of mitoses during the fourteenth nuclear cycle in a Drosophila embryo reflects differences in cell identities. We have analysed the domains of mitotic division in zygotic mutants that exhibit defects in larval cuticular pattern along the dorsoventral axis. This is a powerful means of fate mapping mutant embryos, as the altered position of mitotic domains in the dorsoventral pattern mutants correlate with their late cuticular phenotypes. In the mutants twist and snail, which fail to differentiate the ventrally derived mesoderm, mitoses specific to the mesoderm are absent. The lateral mesectodermal domain shows a partial ventral shift in twist mutants but a proportion of ventral cells do not behave characteristically, suggesting that twist has a positive role in the establishment of the mesoderm. In contrast, snail is required to repress mesectodermal fates in cells of the presumptive mesoderm. In the absence of both genes, the mesodermal and the mesectodermal ...
If you have a question about this talk, please contact Mihoko Tame.. Abstract not available. This talk is part of the Developmental Biology Seminar Series series.. ...
The initial distribution of Decapentaplegic in the dorsal ectoderm of the developing fly is established by a gradient of the maternal Dorsal protein, which is asymmetrically distributed to the ventral portion of the fly. The Dorsal protein regulatory gradient initiates the differentiation of the mesoderm, neuroectoderm and dorsal ectoderm in the early Drosophila embryo. There are two primary Dorsal target genes: snail and dpp, which define the limits of the presumptive mesoderm and dorsal ectoderm, respectively. After gastrulation the Dorsal regulatory gradient defines the limits of inductive interactions between germ layers. Thus dorsal controls the subdivision of the mesoderm and dorsal ectoderm (Maggert, 1995). The contributions made by maternal and zygotic genes to the establishment of the expression patterns of four zygotic patterning genes have been examined: decapentaplegic (dpp), zerknüllt (zen), twist (twi), and snail (sna). All of these genes are initially expressed at the poles and ...
As we have discussed, the Nieuwkoop center is apparently established by activation of a Wnt signaling pathway, of which ß-catenin is a critical component. Recently, evidence has been presented that a consequence of activation of the Wnt pathway is activation of the transcription factor Siamois, which is located downstream of ß-catenin (Carnac et al., 1996). One implication of these results may be that the signaling properties of cells of the Nieuwkoop center depend upon regulation of gene expression by Siamois. This would imply that Nieuwkoop signaling is dependent upon zygotic gene transcription, whereas earlier events, including dorsalization and initiation of mesoderm induction, would be dependent upon maternal messengers. This is a new way of thinking about mesoderm induction. Time will tell whether this dichotomy holds ...
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Involved in the transcriptional regulation of genes required for mesoderm formation and differentiation. Causes dorsal mesodermal differentiation of animal cap ectoderm when co-expressed with wnt8 and noggin. None of these molecules causes dorsal mesoderm formation when expressed alone. Establishes the left/right axis at early gastrula stage by directly up-regulating mesodermal expression of zic3. [-] ...
Formation and Differentiation of Early Embryonic Mesoderm - Mesodenn is a key tissue in early development It is involved in the differentiation of almost every organ in the bod (EAN:9781461534587)
Looking for online definition of paraxial mesoderm in the Medical Dictionary? paraxial mesoderm explanation free. What is paraxial mesoderm? Meaning of paraxial mesoderm medical term. What does paraxial mesoderm mean?
Figure 4: Prolonged Nitric Oxide Exposure Enhances Anoikis Resistance and Migration through Epithelial-Mesenchymal Transition and Caveolin-1 Upregulation
article{63622856-3178-483f-a762-c592e0b05bcc, abstract = {PURPOSE. Structures derived from periocular mesenchyme arise by complex interactions between neural crest and mesoderm. Defects in development or function of structures derived from periocular mesenchyme result in debilitating vision loss, including glaucoma. The determination of long-term fates for neural crest and mesoderm in mammals has been inhibited by the lack of suitable marking systems. In the present study, the first long-term fate maps are presented for neural crest and mesoderm in a mammalian eye. METHODS. Complementary binary genetic approaches were used to mark indelibly the neural crest and mesoderm in the developing eye. Component one is a transgene expressing Cre recombinase under the control of an appropriate tissue-specific promoter. The second component is the conditional Cre reporter R26R, which is activated by the Cre recombinase expressed from the transgene. Lineage-marked cells were counterstained for expression of ...
