Generation and characterization of gsuα:EGFP transgenic zebrafish for evaluating endocrine-disrupting effects.

The glycoprotein subunit alpha(gsu alpha) gene encodes the shared a subunit of the three pituitary heterodimeric glycoprotein hormones: follicle-stimulating hormone beta (Fsh beta), luteinizing hormone beta (Lh beta) and thyroid stimulating hormone beta (Tsh beta). In our current study, we identified and characterized the promoter region of zebrafish gsu alpha and generated a stable gsu alpha:EGFP transgenic line, which recapitulated the endogenous gsu alpha expression in the early developing pituitary gland. A relatively conserved regulatory element set is presented in the promoter regions of zebrafish and three other known mammalian gsu alpha promoters. Our results also demonstrated that the expression patterns of the gsu alpha:EGFP transgene were all identical to those expression patterns of the endogenous gsu alpha expression in the pituitary tissue when our transgenic fish were treated with various endocrine chemicals, including forskolin (FSK), SP600125, trichostatin A (TSA), KCIO4, dexamethasone (Dex),beta-estradiol and progesterone. Thus, this gsu alpha:EGFP transgenic fish reporter line provides another valuable tool for investigating the lineage development of gsu alpha-expressing gonadotrophins and the coordinated regulation of various glycoprotein hormone subunit genes. These reporter fish can serve as a novel platform to perform screenings of endocrine-disrupting chemicals (EDCs) in vivo as well. (C) 2014 Elsevier Inc. All rights reserved.