Differential gene expression in the anterior neural plate during gastrulation of Xenopus laevis

Development ◽  
1989 ◽  
Vol 105 (4) ◽  
pp. 779-786 ◽  
Author(s):  
M. Jamrich ◽  
S. Sato
Keyword(s):  
Gene Expression ◽  
Xenopus Laevis ◽  
Neural Induction ◽  
Neural Plate ◽  
Cement Gland ◽  
Cdna Clones ◽  
Differential Gene ◽  
Anteroposterior Polarity ◽  
Xenopus Laevis Embryos ◽  
Anterior Neural Plate

We have isolated three cDNA clones that are preferentially expressed in the cement gland of early Xenopus laevis embryos. These clones were used to study processes involved in the induction of this secretory organ. Results obtained show that the induction of this gland coincides with the process of neural induction. Genes specific for the cement gland are expressed very early in the anterior neural plate of stage-12 embryos. This suggests that the anteroposterior polarity of the neural plate is already established during gastrulation. At later stages of development, two of the three genes have secondary sites of expression. The expression of these genes can be induced in isolated animal caps by incubation in 10 mM-NH4Cl, a treatment that is known to induce cement glands.

scholarly journals Imaging patterns of calcium transients during neural induction in Xenopus laevis embryos

2000 ◽  
Vol 113 (19) ◽  
pp. 3519-3529 ◽  
Author(s):  
C. Leclerc ◽  
S.E. Webb ◽  
C. Daguzan ◽  
M. Moreau ◽  
A.L. Miller
Keyword(s):  
Xenopus Laevis ◽  
Calcium Signalling ◽  
Neural Induction ◽  
Calcium Transients ◽  
Free Calcium ◽  
Treated Animal ◽  
Cell Stage ◽  
Subsequent Formation ◽  
Xenopus Laevis Embryos

Through the injection of f-aequorin (a calcium-sensitive bioluminescent reporter) into the dorsal micromeres of 8-cell stage Xenopus laevis embryos, and the use of a Photon Imaging Microscope, distinct patterns of calcium signalling were visualised during the gastrulation period. We present results to show that localised domains of elevated calcium were observed exclusively in the anterior dorsal part of the ectoderm, and that these transients increased in number and amplitude between stages 9 to 11, just prior to the onset of neural induction. During this time, however, no increase in cytosolic free calcium was observed in the ventral ectoderm, mesoderm or endoderm. The origin and role of these dorsal calcium-signalling patterns were also investigated. Calcium transients require the presence of functional L-type voltage-sensitive calcium channels. Inhibition of channel activation from stages 8 to 14 with the specific antagonist R(+)BayK 8644 led to a complete inhibition of the calcium transients during gastrulation and resulted in severe defects in the subsequent formation of the anterior nervous system. BayK treatment also led to a reduction in the expression of Zic3 and geminin in whole embryos, and of NCAM in noggin-treated animal caps. The possible role of calcium transients in regulating developmental gene expression is discussed.

Gene expression in Xenopus embryogenesis

Development ◽  
1985 ◽  
Vol 89 (Supplement) ◽  
pp. 113-124
Author(s):  
Igor B. Dawid ◽  
Susan R. Haynes ◽  
Milan Jamrich ◽  
Erzsebet Jonas ◽  
Seiji Miyatani ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Xenopus Laevis ◽  
Cdna Cloning ◽  
Early Embryogenesis ◽  
Gene Activity ◽  
Complex Nature ◽  
Cdna Clones ◽  
Midblastula Transition ◽  
First Time

This article considers some aspects of the storage of macromolecules in the oocyte of Xenopus laevis and the activation of previously unexpressed genes during early embryogenesis. The large quantity and complex nature of poly(A)+ RNA accumulated in the egg provides the cleavage embryo with a supply of mRNA sufficient to sustain protein synthesis for several hours of development. Onset of gene activity at the midblastula transition (MBT) leads to the synthesis and accumulation of molecules of various RNA classes, including tRNAs, rRNAs, mRNAs and mitochondrial RNAs. At gastrulation the poly(A)+ RNA population is still qualitatively similar to that of the egg but some sequences not present in egg RNA have accumulated by this time. Through the use of a subtractive cDNA cloning procedure we have prepared a library of sequences that represent genes activated for the first time between MBT and gastrula. A study of several of these cDNA clones suggests that genes in this class are restricted in their activity to embryonic and tadpole stages.

scholarly journals Incipient forebrain boundaries traced by differential gene expression and fate mapping in the chick neural plate

2009 ◽  
Vol 335 (1) ◽  
pp. 43-65 ◽  
Author(s):  
Luisa Sánchez-Arrones ◽  
José Luis Ferrán ◽  
Lucía Rodríguez-Gallardo ◽  
Luis Puelles
Keyword(s):  
Gene Expression ◽  
Differential Gene Expression ◽  
Neural Plate ◽  
Fate Mapping ◽  
Differential Gene

Differential gene expression profiling of adult murine hematopoietic stem cells

Blood ◽  
2002 ◽  
Vol 99 (2) ◽  
pp. 488-498 ◽  
Author(s):  
In-Kyung Park ◽  
Yaqin He ◽  
Fangming Lin ◽  
Ole D. Laerum ◽  
Qiang Tian ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Differential Gene Expression ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Cdna Clones ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Differential Gene

