Hi there,

I would measure transcription/translation levels of X in wt cells and compare with what is observed in cells deleted for the gene encoding the TF. And then see the effect of ectopically expressed TF both in wt and deleted backgrounds. An other approach would be to neutralize TF binding using specific ntibody for instance (instead of deleting TF encoding gene).

1) why two experiments?

2) is the hypothesis, that it is necessary for the expression, that happens to be in organ Y, or that it is necessary for expression in organ Y (i.e. the gene may be expressed in other organ, but in the other organ the expression is not driven by your TF)?