View full size JPG | PDFTHE SCIENTIST STAFFCELLULAR ENGINEERING IN CONTEXT
In contrast to other engineering disciplines—in which static elements are snapped into an electrical circuit, for example, or sturdy pieces of lumber are assembled into a larger structure—designing circuits inside living cells is messy business. In the hypothetical example depicted here, genetic components, such as transcription factors (TFs) and green fluorescent protein (GFP) reporters, are first integrated into the yeast genome.1 The addition of a chemical inducer initiates expression of the first component in the circuit, TF12, which in turn activates the expression of a second transcription factor, TF23. Finally, TF2 initiates the expression of GFP4, completing the cascade. In order for the circuit to function properly, the TFs must wade through the crowded and chaotic environment of the cell to do their jobs. Once ...
