Molecular and Cellular Biology MCB 52 Study Guide - Hmg-Coa Reductase, Plasmid, Polyadenylation
17 Feb 2014
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[lecture 31] examining noise in low copy plasmids. We want to use a weak promoter, because difficult to detect noise when there is so much signal. You want each cell to only have one copy of each promoter. They also didn"t want the proteins to be too close to each other (as they would be if they were on the same plasmid). Experiment 1: took cells from wt or fh patients. In wild-type patients, cholesterol led to a decrease in hmg co-a reductase activity, but in fh patients, you didn"t get that decrease in activity. Nonsense: a premature stop codon has been introduced. Nonstop: stop codon has been mutated, once ribosome starts translating the polya tail, complexes are degraded. No-go: ribosome becomes stalled, possibly because of secondary structures that it can"t overcome or lack of charged trnas, causes degradation. Wt: white to blue, q mutant: constitutively active, r mutant / s mutant: constitutively repressed.
