"read -through" transcription - (Feb/03/2008 )

Hi..i want to clone a very strong promoter (rrnB P1) in a plasmid. But ive read somewhere that a very strong promoter is difficult to clone unless an efficient terminator is present to prevent read-through transcription. Can somebody explain this phenomenon? Thanks, forgive my ignorance

Read-through transcription occurs when you have transcription of DNA beyond the normal termination signal. So if you are cloning a strong promoter and you do not have an efficient terminator to stop transcription the polymerase will "read-through" or proceed beyond the stop signal. Therefore you need to have a very good terminator to prevent this from happening.