IPTG induces the activity of this structure.
pUC19 [pr. "puck 19"] cloning vectors contain ampicillin resistance and a gene named for this structure. A protein encoded by this structure cleaves ONPG into yellow ortho-nitrophenol, and its activity is measured in blue-white screening tests, when colonies are plated on X-gal. IPTG induces the activity of this structure. It can only be bound by a heterodimer of CAP and cAMP in a common example of catabolite repression. This structure's Z, Y, and A subunits encode a transacetylase, a permease, and a beta-galactosidase. According to the Jacob-Monot model of this structure, it is a negative inducible system, repressed at high levels of glucose, which places three genes under the control of one promoter. For 10 points, name this operon that produces enzymes which break down milk sugar.
pUC19 [pr. "puck 19"] cloning vectors contain ampicillin resistance and a gene named for this structure.
lac operon [or lacA; or lacZ; or lacY; or lacI; or lac promoter; or lac repressor; or beta-galactosidase before it is read; prompt on "operons"]