Combinatorial signals from the neural tube, floor plate and notochord induce myogenic bHLH gene expression in the somite

Development ◽  
1995 ◽  
Vol 121 (3) ◽  
pp. 651-660 ◽  
Author(s):  
A.E. Munsterberg ◽  
A.B. Lassar
Keyword(s):  
Gene Expression ◽  
Neural Tube ◽  
Developmental Stages ◽  
Floor Plate ◽  
Bhlh Gene ◽  
Neural Tubes ◽  
Bhlh Genes ◽  
Early Developmental ◽  
Somitic Mesoderm

The neural tube, floor plate and notochord are axial tissues in the vertebrate embryo which have been demonstrated to play a role in somite morphogenesis. Using in vitro coculture of tissue explants, we have monitored inductive interactions of these axial tissues with the adjacent somitic mesoderm in chick embryos. We have found that signals from the neural tube and floor plate/notochord are necessary for expression of the myogenic bHLH regulators MyoD, Myf5 and myogenin in the somite. Eventually somitic expression of the myogenic bHLH genes is maintained in the absence of the axial tissues. In organ culture, at early developmental stages (HH 11-), induction of myogenesis in the three most recently formed somites can be mediated by the neural tube together with the floor plate/notochord, while in more rostral somites (stages IV-IX) the neural tube without the floor plate/notochord is sufficient. By recombining somites and neural tubes from different axial levels of the embryo, we have found that a second signal is necessary to promote competence of the somite to respond to inducing signals from the neural tube. Thus, we propose that at least two signals from axial tissues work in combination to induce myogenic bHLH gene expression; one signal derives from the floor plate/notochord and the other signal derives from regions of the neural tube other than the floor plate.

Notochord signals control the transcriptional cascade of myogenic bHLH genes in somites of quail embryos

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1475-1488 ◽  
Author(s):  
M.E. Pownall ◽  
K.E. Strunk ◽  
C.P. Emerson
Keyword(s):  
Gene Expression ◽  
Neural Tube ◽  
Bhlh Gene ◽  
Lateral Plate ◽  
Ventral Neural Tube ◽  
Bhlh Genes ◽  
Somite Formation ◽  
Necessary And Sufficient ◽  
Alpha Actin

Microsurgical, tissue grafting and in situ hybridization techniques have been used to investigate the role of the neural tube and notochord in the control of the myogenic bHLH genes, QmyoD, Qmyf5, Qmyogenin and the cardiac alpha-actin gene, during somite formation in stage 12 quail embryos. Our results reveal that signals from the axial neural tube/notochord complex control both the activation and the maintenance of expression of QmyoD and Qmyf5 in myotomal progenitor cells during the period immediately following somite formation and prior to myotome differentiation. QmyoD and Qmyf5 expression becomes independent of axial signals during myotome differentiation when somites activate expression of Qmyogenin and alpha-actin. Ablation studies reveal that the notochord controls QmyoD activation and the initiation of the transcriptional cascade of myogenic bHLH genes as epithelial somites condense from segmental plate mesoderm. The dorsal medial neural tube then contributes to the maintenance of myogenic bHLH gene expression in newly formed somites. Notochord grafts can activate ectopic QmyoD expression during somite formation, establishing that the notochord is a necessary and sufficient source of diffusible signals to initiate QmyoD expression. Myogenic bHLH gene expression is localized to dorsal medial cells of the somite by inhibitory signals produced by the lateral plate and ventral neural tube. Signaling models for the activation and maintenance of myogenic gene expression and the determination of myotomal muscle in somites are discussed.

Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

1974 ◽  
Vol 32 ◽  
pp. 320-321
Author(s):  
J. P. Revel
Keyword(s):  
Developmental Stages ◽  
Three Dimensional ◽  
Cell Movement ◽  
Cellular Interactions ◽  
Serial Sections ◽  
Cell Sheets ◽  
Freeze Etching ◽  
Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

Control of dorsoventral pattern in vertebrate neural development: induction and polarizing properties of the floor plate

Development ◽  
1991 ◽  
Vol 113 (Supplement_2) ◽  
pp. 105-122 ◽  
Author(s):  
Marysia Placzek ◽  
Toshiya Yamada ◽  
Marc Tessier-Lavigne ◽  
Thomas Jessell ◽  
Jane Dodd
Keyword(s):  
Neural Tube ◽  
Neural Development ◽  
Cell Types ◽  
Floor Plate ◽  
Neural Cells ◽  
Dorsoventral Patterning ◽  
Cellular Mechanisms ◽  
Cell Position

Distinct classes of neural cells differentiate at specific locations within the embryonic vertebrate nervous system. To define the cellular mechanisms that control the identity and pattern of neural cells we have used a combination of functional assays and antigenic markers to examine the differentiation of cells in the developing spinal cord and hindbrain in vivo and in vitro. Our results suggest that a critical step in the dorsoventral patterning of the embryonic CNS is the differentiation of a specialized group of midline neural cells, termed the floor plate, in response to local inductive signals from the underlying notochord. The floor plate and notochord appear to control the pattern of cell types that appear along the dorsoventral axis of the neural tube. The fate of neuroepithelial cells in the ventral neural tube may be defined by cell position with respect to the ventral midline and controlled by polarizing signals that originate from the floor plate and notochord.