Abstract Hematopoietic stem cells (HSCs) have self-renewal capacity and multilineage developmental potentials. The molecular mechanisms that control the self-renewal of HSCs are still largely unknown. Here, a systematic approach using bioinformatics and array hybridization techniques to analyze gene expression profiles in HSCs is described. To enrich mRNAs predominantly expressed in uncommitted cell lineages, 54 000 cDNA clones generated from a highly enriched population of HSCs and a mixed population of stem and early multipotent progenitor (MPP) cells were arrayed on nylon membranes (macroarray or high-density array), and subtracted with cDNA probes derived from mature lineage cells including spleen, thymus, and bone marrow. Five thousand cDNA clones with very low hybridization signals were selected for sequencing and further analysis using microarrays on glass slides. Two populations of cells, HSCs and MPP cells, were compared for differential gene expression using microarray analysis. HSCs have the ability to self-renew, while MPP cells have lost the capacity for self-renewal. A large number of genes that were differentially expressed by enriched populations of HSCs and MPP cells were identified. These included transcription factors, signaling molecules, and previously unknown genes.

scholarly journals The stopping response of Xenopus laevis embryos: pharmacology and intracellular physiology of rhythmic spinal neurones and hindbrain neurones

1992 ◽  
Vol 169 (1) ◽  
pp. 65-86 ◽  
Author(s):  
K. M. Boothby ◽  
A. Roberts
Keyword(s):  
Xenopus Laevis ◽  
Kynurenic Acid ◽  
Excitatory Amino Acid ◽  
Pattern Generator ◽  
Cement Gland ◽  
Intracellular Recordings ◽  
Pressure Sensitive ◽  
Inhibitory Postsynaptic Potentials ◽  
Spinal Neurones ◽  
Xenopus Laevis Embryos

1. Xenopus laevis embryos stop swimming in response to pressure on the cement gland. This behaviour and ‘fictive’ stopping are blocked by bicuculline (10 mumol 1(−1)), tubocurarine (110 mumol 1(−1)) and kynurenic acid (0.5 mmol 1(−1)). 2. Intracellular recordings from spinal neurones active during swimming have shown that pressure on the cement gland evokes compound, chloride-dependent inhibitory postsynaptic potentials (IPSPs). These are blocked by bicuculline, tubocurarine and kynurenic acid, but are unaffected by strychnine (2 mumol 1(−1)). 3. When the cement gland is pressed, trigeminal ganglion activity precedes both the IPSPs and the termination of ‘fictive’ swimming activity recorded in rhythmic spinal neurones. The trigeminal discharge is unaffected by the antagonists bicuculline, tubocurarine, kynurenic acid and strychnine. 4. Intracellular recordings from the hindbrain have revealed neurones that are normally silent, but rhythmically inhibited during ‘fictive’ swimming. In these neurones pressure on the cement gland evokes depolarising potentials, often with one or more spikes. 5. We propose that the stopping response depends on the excitation of pressure-sensitive trigeminal receptors which innervate the cement gland. These release an excitatory amino acid to excite brainstem GABAergic reticulospinal neurones, which inhibit spinal neurones to turn off the central pattern generator for swimming. There may also be a less direct pathway.

Expression of Xenopus N-CAM RNA in ectoderm is an early response to neural induction

Development ◽  
1987 ◽  
Vol 99 (3) ◽  
pp. 311-325 ◽  
Author(s):  
C.R. Kintner ◽  
D.A. Melton
Keyword(s):  
Neural Development ◽  
Transcriptional Activation ◽  
Neural Induction ◽  
Early Response ◽  
Neural Plate ◽  
Cdna Clones ◽  
Epidermal Tissue ◽  
Early Expression ◽  
Neural Ectoderm

We have isolated Xenopus laevis N-CAM cDNA clones and used these to study the expression of N-CAM RNA during neural induction. The results show that the first marked increase in N-CAM RNA levels occurs during gastrulation when mesoderm comes in contact with ectoderm and induces neural development. In situ hybridization results show that the early expression of N-CAM RNA is localized to the neural plate and its later expression is confined to the neural tube. Induction experiments with explanted germ layers show that N-CAM RNA is not expressed in ectoderm unless there is contact with inducing tissue. Together these results suggest an approach to studying how ectoderm is committed to form neural rather than epidermal tissue. Specifically, the data suggest that neural commitment is marked and perhaps mediated by the transcriptional activation of genes, like N-CAM, in the neural ectoderm.

Heterogeneity of gene expression in human atheroma unmasked using cDNA representational difference analysis

2002 ◽  
Vol 9 (2) ◽  
pp. 121-130 ◽  
Author(s):  
Kerry L. Tyson ◽  
Peter L. Weissberg ◽  
Catherine M. Shanahan
Keyword(s):  
Gene Expression ◽  
Representational Difference Analysis ◽  
Pcr Analysis ◽  
Cdna Clones ◽  
Difference Analysis ◽  
Complex Interactions ◽  
Atherosclerotic Lesions ◽  
Differential Gene ◽  
Disease Associated Genes

The rupture of an atherosclerotic plaque can have profound consequences, such as myocardial or cerebrovascular infarction. The complex interactions of vascular smooth muscle cells (VSMCs) with inflammatory and immune cells are thought to contribute to both plaque genesis and stability. Key to our understanding of these processes is the identification of genes expressed in human atheromatous lesions. We have employed cDNA representational difference analysis (RDA) to investigate the differences in gene expression between normal and atherosclerotic human vessels. Thirty-one cDNA clones representing sequences expressed in atheroma were isolated, many of which encoded components of inflammatory and immune pathways. The reciprocal experiment, to identify genes expressed in the healthy vasculature, identified two genes associated with the contractile functions of VSMCs. Semiquantitative RT-PCR analysis of expression of these genes in forty samples, derived from healthy and atheromatous vessels, demonstrated marked heterogeneity of gene expression between lesions, although several of the genes were preferentially expressed in atherosclerotic lesions. In situ hybridization identified subsets of macrophages at sites of neovascularization within the lesion and intimal VSMCs as expressing the disease-associated genes. In conclusion, cDNA RDA is a useful, fast, and efficient technique for studying differential gene expression particularly when clinical material is limiting.

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