BIO 198 Lecture Notes - Lecture 35: Lac Operon, Lac Repressor, Dna Footprinting
22 Nov 2016
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Lac operon: dominant and constitutive expression of the lac operon = will always be on in presence or absence of the inducers. Mutations in the operator sequence = never able to turn off the expression of the gene at this locus. Lac repressor is a tetramer: what if only one tetramer is working you won"t be able to work the repressor and things aren"t black and white (cid:523)concentration and affinity(cid:524) Trans acting mutations: functional rna or proteins that diffuses and spreads throughout the cell. If you can make a mutation in the front, you can stop transcription of gene b in polycistronic genes. Genes in e. coli should always have their own binding ribosome sites at each gene site and in turns out that. Polar effects/mutations: affects expression of downstream genes or operons and can also affect the expression of the gene in which it occurs; can have premature termination of protein synthesis.
