Related Experiment Video
Updated: Jul 17, 2026

Stem cell-like Xenopus Embryonic Explants to Study Early Neural Developmental Features In Vitro and In Vivo
Published on: February 2, 2016
SRC-p300 coactivator complex is required for thyroid hormone-induced amphibian metamorphosis
Bindu D Paul1, Daniel R Buchholz, Liezhen Fu
1Laboratory of Gene Regulation and Development, NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA.
Thyroid hormone receptor (TR) coactivators are crucial for development. This study shows p300/CREB-binding protein (CBP) is essential for TR function during Xenopus laevis metamorphosis, highlighting its role in gene activation.
Area of Science:
- Molecular Endocrinology
- Developmental Biology
- Gene Regulation
Background:
- Thyroid hormone (T3) receptor (TR) activation requires coactivator complexes.
- In vivo roles of TR coactivators during development are largely unknown.
- Metamorphosis in Xenopus laevis is a T3-dependent developmental process mediated by TR.
Purpose of the Study:
- To investigate the in vivo role of p300/CREB-binding protein (CBP) in thyroid hormone receptor (TR) function during Xenopus laevis metamorphosis.
- To determine if p300/CBP is an essential component of TR coactivator complexes in vivo.
Main Methods:
- Chromatin immunoprecipitation (ChIP) to detect p300 recruitment to T3-responsive promoters.
- Generation of transgenic Xenopus laevis tadpoles overexpressing a dominant-negative form of p300 (F-dnp300).
- Molecular analysis of gene expression in transgenic tadpoles to assess TR-mediated gene activation.
Main Results:
- p300 is recruited to T3-responsive promoters, indicating its involvement in TR function.
- Overexpression of F-dnp300 disrupted metamorphosis, causing delays or arrest.
- F-dnp300 interfered with endogenous p300 binding and inhibited T3-responsive gene expression.
Conclusions:
- p300/CBP is essential for TR-mediated gene activation in vivo during post-embryonic development.
- p300/CBP and SRC coactivators function within the same complex for TR signaling.
- This study elucidates a critical coactivator's role in a key developmental transition.
Related Concept Videos
Co-activators and Co-repressors
Synthesis and Regulation of Thyroid Hormones
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The iodine is then...
Master Transcription Regulators
Functions of Thyroid Hormones
TH is indispensable for the normal development and maturation of the skeletal, muscular, and nervous systems during fetal and childhood growth. It facilitates bone mineral turnover and regulates protein synthesis in developing tissues, contributing significantly to overall growth and...
RNA Polymerase II Accessory Proteins
Background and Environment Affect Phenotype
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...

