Mb. Hawkins et al., Identification of a third distinct estrogen receptor and reclassification of estrogen receptors in teleosts, P NAS US, 97(20), 2000, pp. 10751-10756
Citations number
37
Categorie Soggetti
Multidisciplinary
Journal title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
This paper describes three distinct estrogen receptor (ER) subtypes: ER alp
ha, ER beta, and a unique type. ER gamma, cloned from a teleost fish, the A
tlantic croaker Micropogonias undulatus; the first identification of a thir
d type of classical ER in vertebrate species. Phylogenetic analysis shows t
hat ER gamma arose through gene duplication from ER beta early in the teleo
st lineage and indicates that ER gamma is present in other teleosts. althou
gh it has not been recognized as such. The Atlantic croaker ER gamma shows
amino acid differences in regions important for ligand binding and receptor
activation that are conserved in all other ER gamma s. The three ER subtyp
es are genetically distinct and have different distribution patterns in Atl
antic croaker tissues. In addition, ER beta and ER gamma fusion proteins ca
n each bind estradiol-17 beta with high affinity. The presence of three fun
ctional ERs in one species expands the role of ER multiplicity in estrogen
signaling systems and provides a unique opportunity to investigate the dyna
mics and mechanisms of ER evolution.