Chapter 14, Problem 3EQ

As described in experimental question E2 and also in Chapter 21, the technique of Northern blotting can be used to detect the level of transcription of a specific RNA. Draw the results you would expect from a Northern blot if bacteria were grown in media that contained lactose (and no glucose) but had the following mutations:

A. Lane 1. Normal strain

B. Lane 2. Strain with a mutation that inactivates lac repressor

C. Lane 3. Strain with a mutation that prevents allolactose from binding to lac repressor

D. Lane 4. Strain with a mutation that inactivates CAP

How would your results differ if these bacterial strains were grown in media that did not contain lactose or glucose?