The previously established fluorescent transgenic line Tg(hsp:eGFP-GGH) will overexpress a fusion of eGFP with γ-glutamylhydrolase (GGH) upon heat-shock, which facilitates the exportation of intracellular folate and leads to folate deficiency with the extent positively correlated to its fluorescence intensity17. The gene discussed is GGH; the disease is folate deficiency.