TY - JOUR. T1 - FGF Can Induce Outgrowth of Somatic Mesoderm both Inside and Outside of Limb-Forming Regions. AU - Mima, Tatsuo. AU - Ohuchi, Hideyo. AU - Noji, Sumihare. AU - Mikawa, Takashi. N1 - Copyright: Copyright 2017 Elsevier B.V., All rights reserved.. PY - 1995/2. Y1 - 1995/2. N2 - In the vertebrate embryo, only somatopleural cells in the limb-forming region are released from the mesodermal layer and undergo outgrowth from the embryonic body to form the limb bud. Molecular signals which regulate limb bud induction are unknown to date. In the present study we examined the ability of fibroblast growth factor (FGF) to induce limb bud formation in chicken embryos. A replication-defective retrovirus encoding FGF type 4 with a reporter, bacterial β-galactosidase, was microinjected into lateral plate mesoderm inside and outside limb-forming regions. Effects of the ectopic and precocious expression of FGF were assessed at various stages after infection. Here we report that somatic mesodermal ...
Gliosarcoma is a rare variant of glioblastoma characterized by a biphasic pattern of glial and mesenchymal differentiation. It is unclear whether mesenchymal differentiation in gliosarcomas is because of extensive genomic instability and/or to a mechanism similar to epithelial-mesenchymal transition (EMT). In the present study, we assessed 40 gliosarcomas for immunoreactivity of Slug, Twist, matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9), which are involved in EMT in epithelial tumors. Nuclear Slug expression was observed in ,50% of neoplastic cells in mesenchymal tumor areas of 33 (83%) gliosarcomas, but not in glial areas (P , 0.0001). Nuclear Twist expression was observed in ,50% of neoplastic cells in mesenchymal tumor areas of 35 (88%) gliosarcomas, but glial tumor areas were largely negative except in four cases (P , 0.0001). Expression of MMP-2 and MMP-9 was also significantly more extensive in mesenchymal than in glial tumor areas. None of 20 ordinary ...
Somitogenesis is the earliest sign of segmentation in the developing vertebrate embryo. This process starts very early, soon after gastrulation has initiated and proceeds in an anterior-to-posterior direction during body axis elongation. It is widely accepted that somitogenesis is controlled by a molecular oscillator with the same periodicity as somite formation. This periodic mechanism is repeated a specific number of times until the embryo acquires a defined specie-specific final number of somites at the end of the process of axis elongation. This final number of somites varies widely between vertebrate species. How termination of the process of somitogenesis is determined is still unknown. Here we show that during development there is an imbalance between the speed of somite formation and growth of the presomitic mesoderm (PSM)/tail bud. This decrease in the PSM size of the chick embryo is not due to an acceleration of the speed of somite formation because it remains constant until the last stages of
Objectives: Mechanisms underpinning Gram-negative bacterial vaginosis-induced birth anomalies are obscure. Ethical issues limit such studies on peri-implantation-stage human embryos. Here we have used embryoid bodies (EBs) as an in vitro model to examine the effect of Gram-negative bacterial endotoxins/lipopolysaccharides (LPS) on the faithful induction of germ lineages during embryogenesis. The role of LPS-inducible cytokine and pluripotency-related DNA-binding protein HMGB1 was also studied in these EBs. Methods: EBs derived from the human embryonic stem cell line HUES9 were exposed to 12.5 pg/ml of LPS for 48 h. The expression profile of the ectoderm, endoderm, mesoderm and trophectoderm lineage markers, such as βIII-tubulin, GATA4, BMP2, Brachury and β-hCG, were studied, by RT-PCR and immunofluorescence. Inhibition of mesoderm induction was confirmed by RT-PCR analysis for hANP, cTnT, ABCG2, GATA2, BMP4 and HAND1. Osteoblast differentiation was induced in the EBs, and confirmed by von Kosa ...
