B. (1 point) Given the different promoter variants fused to lacZ (see Figures 4

Question

B. (1 point) Given the different promoter variants fused to lacZ (see Figures 4 and 5), outline an experiment that uses the variants to address your hypothesis. Include a prediction of results for your experiment.

transcription PromoterH variant the lacZ gene ONPG beta-galactosidase (no color) A420-nitrophenol; A420 yellow!. : o-nitrophenol :yellow).: -translation 420 (vellow Figure 4. Promoter sequences can be attached to the lacZ gene, allowing -galactosidase activity to be used as a reporter of promoter activity

Explanation / Answer

Strain A would produce beta-galactosidase as normally as seen in figure 4 since, in the upstream region of the promoter (-88) there is an activator that can induce the lacZ expression at the higher rate.

Strain B has a mutation in the activator region that prevents the binding of FIS to this site so that, the rate of lacZ expression would reduce by 5-10 folds. Typically, FIS helps in the recruitment of RNA-pol at the promoter.

Strain C also able to transcribe lacZ gene upon binding of RNA-pol to promoter site. But, there is no activator at the upstream region to induce its transcription.

Strain D has no promoter (control) so no chance of lacZ expression to produce beta-galactosidase.

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