::GFP transgene is primarily expressed in neurons and the hypodermis, but very weak fluorescence was also observed in the pharynx and in body wall muscle cells. The cell- specific pattern of abts-1
transcription was identical in the absence or presence of As(III). However, in the presence of As(III), the level of the GFP dramatically increased, and strong GFP expression was observed in the pharynx and body wall muscle cells compared to that of unexposed animals. Moreover, a real-time qRT-PCR was used to measure changes in the steady-state level of ABTS-1 mRNA in response to As(III) exposure. The level of ABTS-1 mRNA in transgenic worms significantly increased in the presence of As(III) compared to that of unexposed nematodes (p < 0.001).