Epithelial-mesenchymal transitions (EMTs) drive the generation of cell diversity during both evolution and development. More and more evidence has pointed to a model where EMT is not a binary switch but a reversible process that can be stabilized at intermediate states. Despite our vast knowledge on the signaling pathways that trigger EMT, we know very little about how EMT happens in a step-wise manner. Live imaging of cells that are undergoing EMT in intact, living, animals will provide us valuable insights into how EMT is executed at both the cellular and molecular levels and help us identify and understand the intermediate states. Here, we describe how to image early stages of EMT in the mesoderm cells of live Drosophila melanogaster embryos and how to image contractile myosin that suspends EMT progression.
Ver más] GATA transcription factors are expressed in the mesoderm and endoderm during development. GATA1-3, but not GATA4, are critically involved in hematopoiesis. An enhancer (G2) of the mouse Gata4 gene directs its expression throughout the lateral mesoderm and the allantois, beginning at embryonic day 7.5, becoming restricted to the septum transversum by embryonic day 10.5, and disappearing by midgestation. We have studied the developmental fate of the G2-Gata4 cell lineage using a G2-Gata4Cre;R26REYFP mouse line. We found a substantial number of YFP+ hematopoietic cells of lymphoid, myeloid and erythroid lineages in embryos. Fetal CD41+ /cKit+ /CD34+ and Lin- /cKit+ /CD31+ YFP+ hematopoietic progenitors were much more abundant in the placenta than in the aorta-gonad-mesonephros area. They were clonogenic in the MethoCult assay and fully reconstituted hematopoiesis in myeloablated mice. YFP+ cells represented about 20% of the hematopoietic system of adult mice. Adult YFP+ hematopoietic stem ...
Summary My lab is interested in the development of the tissue that gives rise to vertebrae and skeletal muscles called the paraxial mesoderm. A striking feature of this tissue is its segmental organization and we have made major contributions to the understanding of the molecular control of the segmentation process. We identified a molecular oscillator associated to the rhythmic production of somites and proposed a model for vertebrate segmentation based on the integration of a rhythmic signaling pulse gated spatially by a system of traveling FGF and Wnt signaling gradients. We are also studying the differentiation of paraxial mesoderm precursors into the muscle, cartilage and dermis lineages. Our work identified the Wnt, FGF and Notch pathways as playing a prominent role in the patterning and differentiation of paraxial mesoderm. In this application, we largely focus on the molecular control of paraxial mesoderm development. Using microarray and high throughput sequencing-based approaches and ...
Mesenchyme. Coalescence of the mesenchyme at the level where the dorsal pancreas will form is the first morphological sign of pancreatic development. Removal of the mesoderm, or the fibroblasts within the mesoderm, prior to pancreatic specification results in pancreatic agenesis (53, 107, 164). Mesoderm removal following specification results in a reduction of the total pancreatic size indicating an ongoing requirement for mesoderm signaling to attain complete organ development (94). Interestingly, culturing of pancreatic mesenchyme with other sections of the dorsal endoderm can promote pancreatic differentiation, while mesenchyme from other regions of the anterior-posterior axis does not have this ability (10). This suggests that the mesenchyme provides signals that promote pancreatic specification, yet limits differentiation, thereby allowing expansion of the organ. These signals come in a variety of sources.. Physical interactions between the mesoderm and developing pancreatic bud affect ...
TY - JOUR. T1 - BMP7 dose-dependently stimulates proliferation and cadherin-11 expression via ERK and p38 in a murine metanephric mesenchymal cell line. AU - Awazu, Midori. AU - Nagata, Michio. AU - Hida, Mariko. N1 - Funding Information: This study was supported by JSPS KAKENHI grant numbers JP17591115, JP26461620, and JP17K10152.. PY - 2017/8. Y1 - 2017/8. N2 - BMP7 is expressed in ureteric buds and cap mesenchyme of the fetal kidney, mediating branching morphogenesis and survival and priming of metanephric mesenchyme. Although dose-dependent effects of BMP7 in collecting duct cells have been reported, studies in metanephric mesenchymal cells are lacking. We examined the effects of BMP7 on MAP kinase activation, proliferation, and expression of cadherins in a metanephric mesenchymal cell line MS7 by thymidine incorporation, immunoblot analysis, and quantitative real-time PCR. The levels of phosphorylated ERK (P-ERK) and phosphorylated p38 (P-p38) were not altered at 10 min, 1 h, and 6 h with ...