A binding site for Gli proteins is essential for HNF-3beta floor plate enhancer activity in transgenics and can respond to Shh in vitro

Development ◽  
1997 ◽  
Vol 124 (7) ◽  
pp. 1313-1322 ◽  
Author(s):  
H. Sasaki ◽  
C. Hui ◽  
M. Nakafuku ◽  
H. Kondoh
Keyword(s):  
Binding Site ◽  
Neural Tube ◽  
Floor Plate ◽  
Signalling Pathway ◽  
Axonal Guidance ◽  
Critical Event ◽  
Enhancer Activity ◽  
Gli Proteins

The floor plate plays important roles in ventral pattern formation and axonal guidance within the neural tube of vertebrate embryos. A critical event for floor plate development is the induction of a winged helix transcription factor, Hepatocyte Nuclear Factor-3beta (HNF-3beta). The enhancer for floor plate expression of HNF-3beta is located 3′ of the transcription unit and consists of multiple elements. HNF-3beta induction depends on the notochord-derived signal, Sonic hedgehog (Shh). Genetic analysis in Drosophila has led to the identification of genes involved in the Hh signalling pathway, and cubitus interruptus (ci), encoding a protein with five zinc finger motifs, was placed downstream. In the present work, we test the involvement of Gli proteins, the mouse homologues of Ci, in activation of the floor plate enhancer of HNF-3beta. Transgenic analysis shows that a Gli-binding site is required for the activity of the minimal floor plate enhancer of HNF-3beta in vivo. Three Gli genes are differentially expressed in the developing neural tube. Gli expression is restricted to the ventral part, while Gli2 and Gli3 are expressed throughout the neural tube and dorsally, respectively. Strong Gli and Gli2, and weak Gli3 expressions transiently overlap with HNF-3beta at the time of its induction. Consistent with ventrally localized expression, Gli expression can be up-regulated by Shh in a cell line. Finally, the Gli-binding site acts as a Shh responsive element, and human GLI, but not GLI3, can activate this binding site in tissue culture. Taken together, these findings suggest that Gli, and probably also Gli2, are good candidates for transcriptional activators of the HNF-3beta floor plate enhancer, and the binding site for Gli proteins is a key element for response to Shh signalling. These results also support the idea that Gli/Ci are evolutionary conserved transcription factors in the Hedgehog signalling pathway.

scholarly journals Comparison of fecundity and offspring immunity in zebrafish fed Lactobacillus rhamnosus CICC 6141 and Lactobacillus casei BL23

Reproduction ◽  
2014 ◽  
Vol 147 (1) ◽  
pp. 53-64 ◽  
Author(s):  
Chubin Qin ◽  
Li Xu ◽  
Yalin Yang ◽  
Suxu He ◽  
Yingying Dai ◽  
...  
Keyword(s):  
Gene Expression ◽  
Oocyte Maturation ◽  
Lactobacillus Casei ◽  
Developmental Stages ◽  
Lactobacillus Rhamnosus ◽  
Reproductive Process ◽  
Beneficial Effects ◽  
Larval Stages ◽  
Probiotic Strains ◽  
Early Developmental

To increase the knowledge of probiotic effects on zebrafish (Danio rerio), we compare the effects of two probiotic strains, Lactobacillus rhamnosus CICC 6141 (a highly adhesive strain) and Lactobacillus casei BL23 (a weakly adhesive strain), on zebrafish reproduction and their offsprings' innate level of immunity to water-borne pathogens. During probiotics treatments from 7 to 28 days, both the Lactobacillus strains, and especially L. casei BL23, significantly increased fecundity in zebrafish: higher rates of egg ovulation, fertilization, and hatching were observed. Increased densities of both small and large vitellogenic follicles, seen in specimens fed either Lactobacillus strain, demonstrated accelerated oocyte maturation. Feeding either strain of Lactobacillus upregulated gene expression of leptin, kiss2, gnrh3, fsh, lh, lhcgr, and paqr8, which were regarded to enhance fecundity and encourage oocyte maturation. Concomitantly, the gene expression of bmp15 and tgfb1 was inhibited, which code for local factors that prevent oocyte maturation. The beneficial effects of the Lactobacillus strains on fecundity diminished after feeding of the probiotics was discontinued, even for the highly adhesive gut Lactobacillus strain. Administering L. rhamnosus CICC 6141 for 28 days was found to affect the innate immunity of offspring derived from their parents, as evinced by a lower level of alkaline phosphatase activity in early larval stages. This study highlights the effects of probiotics both upon the reproductive process and upon the offsprings' immunity during early developmental stages.

