A key objective in gene therapy treatments is the design of a system that delivers the right gene in the right place at the right concentration and at the right time. Inappropriate gene expression in the wrong tissues, or even in the right tissues but at the wrong time, can lead to harmful effects. Several research groups worldwide have focused significant efforts into fine-tuning the mechanics of how and when to turn genes on and off for maximal therapeutic benefit. New studies from a US research team, based at the Centre for Complex Systems and Brain Sciences at Florida Atlantic University, has now reported on the construction of a novel gene promoter regulated by oxygen concentration. The promoter, which may be incorporated upstream of a therapeutic gene, could ultimately be used in the treatment of hypoxia-related retinal disorders, including diabetic retinopathy and age related macular degeneration.