Smad2 role in mesoderm formation, left-right patterning and craniofacial development. Female infertility in mice lacking connexin 37
Summary Mesoderm, the embryonic germ layer between ectoderm and endoderm, gives rise to major organs within the circulatory and excretory systems and to stabilizing tissues (muscles, bones, connective tissue). Although mesoderm is a key-innovation in evolutionary history, its origin and further diversification into the different organs and cell types of a broad range of animals has not been elucidated. Our knowledge of mesoderm development is mainly based on work performed in prominent model systems including vertebrates (fish, frog and mouse) and invertebrates that are distantly-related and considered to be highly derived (Drosophila and C. elegans). The project proposed herein aims to study mesoderm development in a variety of highly informative animal taxa and trace its differentiation into cell types and organs, with the ultimate aim of reconstructing the history of mesoderm during animal evolution. Our approach combines advanced bioinformatics, live-imaging and molecular methods, and will ...
Angerer, L. M., et al. (2001). Sea urchin goosecoid function links fate specification along the animal-vegetal and oral-aboral embryonic axes. Development 128: 4393-4404. 11714666 Armes, N. A. and Smith, J. C. (1997). The ALK-2 and ALK-4 activin receptors transduce distinct mesoderm-inducing signals during early Xenopus development but do not co-operate to establish thresholds. Development 124(19): 3797-3804. PubMed ID: 9367435 Artinger, M., et al. (1997). Interaction of goosecoid and brachyury in Xenopus mesoderm patterning. Mech. Dev. 65(1-2): 187-196. PubMed ID: 9256355 Belo, J. A., et al. (1998). The prechordal midline of the chondrocranium is defective in Goosecoid-1 mouse mutants. Mech. Dev. 72(1-2): 15-25. PubMed ID: 9533949 Broun, M., Sokol, S. and Bode, H. R. (1999). Cngsc, a homologue of goosecoid, participates in the patterning of the head, and is expressed in the organizer region of Hydra. Development 126: 5245-5254. PubMed ID: 10556050 Bruce, A. E. E., et al. (2003). The maternally ...
The use of adult hepatic stem cells for the treatment of diabetes, based both on the close embryological association of the pancreas and liver, and on a putative shared tissue stem cell, has been proposed by a number of studies. This study investigated the capacity of hepatic oval cells to differentiate into pancreatic endocrine cells in the presence of pancreatic mesoderm. The GaIN model of hepatic injury was used to induce oval cell activation in Male Sprague-Dawley rats. A viable and significant oval cell population could not however, be isolated and propagated in culture. In order to continue experimentation, a PHeSC-A2 cell line, derived from normal adult porcine liver, was cultured with quail pancreatic mesoderm in the GFRM-Ham s F12.ITS culture system. Cells demonstrating positive immulocalization of the pancreatic markers, insulin and glucagon, were identified as PHeSC-A2-derived, by visual assessment of their nuclear morphology. Techniques used to confirm these results and preclude the ...
There has been a long debate in the scientific community over the oldest surviving metazoan lineage. Traditionally it has been taught that Porifera, the sponges, occupy that nitche possessing a diploblastic body plan without true organs; however recent phylogentic analysis has suggests that Ctenophora may truly be the oldest lineage, free floating animals with a possible mesoderm layer and complex organs. In this study we searched for the presence of mesoderm in Ctenophora by examining the genome of Pleurobrachia bachei for the presence of tropomyosin, calponin, and β-catenin. Gene expression for all three were found not only in the muscular regions of P. bachei, but in the epidermal tissues as well, indicating there is an unknown function in the metazoan common ancestor. Homology comparisons to the rest of Metazoa reveal little about tropomyosin and calponin, however the ctenophore β-catenin protein appears to be to least derived of all metazoans and suggests Ctenophora may be the most basal ...
