Bioassay of estrogenic compounds in transgenic Arabidopsis plants carrying a recombinant human estrogen receptor gene and a GFP reporter gene.

Transgenic Arabidopsis plants carrying a recombinant human estrogen receptor gene and a green fluorescent protein reporter gene were used to bioassay estrogenic compounds. We constructed four recombinant human estrogen receptor genes by combining the DNA-binding domain of LexA, a synthetic nuclear localization signal, a ligand-binding domain of the human estrogen receptor, and a transactivation domain of VP16 in different orders; the XEV plants were the most sensitive, and were able to detect 0.001 ng ml(-1) of 17ss-estradiol (E(2)). The transgenic plants absorbed E(2) and 4-nonylphenol present in the nutrient solution, whereas most of the other compounds seemed to be retained in, or on, the roots. Estrone, methoxychlor, bisphenol A, 4-nonylphenol, and 4-t-octylphenol in the medium were clearly detected by RT-PCR and PCR of the genomic DNA. The transgenic Arabidopsis XEV plants thus have potential for the bioassay of estrogenic compounds.