An artificial promoter system that can be fused upstream of any desired gene enabling reversible induction or repression of the expression of the gene at will in any suitable host cell or organisms by light is described. The design of the system is such that a molecule of the plant photoreceptor phytochrome is targeted to the specific DNA binding site in the promoter by a protein domain that is fused to the phytochrome and that specifically recognizes this binding site. This bound phytochrome, upon activation by light, recruits a second fusion protein consisting of a protein that binds to phytochrome only upon light activation and a transcriptional activation domain that activates expression of the gene downstream of the promoter.
This invention was funded by grant number DE-FG03-87ER13742 from the Department of Energy; grant number 5335-2100-006-010 from the United States Department of Agriculture and grant number GM 47475 from the National Institutes of Health. The U.S. Government may have certain rights to this invention.