Molecular study on estrogen inducible genes in greenback mukket, Liza subviridis

Abstract

Xenoestrogen can induce vitellogenin (vtg) and choriogenin (chg) genes expression in liver of male and juvenile fish which normally expressed in liver of spawning female fish under estrogen control. In this research we cloned and characterized estrogen receptor (ER), choriogenin (chg) and vitellogenin (vtg) genes in liver of greenback mullet, Liza subviridis and studied estrogen response at mRNA expression level of chg and vtg genes by semi-quantitative RT-PCR for application to biomarker for detecting xenoestrogen in water. The result showed open reading frame of ERα, ERβ, chg-L, and vtg-1 genes at size 1863, 1431, 1260 and 4653 bp that encode ERα, ERβ, Chg-L, and Vtg-1 which include 620, 476, 419, and 1,550 amino acid residues, respectively. We can determine partial coding sequence of chg-H that encode polypeptide which include 310 amino acid residues and 96 % of coding sequence of vtg-3. The result of estrogen response of chg-L, chg-H, and vtg-3 at mRNA expression level by injection estrogen intraperitoneally at dose 0, 0.05, 0.1, 0.25, 0.5, 1 and 5 mg/kg body weight show chg-L and chg-H expression level increase statistical significant (P < 0.05) after 3 and 6 days exposed with estrogen at dose 5 mg/kg and vtg-3 expression level increase statistical significant (P < 0.05) after 3 days exposed with estrogen at dose 5 mg/kg. Measurement of chg-L, chg-H, and vtg-3 expression level in liver of male and/or juvenile greenback mullet Liza subviridis by semi-quantitative RT-PCR that develop in this research can use for detecting xenoestrogen contamination in water.