Which of the following would be a cisdominant mutation loss

Which of the following would be a cis-dominant mutation? loss of function mutation to lacO loss of function mutation to lacP loss of function mutation to the CAP-cAMP binding site loss of function mutation in lacZ Part C Which of the following is an example of allosteric regulation of protein function? The binding of allolactose to the lac repressor The binding of cAMP to CAP Both (a) and (b) are correct.

Solution

B) Loss of function mutation to LacO is the cis-dominant mutation. This operator mutation is cis-dominant and it is dominant to the wild type. It can affect the copy immediately adjacent to it.

C) Binding of allolactose to the lac repressor. Thus the repressor doesnot bind to operator and allow RNAP to transcribe the lac genes and produce high levels of encoded proteins. cAMP acts as an allosteric effector as it increases the binding of CAP to DNA. Hence enhancing the transcription process.

So Both A and B are correct.