Can you name the Paraxial Mesoderm and Musculoskeletal Development? Test your knowledge on this science quiz to see how you do and compare your score to others. Quiz by hellcat
Snail, a zinc finger protein, is required for the formation of the ventral furrow and the mesoderm during gastrulation of the Drosophila embryo. snail homologues have been cloned from Xenopus and mouse. We have isolated a zebrafish homologue of snail, designated sna-1. Like its Drosophila counterpart, Sna-1 protein is nuclear. Maternal and zygotic sna-1 transcripts are ubiquitously distributed in zebrafish embryos of cleavage and blastula stages. In gastrulating embryos, sna-1 is expressed in involuting cells of the germ ring, but not in those at the dorsal midline, the presumptive notochordal region. After involution, the expression is maintained in the paraxial mesoderm and becomes prominent in the muscle pioneer precursors, followed by expression at the posterior somite boundaries. Later, sna-1 is expressed in neural crest and mesodermal derivatives of the head region. Sna-1 expression is induced in animal cap cells by activin A. The early sna-1 expression pattern in gastrulating zebrafish no ...
EndoMT and EMT share many of the same regulators, with members of the TGFβ superfamily being arguably the most prominent players. TGFβ signaling through Smad-dependent and independent pathways leads to direct transcriptional regulation of multiple genes, including several EMT/EndoMT-inducing transcription factors.31 Expression of these transcription factors subsequently drives loss of cell-cell adhesion by repression of epithelial/endothelial genes encoding junction proteins, regulation of cytoskeletal rearrangement, and increased expression and activity of both MT-MMPs and secreted MMPs.32 Moreover, during EndoMT, upregulation of EC Slug by TGFβ and other growth factors results in increased migration and invasion into extracellular matrices of diverse composition, and this is due in part to the indirect activation of membrane type-1-MMP, MMP-2, and MMP-9.26 Interestingly, nuclear Smads form multiprotein complexes with EMT/EndoMT-transcription factors, including Snail, Zeb1, and Zeb2, ...
EndoMT and EMT share many of the same regulators, with members of the TGFβ superfamily being arguably the most prominent players. TGFβ signaling through Smad-dependent and independent pathways leads to direct transcriptional regulation of multiple genes, including several EMT/EndoMT-inducing transcription factors.31 Expression of these transcription factors subsequently drives loss of cell-cell adhesion by repression of epithelial/endothelial genes encoding junction proteins, regulation of cytoskeletal rearrangement, and increased expression and activity of both MT-MMPs and secreted MMPs.32 Moreover, during EndoMT, upregulation of EC Slug by TGFβ and other growth factors results in increased migration and invasion into extracellular matrices of diverse composition, and this is due in part to the indirect activation of membrane type-1-MMP, MMP-2, and MMP-9.26 Interestingly, nuclear Smads form multiprotein complexes with EMT/EndoMT-transcription factors, including Snail, Zeb1, and Zeb2, ...
Gastrulation of the Drosophila embryo is a premier model system for tissue morphogenesis. Particular efforts have focused on the formation of the ventral furrow, whereby ~1,000 presumptive mesoderm cells exhibit coordinated apical constrictions that mediate invagination. Apical constriction depends on a Rho GTPase signaling pathway (Fog/T48) deployed by the developmental regulatory genes twist and snail. The consensus states that coordinate mesoderm constriction depends on high levels of myosin along the ventral midline, although the basis for this myosin localization activity is uncertain. Using the newly developed quantitative live imaging methods, we showed that two key cellular effectors of the Rho signaling pathway, T48 and Fog, exhibit dynamic temporal changes in de novo transcription. Their transcription begins as a narrow strip of 2-3 cells along the ventral midline and coherently expanding into more ventral-lateral regions. Quantitative image analyses suggest these temporal gradients ...
