Abstract: The invention relates to a novel system for gene regulation in eukaryotic cells, and methods of using the same for protein production, tissue engineering and gene therapy. In particular, the invention provides a new system for antibiotic-regulated gene expression in eukaryotic cells based on sequences from Actinomycetes antibiotic resistance promoters, polypeptides that bind to the same in an antibiotic responsive manner, and nucleotides encoding such polypeptides. Further, the invention provides novel and sensitive methods of screening for candidate antibiotics.