Linked Life Data

20417211

Source:http://linkedlifedata.com/resource/pubmed/id/20417211

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2010-8-9
pubmed:abstractText
Thyroid hormones (TH) are the primary morphogen regulating amphibian metamorphosis. However, knowledge about molecular mechanisms regulating thyroid gland activity in anuran tadpoles is very scarce. In this study, we characterized gene expression profiles in thyroids of Xenopus laevis tadpoles during spontaneous metamorphosis. Using real-time PCR, elevated expression of slc5a5, tpo, tshr, and sar1a mRNAs was detected at late prometamorphic and climax stages. For dio2 and dio3 but not dio1, developmental regulation of thyroidal expression was evident from a strong up-regulation at late stages. Conversely, expression of the DNA replication markers mcm2 and pcna declined at climax stages. The presence of functional feedback mechanisms at premetamorphic stages was examined in two experiments. Stage 52 tadpoles were exposed for 72 h to 1.0 microg/l thyroxine (T4). This treatment caused reduced mRNA expression of slc5a5, tpo, and dio2, whereas no significant changes were detectable for tshr expression in thyroids and tshb expression in the pituitary. In another experiment, stage 46 tadpoles were treated with 20 mg/l sodium perchlorate (PER) for 5 and 10 days. Within this period of time, control tadpoles developed to stages 50 and 52, respectively. PER treatment resulted in up-regulation of slc5a5, tpo, and tshr mRNAs at both time points and increased dio2 mRNA expression at day 10. Effects of PER on thyroid histology were only apparent on day 10. Together, our analyses of thyroidal gene expression demonstrate a marked developmental regulation for functional markers of thyroid activity, two deiodinases as well as for DNA replication markers. Expression patterns detected in PER- and T4-treated tadpoles indicate that functional feedback signaling controlling thyroid activity is already active during premetamorphosis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1095-6840
pubmed:author
pubmed:copyrightInfo
Copyright 2010 Elsevier Inc. All rights reserved.
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
168
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
199-208
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Developmental regulation of gene expression in the thyroid gland of Xenopus laevis tadpoles.
pubmed:affiliation
Department of Inland Fisheries, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, D-12587 Berlin, Germany. r.opitz@igb-berlin.de
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't