Hematopoietic stem cells (HSCs) emerge during embryogenesis from hemogenic endothelium, but it remains unclear how the HSC lineage is initially established from mesoderm during ontogeny. In Xenopus, the definitive hemangioblast precursors of the HSC lineage have been identified in dorsal lateral plate (DLP) mesoderm, and a transcriptional gene regulatory network (GRN) controlling hemangioblast programming has been elucidated. Herein, we identify an essential role for microRNAs (miRNAs) in establishing the mesodermal lineage leading to both HSC emergence and vasculogenesis and determine that a single miRNA, miR-142-3p, is primarily responsible for initiation of definitive hemangioblast specification. miR-142-3p forms a double-negative gate unlocking entry into the hemangioblast program, in part by inhibiting TGFβ signaling. Our results table miR-142-3p as a master regulator of HSC lineage specification, sitting at the apex of the hierarchy programming the adult hemangioblast, thus illustrating that
ES Cell Lines and Targeting of ERK2. ERK2-specific primers (forward 5′-TTA TTT ACT CTA CAA AGT GAC CAA GC-3′ and reverse 5′-AGG TTC AGC ATC TGC TGC TAC TTT AC-3′) were used to amplify a 400-bp probe from EST 709653 that was used to screen a lambda FixII 129Sv genomic library (Stratagene). A 5.2-kb BamHI/KpnI fragment and a 4.5-kb XbaI/XbaI fragment were cloned into TK2-PKJ1 as 5′ and 3′ arms of homology, respectively, to create the targeting construct. Alternatively, the PGK-neo cassette was removed and replaced with PGK-hygro for targeting the second erk2 allele for the creation of erk2 null ES lines.. The TC1 ES line (gift of Philip Leder, Harvard University, Cambridge, MA) was maintained in ES medium (13) and electroporated with 25 μg of linearized construct. Electroporated cells underwent selection in ES medium supplemented with G418 (Geneticin G418 sulfate, GIBCO) and ganciclovir. Genomic DNA was isolated, digested with AflII, run on a 0.8% agarose gel, and blotted onto nylon ...
The embryonic disc (green) and embryonic mesoderm (pink). The amnion has been cut.. Keywords: cephalic end of embryonic disc, cephalic end of epiblast, dorsal surface of epiblast, embryonic mesoderm, gastrulation (primitive) groove, gastrulation (primitive) node, gastrulation (primitive) streak, head mesenchyme, junction of amnion and epiblast, notochordal process, outer surface of epiblast, presumptive cloacal membrane, presumptive neural plate, primordium of cloacal membrane, ventral surface of epiblast Source: The Virtual Human Embryo.. ...
TY - JOUR. T1 - A machine learning approach for identifying novel cell type-specific transcriptional regulators of myogenesis. AU - Busser, Brian W. AU - Taher, Leila. AU - Kim, Yongsok. AU - Tansey, Terese. AU - Bloom, Molly J. AU - Ovcharenko, Ivan. AU - Michelson, Alan M. PY - 2012. Y1 - 2012. N2 - Transcriptional enhancers integrate the contributions of multiple classes of transcription factors (TFs) to orchestrate the myriad spatio-temporal gene expression programs that occur during development. A molecular understanding of enhancers with similar activities requires the identification of both their unique and their shared sequence features. To address this problem, we combined phylogenetic profiling with a DNA-based enhancer sequence classifier that analyzes the TF binding sites (TFBSs) governing the transcription of a co-expressed gene set. We first assembled a small number of enhancers that are active in Drosophila melanogaster muscle founder cells (FCs) and other mesodermal cell types. ...
In addition to nourishing the embryo, extra-embryonic tissues (EETs) contribute to early em-bryonic patterning, primitive hematopoiesis, and fetal health. These tissues are of major importance for human medicine, as well as for efforts to improve livestock efficiency, but they remain incompletely understood. In bovines, EETs are accessible easily, in large amounts, and prior to implantation. We took advantage of this system to describe, in vitro and in vivo, the cell types present in bovine EETs at Day 18 of development. Specifically, we characterized the gene expression patterns and phenotypes of bovine extra-embryonic ectoderm (or trophoblast; bTC), endoderm (bXEC), and mesoderm (bXMC) cells in culture and compared them to their respective in vivo micro-dissected cells. After a week of culture, certain characteristics (e.g., gene expression) of the in vitro cells were altered with respect to the in vivo cells, but we were able to identify cores of cell-type-specific (and substrate-independent) genes
In the heart, cells that form the valves are induced to develop by interaction between endothelial cells and adjacent muscle. As a result, cardiac endothelial cells transform into mesenchyme and become the constituents of the valves and walls of the heart. This process is known as an epithelial-mesenchymal transition or EMT. The objective of my research program is to understand the molecular mechanisms that mediate cell transformation in the heart.Using a tissue culture assay, we showed that cardiac endothelia would only transform after stimulation by adjacent muscle. My laboratory has continued to examine the events which take place during this epithelial-mesenchymal cell transformation. Our studies focus upon three basic questions. 1) What is the nature of the signal produced by the muscle? 2) How do the target cells recognize the signal? 3) What events occur in the target cells in response to the stimulus? Answers to these questions will identify potential causes of congenital heart ...
