Current Topics in Microbiology and Immunology / Ergebnisse der Mikrobiologie und Immunitatsforschung

Each control operation is mediated by a pair of complementary genetic elements (hereafter called "control cell"): a control gene which produces a l control (or regulator) protein and a control site which is the target for the regulator protein. Negative control means that the control protein (repressor) prevents gene expression.