title: Essential Role of GATA2 in the Negative Regulation of Type 2 Deiodinase Gene by Liganded Thyroid Hormone Receptor β2 in Thyrotroph.
abstract: The inhibition of thyrotropin (thyroid stimulating hormone; TSH) by thyroid hormone (T3) and its receptor (TR) is the central mechanism of the hypothalamus-pituitary-thyroid axis. Two transcription factors, GATA2 and Pit-1, determine thyrotroph differentiation and maintain the expression of the β subunit of TSH (TSHβ). We previously reported that T3-dependent repression of the TSHβ gene is mediated by GATA2 but not by the reported negative T3-responsive element (nTRE). In thyrotrophs, T3 also represses mRNA of the type-2 deiodinase (D2) gene, where no nTRE has been identified. Here, the human D2 promoter fused to the CAT or modified Renilla luciferase gene was co-transfected with Pit-1 and/or GATA2 expression plasmids into cell lines including CV1 and thyrotroph-derived TαT1. GATA2 but not Pit-1 activated the D2 promoter. Two GATA responsive elements (GATA-REs) were identified close to cAMP responsive element. The protein kinase A activator, forskolin, synergistically enhanced GATA2-dependent activity. Gel-shift and chromatin immunoprecipitation assays with TαT1 cells indicated that GATA2 binds to these GATA-REs. T3 repressed the GATA2-induced activity of the D2 promoter in the presence of the pituitary-specific TR, TRβ2. The inhibition by T3-bound TRβ2 was dominant over the synergism between GATA2 and forskolin. The D2 promoter is also stimulated by GATA4, the major GATA in cardiomyocytes, and this activity was repressed by T3 in the presence of TRα1. These data indicate that the GATA-induced activity of the D2 promoter is suppressed by T3-bound TRs via a tethering mechanism, as in the case of the TSHβ gene.
authors.affiliation: Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Matsunaga
authors.affiliation: Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Shigekazu
authors.initials: S
authors.lastname: Sasaki
authors.affiliation: Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Suzuki
authors.affiliation: Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Matsushita
authors.affiliation: Kuma Hospital, 8-2-35 Shimoyamate-dori, Chuo-ku, Kobe, Hyogo, 650-0011, Japan.
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Nakamura
authors.affiliation: Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Hiroko Misawa
authors.initials: HM
authors.lastname: Nakamura
authors.affiliation: Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Hirahara
authors.affiliation: Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Go
authors.initials: G
authors.lastname: Kuroda
authors.affiliation: Division of Endocrinology, Seirei Hamamatsu General Hospital, 2-12-12 Sumiyoshi, Naka-ku, Hamamatsu, Shizuoka, 430-0906, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Iwaki
authors.affiliation: Duke-NUS Graduate Medical School Singapore, No 8 College Road, Level 8th, 169857, Singapore.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ohba
authors.affiliation: Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Morita
authors.affiliation: Department of Family and Community Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Oki
authors.affiliation: Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Suda
mesh_terms: D000818:Animals; D002460:Cell Line; D002822:Choriocarcinoma / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D005576:Colforsin / Q000737:chemistry; D050989:GATA2 Transcription Factor / Q000235:genetics / Q000502:physiology*; D050991:GATA4 Transcription Factor / Q000378:metabolism; D017353:Gene Deletion; D005786:Gene Expression Regulation; D000882:Haplorhini; D006801:Humans; D007453:Iodide Peroxidase / Q000378:metabolism*; D008024:Ligands; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D020218:Response Elements; D015398:Signal Transduction; D037042:Thyroid Hormone Receptors beta / Q000378:metabolism*; D052684:Thyrotrophs / Q000378:metabolism*; D037322:Thyrotropin, beta Subunit / Q000378:metabolism*; D015533:Transcriptional Activation; D014284:Triiodothyronine / Q000378:metabolism; D000097564:Iodothyronine Deiodinase Type II
chemical_list: D005576:Colforsin; D050989:GATA2 Transcription Factor; D050991:GATA4 Transcription Factor; D007453:Iodide Peroxidase; D008024:Ligands; D012333:RNA, Messenger; D037042:Thyroid Hormone Receptors beta; D037322:Thyrotropin, beta Subunit; D014284:Triiodothyronine; D000097564:Iodothyronine Deiodinase Type II