Expression of thyroid hormone receptor betaA gene assayed by transgenic Xenopus laevis carrying its promoter sequences.
The responsiveness of thyroid hormone responsive element (TRE)-containing promoter sequence to thyroid hormone (TH) was studied utilizing Xenopus laevis carrying a transgene containing 5'-upstream region of TRbetaA1 gene and green fluorescent protein (EGFP) gene. EGFP-expression was seen first in neurulae, which continued to stage 45, then became weak, and again started to increase at the prometamorphic stage, culminating at the metamorphic climax stage. Immunohistochemistry identified eyes, viscera, and muscles as the EGFP-expressing larval tissues. The treatment of premetamorphic tadpoles with TH induced the precocious EGFP-expression. We also showed that the transgenic Xenopus adults were responsive to exogenous TH, a high responsiveness being seen in brain, small intestine, kidney, and bone. TRbeta-expression in the embryo, larva, and adult was verified by Western blotting. Thus, TH not only regulates the metamorphosis, but also might play some biological role(s) in embryos and adults.
Oofusa
K
K
Tissue Regeneration Project, Hiroshima Prefecture Collaboration of Regional Entities for the Advancement of Technological Excellence, Japan.
Tooi
O
O
Kashiwagi
A
A
Kashiwagi
K
K
Kondo
Y
Y
Watanabe
Y
Y
Sawada
T
T
Fujikawa
K
K
Yoshizato
K
K
D000818:Animals; D030801:Animals, Genetically Modified; D015153:Blotting, Western; D004625:Embryo, Nonmammalian / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D005453:Fluorescence; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D017930:Genes, Reporter / Q000235:genetics; D007150:Immunohistochemistry; D007814:Larva / Q000187:drug effects / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011988:Receptors, Thyroid Hormone / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D020218:Response Elements / Q000235:genetics; D019076:Transgenes / Q000235:genetics; D014284:Triiodothyronine / Q000494:pharmacology; D014982:Xenopus laevis / Q000196:embryology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
D011988:Receptors, Thyroid Hormone; D014284:Triiodothyronine