Engineering Control Transcriptional Regulators

Fig. 16.4 Bacterial population control using quorum sensing. Escherichia coli was engineered with luxi and luxR of Vibrio fisheri. In the presence of anhydrotetracycline (aTc), LuxI is expressed and synthesizes the quorum-sensing molecule acyl-homoserine lactone (AHL). The transcriptional regulator LuxR is also expressed and activated by AHL. Then, the AHL-LuxR complex activates and induces the expression of green fluorescent protein (GFP) and the transcriptional repressor CL GFP expression is only activated at low concentrations of AHL at high concentrations Pj j is repressed by CL...

Cyclin-Cdks were appropriately named the cell cycle s engines . The cyclin-dependent protein kinases (Cdks) are soluble serine/threonine kinases of 34-40 kDa. The Cdks share with other serine/threonine protein kinases sequence similarities, including a subset of residues that is essential for catalytic activity. Cdks contribute the catalytic subunit, whereas the regulatory subunit is contributed by a cyclin. Cyclins control the kinase activity, determine the substrate specificity and the subcellular location of Cdks. Each of these processes is a potential site of regulation. The major substrates of the Cdks are proteins regulating gene transcription. Cdks can be controlled in three major ways ... 

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