Meeting Abstract

P1.148  Sunday, Jan. 4  Two cytosolic thyroid-hormone binding proteins (CTHBPs) show tissue-specific mRNA expression patterns across organs throughout frog metamorphosis MOSKALIK, Christine/L.*; BUCHHOLZ, Daniel/R.; University of Cincinnati; University of Cincinnati MOSKALCL@email.uc.edu

Thyroid hormone (TH) plays an integral role in the growth and development of all vertebrates and also influences reproduction and metabolism. Amphibians are a good vertebrate model to study TH signaling because tadpole development is independent of the mother and metamorphosis is totally dependent on TH. Metamorphosis proceeds in an asynchronous fashion (i.e. intestine remodels after limbs but before tail) which is likely due to differential organ/tissue-sensitivity to the TH signal. In vitro studies of TH signaling have identified various cytoplasmic proteins influencing the TH signal during development. It has been suggested that one such protein, a cytosolic thyroid-hormone binding protein (CTHBP), modulates cellular concentrations of free TH; when TH is bound by a CTHBP in the cytoplasm it is unable to enter the nucleus and facilitate transcription of TH-response genes. This research aims to quantify the mRNA expression levels of two known CTHBPs, ALDH1 and PKM2, in various Xenopus tropicalis organs collected at different developmental stages, using quantitative PCR. Preliminary data show high mRNA expression levels of ALDH1 in organs before and after, but not during active remodeling, whereas PKM2 shows a less obvious expression pattern in some of the organs weve examined. Results from this research provide additional support for CTHBP’s role in TH signaling during amphibian development as well as mechanistic insights toward understanding organ/tissue-sensitivity to TH in vertebrate development.