title: The earliest changes in gene expression in tadpole intestine induced by thyroid hormone.
abstract: Genes induced by thyroid hormone (TH) to change their expression in the Xenopus laevis gastrointestinal (GI) tract have been isolated using a subtractive hybridization method. An exhaustive search for down-regulated genes identified a single gene. Thirty-two different cDNA fragments derived from the up-regulated mRNA of tadpole intestine 18 h after addition of TH were cloned. They map to no more than 22 distinct genes. The isolation of multiple cDNA fragments derived from a single mRNA indicates that the complexity of up-regulated genes is limited. Both ubiquitous and intestine-specific up-regulated genes were found in this screen. The majority of these genes respond directly to TH induction as judged by the resistance of up-regulation to inhibitors of protein synthesis. The biological significance of these genes is supported by their dramatic regulation in the GI tract during spontaneous metamorphosis.
authors.affiliation: Laboratory of Molecular Embryology, National Institute of Child Health and Human Development, Bethesda, Maryland 20892.
authors.forename: Y B
authors.initials: YB
authors.lastname: Shi
authors.forename: D D
authors.initials: DD
authors.lastname: Brown
mesh_terms: D000818:Animals; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004625:Embryo, Nonmammalian / Q000502:physiology; D005314:Embryonic and Fetal Development; D015870:Gene Expression / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000187:drug effects / Q000196:embryology; D007700:Kinetics; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger / Q000096:biosynthesis*; D014284:Triiodothyronine / Q000494:pharmacology*; D014982:Xenopus laevis / Q000196:embryology*
chemical_list: D012333:RNA, Messenger; D014284:Triiodothyronine; D012313:RNA; D004247:DNA