AJP - Regulatory, Integrative and Comparative Physiology, Vol 266, Issue 4 1359-R1370, Copyright © 1994 by American Physiological Society

ARTICLES

Evolution of marsupial and other vertebrate thyroxine-binding plasma proteins

S. J. Richardson, A. J. Bradley, W. Duan, R. E. Wettenhall, P. J. Harms, J. J. Babon, B. R. Southwell, S. Nicol, S. C. Donnellan and G. Schreiber
Russell Grimwade School of Biochemistry, University of Melbourne, Parkville, Victoria, Australia.

Binding of radioactive thyroxine to proteins in the plasma of vertebrates was studied by electrophoresis followed by autoradiography. Albumin was found to be a thyroxine carrier in the blood of all studied fish, amphibians, reptiles, monotremes, marsupials, eutherians (placental mammals), and birds. Thyroxine binding to transthyretin was detected in the blood of eutherians, diprotodont marsupials, and birds, but not in blood from fish, toads, reptiles, monotremes, and Australian polyprotodont marsupials. Globulins binding thyroxine were only observed in the plasma of some mammals. Apparently, albumin is the phylogenetically oldest thyroxine carrier in vertebrate blood. Transthyretin gene expression in the liver developed in parallel, and independently, in the evolutionary lineages leading to eutherians, to diprotodont marsupials, and to birds. In contrast, high transthyretin mRNA levels, strong synthesis, and secretion of transthyretin in choroid plexus from reptiles and birds indicate that transthyretin gene expression in the choroid plexus evolved much earlier than in the liver, probably at the stage of the stem reptiles. NH2-terminal sequence analysis suggests a change of transthyretin pre-mRNA splicing during evolution.

This article has been cited by other articles:

				S. J. Richardson, J. A. Monk, C. A. Shepherdley, L. O. E. Ebbesson, F. Sin, D. M. Power, P. B. Frappell, J. Kohrle, and M. B. Renfree Developmentally regulated thyroid hormone distributor proteins in marsupials, a reptile, and fish Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2005; 288(5): R1264 - R1272. [Abstract] [Full Text] [PDF]

				P. Prapunpoj, S. J. Richardson, and G. Schreiber Crocodile transthyretin: structure, function, and evolution Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2002; 283(4): R885 - R896. [Abstract] [Full Text] [PDF]

				P. Prapunpoj, K. Yamauchi, N. Nishiyama, S. J. Richardson, and G. Schreiber Evolution of structure, ontogeny of gene expression, and function of Xenopus laevis transthyretin Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2000; 279(6): R2026 - R2041. [Abstract] [Full Text] [PDF]

				J. A. Wilce, S. G. Love, S. J. Richardson, P. F. Alewood, and D. J. Craik Synthesis of an Analog of the Thyroid Hormone-binding Protein Transthyretin via Regioselective Chemical Ligation J. Biol. Chem., July 6, 2001; 276(28): 25997 - 26003. [Abstract] [Full Text] [PDF]