Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2001-12-3
pubmed:abstractText
Thyroid hormone governs a diverse repertoire of physiological functions through receptors encoded in the receptor genes alpha and beta, which each generate variant proteins. In mammals, the alpha gene generates, in addition to the normal receptor TRalpha1, a non-hormone-binding variant TRalpha2 whose exact function is unclear. Here, we present the phenotype associated with the targeted ablation of TRalpha2 expression. Selective ablation of TRalpha2 resulted in an inevitable, concomitant overexpression of TRalpha1. Both TRalpha2 +/- and -/- mice show a complex phenotype with low levels of free T3 and free T4, and have inappropriately normal levels of TSH. The thyroid glands exhibit mild morphological signs of dysfunction and respond poorly to TSH, suggesting that the genetic changes affect the ability of the gland to release thyroid hormones. However, the phenotype of the mutant mice also has features of hyperthyroidism, including decreased body weight, elevated heart rate, and a raised body temperature. Furthermore, TRalpha2-/- and TRalpha2+/- mice are obese and exhibit skeletal alterations, associated with a late-onset growth retardation. The results thus suggest that the overexpression of TRalpha1 and the concomitant decrease in TRalpha2 expression lead to a mixed hyper- and hypothyroid phenotype, dependent on the tissue studied. The phenotypes suggest that the balance of TRalpha1:TRalpha2 expressed from the TRalpha gene provides an additional level of tuning the control of growth and homeostasis in mammalian species.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0888-8809
pubmed:author
pubmed:issnType
Print
pubmed:volume
15
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2115-28
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:11731613-Animals, pubmed-meshheading:11731613-Blotting, Northern, pubmed-meshheading:11731613-Body Composition, pubmed-meshheading:11731613-Bone Density, pubmed-meshheading:11731613-Crosses, Genetic, pubmed-meshheading:11731613-DNA-Binding Proteins, pubmed-meshheading:11731613-Female, pubmed-meshheading:11731613-Gene Expression Regulation, pubmed-meshheading:11731613-Histocytochemistry, pubmed-meshheading:11731613-Hyperthyroidism, pubmed-meshheading:11731613-Hypothyroidism, pubmed-meshheading:11731613-Male, pubmed-meshheading:11731613-Mice, pubmed-meshheading:11731613-Mice, Inbred BALB C, pubmed-meshheading:11731613-Mice, Knockout, pubmed-meshheading:11731613-Phenotype, pubmed-meshheading:11731613-RNA, pubmed-meshheading:11731613-Receptors, Cytoplasmic and Nuclear, pubmed-meshheading:11731613-Receptors, Thyroid Hormone, pubmed-meshheading:11731613-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:11731613-Telemetry, pubmed-meshheading:11731613-Thyroxine, pubmed-meshheading:11731613-Triiodothyronine
pubmed:year
2001
pubmed:articleTitle
Ablation of TRalpha2 and a concomitant overexpression of alpha1 yields a mixed hypo- and hyperthyroid phenotype in mice.
pubmed:affiliation
Department of Cell and Molecular Biology, Karolinska Institute, S-171 77 Stockholm, Sweden.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't