Document Detail


Thyroid transcription factor-1 activates the promoter activity of rat thyroid Na+/I- symporter gene.
MedLine Citation:
PMID:  9328356     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We have cloned 15 kbp of rat thyroid Na+/I- symporter gene from liver genomic library, which contains 6 kbp upstream sequence from the translation initiation site. Southern blot analysis of the genomic DNA from the liver has revealed that thyroid Na+/I- symporter gene is the single gene in the rat. To study the tissue-selective expression mechanism of the gene, we at first determined the transcriptional start site of the gene. Results of a rapid amplification of cDNA end procedure as well as that of primer extension analysis indicated that the transcriptional start sites clustered between -96, -95, and -93 bp of the gene (A in ATG is designated as +1). Chimeras containing 1.9 kbp (-1967 to -46 bp) of the 5'-flanking sequence of the Na+/I- symporter gene and luciferase gene expressed significant enzyme activity when transfected into a rat thyroid cell line, FRTL-5, but little activity was observed in BRL-3A rat liver cells. Deletion analysis of the constructs indicated that a minimal region, exhibiting promoter activity and cell specificity, is located between -291 and -134 bp of the gene. Deoxyribonuclease I footprinting shows that nuclear extracts from FRTL-5, but not BRL-3A, cells protect a region between -245 and -230 bp. Electrophoretic mobility shift assays have demonstrated that nuclear extracts from FRTL-5 cells formed a specific DNA-protein complex with an oligonucleotide probe corresponding to -250 to -211 bp of the gene, but that from BRL-3A cells did not, suggesting that thyrocyte-selective nuclear factors bind to the region. When the nuclear extracts from FRTL-5 cells were preincubated with antibody against thyroid transcription factor-1 (TTF-1), homeodomain containing nuclear protein, formation of the complex was abolished and the band was supershifted. We also found that the probe formed a DNA-protein complex with the recombinant TTF-1 homeodomain, and mutations of the binding site eliminated factor binding. When pRc/CMV-TTF-1 was cotransfected with the minimal promoter fragment of thyroid Na+/I- symporter gene into FRT cells, which express no TTF-1, it caused a significant increase in the transcriptional activity of the reporter construct, but not of the construct having mutated TTF-1-binding element. These results suggest that TTF-1 confers the cell-selective expression of Na+/I- symporter gene in thyrocytes.
Authors:
T Endo; M Kaneshige; M Nakazato; M Ohmori; N Harii; T Onaya
Related Documents :
9613606 - Differential gene expression of a human alpha2,3-sialyltransferase in leukaemic cell li...
8380196 - Analysis of the human dopamine beta-hydroxylase promoter: transcriptional induction by ...
12758126 - Transcription control of a gene for drosophila transcription factor, dref by dre and ci...
15019996 - Genomic organization and promoter analysis of the gene encoding the mouse chemoattracta...
24611116 - Acid-shock of campylobacter jejuni induces flagellar gene expression and host cell inva...
17105366 - Should every lung cancer patient be tested for egfr mutation?
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Molecular endocrinology (Baltimore, Md.)     Volume:  11     ISSN:  0888-8809     ISO Abbreviation:  Mol. Endocrinol.     Publication Date:  1997 Oct 
Date Detail:
Created Date:  1998-01-12     Completed Date:  1998-01-12     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8801431     Medline TA:  Mol Endocrinol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1747-55     Citation Subset:  IM    
Affiliation:
Third Department of Internal Medicine, Yamanashi Medical University, Tamaho, Japan.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Animals
Base Sequence
Carrier Proteins / genetics*
Cell Line
Cloning, Molecular
DNA Footprinting
Gene Expression Regulation*
Gene Library
Genes, Reporter
Liver / chemistry
Male
Membrane Proteins / genetics*
Molecular Sequence Data
Nuclear Proteins / physiology*
Promoter Regions, Genetic*
Protein Binding
Rats
Rats, Sprague-Dawley
Recombinant Fusion Proteins / biosynthesis,  genetics
Sequence Deletion
Symporters*
Thyroid Gland / metabolism*
Transcription Factors / physiology*
Transcription, Genetic
Chemical
Reg. No./Substance:
0/Carrier Proteins; 0/Membrane Proteins; 0/Nuclear Proteins; 0/Recombinant Fusion Proteins; 0/Symporters; 0/Transcription Factors; 0/sodium-iodide symporter; 0/thyroid nuclear factor 1

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Transcriptional activation and repression by RORalpha, an orphan nuclear receptor required for cereb...
Next Document:  A critical evaluation of ultrasound measurement of inferior vena cava diameter in assessing dry weig...