Fungal and algal gene expression in early developmental stages of lichen-symbiosis

Mycologia ◽  
2011 ◽  
Vol 103 (2) ◽  
pp. 291-306 ◽  
Author(s):  
Suzanne Joneson ◽  
Daniele Armaleo ◽  
François Lutzoni
Keyword(s):  
Gene Expression ◽  
Developmental Stages ◽  
Lichen Symbiosis ◽  
Early Developmental Stages ◽  
Early Developmental ◽  
Algal Gene

scholarly journals Microarray analysis of gene expression during early development: a cautionary overview

Reproduction ◽  
2010 ◽  
Vol 140 (6) ◽  
pp. 787-801 ◽  
Author(s):  
Claude Robert
Keyword(s):  
Gene Expression ◽  
Early Development ◽  
Microarray Analysis ◽  
Developmental Stages ◽  
Sample Handling ◽  
Early Embryos ◽  
High Throughput Method ◽  
Full Benefit ◽  
Key Steps ◽  
Early Developmental

The rise of the ‘omics’ technologies started nearly a decade ago and, among them, transcriptomics has been used successfully to contrast gene expression in mammalian oocytes and early embryos. The scarcity of biological material that early developmental stages provide is the prime reason why the field of transcriptomics is becoming more and more popular with reproductive biologists. The potential to amplify scarce mRNA samples and generate the necessary amounts of starting material enables the relative measurement of RNA abundance of thousands of candidates simultaneously. So far, microarrays have been the most commonly used high-throughput method in this field. Microarray platforms can be found in a wide variety of formats, from cDNA collections to long or short oligo probe sets. These platforms generate large amounts of data that require the integration of comparative RNA abundance values in the physiological context of early development for their full benefit to be appreciated. Unfortunately, significant discrepancies between datasets suggest that direct comparison between studies is difficult and often not possible. We have investigated the sample-handling steps leading to the generation of microarray data produced from prehatching embryo samples and have identified key steps that significantly impact the downstream results. This review provides a discussion on the best methods for the preparation of samples from early embryos for microarray analysis and focuses on the challenges that impede dataset comparisons from different platforms and the reasons why methodological benchmarking performed using somatic cells may not apply to the atypical nature of prehatching development.

scholarly journals Signals from the notochord and floor plate regulate the region-specific expression of two Pax genes in the developing spinal cord

Development ◽  
1993 ◽  
Vol 117 (3) ◽  
pp. 1001-1016 ◽  
Author(s):  
M.D. Goulding ◽  
A. Lumsden ◽  
P. Gruss
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Neural Tube ◽  
Neural Progenitor Cells ◽  
Expression Patterns ◽  
Primitive Streak ◽  
Floor Plate ◽  
Neural Patterning ◽  
Specific Expression ◽  
Early Effect

Members of the paired box (Pax) gene family are expressed in discrete regions of the developing central nervous system, suggesting a role in neural patterning. In this study, we describe the isolation of the chicken homologues of Pax-3 and Pax-6. Both genes are very highly conserved and share extensive homology with the mouse Pax-3 and Pax-6 genes. Pax-3 is expressed in the primitive streak and in two bands of cells at the lateral extremity of the neural plate. In the spinal cord, Pax-6 is expressed later than Pax-3 with the first detectable expression preceding closure of the neural tube. When the neural tube closes, transcripts of both genes become dorsoventrally restricted in the undifferentiated mitotic neuroepithelium. We show that the removal of the notochord, or implantation of an additional notochord, dramatically alter the dorsoventral (DV) expression patterns of Pax-3 and Pax-6. These manipulations suggest that signals from the notochord and floor plate regulate the establishment of the dorsoventrally restricted expression domains of Pax-3 and Pax-6 in the spinal cord. The rapid changes to Pax gene expression that occur in neural progenitor cells following the grafting of an ectopic notochord suggest that changes to Pax gene expression are an early effect of the notochord on spinal cord patterning.

Fibroblast growth factor during mesoderm induction in the early chick embryo

Development ◽  
1990 ◽  
Vol 109 (2) ◽  
pp. 387-393 ◽  
Author(s):  
E. Mitrani ◽  
Y. Gruenbaum ◽  
H. Shohat ◽  
T. Ziv
Keyword(s):  
Developmental Stages ◽  
Culture Conditions ◽  
Mesoderm Induction ◽  
Dependent Manner ◽  
Chick Embryogenesis ◽  
Defined Culture ◽  
High Degree ◽  
Early Developmental ◽  
Dose Dependent

A chick genomic clone that reveals a high degree of homology to the mammalian and Xenopus bFGF gene has been isolated. The pattern of expression of bFGF has been examined during early chick embryogenesis. RNA blot analysis revealed that chick bFGF is already transcribed at pregastrula stages. Immunolabeling analysis indicated that bFGF protein is present at these early developmental stages and is distributed evenly in the epiblast, hypoblast and marginal zone of the chick blastula. Substances that can inhibit FGF action were applied to early chick blastoderms grown in vitro under defined culture conditions (DCM). Both heparin and suramin were capable of blocking the formation of mesodermal structures in a dose-dependent manner. Our results indicate that FGF-like substances may need to be present for axial structures to develop although they may be acting earlier during the induction of non-axial mesoderm.

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