ADAMTS9, a member of the ADAMTS family, in Xenopus development

The c-erbA proto-oncogene encodes the thyroid hormone receptor, a ligand-dependent transcription factor which plays an important role in vertebrate growth and development. To define the role of the thyroid hormone receptor in developmental processes, we have begun studying c-erbA gene expression during the ontogeny of Xenopus laevis, an organism in which thyroid hormone has well-documented effects on morphogenesis. Using polymerase chain reactions (PCR) as a sensitive assay of specific gene expression, we found that polyadenylated erbA alpha RNA is present in Xenopus cells at early developmental stages, including the fertilized egg, blastula, gastrula, and neurula. By performing erbA alpha-specific PCR on reverse-transcribed RNAs from high-density sucrose gradient fractions prepared from early-stage embryos, we have demonstrated that these erbA transcripts are recruited to polysomes. Therefore, erbA is expressed in Xenopus development prior to the appearance of the thyroid gland anlage in tailbud-stage embryos. This implies that erbA alpha/thyroid hormone receptors may play ligand-independent roles during the early development of X. laevis. Quantitative PCR revealed a greater than 25-fold range in the steady-state levels of polyadenylated erbA alpha RNA across early stages of development, as expressed relative to equimolar amounts of total embryonic RNA. Substantial increases in the levels of erbA alpha RNA were noted at stages well after the onset of zygotic transcription at the mid-blastula transition, with accumulation of erbA alpha transcripts reaching a relative maximum in advance of metamorphosis. We also show that erbA alpha RNAs are expressed unequally across Xenopus neural tube embryos. This differential expression continues through later stages of development, including metamorphosis. This finding suggests that erbA alpha/thyroid hormone receptors may play roles in tissue-specific processes across all of Xenopus development.

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Functional dissection of XDppa2/4 structural domains in Xenopus development

Mechanisms of Development ◽

10.1016/j.mod.2009.09.007 ◽

2009 ◽

Vol 126 (11-12) ◽

pp. 974-989 ◽

Cited By ~ 11

Author(s):

Doreen Siegel ◽

Maximilian Schuff ◽

Franz Oswald ◽

Ying Cao ◽

Walter Knöchel

Keyword(s):

Structural Domains ◽

Xenopus Development

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A functional test for maternally inherited cadherin in Xenopus shows its importance in cell adhesion at the blastula stage

Development ◽

10.1242/dev.120.1.49 ◽

1994 ◽

Vol 120 (1) ◽

pp. 49-57 ◽

Cited By ~ 7

Author(s):

J. Heasman ◽

D. Ginsberg ◽

B. Geiger ◽

K. Goldstone ◽

T. Pratt ◽

...

Keyword(s):

Cell Adhesion ◽

Protein Level ◽

Mrna Level ◽

Functional Test ◽

Gastrula Stage ◽

Blastula Stage ◽

Xenopus Development ◽

Dose Dependent ◽

Embryonic Ectoderm ◽

E Cadherin

We report here on the consequences of reducing the expression of EP-cadherin at the earliest stages of Xenopus development. Injection of oligodeoxynucleotides antisense to maternal EP-cadherin mRNA into full-grown oocytes reduced the mRNA level in oocytes, and the protein level in blastulae. Adhesion between blastomeres was significantly reduced, as seen in whole embryos, and in assays of the ability of blastomeres to reaggregate in culture. This effect was especially conspicuous in the inner cells of the blastula and included the disruption of the blastocoel. The severity of the EP-cadherin mRNA depletion and of the disaggregation phenotype was dose dependent. This phenotype was rescued by the injection into EP-cadherin mRNA-depleted oocytes of the mRNA coding for a related cadherin, E-cadherin, that is normally expressed at the gastrula stage in the embryonic ectoderm.

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Dorsal-ventral patterning and differentiation of noggin-induced neural tissue in the absence of mesoderm

Development ◽

10.1242/dev.121.6.1927 ◽

1995 ◽

Vol 121 (6) ◽

pp. 1927-1935 ◽

Cited By ~ 28

Author(s):

A.K. Knecht ◽

P.J. Good ◽

I.B. Dawid ◽

R.M. Harland

Keyword(s):

Nervous System ◽

Binding Proteins ◽

Rna Binding ◽

Rna Binding Proteins ◽

Neural Tissue ◽

Expression Domain ◽

Xenopus Development ◽

Dorsal Mesoderm

In Xenopus development, dorsal mesoderm is thought to play a key role in both induction and patterning of the nervous system. Previously, we identified a secreted factor, noggin, which is expressed in dorsal mesoderm and which can mimic that tissue's neural-inducing activity, without inducing mesoderm. Here the neural tissue induced in ectodermal explants by noggin is further characterized using four neural-specific genes: two putative RNA-binding proteins, nrp-1 and etr-1; the synaptobrevin sybII; and the lipocalin cpl-1. First we determine the expression domain of each gene during embryogenesis. Then we analyze expression of these genes in noggin-treated explants. All markers, including the differentiated marker sybII, are expressed in noggin-induced neural tissue. Furthermore, cpl-1, a marker of dorsal brain, and etr-1, a marker absent in much of the dorsal forebrain, are expressed in non-overlapping territories within these explants. We conclude that the despite the absence of mesoderm, noggin-induced neural tissue shows considerable differentiation and organization, which may represent dorsal-ventral patterning of the forebrain.

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Analysis of Dishevelled signalling pathways during Xenopus development

Current Biology ◽

10.1016/s0960-9822(96)00750-6 ◽

1996 ◽

Vol 6 (11) ◽

pp. 1456-1467 ◽

Cited By ~ 260

Author(s):

Sergei Y. Sokol

Keyword(s):

Signalling Pathways ◽

Xenopus Development

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The 5' untranslated region of mRNA for ribosomal protein S19 is involved in its translational regulation during Xenopus development.

Molecular and Cellular Biology ◽

10.1128/mcb.10.2.816 ◽

1990 ◽

Vol 10 (2) ◽

pp. 816-822 ◽

Cited By ~ 57

Author(s):

P Mariottini ◽

F Amaldi

Keyword(s):

Ribosomal Protein ◽

Untranslated Region ◽

Ribosomal Proteins ◽

Translational Regulation ◽

Xenopus Development ◽

Untranslated Sequence ◽

Gene Coding ◽

Ribosomal Protein S19 ◽

Fused Gene

During Xenopus development, the synthesis of ribosomal proteins is regulated at the translational level. To identify the region of the ribosomal protein mRNAs responsible for their typical translational behavior, we constructed a fused gene in which the upstream sequences (promoter) and the 5' untranslated sequence (first exon) of the gene coding for Xenopus ribosomal protein S19 were joined to the coding portion of the procaryotic chloramphenicol acetyltransferase (CAT) gene deleted of its own 5' untranslated region. This fused gene was introduced in vivo by microinjection into Xenopus fertilized eggs, and its activity was monitored during embryogenesis. By analyzing the pattern of appearance of CAT activity and the distribution of the S19-CAT mRNA between polysomes and messenger ribonucleoproteins, it was concluded that the 35-nucleotide-long 5' untranslated region of the S19 mRNA is able to confer to the fused S19-CAT mRNA the translational behavior typical of ribosomal proteins during Xenopus embryo development.

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