3 Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA * Author for correspondence (e-mail: [email protected] ) The hematopoietic and endothelial lineages derive from mesoderm and are thought to develop through the maturation of a common progenitor, the hemangioblast. To investigate the developmental processes that regulate mesoderm induction and specification to the hemangioblast, we generated an embryonic stem cell line with the green fluorescent protein (GFP) targeted to the mesodermal gene, brachyury. After the in vitro differentiation of these embryonic stem cells to embryoid bodies, developing mesodermal progenitors could be separated from those with neuroectoderm potential based on GFP expression. Co-expression of GFP with the receptor tyrosine kinase Flk1 revealed the emergence of three distinct cell populations, GFP-Flk1-, GFP+Flk1- and GFP+Flk1+ cells, which represent a developmental progression ranging from pre-mesoderm to prehemangioblast ...
Abstract-since the advent of high throughput methodologies, like microarrays, the load of genomic data has increased geometrically and along with that the need for computational methods which will interpret these data. In the present work we have studied the common gene expression patterns between two tumor cell types of mesodermal origin. In particular, we have attempted to find causal relations between gene expression levels with respect to chromosomal location. We have found that several genes manifested significant relations, using regression analysis and as such they could pose interesting targets for further investigations. This type of analysis can lead to the understanding of the common mechanisms that transform physiological cells to malignant, as well as it reveals a new holistic way to understand the dynamics of tumor onset as well as the mechanistic of oncogenic drivers. Such approaches could prove to be useful in the prediction of genomic targets that could be further studied in ...
Dr Lesley Forresters group at the MRC Centre for Regenerative Medicine, University of Edinburgh, works on Mesoderm and haematopoietic differentiation
Little is known about how the sizes of animal tissues are controlled. A prominent example is somite size which varies widely both within an individual and across species. Despite intense study of the segmentation clock governing the timing of somite generation, how it relates to somite size is poorly understood. Here we examine somite scaling and find that somite size at specification scales with the length of the presomitic mesoderm (PSM) despite considerable variation in PSM length across developmental stages and in surgically size-reduced embryos. Measurement of clock period, axis elongation speed, and clock gene expression patterns demonstrate that existing models fail to explain scaling. We posit a clock and scaled gradient model, in which somite boundaries are set by a dynamically scaling signaling gradient across the PSM. Our model not only explains existing data, but also makes a unique prediction that we experimentally confirm-the formation of periodic echoes in somite size ...
Mammalian Nck1 and Nck2 are closely related adaptor proteins that possess three SH3 domains, followed by an SH2 domain, and are implicated in coupling phosphotyrosine signals to polypeptides that regulate the actin cytoskeleton. However, the in vivo functions of Nck1 and Nck2 have not been defined. We have mutated the murine Nck1 and Nck2 genes and incorporated β-galactosidase reporters into the mutant loci. In mouse embryos, the two Nck genes have broad and overlapping expression patterns. They are functionally redundant in the sense that mice deficient for either Nck1 or Nck2 are viable, whereas inactivation of both Nck1 and Nck2 results in profound defects in mesoderm-derived notochord and embryonic lethality at embryonic day 9.5. Fibroblast cell lines derived from Nck1−/− Nck2−/− embryos have defects in cell motility and in the organization of the lamellipodial actin network. These data suggest that the Nck SH2/SH3 adaptors have important functions in the development of mesodermal ...