Hepatic gene expression changes in hypothyroid juvenile mice: characterization of a novel negative thyroid-responsive element.
The molecular mechanisms involved in the response of developing mice to disruptions in maternal thyroid hormone (TH) homeostasis are poorly characterized. We used DNA microarrays to examine a broad spectrum of genes from the livers of mice rendered hypothyroid by treating pregnant mice from gestational d 13 to postnatal d 15 with 6-propyl-2-thiouracil in drinking water. Twenty-four individuals (one male and one female pup from six litters of control or 6-propyl-2-thiouracil treatment groups, respectively) were profiled using Agilent oligonucleotide microarrays. MAANOVA identified 96 differentially expressed genes (false discovery rate adjusted P < 0.1 and fold change > 2 in at least one gender). Of these, 72 genes encode proteins of known function, 15 of which had previously been identified as regulated by TH. Pathway analysis revealed these genes are involved in metabolism, development, cell proliferation, apoptosis, and signal transduction. An immediate-early response gene, Nr4a1 (nuclear receptor subfamily 4, group A, member 1), was up-regulated by 3-fold in hypothyroid juvenile mouse liver; treatment of HepG2 cells with T(3) resulted in down-regulation of Nr4a1. A potential thyroid response element -1218 to -1188 bp upstream of the promoter region of Nr4a1 was identified and demonstrated to bind TH receptor (TR)-alpha and TRbeta. Point mutation or deletion of the sequence containing the potential Nr4a1-thyroid response element in transient gene expression studies resulted in both higher basal expression and loss of T(3) regulatory capacity, suggesting that this site is responsible for the negative regulation of gene expression by TR and TH.
Dong
Hongyan
H
Environmental and Occupational Toxicology Division, Healthy Environments and Consumer Safety Branch, Health Canada, 50 Columbine Driveway, Ottawa, Ontario, Canada K1A 0L2.
Yauk
Carole L
CL
Williams
Andrew
A
Lee
Alice
A
Douglas
George R
GR
Wade
Michael G
MG
D000367:Age Factors; D000818:Animals; D013956:Antithyroid Agents / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015870:Gene Expression / Q000502:physiology; D020869:Gene Expression Profiling; D007037:Hypothyroidism / Q000139:chemically induced / Q000235:genetics* / Q000503:physiopathology; D008099:Liver / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D020411:Oligonucleotide Array Sequence Analysis / Q000592:standards; D011247:Pregnancy; D011401:Promoter Regions, Genetic / Q000502:physiology; D011441:Propylthiouracil / Q000494:pharmacology; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics* / Q000378:metabolism; D011987:Receptors, Steroid / Q000235:genetics* / Q000378:metabolism; D015203:Reproducibility of Results; D020218:Response Elements / Q000502:physiology*; D013963:Thyroid Hormones / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
D013956:Antithyroid Agents; D004268:DNA-Binding Proteins; C539818:Nr4a1 protein, mouse; D057105:Nuclear Receptor Subfamily 4, Group A, Member 1; D018160:Receptors, Cytoplasmic and Nuclear; D011987:Receptors, Steroid; D013963:Thyroid Hormones; D014157:Transcription Factors; D011441:Propylthiouracil