Stories by Mark Ptashne

Much is known about how genes are turned on and off in bacterial cells. Now molecular biologists show that what they have learned is relevant to gene regulation in higher organisms as well

Two regulatory proteins interact with a region of viral DNA to turn one set of genes off and another on in response to an environmental change. The switch is described in terms of its molecular structure

An operator is a segment of DNA adjacent to a gene; a repressor is a protein that binds to the operator and controls the expression of the gene. How such a system works in a virus is explored in detail

Genes do not operate continuously but are switched on and off. One control mechanism is repression. Now the first specific repressors have been isolated, confining hypotheses put forward a decade ago