HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Accepted manuscript (PDF) All Versions of this Article: JME-08-0030v1 41/4/219    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Freamat, M. Articles by Sower, S. Search for Related Content PubMed PubMed Citation Articles by Freamat, M. Articles by Sower, S.

M Freamat, Biochemistry and Molecular Biology, University of New Hampshire, Durham, United States
S Sower, Biochemistry and Molecular Biology, University of New Hampshire, Durham, 03824, United States

Correspondence: Stacia Sower, Email: sasower{at}cisunix.unh.edu

Abstract

The specificity of the vertebrate hypothalamic-pituitary-gonadal (HPG) and hypothalamic-pituitary-thyroid (HPT) axes is explained by the evolutionary refinement of the specificity of expression and selectivity of interaction between the glycoprotein hormones GpH (FSH, LH and TSH) and their cognate receptors GpH-R (FSH-R, LH-R and TSH-R). These two finely tuned signaling pathways evolved by gene duplication and functional divergence from an ancestral GpH/GpH-R pair. Comparative analysis of the Protochordate and Gnathostome endocrine systems suggests that this process took place prior or concomitantly with the emergence of the Gnathostome lineage. Here we report identification and characterization of a novel glycoprotein hormone receptor (lGpH-R II) in the Agnathan sea lamprey. This 781 residues protein was found ca. 43% identical with mammalian TSH-R and FSH-R representative sequences and similarly with these two classes of mammalian receptors it is assembled from 10 exons. A synthetic ligand containing the lamprey glycoprotein hormone β chain tethered upstream of a mammalian chain activated the lGpH-R II expressed in COS-7 cells but in a lesser extent than lGpH-R I. Molecular phylogenetic analysis of vertebrate GpH-R protein sequences suggests a closer relationship between lGpH-R II and Gnathostome thyrotropin receptors. Overall, the presence and characteristics of the lamprey glycoprotein hormone receptors suggest existence of a primitive, functionally overlapping glycoprotein hormone/glycoprotein hormone receptor system in this animal.