In an experiment, you are trying to pull down the site where guanyl transferase binds by co-immunoprecipitation. You run a gel and autoradiograph to see a band denoting GSK-RNA pol II (phosphorylated). What will you see when you perform the same experiment with overexpression of GSK in one setup and overexpression of unlabelled GSK-RNA pol II in the other setup?

There will not be any change in the intensity of the 1st band as GT is not binding to GSK tag. The 2nd case also doesn’t change the intensity of the band as GT binds to phosphorylated –GSK-RNA pol II, so no GT bound unlabelled RNA exists to compete with the labeled band and decrease its intensity.