Molecular Cloning Of MRNA And Tissue Distribution Of Estrogen Receptor Alpha In Lizard (Gekko Swinhonis)

Estrogen is an essential component of the endocrine system of all vertebrates, involved in many aspects of physiology of vertebrate including reptiles.Estrogen also has an active role during development of the gonad and female duct system in reptiles. Estrogen appears to play a central role in the determination of sex in reptiles with temperature sex determination (TSD); however, the precise mechanisms of estrogen action during sex determination in the reptiles are still unclearly, in large part because of a lack of information in the molecular biology of ER in reptiles. Except for the role of estrogen in the reproductive biology and the determination of sex, we are far from understanding its complete range of actions in reptiles. Recent researches indicate that estrogen also has impacts on other tissues, such as live, heart, lung, brain, and so on.In order to study the molecular mechanism of reptiles, we isolated and sequenced ERαfrom ovarian tissue obtained from Gekko swinhonis. Compared the obtained sequences of D-domain, LBD and large part of the F-domain with the other reptiles, the identity of LBD is are highly conserved among all reptilian ERαwith which Eulepharis macularius of lizards was 93%; The lizards of squamates show greater invariability, while ERαsequences are highly conserved among crocodilians; And the TSD may belong to an evolution system in which E plays an important role in reptiles.To better understand the function of estrogen in every tissue of Gekko, we characterized the tissue distribution of ERαexpression by RT-PCR immunochemistry. The results of RT-PCR indicate that the diencephalon and diencephalon of brain, ovary and oviduct show the relatively high expression, while weak bands are detected in female heart, liver and lung. However, no band was observed in testis. And with immunochemistry ERαprotein was further examined in the brain, liver, heart and lung of adult Gekko swinhonis. In the liver, heart and lung, ERα-ir profiles appeared as a brown precipitate within the cell nucleus, while faint cytoplasmic labeling for ERαwas detected in the brain. But the ovary is negative, which indicates the expression of ERαprotein in ovary shows a seasonal cycle coincident with reproductive activity.