An estrogen receptor‐based transactivator XVE mediates highly inducible gene expression in transgenic plants

TLDR

The authors developed an estrogen receptor‑based chemical‑inducible system for transgenic plants. The system employs a chimeric XVE activator—combining LexA DNA‑binding, VP16 transactivation, and human estrogen receptor domains—that, when activated by estradiol, drives reporter expression from a LexA‑operator‑containing minimal promoter in transgenic Arabidopsis and tobacco. Estradiol induction of XVE yields up to eightfold higher GFP expression than the constitutive 35S promoter, with no detectable expression in uninduced controls, and the system shows no toxicity or adverse effects, demonstrating reliable, efficient chemical‑inducible transgene regulation.

Abstract

We have developed an estrogen receptor-based chemical-inducible system for use in transgenic plants. A chimeric transcription activator, XVE, was assembled by fusion of the DNA-binding domain of the bacterial repressor LexA (X), the acidic transactivating domain of VP16 (V) and the regulatory region of the human estrogen receptor (E; ER). The transactivating activity of the chimeric XVE factor, whose expression was controlled by the strong constitutive promoter G10-90, was strictly regulated by estrogens. In transgenic Arabidopsis and tobacco plants, estradiol-activated XVE can stimulate expression of a GFP reporter gene controlled by the target promoter, which consists of eight copies of the LexA operator fused upstream of the -46 35S minimal promoter. Upon induction by estradiol, GFP expression levels can be eightfold higher than that transcribed from a 35S promoter, whereas the uninduced controls have no detectable GFP transcripts, as monitored by Northern blot analysis. Neither toxic nor adverse physiological effects of the XVE system have been observed in transgenic Arabidopsis plants under all the conditions tested. The XVE system thus appears to be a reliable and efficient chemical-inducible system for regulating transgene expression in plants.