Gene expression changes at metamorphosis induced by thyroid hormone in Xenopus laevis tadpoles

Biswajit Das, Liquan Cai, Mark G. Carter, Yu Lan Piao, Alexei A. Sharov, Minoru S.H. Ko, Donald D. Brown

Research output: Contribution to journalArticlepeer-review

102 Citations (Scopus)


Thyroid hormone (TH) controlled gene expression profiles have been studied in the tail, hind limb and brain tissues during TH-induced and spontaneous Xenopus laevis metamorphosis. Amplified cRNA probes mixed with a universal standard were hybridized to a set of 21,807-sense strand 60-mer oligonucleotides on each slide representing the entries in X. laevis UniGene Build 48. Most of the up-regulated genes in hind limb and brain are the same. This reflects in part the fact that the initial response to TH induction in both tissues is cell proliferation. A large number of up-regulated genes in the limb and brain programs encode common components of the cell cycle, DNA and RNA metabolism, transcription and translation. Notch is one of the few genes that is differentially expressed exclusively in the brain in the first 48 h of TH induction studied in these experiments. The TH-induced gene expression changes in the tail are different from the limb and brain programs. Distinct muscle and fibroblast programs were identified in the tail. Dying muscle fibers in tail (marked by active caspase-3) up-regulate a group of genes that include proteolytic enzymes. At the climax of metamorphosis, tail muscle down-regulates more than half of the genes that encode the glycolytic enzymes in the cytoplasm and the tricarboxylic acid pathway and all five complexes of the electron transport system in mitochondria. These changes in gene expression precede the activation of caspase-3. Some of these same energy metabolism-related genes are up-regulated in the limb and brain programs by TH. A prominent feature of the tail fibroblasts is the down-regulation of several collagen and other extra cellular matrix genes and the up-regulation of hydrolytic enzymes that are responsible for dissolving the notochord and resorbing the tail.

Original languageEnglish
Pages (from-to)342-355
Number of pages14
JournalDevelopmental Biology
Issue number2
Publication statusPublished - 2006 Mar 15
Externally publishedYes


  • Brain ventricle proliferation
  • Cell cycle
  • Limb growth
  • Metamorphosis
  • Mitochondrial electron transport chain
  • Tadpole
  • Tail resorption
  • Thyroid hormone
  • Transcriptional regulation
  • Xenopus laevis

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology
  • Cell Biology


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