Sequences at the right end of Escherichia coli phage Mu DNA influence expression of the early operon

Abstract

The early operon of Mu DNA was fused transcriptionally to the galK indicator gene using the HpaI site at the end of the B gene. From this plasmid the indicator gene was expressed at low and high temperature indicating that the repressor gene is not expressed. When this construction was complemented in cis with the right end 115-bp sequence of Mu DNA, repression is restored at low temperature. It could be shown that the 115-bp sequence acts in both orientations and must be present in cis. Deletion of attL, at the right end of Mu DNA, does not interfere with the effect exerted by the 115-bp sequence.