scholarly journals Abnormal Thyroid Gland Occurred in a Colony of Xenopus laevis Maintained at Gunma University

1981 ◽  
Vol 30 (4) ◽  
pp. 471-480
Author(s):  
Toshima NOBUNAGA ◽  
Matsutaro SAITO ◽  
Sakae INOUE
Keyword(s):  
Thyroid Gland ◽  
Xenopus Laevis

scholarly journals The thyroid hormone receptor gene (c-erbA alpha) is expressed in advance of thyroid gland maturation during the early embryonic development of Xenopus laevis.

1991 ◽  
Vol 11 (10) ◽  
pp. 5079-5089 ◽  
Author(s):  
D E Banker ◽  
J Bigler ◽  
R N Eisenman
Keyword(s):  
Gene Expression ◽  
Thyroid Hormone ◽  
Thyroid Gland ◽  
Xenopus Laevis ◽  
Hormone Receptor ◽  
Hormone Receptors ◽  
Thyroid Hormone Receptor ◽  
Thyroid Hormone Receptors ◽  
Stages Of Development ◽  
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.

THE BIOSYNTHESIS OF THYROXINE AND 3:5:3′-TRIIODOTHYRONINE IN LARVAL AND ADULT TOADS

1959 ◽  
Vol 18 (1) ◽  
pp. 98-101 ◽  
Author(s):  
CLAIRE J. SHELLABARGER ◽  
JUDITH R. BROWN
Keyword(s):  
Thyroid Gland ◽  
Xenopus Laevis ◽  
Thyroid Hormones ◽  
Radioactive Iodine ◽  
Early Stages

SUMMARY 1. A study has been made of the compounds synthesized by and present in the thyroid gland of larval and adult Xenopus laevis using radioactive iodine and chromatography. 2. Tadpoles undergoing active metamorphosis produced thyroxine and trace amounts of 3:5:3′-triiodothyronine. Less thyroxine and no triiodothyronine was detected in tadpoles approaching the end of metamorphosis, and neither compound was detected in tadpoles in early stages of metamorphosis. Adult toads produced thyroxine and trace amounts of triiodothyronine. The presence of monoiodotyrosine and diiodotyrosine was a constant finding. 3. It is suggested that the synthesis of thyroid hormones in amphibia is similar to that in other vertebrates.

The thyroid hormone receptor gene (c-erbA alpha) is expressed in advance of thyroid gland maturation during the early embryonic development of Xenopus laevis

1991 ◽  
Vol 11 (10) ◽  
pp. 5079-5089
Author(s):  
D E Banker ◽  
J Bigler ◽  
R N Eisenman
Keyword(s):  
Gene Expression ◽  
Thyroid Hormone ◽  
Thyroid Gland ◽  
Xenopus Laevis ◽  
Hormone Receptor ◽  
Hormone Receptors ◽  
Thyroid Hormone Receptor ◽  
Thyroid Hormone Receptors ◽  
Stages Of Development ◽  
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.

The Development of the Ultimobranchial Body in Xenopus laevis Daudin and its Relation to the Thyroid Gland and Epithelial Bodies

Development ◽  
1955 ◽  
Vol 3 (4) ◽  
pp. 376-384
Author(s):  
Lauri Saxén ◽  
Sulo Toivonen
Keyword(s):  
Thyroid Gland ◽  
Xenopus Laevis ◽  
Ultimobranchial Body ◽  
Pharyngeal Cavity ◽  
Stage Of Development ◽  
Consistent Picture ◽  
Ventral Wall ◽  
Accessory Thyroid

The ultimobranchial body is a derivate of the pharyngeal cavity which has been found in all vertebrates studied at least at some stage of development. Its origin, development, and structure has been studied in many species but nevertheless nothing certain is known about its significance and activity. Earlier authors have used several terms for this organ, e.g. accessory thyroid gland, lateral thyroid, corpus Y, suprapericardial body, telobranchial body, and postbranchial body. The term mostly used at present, ultimobranchial body, was suggested by Greil (1904). It is not possible to give a consistent picture of the formation of the ultimobranchial body, since it is evidently different in different vertebrates. In fishes it is formed from the sixth rudimentary visceral pouch (van Bemmelen, 1889); in amphibians Maurer (1888) regards it as being formed from the ventral wall of the pharyngeal cavity, while Greil (1904) derives it from the sixth visceral pouch.

scholarly journals Expression of sodium-iodide symporter mRNA in the thyroid gland of Xenopus laevis tadpoles: developmental expression, effects of antithyroidal compounds, and regulation by TSH

2006 ◽  
Vol 190 (1) ◽  
pp. 157-170 ◽  
Author(s):  
Robert Opitz ◽  
Achim Trubiroha ◽  
Claudia Lorenz ◽  
Ilka Lutz ◽  
Sabine Hartmann ◽  
...  
Keyword(s):  
Gene Expression ◽  
Thyroid Gland ◽  
Xenopus Laevis ◽  
Mrna Expression ◽  
Sodium Iodide ◽  
Developmental Expression ◽  
Intracellular Camp ◽  
Sodium Iodide Symporter ◽  
Thyroid Glands

The uptake of iodide represents the first step in thyroid hormone synthesis by thyroid follicular cells and is mediated by the sodium-iodide symporter (NIS). In mammals, expression of NIS is stimulated by TSH and transcription of the NIS gene involves regulation by the thyroid-specific transcription factors Pax8 and Nkx2.1. In this study, we examined the mRNA expression of NIS, Pax8 and Nkx2.1 in the thyroid gland of Xenopus laevis tadpoles by semi-quantitative reverse transcriptase (RT)-PCR. During spontaneous metamorphosis, NIS mRNA expression was low in premetamorphic tadpoles, increased throughout prometamorphosis, and peaked at climax stage 60. Analysis of TSH β-subunit (TSHβ) mRNA in the pituitary of the same tadpoles revealed a close temporal relationship in the expression of the two genes during metamorphosis, suggesting a regulatory role of TSH in the developmental expression of NIS. Treatment of tadpoles with goitrogenic compounds (sodium perchlorate and ethylenethiourea) increased TSHβ mRNA expression (approximately twofold) and caused thyroid gland hyperplasia, confirming that feedback along the pituitary–thyroid axis was operative. Analysis of gene expression in the thyroid gland revealed that goitrogen treatment was correlated with increased expression of NIS mRNA (~20-fold). In the thyroid gland organ culture experiments, bovine TSH (bTSH; 1 mU/ml) strongly induced NIS mRNA expression. This effect was mimicked by co-culture of thyroid glands with pituitaries from stage 58 tadpoles and by agents that increase intracellular cAMP (forskolin, dibutyryl-cAMP). In addition, it could be shown that thyroid glands of X. laevis tadpoles express Pax8 and Nkx2.1 mRNA in a developmentally regulated manner and that ex vivo treatment of thyroid glands with bTSH, forskolin, and cAMP analogs increased the expression of Pax8 and Nkx2.1 mRNA. This is the first report on developmental profiles and hormonal regulation of thyroid gland gene expression in amphibian tadpoles and, together, results reveal a critical role of TSH in the regulation of NIS mRNA expression in the thyroid gland of X. laevis tadpoles.

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